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New antibiotic could make food safer and cows healthier

Food-borne diseases might soon have another warrior to contend with, thanks to a new molecule discovered by chemists at the University of Illinois. The new antibiotic, an analog of the widely used food preservative nisin, also has potential to be a boon to the dairy industry as a treatment for bovine mastitis. The antibiotic nisin occurs naturally in milk, a product of bacteria resident in the cow’s udder. It helps keep milk from spoiling and kills a broad spectrum of bacteria that cause food-borne illness, most notably listeria and clostridium. It was approved as a food additive in 1969, and since then has become prevalent in the food industry in more than 50 countries. “It’s good to know that there are natural products added to our food that protect us from diseases,” said lead researcher Wilfred van der Donk, a chemistry professor at the University of Illinois. “Many people probably don’t even realize that, or think it’s some kind of a non-natural chemical. Last summer we had the listeria outbreak, and that’s a good example of people dying from pathogens in food. You don’t hear of such outbreaks often, and that’s in part because of the compounds that are added to food to kill the pathogens.”

Nisin also shows promise as a treatment for bovine mastitis, an infection in cows that costs the dairy industry billions each year since milk produced during and shortly after antibiotic treatment has to be thrown out. Since nisin already is present in low levels in milk, farmers using nisin to treat mastitis may not need to discard milk or meat from recently treated animals. However, for all its utility, nisin has drawbacks. It’s produced in an acidic environment, but it becomes unstable at the neutral pH levels needed for many foods or pharmaceuticals. It also becomes unstable at higher temperatures, limiting its uses.

While studying the genome of another bacterium that lives at high temperatures, van der Donk’s group found genes to make a molecule with a similar structure and function to nisin, known as an analog. They isolated the genes and inserted them into E. coli so they could produce the new antibiotic, dubbed geobacillin, in large enough quantities to study its structure and function. “As it turns out, geobacillin is more stable, both in respect to pH and temperature,” van der Donk said. “We think this is good news for potential use of geobacillin in food.” Nisin, and presumably geobacillin, work by binding to a molecule the pathogen needs to build its cell wall and then poking holes in the bacterial cell’s membrane, a one-two punch that quickly kills the invader. However, the two antibiotics have slight structural differences. Nisin’s structure has five looped regions, formed by cross-links in the protein chain. Geobacillin has seven loops thanks to two additional cross-links, which give the protein added stability.

The team tested geobacillin against several foodborne and disease-causing bacteria and found it similarly effective or more effective than nisin, depending on the bacteria. Most significantly, it was three times more active against the main contagious bacteria responsible for bovine mastitis. Contagious mastitis is devastating for dairy farmers, as the bacteria can quickly spread throughout a herd. In addition, since mastitis could be caused by a number of different infections, geobacillin’s broad-spectrum activity makes it a very attractive treatment option. Next, the researchers plan to test geobacillin against a wider spectrum of disease-causing bacteria. Many tests of safety, efficacy and economic production lie ahead, although geobacillin has shown great promise in tests to date. The researchers hope that its greater stability will enable medicinal applications for geobacillin that nisin could not realize, both for bovine mastitis and possibly for human disease. “Nisin was very promising in early preclinical trials in that it was very effective in killing multi-drug-resistant bacteria in mouse models,” said van der Donk, “but because of its instability, it has a very short half-life in blood. So we’re looking to see whether geobacillin has greater serum stability.” The researchers published their findings in the Proceedings of the National Academy of Science.

Science Daily
April 17, 2012

Original web page at Science Daily

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US National Academy of Sciences reassesses risks of high-security work in cattle country

Livestock in the heart of US cattle country will be put at risk if foot-and-mouth disease escapes from the proposed National Bio and Agro-Defense Facility. For Katharine Bossart, a trip to the lab can involve a 22-hour flight. Bossart, a microbiologist at Boston University in Massachusetts, works on treatments and vaccines for the Nipah and Hendra viruses, which are deadly to both horses and humans. Her research requires the highest level of biological security containment — BSL-4 — but no BSL-4 labs in the United States can accommodate horses, so she collaborates with researchers in Australia. “If we want to protect large animals from these infections, then we have to test vaccines in them,” says Bossart. The US Department of Homeland Security (DHS) has broken ground for a facility that would have allowed researchers such as Bossart to work closer to home. The National Bio and Agro-Defense Facility (NBAF) in Manhattan, Kansas, is designed to provide BSL-4 containment for large-animal studies and replace the Plum Island Animal Disease Center, the federal government’s 58-year-old BSL-3 installation off Long Island in New York. But the NBAF’s future has been thrown into question, with no new money allocated for it in the president’s proposed 2013 federal budget and reviewers considering fears about whether it could keep pathogens safely contained in the middle of prime US cattle country.

Last week, the US National Academy of Sciences (NAS) convened a closed meeting to review a revised risk assessment from the DHS, which it received on 10 February but has not yet made public. Congress ordered the report last year, after the NAS harshly criticized a 2010 assessment, citing factors such as the absence of back-up high-efficiency particulate filters in the building plans; flawed estimates of how quickly an outbreak could be detected and stopped; and poor consideration of the facility’s proximity to metropolitan areas and livestock. Beef producers have been particularly alarmed that the 2010 assessment put the cumulative risk of foot-and-mouth disease escaping from the NBAF over the facility’s projected 50-year lifespan at 70%. The virus that causes the disease spreads quickly and would have a devastating effect on the US cattle industry if it escaped. US research with live foot-and-mouth virus is currently restricted to Plum Island.

Both the latest assessment and the review of it by the NAS, expected by June, are required by Congress before the US$50 million designated for the NBAF in the 2012 federal budget can be spent. The 2013 budget not only commits no further funds to the NBAF, but also creates a new hurdle, requiring the NAS to examine whether current disease threats justify the facility, which could cost up to $1 billion to build. “We understood going into this that issues would arise,” says Ron Trewyn, vice-president for research at Kansas State University (KSU) in Manhattan, which in 2009 helped the state to win its bid to host the NBAF. “Budget is a big deal these days, but given the importance of the NBAF to national security and to protecting our agricultural economy, we are confident that these issues will be worked through and it will move forward.” Kansas has committed $105 million in bonds to support the facility, which is touted as an economic boon for the state. The site is adjacent to the KSU Biosecurity Research Institute, a BSL-3 facility that studies animal and plant pathogens. The university is now considering whether to send graduate students to Plum Island to build expertise. “We are working with Homeland Security and the US Department of Agriculture on Plum Island to develop the workforce that will ultimately work at the NBAF,” says Stephen Higgs, director of the Biosecurity Research Institute.

But critics of the facility welcomed the decision by President Barack Obama’s administration not to request further funding for it. “We are optimistic,” says Tom Manney, a retired KSU biophysicist who helps to lead a group called No NBAF in Kansas. The group says that a facility that works on highly infectious animal diseases does not belong “in the centre of the food-animal health corridor”. Opponents voiced their concerns about the project at an NAS public meeting in Manhattan in January. “It is easy for those promoting the facility to argue for the Kansas site because their livelihoods are not at stake,” wrote cattle rancher Paul Irvine in a submitted statement. What happens next will depend, in part, on the NAS’s judgement of the facility’s risks and benefits. The DHS says that the NBAF is needed to develop countermeasures against bioterrorism — a threat that resonates less now than it did immediately after the anthrax attacks on the United States in 2001. But the department also cites three threats that receive far less public attention. One is the growing likelihood of foreign animal diseases entering the United States as a result of international animal movement from commerce and smuggling. A second is the risk of animal-borne diseases spreading to humans as population growth and dispersal puts people into greater contact with wild animals. The third is the potential for global warming to expand the range of insect-borne diseases.

“Not having a facility like this is almost negligent,” says Higgs. “We have the capabilities to build a facility that will better prepare us in the event of some pathogen coming in. The NBAF will be the shining star in these types of labs.” Soren Alexandersen, director of a BSL-4 facility in Winnipeg, Canada, that can accommodate small numbers of livestock, says that the challenges of running such labs can be met with technical measures. He adds that although many of the diseases studied in Winnipeg, including the Nipah Virus, are not currently found in North America, preparedness matters. “We have the methods and the facility in place so that we can start working,” he says.

Nature
March 20, 2012

Original web page at Nature

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Novel Orthobunyavirus in cattle, Europe, 2011

In 2011, an unidentified disease in cattle was reported in Germany and the Netherlands. Clinical signs included fever, decreased milk production, and diarrhea. Metagenomic analysis identified a novel orthobunyavirus, which subsequently was isolated from blood of affected animals. Surveillance was initiated to test malformed newborn animals in the affected region. In summer and autumn 2011, farmers and veterinarians in North Rhine-Westphalia, Germany, and in the Netherlands reported to the animal health services, local diagnostic laboratories, and national research institutes an unidentified disease in dairy cattle with a short period of clear clinical signs, including fever, decreased milk production, and diarrhea. All classical endemic and emerging viruses, such as pestiviruses, bovine herpesvirus type 1, foot-and-mouth disease virus, bluetongue virus, epizootic hemorrhagic disease virus, Rift Valley fever virus, and bovine ephemeral fever virus, could be excluded as the causative agent. To identify the cause of the disease, we analyzed blood samples from affected cattle.

The detection of a novel orthobunyavirus in cattle in Germany (Schmallenberg virus) demonstrates the power of a metagenomic approach to discovering emerging pathogens. Specific and sensitive RT-qPCRs could be developed quickly and used in analyzing infected herds. The role of the virus in the disease needs to be further investigated. However, the clinical signs in 2 of the inoculated animals, together with virus detection in samples of diseased animals in Germany and the Netherlands and in the brain of malformed lambs in the Netherlands, strongly indicate that Schmallenberg virus caused the clinical illness. In further investigations, we will use serology to analyze distribution in the field and will sequence the complete genomes of other members of the Simbu serogroup to better understand the phylogenetic background of Schmallenberg virus.

Concern exists about the congenital defects the virus might induce in newborn calves, goats, and lambs during the next months. Therefore, surveillance has been initiated to test all malformed animals in the affected region. Some members of the Simbu serogroup, e.g., Oropouche virus, are zoonotic. However, because of the close relationship to Shamonda virus and the absence of reports of clinical signs in humans, the risk to humans currently is assessed as very low to negligible. Nevertheless, clinical and serologic surveillance in humans should be conducted in regions with infected animals to update the risk assessments. Dr Hoffmann is a veterinarian and senior scientist at the Institute of Diagnostic Virology at the Friedrich-Loeffler-Institut and head of the National Reference Laboratory for Orbiviruses. His research interests are emerging animal viruses, molecular diagnostics, and pathogenesis.

Emerging Infectious Diseases
March 6, 2012

Original web page at Emerging Infectious Diseases

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First test-tube hamburger ready this fall

The world’s first “test-tube” meat, a hamburger made from a cow’s stem cells, will be produced this fall, Dutch scientist Mark Post told a major science conference on Sunday. Post’s aim is to invent an efficient way to produce skeletal muscle tissue in a laboratory that exactly mimics meat, and eventually replace the entire meat-animal industry. The ingredients for his first burger are “still in a laboratory phase,” he said, but by fall “we have committed ourselves to make a couple of thousand of small tissues, and then assemble them into a hamburger.” Post, chair of physiology at Maastricht University in the Netherlands, said his project is funded with 250,000 euros from an anonymous private investor motivated by “care for the environment, food for the world, and interest in life-transforming technologies.” Post spoke at a symposium titled “The Next Agricultural Revolution” at the annual meeting of the American Association for the Advancement of Science in Vancouver. Speakers said they aim to develop such “meat” products for mass consumption to reduce the environmental and health costs of conventional food production. Conventional meat and dairy production requires more land, water, plants and disposal of waste products than almost all other human foods, they said.

The global demand for meat is expected to rise by 60 percent by 2050, said American scientist Nicholas Genovese, who organized the symposium. “But the majority of earth’s pasture lands are already in use,” he said, so conventional livestock producers can only meet the booming demand by further expansion into nature. The result would be lost biodiversity, more greenhouse and other gases, and an increase in disease, he said. In 2010 a report by the United Nations Environment Program called for a global vegetarian diet. “Animal farming is by far the biggest ongoing global catastrophe,” Patrick Brown of the Stanford University School of Medicine told reporters. “More to the point, it’s incredibly ready to topple … it’s inefficient technology that hasn’t changed fundamentally for millennia,” he said. “There’s been a blind spot in the science and technology community (of livestock production) as an easy target.” Brown, who said he is funded by an American venture capital firm and has two start-ups in California, said he will devote the rest of his life to develop products that mimic meat but are made entirely from vegetable sources. He is working “to develop and commercialize a product that can compete head on with meat and dairy products based on taste and value for the mainstream consumer, for people who are hard-core meat and cheese lovers who can’t imagine ever giving that up, but could be persuaded if they had a product with all taste and value.” Brown said developing meat from animal cells in a laboratory will still have a high environmental cost, and so he said he will rely only on plant sources.

PhysOrg.com
March 6, 2012

Original web page at Phys.Org.com

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Bacteria may readily swap beneficial genes: Microbes trade genetic coding for antibiotic resistance and more

Much as people can exchange information instantaneously in the digital age, bacteria associated with humans and their livestock appear to freely and rapidly exchange genetic material related to human disease and antibiotic resistance through a mechanism called horizontal gene transfer (HGT). In a paper appearing in Nature online Oct. 30, researchers — led by Eric Alm of MIT’s Department of Civil and Environmental Engineering and Department of Biological Engineering — say they’ve found evidence of a massive network of recent gene exchange connecting bacteria from around the world: 10,000 unique genes flowing via HGT among 2,235 bacterial genomes. HGT is an ancient method for bacteria from different lineages to acquire and share useful genetic information they didn’t inherit from their parents. Scientists have long known about HGT and known that when a transferred gene confers a desirable trait, such as antibiotic resistance or pathogenicity, that gene may undergo positive selection and be passed on to a bacterium’s own progeny, sometimes to the detriment of humans. (For example, the proliferation of antibiotic-resistant strains of bacteria is a very real threat, as seen in the rise of so-called “superbugs.”)

But until now, scientists didn’t know just how much of this information was being exchanged, or how rapidly. The MIT team’s work illustrates the vast scale and rapid speed with which genes can proliferate across bacterial lineages. “We are finding completely identical genes in bacteria that are as divergent from each other as a human is to a yeast,” says Alm, the Karl Van Tassel Associate Professor. “This shows that the transfer is recent; the gene hasn’t had time to mutate.” “We were surprised to find that 60 percent of transfers among human-associated bacteria include a gene for antibiotic resistance,” adds computational systems biology graduate student Chris Smillie, one of the lead authors of the paper. These resistance genes might be linked to the use of antibiotics in industrial agriculture: The researchers found 42 antibiotic-resistance genes that were shared between livestock-associated and human-associated bacteria, demonstrating a crucial link connecting pools of drug resistance in human and agricultural populations. “Somehow, even though a billion years of genome evolution separate a bacterium living on a cow and a bacterium living on a human, both are accessing the same gene library,” Alm says. “It’s powerful circumstantial evidence that genes are being transferred between food animals and humans.”

Moreover, the team identified 43 independent cases of antibiotic-resistance genes crossing between nations. “This is a real international problem,” says microbiology graduate student Mark Smith, another lead author of the study. “Once a trait enters the human-associated gene pool, it spreads quickly without regard for national borders.” The practice of adding prophylactic antibiotics to animal feed to promote growth and prevent the spread of disease in densely housed herds and flocks is widespread in the United States, but has been banned in many European countries. According to the Federal Drug Administration, more than 80 percent of the 33 million pounds of antibiotics sold in the United States in 2009 was for agricultural use, and 90 percent of that was administered subtherapeutically through food and water. This includes antibiotics such as penicillins and tetracyclines commonly used to treat human illness. The MIT researchers found that HGT occurs more frequently among bacteria that occupy the same body site, share the same oxygen tolerance or have the same pathogenicity, leading them to conclude that ecology — or environmental niche — is more important than either lineage or geographical proximity in determining if a transferred gene will be incorporated into a bacterium’s DNA and passed on to its descendants. “This gives us a rulebook for understanding the forces that govern gene exchange,” Alm says.

The team applied these rules to find genes associated with the ability to cause meningitis and other diseases, with the hope that transferred traits and the genes encoding those traits might make especially promising targets for future drug therapies. “This is a very interesting piece of work that really shows how the increasing databases of complete genome sequences, together with detailed environmental information, can be used to discover large-scale evolutionary patterns,” says Rob Knight, associate professor of chemistry and biochemistry at the University of Colorado at Boulder, who says he agrees with the authors’ findings. “The availability of vast datasets with excellent environmental characterization will give us an unprecedented view of microbes across the planet.” Continuing the work, the researchers are now comparing rates of exchange among bacteria living in separate sites on the same person and among bacteria living on or in people with the same disease. They’re also studying an environmentally contaminated site to see which swapped genes might facilitate microbial cleanup by metal-reducing bacteria.

Science Daily
November 15, 2011

Original web page at Science Daily

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Want fatter cows? Bring in a zebra

Climb to the top of a hill along one of the few remaining undisturbed grasslands in East Africa, pull out the binoculars, and you may spy a black-and-white zebra herd. You may also see a few gazelles, buffaloes, and elephants. “Natural selection has favored that mix,” says Johan du Toit, an ecologist at Utah State University in Logan. Natural selection, maybe, but not people. Convinced that other grass-chomping animals will drive their herds to starvation, ranchers in Kenya and elsewhere tend to keep their cattle separate from wildlife. But a new study suggests that thinking may be wrong. Wildlife, particularly zebras, can actually help a ranch thrive. To test the common wisdom, Wilfred Odadi, a rangeland ecologist at the Mpala Research Centre in Nanyuki, Kenya, and colleagues visited a local 20,000-hectare savanna where livestock and protected wildlife, including close to 2000 zebras, still mingle. The team fenced off pastures within the grazing lands, opening some to cows only and the others to cows and whatever wildlife happened to pop by. And many animals did. Throughout the study, the unrestricted cow herds brushed shoulders with a veritable Disney movie cast of creatures, including zebras, oryx, hartebeest, elephants, and even giraffes.

During the dry season, when much of the grass turns wispy, the constant rotation of wild ungulates did seem to take a toll on the cattle, and many lost significant weight. But during the wet season, the livestock rebounded. In rainy months, cows with wild companions beefed up much faster than their solo counterparts, Odadi and colleagues report today in Science. Zebras seem to be responsible for the effect. Giraffes only nibble trees, and elephants don’t gorge on grass in dry months. But zebras, easily the most abundant wild grazers in the region, can swallow grasses that many other herbivores avoid, thanks to their specialized digestive tracts. Throughout the study, herds of the animals tramped through the pastures, chewing the taller, less nutritious leaves, possibly exposing the richer vegetation below. That hoof print was obvious even to the naked eye, Odadi says: “You would see that the grassland is greener and leafier, especially after it had started raining.”

The team’s findings are “of wide, practical importance,” although not necessarily surprising, says Norman Owen-Smith, an ecologist at the University of the Witwatersrand in Johannesburg, South Africa, who was not involved in this study. Wild ungulates such as zebras are, by nature, wanderers. In the dry season, they cluster around water holes, then cut a wide path in the rainy months to track down quality feed. But in recent decades, most have been confined to relatively small national parks that can’t sustain large herds. If ranchers learned to tolerate a few zebra visitors, he says, some fences could come down, and the animals could return to their routine. Zebras are few and far between in the western U.S., adds du Toit, who was not involved in the study, but the same rules may apply. He points to old prairies in the Great Plains, where plentiful bison would march along, followed closely by pronghorn and then prairie dogs. Changing ranchers’ minds in the United States and elsewhere on wildlife would be tough, he admits, but might be possible if scientists and policymakers can communicate the potential economic benefits. “The traditional inertia is huge,” he says. “But, you know, money talks.”

ScienceNow
October 4, 2011

Original web page at ScienceNow

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Feeding cows natural plant extracts can reduce dairy farm odors and feed costs

With citizens’ groups seeking government regulation of foul-smelling ammonia emissions from large dairy farms, scientists report that adding natural plant extracts to cow feed can reduce levels of the gas by one-third while reducing the need to fortify cow feed with expensive protein supplements. They reported in Denver at the 242nd National Meeting & Exposition of the American Chemical Society (ACS). J. Mark Powell, Ph.D., described the results of three studies undertaken to determine how adding plant substances called “tannins” to cow feed affects the emission of ammonia from dairy barn floors and farm fields fertilized with mixtures of cow manure and urine. “For dairy farms, cow urine is the source of the ammonia emission problem,” said Powell, who is with the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS). “Dairy cows excrete large amounts of urine, about 3.5 gallons daily for each cow. That’s almost 1,300 gallons per year. And there are about 10 million dairy cows in the United States alone. Cows usually are fed a high-protein diet, and they produce various nitrogen compounds when they digest protein. They release the excess nitrogen mainly in their urine, and enzymes convert it into ammonia.”

Ammonia has an acrid, eye-tearing odor and has potential adverse health effects on both cows and humans. Citizens’ groups several months ago petitioned the U.S. Environmental Protection Agency (EPA) to begin regulating ammonia under the Clean Air Act, intensifying the search for practical, inexpensive ways to reduce emissions of the noxious gas. Besides its pungent odor, ammonia adds to air pollution, forming particles that travel long distances and contribute to environmental issues such as smog, acid rain and nutrient pollution. The ammonia problem originates with the nitrogen-rich protein in cow feed. Cows’ digestive systems are inefficient, and barely one-third of the nitrogen in their feed ends up in milk. The rest exits in urine and feces. The nitrogen in urine is in the form of urea, and enzymes contained in cow manure on the barn floor quickly convert it into ammonia gas. Tannins apparently reduce urea production by allowing more protein to escape digestion in the stomach and enter the cow’s intestines, where it’s used to produce milk protein.

Powell began investigating tannins in animal feed 20 years ago in West African communities where he lived and worked. Tannin-rich shrubs were grown as windbreaks to reduce soil erosion and to feed livestock. Tannins also are a key part of the diets of cattle, sheep and goats in tropical areas where vegetation tends to be naturally higher in the astringent plant chemicals. However, tannins have attracted relatively little attention elsewhere, Powell said. He hopes the addition of tannins to animal feed will become much more widespread in light of the findings about their potential for curbing ammonia emissions. The tannin extracts used in the studies are already approved for animal feed and would cost only a few cents a day, he said. Tannins are perhaps best known for their use in tanning leather, and the quebracho and chestnut trees are sources for both leather tanning and cattle feed. Powell said that it may be possible to produce synthetic tannins at a lower cost. Next on Powell’s agenda is research to determine whether tannins also can reduce emissions of methane gas — a potent greenhouse gas involved in global warming — from cattle production. About 25 percent of methane emissions in the United States are from enteric fermentation (mostly belches) of domestic cattle.

Science Daily
September 20, 2011

Original web page at Science Daily

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Genetic link to cattle diseases uncovered

The origin of three costly cattle diseases is genetically linked, according to findings from U.S. Department of Agriculture (USDA) researchers. Scientists at the Agricultural Research Service (ARS) Roman L. Hruska U.S. Meat Animal Research Center (USMARC) in Clay Center, Neb., have discovered a location on bovine chromosome 20 that is associated with the incidence of the most prevalent bacterial diseases — pinkeye, foot rot and bovine respiratory disease (pneumonia) — that affect feedlot cattle. ARS is USDA’s chief intramural scientific research agency, and this research supports USDA’s priority of promoting international food security. Bovine respiratory disease accounts for 75 percent of feedlot illnesses and up to 70 percent of all deaths, with economic losses to cattle producers exceeding $1 billion annually. The estimated costs for pinkeye are $150 million yearly, and losses to dairy producers due to foot rot range from $120 to $350 per animal. Eduardo Casas, research leader of the Ruminant Diseases and Immunology Research Unit at the ARS National Animal Disease Center in Ames, Iowa, and a former USMARC geneticist, examined the genetic makeup of cattle for evidence of genes associated with resistance or tolerance to diseases.

Casas and his colleagues combined pinkeye, foot rot and bovine respiratory disease to represent overall pathogenic disease incidence. They developed half-sibling families from crossbreed bulls: a Brahman-Hereford, a Brahman-Angus, a Piedmontese-Angus and a Belgian Blue-MARC III (part Red Poll, Pinzgauer, Hereford and Angus). An analysis of DNA samples from the 240 offspring infected with one or more of the diseases revealed a genetic marker, called a quantitative trait locus (QTL), on chromosome 20. This QTL is associated with the three diseases. Chromosome 20 is located near genetic markers related to other diseases and may have a significant effect on the overall health of cattle, according to Casas. Identifying genetic markers responsible for disease would provide an opportunity to produce cattle with increased disease tolerance, which also could help reduce economic loss associated with diseases. Results from the research were published in the Journal of Animal Science.

Science Daily
September 20, 2011

Original web page at Science Daily

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Cows clock-in for monitored mealtimes will help to detect diseases

Electronic ear tags are being used to provide an early warning system that will help farmers identify sick animals within a herd. The new system, being trialled by scientists at Newcastle University, tracks the feeding behaviour of each individual animal, alerting farmers to any change that might indicate the cow is unwell. Using RFID (radio frequency identification) technology — similar to that used in the Transport for London Oyster card — each calf is ‘clocked’ in and out every time they approach the trough, with the time spent feeding being logged by a computer. Ollie Szyszka, a PhD student in Newcastle University’s School of Agriculture, Food and Rural Development, who is leading the project with Professor Ilias Kyriazakis, said the aim was to help farmers spot any illness in the herd much earlier on and treat the animals more effectively. “Just as we know when we are sickening for something because we perhaps lose our appetite or feel more lethargic, animals also demonstrate subtle changes in behaviour when unwell,” explains Ollie.

“Like any animal, the earlier you can spot and start treating an infection or disease the better chance there is of it making a full recovery. You also reduce the risk of the infection spreading if you can identify and isolate a sick animal but for a farmer with a herd of maybe 500 cattle it is easy to miss any early signs of disease. “By giving each calf a unique code and tracking its feeding pattern our system is able to alert farmers to small — but significant — changes in behaviour which might indicate the animal is unwell.” The project is part of Newcastle University’s drive to improve animal welfare on farms and research ways in which agriculture can become more sustainable. Published in the Annual Proceedings of the British Society for Animal Science Conference 2011, the work is being trialled at the University’s Cockle Park farm, in Northumberland. The tracking system — developed by Newcastle University computing technician Steven Hall — uses RFID chips fitted into the ear tag of each animal and short-range antennae mounted to their feeding troughs. The antennae pick up a signal every time the animal approaches to feed. The signal is blocked when the animal moves away.

The animals have also been fitted with pedometers which allow the Newcastle team to measure posture, relaying information about how active the calf is and how much time they spend lying down. The results so far have shown that cattle suffering from an underlying health ‘challenge’ or infection do show significant changes in their behaviour. Professor Kyriazakis adds: “Modern farming systems have minimised the contact between the animal and its keeper so we need to constantly look for ways to re-address the balance. “What we are trying to do here at Newcastle is find ways to detect early infection or deterioration of an individual — regardless of the size of the herd — so the farmer can intervene at an early stage. “In the light of recent outbreaks of diseases such as Foot and Mouth and TB, finding ways of detecting changes in behaviour before there are any obvious signs of disease, is becoming increasingly more important.”

Science Daily
August 23, 2011

Original web page at Science Daily

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New method used to detect 20 drugs in cow, goat and human milk

A Spanish-Moroccan research team has developed a method that makes it possible to simultaneously detect 20 pharmaceutical products in cow, goat and human milk. The samples of the three types of milk studied showed that they all contain anti-inflammatories, although the largest number of drugs was found in whole cows’ milk. Up to 20 kinds of antibiotics, anti-inflammatories, antiseptics, lipid regulators, beta-blockers and hormones can be detected simultaneously in various kinds of milk, thanks to a new method developed by researchers at the universities of Jaén and Córdoba in Spain and the Abdelmalek Essaadi University in Morocco. “We used this methodology to analyse 20 samples of cows’ milk (fresh, whole, semi-skimmed, skimmed and powdered), goats’ milk (whole and semi-skimmed) and breast milk from human volunteers, and we found that the drug content differs according to the type of milk,” Evaristo Ballesteros, a researcher at the University of Jaén and the study director, said.

The highest number of pharmacological substances was found in whole cows’ milk, particularly niflumic acid, mefenamic acid and ketoprofen (three anti-inflammatory drugs) and the hormone 17-beta-estradiol. Niflumic acid was also found in goats’ milk, along with flunixin. The human milk analysed, meanwhile, also contained anti-inflammatory drugs (such as ibuprofen and naproxen), as well as the antiseptic triclosan and some hormones, such as 17-alfa-ethinyl estradiol, 17-beta-estradiol and estrone. The researchers acknowledge that the results of the study, published in the Journal of Agricultural and Food Chemistry, cannot be extrapolated to all kinds of milk in general due to the small number of samples analysed, but they say it does confirm the validity of the method. The technique uses a “system of continuous extraction of substances in solid phase” and classifies them using “gas chromatography-mass spectrometry.” “The validation results clearly show that this method is the most sensitive and one of the most selective described to date in the scientific literature,” explains Ballesteros. “It is also highly precise and exact, with short analysis times (around 30 minutes).” The scientists believe the new methodology will help to provide a more effective way of determining the presence of these kinds of contaminants in milk or other products. Food quality control laboratories could use this new tool to detect these drugs before they enter the food chain. “This would raise consumers’ awareness and give them the knowledge that food, aside from its good organoleptic properties and good value, is also harmless, pure, genuine, beneficial to health and free of toxic residues,” the researcher concludes.

Science Daily
July 26, 2011

Original web page at Science Daily

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Chillingham cattle cowed by climate change

The team of ecologists lead by Dr Sarah Burthe of the Centre for Ecology & Hydrology were able to use the cattle to discover more about the impact of climate change on phenology in mammals because – encouraged by Charles Darwin – information about the cattle has been collected since 1860. According to Dr Burthe: “Charles Darwin encouraged the owner to keep records of births, deaths and ‘notable occurrences’, but he couldn’t have anticipated that these records could contribute to our understanding of the biology of global climate change.” Long-term datasets are crucial tools for studying climate change, yet very few exist. “The Chillingham cattle data are unique and, as far as we know, the longest mammal phenology dataset in the world. It’s an amazing dataset,” she says. The Chillingham cattle are feral – previously domesticated but now kept wild and unmanaged – and have distinctive white coats, red ears and horns. As well as being monitored for decades, the Chillingham cattle differ from most other UK mammals because they give birth throughout the year, not only during spring and summer. Examining data for the past 60 years, they found the biggest change was the increasing number and proportion of Chillingham calves born during the winter. And when they compared winter births with UK Met Office weather data, they found warmer springs nine months earlier were responsible.

“Cattle have a nine-month gestation period. Warm springs allow vegetation to start growing earlier, providing the cattle with more nutritious plant growth, and more cows conceive earlier as a result,” Dr Burthe explains. More calves being born in the winter, however, is bad news for the herd, she says: “Winter-born calves don’t do very well and are more likely to die before they reach the age of one. This suggests that the cattle are responding to climate change but this is having a negative impact on them.” The results are important because they show that even species able to breed year-round, which might be expected to cope better with environmental change, are altering the timing of their breeding schedules and these changes are having negative consequences. The study also plugs a major gap in understanding about phenology and climate change in an important group of animals. “Feral animals are often important components of ecosystems and used as tools for managing habitat, but we know very little about how they might respond to climate change.” “Understanding the consequences of phenology change and how widespread these responses are, even in relatively flexible species such as cattle that are able to breed year-round, helps us to predict the potential magnitude of changes caused by a warming climate.”

PhysOrg.com
June 28, 2011

Original web page at PhysOrg.com

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Methane gas from cows: The proof is in the feces

Scientists could have a revolutionary new way of measuring how much of the potent greenhouse gas methane is produced by cows and other ruminants, thanks to a surprising discovery in their poo. Researchers from the University of Bristol and the Teagasc Animal and Grassland Research Centre in Ireland, have found a link between methane production and levels of a compound called archaeol in the feces of several fore-gut fermenting animals including cows, sheep and deer. The compound could potentially be developed as a biomarker to estimate the methane production from domestic and wild animals, allowing scientists to more accurately assess the contribution that ruminants make to global greenhouse gas emissions. Co-author Dr Fiona Gill, who conducted the work as a postdoctoral researcher at Bristol and is now at the University of Leeds, said: “When it comes to calculating carbon budgets there is currently a lot of uncertainty surrounding animal methane contributions, particularly from wild ruminants.

“We’re quite good at measuring man-made CO2 emissions, but techniques to measure the animal production of methane — a much more potent greenhouse gas — have serious limitations. “If we can identify a simple biomarker for methane production in animal stools, then we can use this along with information on diet and animal population numbers to estimate their total contribution to global methane levels.” Cows, sheep and other ruminants are thought to be responsible for around one-fifth of global methane production but the precise amount has proved difficult to quantify. Methane production from animals is often measured using respiration chambers, which can be laborious and are unsuitable for grazing animals. Archaeol is thought to come from organisms called archaea, which are symbiotic or ‘friendly’ microbes that live in the foregut of ruminant animals. These microbes produce methane as a by-product of their metabolism and this is then released by the animal as burping and flatulence.

Principal investigator, Dr Ian Bull of Bristol’s School of Chemistry said: “We initially detected archaeol in the feces of several foregut fermenters including camels, cows, giraffes, sheep and llamas. We then expanded the study to evaluate the quantities of this compound in the feces of cows with different diets. “Two groups of cows were fed on different diets and then their methane production and fecal archaeol concentration were measured. The animals that were allowed to graze on as much silage as they wanted emitted significantly more methane and produced feces with higher concentrations of archaeol than those given a fixed amount of silage, supplemented by concentrate feed. “This confirms that manipulating the diet of domestic livestock could also be an important way of controlling methane gas emissions.”

Science Daily
June 28, 2011

Original web page at Science Daily

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New strain of MRSA discovered: Antibiotic resistant bacteria found in both humans and dairy cows

Scientists have identified a new strain of methicillin-resistant Staphylococcus aureus (MRSA) which occurs both in human and dairy cow populations.The study, led by Dr Mark Holmes at the University of Cambridge, identified the new strain in milk from dairy cows while researching mastitis (a bacterial infection which occurs in the cows’ udders). The new strain’s genetic makeup differs greatly from previous strains, which means that the ‘gold standard’ molecular tests currently used to identify MRSA — a polymerase chain reaction technique (PCR) and slide agglutination testing — do not detect this new strain. The research findings are published in the journal The Lancet Infectious Diseases. Dr Laura García-Álvarez, first author of the paper, who discovered the new strain while a PhD student at the University of Cambridge’s Veterinary School, said: “To find the same new strain in both humans and cows is certainly worrying. However, pasteurization of milk will prevent any risk of infection via the food chain. Workers on dairy farms may be at higher risk of carrying MRSA, but we do not yet know if this translates into a higher risk of infection. In the wider UK community, less than 1% of individuals carry MRSA — typically in their noses — without becoming ill.”

The scientists discovered the antibiotic resistant strain while researching S. aureus, a bacterium known to cause bovine mastitis. Despite the strain being able to grow in the presence of antibiotics, when they attempted to use the standard molecular tests available — which work by identifying the presence of the gene responsible for methicillin resistance (the mecA gene) — the tests came back negative for MRSA. When Dr Matt Holden and a research team at the Wellcome Trust Sanger Institute sequenced the entire genome (decoding all of the genes in the bacteria’s DNA) they realised that the new strain possessed unconventional DNA for MRSA. They found that the new strain does have a mecA gene but with only 60% similarity to the original mecA gene. Unfortunately, this results in molecular tests (which identify MRSA by the presence of the mecA gene) giving a false negative for this strain of MRSA. Subsequent research revealed that the new strain was also present in humans. During the study, the new strain was found in samples from Scotland, England and Denmark (some from screening tests and others from people with MRSA disease). It has since been identified in Ireland and Germany. Additionally, by testing archived S. aureus samples, the researchers have also identified a recent upward trend in the prevalence of the antibiotic resistant bacteria.

Dr Mark Holmes said: “The majority of MRSA testing in British hospitals is performed by seeing if the bacteria will grow in the presence of antibiotics, typically oxacillin and cefoxitin, rather than methicillin — which is now no longer manufactured. This type of testing detects both the new MRSA and conventional MRSA. “However, it is important that any of the MRSA testing that is based on detection of the mecA gene — i.e. PCR based testing, or slide agglutination testing — be upgraded to ensure that the tests detect the new mecA gene found in the new MRSA. We have already been working with public health colleagues in the UK and Denmark to ensure that testing in these countries now detects the new MRSA.” The new research also raises questions about whether cows could be a reservoir for the new strains of MRSA. Dr Holmes added: “Although there is circumstantial evidence that dairy cows are providing a reservoir of infection, it is still not known for certain if cows are infecting people, or people are infecting cows. This is one of the many things we will be looking into next. “Although our research suggests that the new MRSA accounts for a small proportion of MRSA — probably less than 100 isolations per year in the UK, it does appear that the numbers are rising. The next step will be to explore how prevalent the new strain actually is and to track where it is coming from. If we are ever going to address the problem with MRSA, we need to determine its origins.”

Science Daily
June 15, 2011

Original web page at Science Daily

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Foot and mouth disease may spread through shedding skin cells

Skin cells shed from livestock infected with foot and mouth disease could very well spread the disease. An a new paper appearing in the Proceedings of the Royal Society B, Lawrence Livermore National Laboratory scientist Michael Dillon proposed that virus-infected skin cells could be a source of infectious foot and mouth disease virus aerosols. His proposal is based on the facts that foot and mouth disease virus is found in skin and that airborne skin cells are known to transmit other diseases. The proposal could lead to new methods for surveillance for foot and mouth disease (as in settled dust), the development of more effective control measures, and improved studies of the persistence of the disease in the environment. The research also may be applicable to how other infectious diseases are spread.

Foot and mouth is a highly contagious viral disease capable of causing widespread epidemics in livestock. The foot and mouth disease virus (FMDV) has multiple known routes of transmission. These include direct contact (animal-to-animal contact at mucous membranes, cuts or abrasions), indirect contact (such as contaminated bedding), ingestion (contaminated feed) and the respiratory or airborne pathway (inhalation of infectious aerosols). “The airborne pathway may play a role in some outbreaks by causing disease ‘sparks’ (disease spread to regions remote from a primary infection site),” Dillon said. “If the disease isn’t detected quickly, these ‘sparks’ can lead to major outbreaks.” Dillon cited the widespread dissemination of FMDV during the catastrophic 2001 United Kingdom outbreak, which is thought to be caused by the inadvertent transport of animals with unrecognized FMDV infection from a Prestwick area farm to areas previously free of FMDV. Mammals actively shed skin cells into the environment. Skin cells comprise a significant fraction (1 percent to 10 percent) of measured indoor and outdoor aerosols and indoor dust. These cells; and the bacteria, yeast, fungi and viruses known to be present on the surface of (or in some cases inside) skin cells; can become airborne by being shed directly into the air or when dust is disturbed.

“Infectious material can become airborne on skin cells and cause infection when inhaled or deposited directly onto the skin of the new host,” Dillon said. “This is believed to be a significant source of bacterial infection for surgical procedures and other infections that are a result of treatment in a hospital.” “While not a typical site for the initial FMDV infection, the skin is a major viral replication site in most animals,” Dillon said. “The outermost layer of FMDV-infected skin needs to be analyzed to find out how stable the virus is in these skin cells.” Dillon’s proposal suggests a number of practical possibilities for FMDV surveillance and control:
•The sampling and management of settled dust could prove to be a useful tool for disease surveillance and control.
•Slaughtered animals may emit airborne FMDV via infected skin cells simply by exposure to wind and/or mechanical abrasion (e.g. moving animal carcasses, spraying hides with water).
•Airborne emissions from cattle and sheep may need to be revisited as infected skin cells trapped in hair may later become airborne (currently these animals are believed to contribute little to aerosol emissions relative to swine).
“Given the potential for skin cells to protect infectious virus from the environment, the management of other viral diseases may also benefit from enhanced dust surveillance and management, and skin decontamination,” Dillon said.

Science Daily
May 31, 2011

Original web page at Science Daily

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When livestock can transmit foot-and-mouth disease: Findings suggest fewer cattle could be culled in the future

A new study of foot-and-mouth disease shows that cattle afflicted with the virus are only infectious for a brief window of time — about half as long as previously thought. This finding suggests that the controversial control measures used to halt the disease’s spread, such as killing large numbers of livestock, could be reduced. The discovery is also changing the way that scientists think about infectious diseases in general. “This study shows that what we thought we knew about foot-and-mouth disease is not entirely true,” said Mark Woolhouse from the University of Edinburgh, a co-author of the study. “So, what we think we know about human influenza and other infectious pathogens might not be completely accurate either.” The report appears in the 6 May issue of the journal Science.

Foot-and-mouth disease virus, or FMDV, is an RNA virus that infects cattle and other livestock animals, causing lesions on the tongue and feet, fever, and a runny nose. Each year, it’s responsible for huge losses in the global livestock trade. Countries with endemic FMDV spend tremendous amounts of money vaccinating their cattle and farmers often kill off large numbers of livestock to control the disease once a clinical case has been confirmed. In 2001, the United Kingdom experienced the biggest FMDV epidemic to strike a developed country in several decades. Hundreds of thousands of animals were killed and billions of British Pounds were lost before the disease was controlled. Now, researchers have performed experiments with cattle to characterize the precise incubation and infectious periods of the disease-causing virus in live animals. They found that even if the virus can be detected in a cow’s blood sample — the traditional way of measuring infectiousness — it does not actually mean that the animal is infectious. In fact, a cow with FMDV is only infectious for 1.7 days, they say. After that, immune responses kick in and limit virus replication.

Bryan Charleston and colleagues from Pirbright Laboratory in the United Kingdom, along with Dr. Woolhouse, infected “source” cows with FMDV and studied how the virus was transmitted to other, uninfected cows. Their experiment is different from previous studies that have only estimated transmission rates for groups of animals, rather than individuals. “We have pinned down, very specifically, the relationship between when the animals are infectious with FMDV and when they show clinical signs of the infection,” said Woolhouse. “Normally, we only know if a person or animal is infected with disease when their clinical signs appear. But, what we didn’t know before this is how those signs relate to infectiousness. In the case of FMDV, the clinical signs and infectiousness seem to occur around the same time.” In 28 attempts to infect healthy cows with FMDV (by placing them in close proximity to an infected cow for eight hours), the researchers only observed eight successful transmissions of the virus. In light of their results, Charleston and his colleagues suggest that cows with FMDV only become infectious for a brief period of time — approximately 0.5 days after clinical signs of the disease appear.

“We now know that there is a window where, if affected cattle are detected and removed from the herd promptly, there may be no need for pre-emptive culling in the immediate area of an infected farm,” said Woolhouse. “We have an opportunity now to develop new test systems which can detect infected animals earlier and reduce the spread of the disease.” Their findings are consistent with a rarely tested theory that disease symptoms may be functionally linked to infectiousness. “If you do things like measure virus in the blood, you’re taking no account of the clinical state of the animal,” said Woolhouse. “People might imagine that the clinical signs of a virus — the symptoms, such as sneezing — have something to do with its transmission. But, while there has been a lot of thoughtful speculation on the topic, there haven’t been many actual studies.” Charleston and his team are now calling for practical tools that could diagnose foot-and-mouth disease in the field before clinical signs appear. According to the researchers, if FMDV could be detected in livestock just 24 hours before clinical signs appear, then farmers might have time to remove the infected animals before they transmit the virus.

“If the benefits of this research are going to be realized in the field, we are going to have to implement pre-clinical diagnostics,” said Woolhouse. “It’s technically and logistically challenging, but our work shows that the potential benefits would be much greater than we’ve previously realized. So, at the very least, we should take a look at the possibilities for detecting FMDV early on.” The researchers also propose that similar studies could reveal much more about other animal (and human) pathogens in the future. “We urgently need to evaluate other infections,” said Woolhouse. “Until we do that, we can’t evaluate how effective control measures like quarantining individuals, prophylaxis, anti-virals or the pre-emptive culling of livestock are going to be.” The funding for this research was born out of a special initiative, launched by the U.K. Biotechnology and Biological Sciences Research Council after the horrific 2001 outbreak of foot-and-mouth disease in that country. The researchers involved say that such direct experiments are vital to our understanding of public health.

“If you’re going to make informed decisions about controlling infectious diseases, you need the right kinds of scientific evidence — and this study provides that, even if it wasn’t easy or cheap to come by,” concluded Woolhouse. “People have used short-cuts before and we can end up with misleading information. This new research tells me that we can’t afford to take those short-cuts. This is the kind of work we need to be doing to learn how to manage infectious diseases in the future.”

Science Daily
May 31, 2011

Original web page at Science Daily

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Europe fails to reach deal on cloned meat

Negotiations over the sale of products from cloned animals in the European Union have broken down and run out of time. The stalemate means that existing regulations, dating from 1997, remain in place. These state that although authorization is required to market food from clones, the use of their progeny as well as nanomaterials in foods will remain unregulated — meaning that meat from the offspring of cloned animals can go on sale unlabelled. The European Parliament had sought a ban on meat and derivative products from the descendants of cloned animals as well as from clones. The European Union (EU) Council, which represents EU member states, and the European Commission insisted on limiting the ban to the clones themselves. Three years of talks ended in failure on Tuesday after an all-night meeting in Brussels, with each side blaming the other.

At first, a compromise over labelling seemed attainable. The Council offered an eight-point package, including tracing and labelling for meat from cloned cattle in the next six months and labelling for all other food from clones’ offspring in two years, if a feasibility study conducted by the Commission was positive. It also offered to draw up separate legislation on cloning by 2013. But that did not satisfy the Parliament. “A commitment to label all food products from cloned offspring is a bare minimum,” delegation chair Gianni Pittella of Italy and novel foods rapporteur Kartika Liotard of the Netherlands said in a joint statement. “It is deeply frustrating that Council would not listen to public opinion and support urgently needed measures to protect consumer and animal welfare interests,” they said. “Measures regarding clone offspring are absolutely critical because clones are commercially viable only for breeding, not directly for food production. No farmer would spend €100,000 on a cloned bull, only to turn it into hamburgers.”

A 2008 Eurobarometer survey of 25,000 EU citizens found that 58% of respondents considered cloning for food to be “unjustified”; 83% believed that food from clones should be labelled if put on sale, and 63% said it was “unlikely” they would buy such food. Although the Commission is supposed to mediate between the Council and Parliament, Liotard alleged that it took the Council’s side on many issues, including warning that the Parliament’s position could trigger a trade war. The Council blamed the Parliament for the talks’ collapse. In a statement, it said that it had “exhausted every possibility” to reach a solution on food from cloned animals and condemned the “European Parliament’s inability to compromise on its request for mandatory labelling for food derived from offspring of cloned animals”, irrespective of the technical and practical implications. Members of the European Parliament dismissed the Commission’s argument that the descendants of clones are scientifically indistinguishable from traditionally bred animals. As illegally harvested wood can be traced through documentation along the supply chain, they see no reason why food from a clone’s lineage cannot receive the same treatment. “It is a question of political will,” Liotard told Nature. The European Food Safety Authority (EFSA) said last year that not enough studies had been conducted to assess the risks of food from cloning. It concluded that, although many cloned animals have fatal health problems, there is no sign of any differences between the meat and milk of clones and their offspring and products from conventionally bred animals.

Nature
April 19, 2011

Original web page at Nature

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Livestock plagues are spreading

Livestock plagues are on the rise globally, owing to increasingly intensive farming practices and the world’s growing taste for meat and other animal products. The warning comes from scientists at the International Livestock Research Institute (ILRI), based in Nairobi, Kenya, who argue that different approaches are needed to curb these diseases. A new infectious disease emerges every four months, and 75% of them originate in animals, according to ILRI figures. They can have severe socio-economic, health and environmental impacts: some of the most damaging diseases are Rift Valley fever (Phlebovirus), which can sometimes cause a haemorrhagic fever, and Bluetongue disease (Orbivirus). Whereas rich nations are controlling livestock diseases effectively, developing countries, including many in Africa and Asia, lag “dangerously behind”, says John McDermott, deputy director general for research at the ILRI.

This gap could imperil food security in the developing world, where up to 40% of household income can depend on livestock, McDermott and his ILRI colleague Delia Grace warn today at a conference in New Delhi (Leveraging agriculture for improving nutrition and health). “Over the past 10 years, the number of emerging diseases has increased,” agrees Alejandro Thiermann, who is in charge of setting international standards for animal health at the World Organisation for Animal Health based in Paris, France. Understanding the links between human and animal diseases will be “critical” in controlling the spread of diseases, he adds. McDermott points out that methods need to be tailored to the circumstances in developing countries to control the spread of livestock diseases. For example, some diseases, such as contagious bovine pleuropneumonia — a respiratory disease with high death rates — can be controlled in Western countries by quarantine and slaughtering affected animals. But these methods are not always effective for herds in Africa, where animal movements are not as easily controlled. In these cases, vaccines should be developed, McDermott says. Agricultural research has traditionally focused on increasing production, he says, too little is known about the risks associated with intensification. “These systems are intensifying anyway. So how do we intensify in a sustainable way and how do we manage the risk?” he asks.

Nature
February 22, 2011

Original web page at Nature

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Why some strains of Toxoplasma are more dangerous than others

About one-third of the human population is infected with a parasite called Toxoplasma gondii, but most of them don’t know it. Though Toxoplasma causes no symptoms in most people, it can be harmful to individuals with suppressed immune systems, and to fetuses whose mothers become infected during pregnancy. Toxoplasma spores are found in dirt and easily infect farm animals such as cows, sheep, pigs and chickens. Humans can be infected by eating undercooked meat or unwashed vegetables. Jeroen Saeij, an assistant professor of biology at MIT is investigating a key question: why certain strains of the Toxoplasma parasite (there are at least a dozen) are more dangerous to humans than others. He and his colleagues have focused their attention on the type II strain, which is the most common in the United States and Europe, and is also the most likely to produce symptoms. In a paper appearing in the Jan. 3 online edition of the Journal of Experimental Medicine, the researchers report the discovery of a new Toxoplasma protein that may help explain why type II is more virulent than others.

Toxoplasma infection rates vary around the world. In the United States, it’s about 10 to 15 percent, while rates in Europe and Brazil are much higher, around 50 to 80 percent. However, these are only estimates — it is difficult to calculate precise rates because most infected people don’t have any symptoms. After an infection is established, the parasite forms cysts, which contain many slowly reproducing parasites, in muscle tissue and the brain. If the cysts rupture, immune cells called T cells will usually kill the parasites before they spread further. However, people with suppressed immune systems, such as AIDS patients or people undergoing chemotherapy, can’t mount an effective defense. “In AIDS patients, T cells are essentially gone, so once a cyst ruptures, it can infect more brain cells, which eventually causes real damage to the brain,” says Saeij. The infection can also cause birth defects, if the mother is infected for the first time while pregnant. (If she is already infected before becoming pregnant, there is usually no danger to the fetus.) There are drugs that can kill the parasite when it first infects someone, but once cysts are formed, it is very difficult to eradicate them. A few years ago, Saeij and colleagues showed that the Toxoplasma parasite secretes two proteins called rhoptry18 and rhoptry16 into the host cell. Those proteins allow the parasite to take over many host-cell functions.

In the new study, the MIT team showed that the parasite also secretes a protein called GRA15, which triggers inflammation in the host. All Toxoplasma strains have this protein, but only the version found in type II causes inflammation, an immune reaction that is meant to destroy invaders but can also damage the host’s own tissues if unchecked. In the brain, inflammation can lead to encephalitis. This ability to cause inflammation likely explains why the type II strain is so much more hazardous for humans, says Saeij. Saeij and his team, which included MIT Department of Biology graduate students Emily Rosowski and Diana Lu, showed that type II GRA15 leads to the activation of the transcription factor known as NF-kB, which eventually stimulates production of proteins that cause inflammation. The team is now trying to figure out how that interaction between GRA15 and NF-kB occurs, and why it is advantageous to the parasite. Ultimately, Saeij hopes to figure out how the parasite is able to evade the immune system and establish a chronic infection. Such work could eventually lead to new drugs that block the parasite from establishing such an infection, or a vaccine that consists of a de-activated form of the parasite.

Science Daily
January 24, 2011

Original web page at Science Daily

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Babesiosis in immunocompetent patients

We report 2 cases of babesiosis in immunocompetent patients in France. A severe influenza-like disease developed in both patients 2 weeks after they had been bitten by ticks. Diagnosis was obtained from blood smears, and Babesia divergens was identified by PCR in 1 case. Babesiosis in Europe occurs in healthy patients, not only in splenectomized patients. Babesiosis, a tick-borne infectious disease that occurs worldwide, is caused by species of Babesia, an intraerythrocytic parasite. Babesia spp. parasites infect wild and domesticated animals and may cause a malaria-like syndrome. The first human case was described in 1957 in a splenectomized Yugoslavian farmer who died. More than 100 Babesia species infect animals, but human infection has been associated with only a few species, mainly B. microti and B. divergens. B. microti parasites are transmitted by Ixodes scapularis ticks and infect rodents. Since 1957, these parasites have caused hundreds of human babesiosis cases in the United States, the most affected country. Infections are found mainly in healthy persons and manifest as asymptomatic or mild to moderate illness; severe disease, even in immunocompromised or elderly patients, is seldom reported. B. divergens parasites are endemic to Europe; they are transmitted by I. ricinus ticks and infect bovines.

In Europe, the disease is rare in humans; ≈40 cases have been reported. These cases are almost exclusively severe in immunocompromised patients, especially those whose spleens have been removed. B. divergens parasites are responsible for >70% of these cases, although the disease is not always confirmed by molecular-based methods. We report 2 cases of human babesiosis in Colmar, Alsace, a northeastern region of France in which Lyme disease is endemic. The disease was diagnosed in spring 2009 in healthy young persons without history of travel abroad who experienced a marked influenza-like syndrome and recovered. These cases should change the classic description of babesiosis in Europe, in which the disease was thought to affect immunocompromised patients exclusively. Our study indicates that this disease also occurs in Europe among immunocompetent patients.

Emerging Infectious Diseases
January 11, 2011

Original web page at Emerging Infectious Diseases

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How foot-and-mouth disease virus begins infection in cattle

U.S. Department of Agriculture (USDA) scientists have identified the primary site where the virus that causes foot-and-mouth disease (FMD) begins infection in cattle. This discovery could lead to development of new vaccines to control and potentially eradicate FMD, a highly contagious and sometimes fatal viral disease of cloven-hoofed animals that is considered the most economically devastating livestock disease in the world. The discovery was made by scientists with the Agricultural Research Service (ARS) Foreign Animal Disease Research Unit at the Plum Island Animal Disease Center at Orient Point, N.Y. ARS is USDA’s principal intramural scientific research agency, and this research supports the USDA priority of promoting international food security. Veterinary medical officer Jonathan Arzt, research leader Luis Rodriguez and microbiologist Juan Pacheco found that after just six hours of exposure to the FMD virus through the cow’s nasal passages, the virus selectively infects epithelial cells in the nasopharynx, a specific region of the back of the cow’s throat.

“Because we have determined the actual route the FMD virus takes in infected cattle, we can now begin to target the virus-host interaction in an effort to develop better vaccines and biotherapeutic countermeasures against the disease,” Arzt said. Although the United States has not had an FMD outbreak since 1929, the disease is still considered a serious threat. Epidemics in other countries have resulted in the slaughter of millions of infected and uninfected animals to prevent the virus from spreading. Outbreaks of this disease in previously FMD-free countries could cause billions of dollars in economic losses related to eradication efforts and trade bans. Vaccines that offer temporary immunity for livestock have been developed, but there is no universal FMD vaccine against the disease. Because there are seven different types of FMD viruses and more than 60 subtypes, vaccines must be highly specific, matched to the type and subtype present in the area of an outbreak, to protect animals against developing clinical signs of disease. Blocking the initial site of infection may be the most effective way to achieve complete protection.

The research was published in the November issue of Veterinary Pathology and featured on the cover of that issue. The findings have allowed Arzt and his colleagues to answer some basic, yet long-standing mysteries regarding how the FMD virus first invades and propagates in susceptible cattle. The scientists now are conducting further research to answer questions about why the particular epithelial cells are susceptible, and how the initial infection site can be blocked. “The answers to these questions will result in a new era of FMD prevention in which highly effective vaccines will provide rapid and long-lasting immunity to even the most virulent strains of FMD virus,” Arzt said.

Science Daily
January 11, 2011

Original web page at Science Daily

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New prion discovery reveals drug target for mad cow disease and related illnesses

In a new research report in the December 2010 print issue of The FASEB Journal, scientists found that a protein our body uses to break up blood clots speeds up the progress of prion diseases. This substance, called plasminogen, is a new drug target for prion diseases in both humans and animals. “I hope that our study will aid in developing therapy for prion diseases, which will ultimately improve the quality of life of patients suffering from prion diseases,” said Chongsuk Ryou, Ph.D., a researcher involved in the work from the University of Kentucky in Lexington. “Since prion diseases can lay undetected for decades, delaying the ability of the disease-associated prion protein to replicate by targeting the cofactor of the process could be a monumental implication for treatment.” To make this discovery, the researchers used simple test tube reactions to multiply disease-associated prion proteins. The reactions were conducted in the presence or absence of plasminogen. They found that the natural replication of the prions was stimulated by plasminogen in both human and animal cells.

“Rogue prions are one of nature’s most interesting, deadly and least understood biological freakshows,” said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. “They are neither virus nor bacteria, but they kill or harm you just the same. By showing how prions hijack our own clot-busting machinery, this work points to a new target for anti-prion therapy.” According to the U.S. National Institute of Allergy and Infectious Diseases, prion diseases are a related group of rare, fatal brain diseases that affect animals and humans. The diseases are characterized by certain misshapen protein molecules that appear in brain tissue. Normal forms of these prion protein molecules reside on the surface of many types of cells, including brain cells, but scientists do not understand what normal prion protein does.

On the other hand, scientists believe that abnormal prion protein, which clumps together and accumulates in brain tissue, is the likely cause of the brain damage that occurs. Scientists do not have a good understanding of what causes the normal prion protein to take on the misshapen abnormal form. Prion diseases are also known as transmissible spongiform encephalopathies, and include bovine spongiform encephalopathy (“mad cow” disease) in cattle; Creutzfeldt-Jakob disease in humans; scrapie in sheep; and chronic wasting disease in deer and elk. These proteins may be spread through certain types of contact with infected tissue, body fluids, and possibly, contaminated medical instruments.

Science Daily
December 21, 2010

Original web page at Science Daily

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Stricter testing for federal ground beef program may not lead to safer meat

A new National Research Council report finds no scientific basis that more stringent testing of meat purchased through the government’s ground beef purchase program and distributed to various federal food and nutrition programs — including the National School Lunch Program — would lead to safer meat. The U.S. Department of Agriculture’s Agricultural Marketing Service (AMS) buys ground beef from suppliers who must meet mandatory process, quality, traceback, and handling controls as well as comply with strict limitations on the amounts of bacteria in the meat, such as E. coli and salmonella. AMS then distributes the ground beef to federal programs, including food banks, emergency feeding programs, Indian reservations, and disaster relief agencies. In its assessment of AMS’s ground beef purchase program, the committee that wrote the report said validated cooking processes provide greater assurance of ground beef’s safety than would additional testing for pathogens. Testing alone cannot guarantee the complete absence of pathogens because of statistical implications associated with how beef is sampled during testing.

The committee’s analysis of the number of illnesses since 1998 linked with AMS ground beef provided to schools suggests that outbreaks were rare events before AMS requirements became more stringent in February, implying that controls already in place were appropriate for protecting public health. For instance, no recorded outbreaks of E. coli or salmonella associated with AMS ground beef have occurred in more than a decade. Prevention of future outbreaks will depend on eliminating contamination during production and ensuring meat is properly handled, stored, and cooked before it is served, the committee emphasized. As part of its review, the committee also attempted to compare the AMS specifications with those of large industry purchasers of ground beef. Among purchasers, the committee found considerable differences in testing and safety standards and suspected that the intended use of the ground beef could account for the variations. For example, all raw AMS ground beef is distributed in frozen form, but distributors of fresh meat products may require different standards designed to improve shelf life. While AMS safety requirements appear comparable to or more demanding than those of commercial companies on the surface, the lack of information detailing the science used for corporate specifications prevented the committee from making direct comparisons.

Additional specifications under the AMS program call for testing food samples and surfaces at the suppliers to look for the presence of “indicator” microorganisms that could denote unsanitary conditions, improper hygiene and processing techniques, post-processing contamination, and storage-temperature abuse. Although a reduction in the number of indicator organisms implies a reduction in the amount of pathogens, the presence of an indicator does not guarantee that a pathogen is also present, the committee said. For an indicator to be an effective predictor of a pathogen’s presence, a statistical association needs to be established. Therefore, the committee recommended that AMS assess the usefulness of its microbiological data as a scientific basis for testing for indicators. “The report encourages AMS to strengthen its established specifications and requirements for ground beef by utilizing a transparent and clearly defined science-based process,” said Gary Acuff, chair of the committee and professor and director of the Center for Food Safety at Texas A&M University, College Station.

In addition, the report says that some of the requirements were founded on expert opinion and industry practices where the scientific basis was unclear. The committee recommended that AMS base their requirements on standards supported by the International Commission on Microbiological Safety of Foods, the Codex Alimentarius Commission, and the Research Council report An Evaluation of the Role of Microbiological Criteria for Foods and Food Ingredients. It also suggested that AMS analyze data from the suppliers’ bacterial testing to evaluate the safety requirements over time and use statistical methods to set testing sample and lot sizes. Overall, AMS should develop a systematic, transparent, and auditable system for modifying, reviewing, updating, and justifying purchasing specifications.

The committee noted that maintaining people’s confidence in the safety, quality, and nutritional value of the products AMS purchases is especially important because of the nature of the program and the clientele it serves. Though AMS may find it appropriate to adopt and implement conservative standards and requirements that both protect public health and provide the best quality product, it needs to consider the potential unintended consequences of increased testing and product requirements, the committee said. Additional testing would likely increase costs to producers, which could impact the purchase price of ground beef available through the program. Under such circumstances, schools might decide to buy their ground beef on the open market at a lower cost.

Science Daily
December 21, 2010

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Can naturally raised beef find its place in the industry?

As consumer demand for naturally raised beef continues to increase, researchers at the University of Illinois have discovered that naturally raised beef can be produced effectively for this niche market as long as a substantial premium is offered to cover additional production and transportation costs. Naturally raised beef is produced without hormones or antibiotics, whereas traditional systems take advantage of technologies the industry offers such as ionophores like Rumensin® to improve feed efficiency and implants to improve gain and efficiency. “Producers are asking many questions about the value of natural programs and the premiums needed to remain profitable,” said Dan Faulkner, U of I professor of animal sciences. “Our goal was to find out the costs involved in natural systems focused on producing environmentally friendly, locally raised beef.” Researchers studied the effects of finishing management (confinement versus pasture) and production system (traditional versus naturally raised) on performance, carcass and economic characteristics in a group of early weaned Angus x Simmental steer calves at the Dixon Springs Agricultural Center in Simpson, Ill. The calves were fed on fescue pastures or confinement feedlots.

The study revealed that naturally raised steers can be produced effectively in either confinement or with a pasture finishing system, but they require a substantial premium of $110 with today’s feed prices to justify the costs and returns. Faulkner said that pasture finishing is $35 more profitable than confinement feeding using current feed prices, making it an attractive option for producers interested in raising locker beef for local markets with either natural or traditional production systems. “I think this information will benefit smaller operations that would like to pursue a naturally raised market in a pasture finishing system, but may not be able to use a traditional confinement system,” Faulkner said. In addition, naturally raised beef in either pasture or confinement settings resulted in beef with higher quality grades. “There continues to be more interest in naturally raised beef because organic beef standards are so high,” Faulkner added. “We need to increase consumer education efforts because naturally raised beef is actually what many consumers are looking for these days.”

Both organic and naturally raised steers do not receive hormones or antibiotics. The major difference between naturally raised beef and organic beef is that organic beef comes from cattle that are raised on organic pastures that have not been treated with chemicals or chemical fertilizers. In addition, these cattle can only be fed organic certified feeds. Faulkner also differentiated pasture-fed beef from grass-fed beef. “Grass-fed cattle cannot be fed any concentrate – they can only receive roughage,” Faulkner said. “And that roughage must meet strict guidelines set by the USDA. On the other hand, pasture-fed cattle have access to a finishing diet and pasture.” Pasture-fed cattle have carcass and meat characteristics that are the same as traditionally finished cattle, he added. The meat characteristics of grass-fed cattle are quite different than the average consumer is used to eating. Faulkner said naturally raised beef, regardless of finishing management, is a niche market that has great potential if consumers will pay premium prices. “As producers, we need to be responsive to consumer demand,” he said. “Currently, naturally raised beef is a very small percentage of the market. But it is a market that is growing at several hundred percent a year, and has been identified as a niche that consumers are very interested in.”

eBioNews.com
November 9, 2010

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Don’t blame dairy cows for (greenhouse) gas emissions

Forget all the tacky jokes about cow flatulence causing climate change. A new study reports that the dairy industry is responsible for only about 2.0 percent of all US greenhouse gas emissions. The study, led by the University of Arkansas in association with Michigan Technological University, measures the carbon footprint of a gallon of fluid milk from farm to table and uses 2007 and 2008 data from more than 500 dairy farms and 50 dairy processors, as well as data from more than 210,000 round trips transporting milk from farm to processing plant. It was commissioned by the Innovation Center for the US Dairy, an industry-wide group. The University of Arkansas addressed carbon emissions from the dairy to the milk in your cereal bowl. The Michigan Tech group looked further upstream. “We focused on the carbon footprint of the feed crops,” said chemical engineering professor David Shonnard, director of the Sustainable Futures Institute. “Animal feed is a major contributor to carbon emissions.” Using US Department of Agriculture data, Shonnard’s team, including PhD student Felix Adom and four undergraduates (Ashely Maes, Charles Workman, Zachary Bergmann and Lilian Talla), analyzed the impact of variables ranging from fertilizer and herbicides to harvesting and transportation. “We also looked at a Michigan feed mill, where grain gets combined with any of over a hundred different additives,” he said.

The team concluded that the cumulative total emission of greenhouse gases associated with all fluid milk consumed in the US was approximately 35 million metric tons in 2007. While the emissions are lower than sometimes reported, there is still room for improvement for dairy farms and businesses of all kinds, the study concluded. In particular, manure management, feed production and enteric methane (cow gas) were cited as areas that are ripe for innovation on farms. Energy management provides the greatest opportunity in the processing, transportation and retail segments. The project has also raised other dairy-related issues that Shonnard’s group is investigating. They are studying the eutrophication of water — what happens when nutrients such as manure and fertilizers get into surface water, causing an overbloom of algae that sucks oxygen from the water and kills fish. The team is also investigating water consumption and land use in the dairy industry. “Growing crops is becoming more productive all the time, and we may be able to use less land to satisfy demand,” Shonnard said.

Science Daily
November 9, 2010

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Rinderpest, a disease that has wiped out cattle herds in South Africa, appears to be eradicated

Rinderpest, an infectious disease that has wiped out cattle and devastated their keepers for millennia, is gone. The United Nations Food and Agricultural Organization (FAO) announced today in Rome that an eradication effort launched in 1994 has achieved its goal and that fieldwork has ended. “It is probably the most remarkable achievement in the history of veterinary science,” says Peter Roeder, a British veterinarian involved with FAO’s Global Rinderpest Eradication Programme (GREP) from its launch in 1994 until he retired in 2007. Rinderpest’s eradication won’t be official, however, until the Paris-based World Organisation for Animal Health (OIE) certifies the rinderpest-free status of a handful of remaining countries. That process should be completed by the time of OIE’s May assembly, at which time a formal declaration will be made. It will be just the second time in history a devastating viral disease has been wiped off the face of the earth, the first being the human disease smallpox, declared vanquished in 1980.

Although nearly forgotten in much of the West, as recently as the early 1900s, outbreaks of rinderpest—from the German for “cattle plague”—regularly ravaged cattle herds across all of Eurasia and throughout the Middle East and Africa. The virus, a relative of those that cause canine distemper and human measles, spreads through exhaled droplets and feces of sick animals; it causes fever, diarrhea, dehydration, and death in a matter of days. It primarily affects the young; animals that survive an infection are immune for life. Outbreaks in Eurasia, where rinderpest was endemic throughout history, often claimed one-third or more of the calves in any herd. The horrific impact on naïve herds was seen when the virus was inadvertently introduced to the horn of Africa in 1889. In less than a decade, the virus reached South Africa. Throughout sub-Saharan Africa, it killed 90% of the cattle and large proportions of domestic oxen used to pull plows, and decimated wild buffalo, giraffe, and wildebeest populations. With herding, farming, and hunting devastated, famine claimed an estimated one-third of the population of Ethiopia and two-thirds of the Maasai people of Tanzania.

European countries gradually eliminated rinderpest in the early years of the 20th century through surveillance and culling of sick and exposed animals. It continued to afflict Asia and Africa in the second half of the 20th century, re-emerging when several eradication campaigns were shut down in the mistaken belief that the virus had been wiped out. In 1994, FAO brought together several regional rinderpest-control programs into GREP with the goal of eliminating the disease by 2010. “At times, I was pessimistic that we were going to get anywhere,” says Roeder. The key technical breakthrough was understanding the epidemiology of the virus: that it was re-emerging from just a handful of reservoirs that could be the targets of improved vaccines. As the program started demonstrating progress, countries initially skeptical or reluctant to share information on the extent of their rinderpest problem started cooperating. The virus was last detected in 2001 in wild buffaloes in Meru National Park in Kenya. “From a food security point of view, this is a tremendous accomplishment,” says FAO’s chief veterinary officer Juan Lubroth in an interview on the organization’s Web page. With one down, animal-health experts are pondering how to apply the lessons learned to the next target, which could be the peste des petites ruminants virus, which is highly contagious and lethal among sheep and goats. Another issue facing FAO is ensuring the safe keeping of viral samples and vaccines accumulated in labs around the world.

ScienceNow
October 26, 2010

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Milk from cloned cow’s offspring – experts respond

The UK’s Food Standards Agency is investigating claims that milk from the offspring of a cloned cow is on sale in British supermarkets, according to a statement released overnight. European Union rules on novel foods ensure no products from clones’ offspring can be sold legally without a scientific assessment of safety. In New Zealand, the New Zealand Food Safety Authority (NZFSA) and Food Standards Australia New Zealand (FSANZ) advise that the cloning of livestock animals in Australasia is still in the experimental stages and is restricted to small numbers of elite breeding stock, predominantly dairy and beef cattle and small numbers of sheep. A FSANZ statement indicates that cloned animals produced in Australasia are currently confined to the research environment and do not enter the food chain. The following comments were gathered by our colleagues at the UK SMC. Contact us if you’d like help locating a New Zealand expert on this topic.

Prof Keith Campbell, Head of Animal Physiology at the University of Nottingham, said: “The production of animals by the technique of somatic cell nuclear transfer has many uses in the fields of agriculture and biomedicine. For example in agriculture it allows the multiplication of elite animals and facilitates dissemination of superior production traits into the population when integrated into a breeding program, the major aim of commercial farming. There is no scientific evidence that the products of so called ‘cloned’ animals or their offspring differ from non-cloned animals or present any danger to the public. ”

Prof Grahame Bulfield, former director of the Roslin Institute when Dolly the sheep was cloned, said: “Given that the farmer wishes to remain ‘anonymous’, it is very difficult to evaluate this story so it should be taken with a pinch of salt. I don’t know of any cloned animals in the UK so I would be very suspicious. “If it is true, it is important to remember two things First, cloned animals are not genetically modified in any way; they are the exact equivalent of identical twins. And second, the milk comes not from the clone itself but from its offspring, which are born naturally. This makes a nonsense of the FSA ruling that milk or meat from such offspring should be considered a ‘novel food’, and they have never provided a scientific basis for this. There’s nothing novel about it, and you might as well say every new type of cereal should be treated with the same caution. “That said, I don’t think there is much value in using cloned cattle to produce milk or meat. Although there is no reason to think that products from the offspring of cloned animals would pose any kind of a health risk, cloning is a very expensive procedure and so unlikely to catch on.”

Prof Robin Lovell-Badge, Head of Stem Cell Biology and Developmental Genetics at the National Institute for Medical Research, said: “Cloning cattle has turned into a serious, although not particularly large business in several countries, notably the USA. It is used as a way to effectively copy individual dairy cows that give exceptionally high yields or bulls that are either themselves judged to be excellent for beef or that are able to sire offspring of high quality. In addition, using such a cloned animal in a breeding programme can increase the quality and yield of a herd of cattle. Perhaps it sounds paradoxical, but in theory, this could also be used to increase genetic diversity, by cloning rare breeds of cattle, many of which have special properties but are not very economical as isolated breeds, and crossing them with more common ones. “The production of the original clones might have some welfare issues, but a valuable animal is going to be looked after extremely well. Moreover, cattle cloning turns out to be more efficient than most other species, and the abnormalities that are frequently seen in other cloned animals are far less evident in cattle and sometimes absent altogether. Furthermore, the offspring of a cloned animal are always perfectly normal, and with cattle they will be just like any other cow or bull, although as special individuals they will be looked after with more care than others in the field. “There is no genetic modification. It was for this reason that the FDA has approved consumption of milk and beef from the offspring of cloned cattle – they are just normal animals, and I do not understand the EU position on this. Obviously the FSA have their rules and need to look into what has happened, but it is more likely to be the milk of kindness than a horror story.”

Dr Brendan Curran, a geneticist from the School of Biological and Chemical Sciences at Queen Mary, University of London, said: “This type of cloning is an extension of the process by which identical twins arise in nature Therefore if you have a healthy cow that is producing milk, it will produce healthy milk. I would argue that once the animal has been certified by veterinary surgeons as a fit animal, I can’t see how it would be in any way dangerous. “I could see an argument for the animal welfare people being concerned, but since these procedures have to be done under very strict conditions and in a compassionate way for the animal, this also shouldn’t be a problem. After the animal has been born and grows to be an adult, it reproduces normally and does everything normally.”

eBioNews.com
August 17, 2010

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Hops helps reduce ammonia produced by cattle

An Agricultural Research Service (ARS ) scientist may have found a way to cut the amount of ammonia produced by cattle. To do it, he’s using a key ingredient of the brewer’s art: hops. Cattle, deer, sheep, goats and other ruminant animals depend on a slew of naturally occurring bacteria to aid digestion of grass and other fibrous plants in the first of their four stomach chambers, known as the rumen. The problem, according to ARS microbiologist Michael Flythe, comes from one group of bacteria, known as hyper-ammonia-producing bacteria, or HABs. While other bacteria are helping their bovine hosts convert plant fibers to cud, HABs are breaking down amino acids, a chemical process that produces ammonia and robs the animals of the amino acids they need to build muscle tissue, according to Flythe, who works at the ARS Forage Animal Production Research Unit (FAPRU) in Lexington, Ky.

To make up for lost amino acids, cattle growers have to add expensive and inefficient high-protein supplements to their animals’ feed. According to Flythe, hops can reduce HAB populations. Hops, a natural preservative, were originally added to beer to limit bacterial growth. Flythe put either dried hops flowers or hops extracts in either cultures of pure HAB or a bacterial mix collected from a live cow’s rumen. Both the hops flowers and the extracts inhibited HAB growth and ammonia production. Flythe and FAPRU plant physiologist Isabelle Kagan have completed a similar project with more typical forage. They recently identified a compound in red clover that inhibits HAB. Results of that study were published recently in Current Microbiology. Flythe also collaborated with FAPRU animal scientist Glen Aiken on a study in which hops had a positive effect on the rumen’s volatile fatty acid ratios, which are important to ruminant nutrition.

Science Daily
August 3, 2010

Original web page at Science Daily

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Keeping feces on the farm

To your health! Dairy cows graze next to a spray irrigator on a New Zealand farm. Think dairy farm, and your mind may wander to images of cows grazing dewy green pastures, as glistening silos and red-walled farmhouses slumber in the distance. But something sinister is lurking in the grass: cow feces crawling with disease-causing Escherichia coli bacteria. A new study, however, reveals that these bacteria are much less likely to enter groundwater and cause illness if farmers spray their fields with water rather than flooding them, as is traditional. In a previous study, chemist and environmental scientist Murray Close of the Institute of Environmental Science and Research in Christchurch, New Zealand, and colleagues investigated a high incidence of digestive illnesses among residents of a rural community in the southeastern region of the country. It turned out that nearby drinking wells were contaminated. When the researchers examined water from wells located near dairy pastures that used flood irrigation, they found E. coli from cow feces in about three-fourths of the samples.

In the new study, Close and colleagues looked at groundwater under New Zealand pastures watered with spray irrigation. During the 6-year study, they sampled groundwater from 10 plots of land every month for a total of roughly 700 samples. They found that only about 3% of the samples contained E. coli, compared with 77% in the previous experiment. Close attributes the large difference to the fact that bacteria escape to the groundwater more easily if the soil is wetter.

These results, reported in the May-June issue of the Journal of Environmental Quality, aren’t just important for human health, say experts. They should also help countries conserve more water, as some spray-irrigation systems are up to twice as efficient as flood irrigation. “About 70% of the freshwater use on the planet is related to agriculture, so there is going to be a need to make more investments in spray irrigation and use less water,” says economist Neilson Conklin, president of the Farm Foundation, a think tank in Oakbrook, Illinois. Plant biologist Molly Jahn, dean of the College of Agriculture and Life Sciences at the University of Wisconsin, Madison, says the new health incentive tips the balance in favor of spray irrigation despite the hefty price tag. (On a field housing 70 hungry cows, the cost of equipment alone can exceed $35,000.) Jahn says the next challenge will be to balance the costs and benefits. “What we’re trying to do in sustainable agriculture is make sure we get that calculus right.”

ScienceNow
July 6, 2010

Original web page at ScienceNow

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Mechanism that may stop E. Coli from developing in cattle identified

Microbiologists at UT Southwestern Medical Center, working with the Department of Agriculture, have identified a potential target in cattle that could be exploited to help prevent outbreaks of food-borne illnesses caused by a nasty strain of Escherichia coli. In the study, available online and in an upcoming issue of the Proceedings of the National Academy of Sciences, researchers interfered with a genetic sensing mechanism that allows the E. coli strain known as enterohemorrhagic O157:H7, or EHEC, to form colonies within cattle, causing the bacteria to die off before they could reach the animals’ recto-anal junction, the primary site of colonization. Most other strains of E. coli gather in the colon. “We’re diminishing colonization by not letting EHEC go where it needs to go efficiently,” said Dr. Vanessa Sperandio, associate professor of microbiology and biochemistry at UT Southwestern and senior author of the study. “If we can find a way to prevent these bacteria from ever colonizing in cattle, it’s possible that we can have a real impact on human disease. “This could be something as simple as including some sort of antagonist in cattle feed, which would result in less shedding of the bacteria in fecal matter with less contamination down the road in food products.” Dr. Sperandio said the finding is important because an estimated 70 percent to 80 percent of the cattle herds in the U.S. carry EHEC.

Although EHEC can be a deadly pathogen to humans, the bacterium is part of cattle’s normal gastrointestinal flora. EHEC harbors a gene called sdiA, which makes the SdiA protein. The SdiA protein senses a chemical made by microbes in the animal’s rumen, the first of a cow’s four stomachs, which serves as a large fermentation chamber. Detecting this signal allows EHEC to pass through the rumen and colonize the recto-anal junction. For the study, the researchers injected two types of EHEC into the rumens of eight grain-fed adult cows. One mutant version lacked SdiA and could not detect the signal in the rumen. Another strain produced an enzyme that destroyed the chemicals in the rumen sensed by SdiA. The researchers found that colonization diminished significantly when these EHEC strains were unable to sense the rumen chemicals. The process prevented the bacteria from moving on through the stomach and colonizing. “If there’s no signal, then there’s no acid resistance, a requirement for the pathogen to make it to the recto-anal junction,” Dr. Sperandio said. “Everybody had thought that this type of signaling occurred naturally in the gastrointestinal tract of mammals. Our finding serves as a proof-of-principle that we might be able to target this system to prevent food contamination.”

EHEC, like other E. coli strains, is usually transmitted through contaminated food. Recent outbreaks in the U.S. have been found in ground beef, spinach and raw sprouts. EHEC is responsible for outbreaks throughout the world of bloody diarrhea and hemolytic uremic syndrome — a condition that can lead to renal failure and death. Severe symptoms are most common in children, the elderly and immune-suppressed people. Cattle are the primary source for most E. coli infections in the U.S. When cattle waste reaches water sources near food crops, contamination can occur. Unsanitary slaughtering of cattle also can lead to cross-contamination of the beef itself, and shipment of infected food speeds the rate at which the public can become ill.

Science Daily
June 8, 2010

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High-quality beef: Start cattle on corn, finish on co-products, researchers find

The traditional practice of finishing cattle on corn may not be the only way to achieve high marbling, a desirable characteristic of quality beef. Researchers at the University of Illinois have discovered that high-quality beef and big per-head profits can be achieved by starting early-weaned cattle on corn and finishing them on a diet high in co-products. “The goal is to get the highest quality beef product in the most profitable way,” said U of I animal scientist Dan Shike. “If you can initiate marbling at a young age with corn, calves are smaller and they eat much less, so feeding them corn for 100 days early saves on feed costs. This system will use considerably less corn and achieve the same effect.” For the study, heifers from the Dixon Springs Agricultural Center were weaned at an average age of 77 days and fed a high-corn ration for the next 146 days to initiate marbling. Then the cattle were divided into four groups: pasture-fed; high starch; intermediate starch; and low starch. The cattle remained on these treatments for 73 days. Then, all cattle were fed the intermediate-starch diet for the remainder of the finishing period. Before being divided into the four treatment groups, the calves were ultrasounded to determine marbling.

The ultrasounds revealed that marbling was initiated with the early corn diet. The cattle were ultrasounded again at the completion of the 73-day treatment period. “The cattle on pasture had significantly lower marbling,” Shike said. “But there were no differences in the cattle fed varying levels of starch.” These results remained constant through harvest with pasture-fed cattle receiving lower marbling scores and fewer cattle grading low-choice. The cattle fed varying levels of starch had no difference in marbling scores. However, there were differences in profit per head. “If you look at the overall profitability, we actually lost a little money on the high-starch group, the pastured cattle barely made any money, but the intermediate- and the low-starch groups showed a big swing. There’s about a $45 difference between the high-starch and intermediate-starch treatment groups, and low starch was comparable to intermediate.” Why were the intermediate- and low-starch groups more profitable? Cattle fed these diets achieved higher gains as efficiently or more efficiently as the high-starch group. Another advantage to weaning calves earlier and starting them on feed means they can be harvested much earlier.

“Our system is really an accelerated finishing system. It’s not uncommon for our cattle to reach market end point and be harvested at 12 to 13 months of age. Whereas, in a more traditional weaning system, they might be 15, 16, or even 17 months of age. So, we’re really taking four or five months off of that,” Shike said. Shike commented that when corn prices are high, this system is more cost effective because it utilizes lower priced co-products such as distillers dried grain, corn gluten feed, and soy hulls without sacrificing marbling quality. “Additional research is needed,” Shike said. “But we believe feeding a high-grain ration to cattle at a young age and finishing them on co-products is the most profitable way to produce high-quality beef.”

Science Daily
June 8, 2010

Original web page at Science Daily