Tag: Herd Health

Using mathematical modelling, researchers at the University of Cambridge and Animal & Plant Health Agency, Surrey, show that it is the specificity of the test — the proportion of uninfected animals that test negative — rather than the efficacy of a vaccine, that is the dominant factor in determining whether vaccination can provide a protective economic benefit when used to supplement existing controls.

Bovine TB is a major economic disease of livestock worldwide. Despite an intensive, and costly, control programme in the United Kingdom, the disease continues to persist. Vaccination using the human vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) offers some protection in cattle, but is currently illegal within the European Union (EU) due to its interference with the tuberculin skin test. This test is the cornerstone of surveillance and eradication strategies and is used to demonstrate progress towards national eradication and as the basis of international trade in cattle. The current tuberculin skin test has a very high estimated specificity of over 99.97%, which means that less than three animals in 10,000 will test falsely positive. The test as carried out in Great Britain is thought to have at best an 80% sensitivity — a measure of how many infected animals will correctly test positive — missing around 1 in 5 bovine TB-infected cattle. It is used to determine if animals, herds and countries are officially free of bovine TB. Vaccinated animals that test positive have to be treated as infected animals. Under European law, if an animal tests positive, it must be slaughtered. The remaining herd is put under movement restrictions and tested repeatedly using both the skin test and post-mortem examinations until it can be shown to be officially clear of infection. The duration of movement restrictions is important due to the considerable economic burden they place on farms. The cost to the UK government alone, which depends on the number of visits to farms by veterinarians, tests carried out and compensation for the slaughter of infected animals, is estimated to be up to £0.5 billion pounds over the last ten years.

For vaccination to be feasible economically and useful within the context of European legislation, the benefits of vaccination must be great enough to outweigh any increase in testing. A new generation of diagnostic tests, known as ‘Differentiate Vaccinated from Infected Animals’ (DIVA) tests, opens up the opportunity for the use of BCG within current control programmes. The EU has recently outlined the requirements for changes in legislation to allow cattle vaccination and a recent report from its European Food Safety Authority emphasized the importance of demonstrating that BCG is efficacious and that DIVA tests can be shown to have a comparable sensitivity to tuberculin testing in large-scale field trials.

However, a key factor overlooked in this report was that the currently viable DIVA tests have a lower specificity than tuberculin testing; this could lead to vaccinated herds being unable to escape restrictions once a single test-positive animal has been detected, as the more times the herd is tested, the more likely the test is to record a false positive. In the study published recently, the researchers from Cambridge and the Animal & Plant Health Agency used herd level mathematical models to show that the burden of infection can be reduced in vaccinated herds even when DIVA sensitivity is lower than tuberculin skin testing — provided that the individual level protection is great enough. However, in order to see this benefit of vaccination the DIVA test will need to achieve a specificity of greater than 99.85% to avoid increasing the duration and number of animals condemned during breakdowns. A data set of BCG vaccinated and BCG vaccinated/experimentally M. bovis infected cattle suggests that this specificity could be achievable with a relative sensitivity of the DIVA test of 73.3%. However, validating a test to such a high specificity will likely prove a challenge. Currently, there is no gold standard test to diagnose TB in cattle. Cattle that test positive are slaughtered immediately and therefore have rarely developed any physical signs — in fact, only around a half of animals examined post-mortem show physical signs of infection even if they are, indeed, infected. Dr Andrew Conlan from the Department of Veterinary Medicine at the University of Cambridge says: “In order for vaccination to be viable, we will need a DIVA test that has extremely high specificity. If the specificity is not good enough, the test will find false positives, leading to restrictions being put in place and a significant financial burden for the farmer. But validating a test that has a very high specificity will in itself be an enormous challenge. We would potentially need to vaccinate, test and kill a large number of animals in order to be confident the test is accurate. This would be very expensive.”

The need for a better DIVA test was acknowledged by the Government at the end of last year. In a written statement to the House of Commons noting data from the University of Cambridge and Animal Health and Veterinary Laboratories Agency, the Rt Hon Elizabeth Truss, Secretary of State for Environment, Food and Rural Affairs, said: “An independent report on the design of field trials of cattle vaccine and a test to detect infected cattle among vaccinated cattle (DIVA) shows that before cattle vaccination field trials can be contemplated, we need to develop a better DIVA test.”

http://www.sciencedaily.com/ Science Daily

http://www.sciencedaily.com/releases/2015/02/150219144639.htm Original web page at Science Daily

Scientists have long known that cattle produce carbon dioxide and methane throughout their lives, but a new study pinpoints the cow-calf stage as a major contributor of greenhouse gases during beef production. In a new paper for the Journal of Animal Science, scientists estimate greenhouse gas emissions from beef cattle during different stages of life. They show that, depending on which production system farmers used, beef production has a carbon footprint ranging from 10.7 to 22.6 kg of carbon dioxide equivalent per kg of hot carcass weight. According to study co-author Frank Mitloehner, an associate professor in the Department of Animal Science at UC Davis, one source of greenhouse gases was surprising. “If you look at everything that contributes to greenhouse gases through the beef supply chain, then it is the cow-calf that produces the greatest greenhouse gases,” Mitloehner said. In the cow-calf phase, the cow gives birth and nurses the calf until the calf is six to 10 months old. During this time, the cow eats rough plants like hay and grasses. The methane-producing bacteria in the cow’s gut thrive on these plants. “The more roughage is in the diet of the ruminant animal, the more methane is produced by the microbes in the gut of the ruminant, and methane comes out the front end,” Mitloehner said.

In feedlots, by contrast, cattle eat mostly corn and grains, which the methane-producing bacteria cannot use as effectively. Methane is one of the most important greenhouse gases. Methane has a greater capacity to trap heat in the atmosphere than carbon dioxide. The beef industry has been paying close attention to greenhouse gas emissions in recent years. “We are doing a lot to measure and mitigate our impact,” said Chase Adams, director of communications for the National Cattlemen’s Beef Association. In a 2011 paper for the Journal of Animal Science, researcher Jude Capper showed that the beef industry today uses significantly less water and land than 30 years ago. The industry has also reduced its carbon footprint by 16.3 percent per billion kilograms of beef produced. According to Mitloehner, beef producers can further reduce their carbon impact by using new technologies like growth promotants. However, consumers are often uncomfortable with these methods, and they choose organic beef or beef with reduced amounts of growth promotants. “The technologies many consumers are critical of are those that help us receive the greatest environmental gains,” Mitloehner said.

Eurek Alert! Medicine
February 19, 2013

Original web page at Eurek Alert! Medicine

Beef production in the United States is expected to decrease 4.8 percent in 2013, the second largest year-over-year decrease in 35 years, trailing only the 6.4 percent drop in 2004. The reason is a combination of mostly steady carcass weights and a projected 5 percent or more decrease in cattle slaughter, said Derrell Peel, Oklahoma State University Cooperative Extension livestock marketing specialist. “Many analysts expect the 2013 numbers to be followed by a 2014 decrease of 4.5 percent or more,” he said. “These two years would represent the largest percentage decrease since the late 1970s.” Beef production in 2012 decreased by approximately 1.1 percent compared to 2011 with a 3.3 percent decrease in slaughter, which was partially offset by a 2.3 percent increase in carcass weights. However, the effect on consumption of beef does not always match the change in production. Domestic per capita consumption will depend on production levels but must be adjusted for beef imports and exports.

“In 2013, per capita beef consumption is expected to drop 3.5 percent, less than the production decrease because beef imports will increase and beef exports will decrease,” Peel said. “The decrease in per capita beef consumption in 2013 should be similar to the year-over-year decrease in 2011 compared to 2010.” In 2011, domestic per capita beef consumption decreased 3.8 percent, in large part because of a sharp increase in beef exports despite a minimal decrease in beef production. Though 2004 had a sharper production decrease, per capita beef consumption that year increased nearly 2 percent because of a sharp drop in beef exports, largely attributed to the first case of Bovine spongiform encephalopathy, also referred to as BSE, in the United States. “Beef consumption may drop more sharply in 2014 with a 5 percent decrease in per capita consumption compared to the lower 2013 level,” Peel said. “Furthermore, these decreases in beef production and consumption almost certainly imply higher wholesale and retail beef prices, although other factors will impact the price response to lower supplies.”

Choice boxed beef has been trapped in a narrow range between $193 and $198 per hundredweight for the past three months. Retail beef prices were flat to slightly lower through much of 2012 but did jump sharply in November. “In 2011, a similar decrease in beef consumption resulted in a 15 percent increase in boxed beef prices and a nearly 10 percent increase in retail prices,” Peel said. “Total meat consumption decreased about 2 percent in 2011 and a similar 2.1 percent decrease is expected in 2013 with both pork and broiler consumption expected to drop approximately 1.5 percent each.” The pressure for higher boxed beef prices will increase significantly with an expected 4.5 percent decrease in beef production in the first quarter of 2013. Choice boxed beef should move above $200 per hundredweight in the next few weeks. Beyond that, Peel believes it will be a question of how much and how fast retailers can pass along the higher wholesale prices to consumers. “It is not really a question of whether retail prices will go up but rather a question of how much and how fast,” he said. “Beef demand remains the biggest unknown in the beef industry. Time will tell just how severe the squeeze will be on industry margins in 2013.” Cattle and calves represent the number one agricultural commodity produced in Oklahoma, accounting for 46 percent of total agricultural cash receipts and adding approximately $2 billion to the state economy, according to National Agricultural Statistics Service data. NASS data indicates Oklahoma is the nation’s fifth-largest producer of cattle and calves, with the third-largest number of cattle operations in a state.

Science Daily
February 5, 2013

Original web page at Science Daily

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

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

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

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

Lots of leaves growing in easy reach of a cow’s tongue means less time and less land needed to raise beef cattle, according to Agricultural Research Service (ARS) and DairyNZ (New Zealand) scientists. Ranchers may be able to tell how long to leave cattle in a pasture, and how large to make the pasture, by the height and leafiness of plants growing there, according to Stacey Gunter, research leader at the ARS Southern Plains Range Research Station in Woodward, Okla. He worked with former Ph.D. student Pablo Gregorini and colleagues at Woodward to demonstrate this approach with beef steers grazing in fenced-off corridors in wheat pastures. The pastures were chosen to represent a range of natural variations in plant heights and upper plant leafiness. The steers were allowed to graze the corridors freely and were removed when they reached the end of the corridor, regardless of how much time the steers took. While grazing the corridors, each steer was videotaped and had two trained observers who counted bites and walking steps.

The reason for this real-life pasture study is that most studies of grazing behavior are done on “artificial seedings,” specially planted pastures, or small plots that are fairly uniform. To provide the best possible recommendations to ranchers, Gunter and Gregorini integrated studies of the standard type with “in field” pasture conditions which are much less uniform. Besides the taste and nutrition of large leaves, cattle like their food to be accessible, with leaves high on the plant and a minimum of stem interference with the cattle’s tongues, which they use to wrap around and pull off leaves. Cattle faced with a nice canopy of luscious leaves took larger bites and were able to get their daily rations with lower calorie expenditure. This resulted in greater eating efficiency. Gunter and Gregorini measured eating efficiency by dividing the total amount of pasture plants eaten per steer by the total eating time. This is known as herbage intake rate, a key determinant of weight gain for cattle grazing pasture.
Source: Journal of Animal Science.

Science Daily
April 13, 2010

Original web page at Science Daily

Combining technology and animal health, a group of Kansas State University researchers is developing a more effective way to predict the spread of foot-and-mouth disease and the impact of preventative measures. The researchers are finding that if a foot-and-mouth disease outbreak is not in the epidemic stage, preemptive vaccination is a minimally expensive way to halt the disease’s spread across a network of animals. But if there’s a high probability of infection, computer models show that culling strategies are better. “We are trying to do predictive as well as preventative modeling using a network-based approach,” said Sohini Roy Chowdhury, a master’s student in electrical engineering. “First we track how the infection is spreading in space and time. Then we try to mitigate that with certain strategies. The novel contribution of this project is that we considered networks in countries like Turkey, Iran and Thailand that don’t have a highly built database.”

Roy Chowdhury is working with Caterina Scoglio, associate professor of electrical and computer engineering, and William Hsu, associate professor of computing and information sciences. They presented the work in December 2009 at the Second International Conference on Infectious Diseases Dynamics in Athens, Greece. The researchers used mathematical equations to predict how foot-and-mouth disease spreads over a network of infected herds. In the network, the nodes are places like stockyards and grazing lands where animals are held. They are connected in various ways, such as by animals’ grazing movements and by how people and vehicles move among the herds. Hsu said the researchers’ goal is to increase the accuracy of models that predict disease spread in these networks over space and time. In the experiments, the researchers ran up to a week of predictive modeling on a real network and saw how well it matched data from the actual episode. Roy Chowdhury said they also used artificial intelligence-based modules to cross compare the model’s accuracy.

The researchers also tested such mitigation strategies as vaccination, culling and isolation to see how they affected the network. In real-world outbreaks of foot-and-mouth disease, culling often is presumed to be the best strategy, but Scoglio said their research could shed more light on the effectiveness of this practice. “It is the hope to properly contain a disease like foot-and-mouth disease that is so infectious while minimizing the economic losses,” Scoglio said. Hsu said this study also could benefit relief workers sent to help contain foot-and-mouth disease. The K-State network models improve upon existing ones, he said, because they consider such factors as wind, animal grazing and human movements between regions, as well as the number of meat markets in an area. Scoglio’s research group has studied disease outbreaks using computer models of networks before, but this project is different in that it considers a specific disease, she said. Hsu contributed his research in data mining, which seeks to scour news stories and other online public sources and extract information that could offer clues about disease outbreaks. For this project, Hsu’s system crawled and analyzed Web articles from news agencies like the BBC and CNN, as well as such sources as disease control fact sheets from universities.

Science Daily
February 9, 2010

Original web page at Science Daily

Switching from warm-season grasses to cool-season forages can give livestock a belly ache, in some cases a deadly one, according to Texas AgriLife Research scientists. Dr. Bill Pinchak, Texas AgriLife Research animal nutritionist at Vernon, is leading a team of scientists who are using state-of-the-art technology — metagenomics — to determine how changes in diets affect microbial communities in the digestive tract of cattle and how these changes may increase risk of disease. Metagenomics is a field of molecular microbiology where the presence of a microbe is determined by identifying its DNA in a sample rather than trying to grow the organism in culture, said Dr. Jason Osterstock, AgriLife Research ruminant animal health scientist in Amarillo and part of the team. Pinchak, who is head of the Bloat Research Project, said they want to understand the role of rumen microbial communities in metabolic disease, specifically frothy bloat of cattle grazing winter wheat pastures. Bloat is a costly and sometimes fatal disease of cattle, with an estimated $400 million negative impact on the beef cattle industry. Their goal is to determine the interactions among rumen microbes that lead to the onset and duration of disease, he said.

Studying individual microbial genus or species in the rumen only provides part of the story, Osterstock said. In fact, the rumen is a complex microbial system comprised of bacteria, protozoa and fungi where the impact of a specific microbial species is dependent upon the activity of other microbes in the system. Metagenomics is an ideal approach to studying these microbial communities because less than 10 percent of rumen microbes can be grown in culture using routine anaerobic methods, Osterstock said. The team’s current work has focused on bacterial populations in the rumen using sequencing methods and bioinformatics to classify which bacterial genera are present under different dietary conditions. The bloat team recently completed the first genomics-based characterization of bacterial populations from steers associated with changing from a warm-season grass hay diet to a cool-season grazed forage diet. Their study included 14 steers sampled at two time points, the largest study of its kind to date, the scientists said.

During their research, the scientists found that the distribution of bacterial genera changes dramatically when stocker cattle transition from Bermuda grass hay to winter wheat forage diets, Pinchak said. In addition, analyses determined that bacterial communities were clearly different in the fiber, liquid and whole rumen fractions within the rumen, he said. Overall, more groups of different bacteria occurred on Bermuda grass hay than wheat forage diets, which is consistent with the increased rumen retention time of the less digestible Bermuda grass hay, Pinchak said. During the study, they found that specific bacterial groups would increase, decrease, appear or disappear from one diet to the other, highlighting the complexity, plasticity and specificity of rumen bacterial populations, he said. These results point toward the potential to use deeper metagenomic sequencing, including characterization of non-bacterial microbes, to gain better resolution and begin to unravel more complex relationships in future studies, Pinchak said.

Science Daily
January 26, 2010

Original web page at Science Daily

Rinderpest, the world’s most devastating cattle disease, will be declared eradicated within 18 months, according to world health bodies. The effort will make it only the second disease to be wiped from the globe — the first was smallpox, eradicated in 1980. “Rinderpest tops the list of killer diseases in animals,” says Juan Lubroth, chief veterinary officer for the Food and Agricultural Organization of the United Nations (FAO) in Rome. It not only kills cattle and other wildlife, it also causes famines when people in developing countries lose the beasts they need to plough their fields, he adds. Eradication of the disease would be a “massive achievement for the veterinary community”, says Chris Oura, head of the Non-Vesicular Disease Reference Laboratory Group at the Institute for Animal Health in Pirbright, UK. Rinderpest, otherwise known as cattle plague, has killed many millions of cattle and other wildlife around the world since it first spread from Asia to Europe in the herds of the invading tribes, causing outbreaks during the Roman Empire in 376-386. Since then, the disease has spread throughout Europe and on to Africa, the Middle East and the Indian sub-continent. Outbreaks in Nigeria during the 1980s cost around $2 billion, according to the FAO.

The disease is caused by a virus called a morbillivirus — a group that also includes the measles virus. Clinical signs include fever, discharges from the eyes and nose, diarrhoea and dehydration and the disease kills 80-90% of infected cattle in just 7-10 days. The last outbreak in Asia was in 2000 and the last known cases of the disease were in Kenya in 2001. The FAO and the World Organisation for Animal Health (OIE), based in Paris, headed up an international effort to eradicate the disease, which began in 1994 with the launch of the Global Rinderpest Eradication Programme. The programme’s success depended on widespread vaccination programmes and long-term monitoring of cattle and wildlife. A breakthrough in controlling the disease came in the 1980’s when a heat-stable vaccine was developed that contained the attenuated virus, allowing the vaccine to be stored and transported over long distances. Oura says that the biggest scientific challenges in eradicating the virus is the large-scale monitoring and surveillance needed to ensure that the virus is gone. “It’s a huge task when you have the virus in developing countries and war zones, such as Somalia, to carry out monitoring and surveillance,” he says.

Although the vaccine can provide life-long protection, it has also caused some problems. Because it contains the live virus, diagnostic tests can’t differentiate between infected and vaccinated animals, as both will test positive for antibodies against the virus. Cows also pass on antibodies to their offspring through their milk. To evaluate whether the virus has been eradicated, vaccinations must stop for a period of two years and calves less than two years old tested. “It is a difficult, long process to make sure nothing is there,” says Oura. Lubroth says he is “confident” that the world is already free of the disease but that the FAO and the OIE expect to make an official declaration that rinderpest has been eradicated in 18 months. Bernard Vallat, director-general of the OIE, says that the hold-up is because 12 countries have not yet submitted their final test and surveillance results to the organization. He adds that over the next year and a half, the OIE will be drawing up an inventory of which governments and laboratories around the world are keeping a stock of the virus.

Nature
December 15, 2009

Original web page at Nature

A 14-year study by Agricultural Research Service (ARS) scientists in Oregon found that rangelands that have been grazed by cattle recover from fires more effectively than rangelands that have been protected from livestock. These surprising findings could impact management strategies for native plant communities where ecological dynamics are shifting because of climate change, invasive weeds and other challenges. Much of the rangeland in the western United States is threatened by the spread of cheatgrass and medusahead, invasive non-native annual grasses that fuel wildfires and readily infest landscapes, especially after fires. These rangelands historically were burned by wildfires every 50 to 100 years, but over the past century these fires have been suppressed by humans. This suppression allowed some dead plant litter to accumulate, but when cattle were introduced to the region, their grazing helped keep litter accumulation in check. Rangeland scientists Kirk Davies and Jon Bates and research leader Tony Svejcar, who work in the ARS Range and Meadow Forage Management Research Unit at the Eastern Oregon Agricultural Research Center in Burns, Ore., carried out studies comparing how native plants on grazed and ungrazed sagebrush rangelands recovered from fires. All the sites had similar vegetation profiles and were virtually free of cheatgrass.

In the grazed areas, cattle consumed around 40 percent of the available forage, which removed much of the potential litter. The ungrazed sites, where livestock had been excluded since 1936, had almost twice as much litter as the grazed sites. The scientists conducted a controlled burn on all the sites in 1993, and then measured vegetation cover, vegetation density and biomass production in 2005, 2006 and 2007. They found cheatgrass had infested a large portion of the ungrazed sites, leaving these areas even more vulnerable to future fires. However, cheatgrass did not become problematic on the sites that had been grazed. On these sites, native bunchgrass cover was almost twice as dense as bunchgrass cover on the ungrazed sites. The team concluded that the litter in the ungrazed sites fueled hotter fires that killed off much of the perennial vegetation, which allowed quick-growing invasive annuals to become established.

Science Daily
October 20, 2009

Original web page at Science Daily

With more than 2 million cows on 68,000 farms, Missouri is the third-largest beef producer in the nation. Due to rising feed prices, farmers are struggling to provide feed for the cows that contribute more than $1 billion to Missouri’s economy. University of Missouri researcher Monty Kerley, professor of animal nutrition in the College of Agriculture, Food and Natural Resources, is studying how cows might be able to gain more weight while consuming less, potentially saving farmers up to 40 percent of feed costs. Two years ago, MU researchers started studying which biological processes could make cows feed-efficient. They examined the basic compound that cells use for energy, commonly known as ATP, using previous research that demonstrated how DNA influences weight gain in cows. Some animals can synthesize ATP faster than others, helping them to use energy more efficiently and, thus, gain more weight with less food. Kerley hopes that farmers will use this research to breed more feed-efficient cattle.

“We would love to go to the rancher and say, ‘you can reduce your feed cost 40 percent with the same weight gain,'” Kerley said. Kerley and his team are using a feed and weighing system that records individual intake and body weight of cattle daily. This research is being done at the Beef Research and Teaching Farm facility in MU’s South Farm Agricultural Experiment Station. Whenever an animal steps to the bunk, or a trough, a computer notes the cows’ arrival and departure times and how much they eat. When they drink, they stand on scales that keep track of their weights. If a beef producer just selected the top one-third of their most efficient cows, forage intake would be reduced by 20 percent, Kerley said. Kerley said that when feed intake is reduced, methane emissions and manure production also decrease. “If ‘cap and trade’ regulations, in some form, become part of America, it is likely that cattle producers will have to defend themselves against claims of methane emission by ruminants,” Kerley said. “If a farmer can demonstrate reduced carbon production, then he or she might be able to ‘sell’ production credits on an exchange. That could provide the farmer with an additional income stream.” Beef producers are using this research to make genetic selections in their beef herds. Missouri was one of the first states to have a private bull testing facility that tests for efficiency. The Division of Animal Sciences also has a research emphasis to study genetic control of feed efficiency and methods to predict animal efficiency. Kerley’s research has been published in a variety of scientific journals.

Science Daily
October 20, 2009

Original web page at Science Daily

Millions of African families could be saved from destitution thanks to a much-needed vaccine that is being mass-produced in a drive to protect cattle against a deadly parasite. East Coast fever is a tick-transmitted disease that kills one cow every 30 seconds – with one million a year dying of the disease. Calves are particularly susceptible to the disease. In herds kept by the pastoral Maasai people, for example, the disease kills from 20 to over 50 per cent of all unvaccinated calves. This makes it difficult and often impossible for the herders to plan for the future, to improve their livestock enterprises and thus to raise their standard of living. An experimental vaccine against East Coast fever was first developed more than 30 years ago. This has been followed by work to allow the vaccine to be produced on a large scale, with major funding from the UK Department for International Development (DFID) and others.

East Coast Fever puts the lives of more than 25 million cattle at risk in the 11 countries where the disease is now endemic, and endangers a further 10 million animals in new regions such as southern Sudan, where the disease has been spreading at a rate of more than 30 kilometres a year. The vaccine could save the 11 affected countries at least £175 million a year. The immunization procedure – called “infection-and-treatment” because the animals are infected with whole parasites while being treated with antibiotics to stop development of disease – has proved highly effective. However, initial stocks produced in the 1990s recently ran low. The International Livestock Research Institute (ILRI), at the request of the Africa Union/Interafrican Bureau for Animal Resources and chief veterinary officers in affected countries, produced one million doses of vaccine to fill this gap. However, for the longer term it is critical that sustainable commercial systems for vaccine production, distribution and delivery are established.

With UK£16.5 million provided by DFID and the Bill & Melinda Gates Foundation, the charity GALVmed is fostering innovative commercial means to do just this, beginning with the registration and commercial distribution and delivery of this new batch of the vaccine. This will ensure that the vaccine is made available, accessible and affordable to livestock keepers who need it most and to scale up its production for the future. International Development Minister Mike Foster said: “Some 1.3 billion of the world’s poorest people rely on livestock for their livelihoods. Many Africans depend on the health of their cattle for milk, meat and as their only hard asset for trade and investment. A smallholder dairy farmer can take years to recover economically from the death of a single milking cow. That’s why it’s vital that every possible step is taken to ensure that these essential vaccine doses are sustainably produced, tested and made available to the people who need them. “DFID is supporting GALVmed to explore ways of transferring the production and distribution of the vaccine into the private sector through local manufacturers and distributors. This is extremely important in making the vaccine affordable, accessible and – crucially – sustainable.”

GALVmed CEO Steve Sloan said: “Funded by DFID and the Bill & Melinda Gates Foundation, GALVmed is working to protect livestock and the livelihoods of their owners. Thanks to the highly effective East Coast fever vaccine developed over many years by researchers working in East Africa and then refined and mass produced by ILRI, cattle invaluable to pastoralists such as the Maasai as well as smallholder dairy farmers are being protected. “The survival of cattle for the millions who live on tiny margins has a direct effect on quality of life and the dignity of choice and self-determination. Collaborating with ILRI and partners in the developing world, including governments and veterinary distributors and those from the private sector, GALVmed is working to embed the vaccine through registration in East African countries and to scale up its production so that it remains accessible to poor people. “This pioneering registration effort aims to ensure that the vaccine is approved and monitored by affected nations and enables local firms to sell and distribute it, embedding its sustainability. Registration in Malawi is already complete, with significant progress in Tanzania, Kenya and Uganda.”

Science Daily
October 20, 2009

Original web page at Science Daily

A new study suggests that when compared to conventionally raised beef cattle, organic and natural production systems do not impact antibiotic susceptibility of Escherichia coli O157:H7. This discovery emphasizes that although popular for their suggested health benefit, little is actually known about the effects of organic and natural beef production on food-borne pathogens. The researchers from Kansas State University detail their findings in the August 2009 issue of the journal Applied and Environmental Microbiology. Increased outbreaks of foodborne illness, as well as the growing awareness and popularity of organic and natural foods, have forced many cattle farmers to adopt new production methods to meet consumer demand for safe and healthy beef. Organic food sources receive only certified organic feed, are raised without the use of antibiotics, hormones, and other veterinary products, and are regulated by the U.S. Department of Agriculture. Natural production guidelines completely restrict the use of antibiotics and hormones, but do allow nonorganic food sources and are only regulated by the brand name owner.

Cattle are major reservoirs of E. coli O157:H7 and their feces are the main source of food and water contamination that lead to foodborne illness in humans. In the study fecal samples were collected from organically and naturally raised cattle and tested for the presence of E. coli O157:H7. Results showed prevalence rates of 14.8 % in organically raised and 14.2 % in naturally raised cattle. These E. coli O157:H7 levels were comparable to those previously identified in conventionally raised cattle. Additionally, the minimum inhibitory concentration of a variety of antibiotics for E. coli O157:H7 isolates were analyzed to determine the effects of all three production systems and no significant difference in antibiotic susceptibility was noted. “The prevalences of E. coli O157:H7 that we observed in organically and naturally raised beef cattle were similar to the previously reported prevalence in conventionally raised cattle,” say the researchers. “No major difference in antibiotic susceptibility patterns among the isolates were observed.”

Science Daily
September 8, 2009

Original web page at Science Daily

Last winter, government agencies killed one third of Yellowstone National Park’s bison herd due to concerns about the possible spread of a livestock disease to cattle that graze in areas around the park. Such drastic measures may be unnecessary, however, according to researchers who have assessed the risk of disease transmission from Yellowstone bison to cattle. There are more cost-effective management solutions than the current approach, which has been highly controversial,” said Marm Kilpatrick, assistant professor of ecology and evolutionary biology at the University of California, Santa Cruz, and lead author of the new study. The alternatives suggested by the study, such as buying grazing rights from cattle ranchers in a few areas around the park or testing all cattle within a special zone around the park, are not new ideas. But Kilpatrick said his group’s quantitative risk assessment highlights the substantial benefits of these strategies, as well as their consequences. He worked with Colin Gillin of the Oregon Department of Fish and Wildlife in Corvallis and Peter Daszak of the Consortium for Conservation Medicine in New York on the study, which is scheduled for publication in the February issue of the British Ecological Society’s Journal of Applied Ecology and will be published online January 12.

The researchers developed a quantitative risk assessment model for the transmission of brucellosis from bison to cattle in the Yellowstone area. Brucellosis is a bacterial disease that causes weight loss, abortion, and reduced milk production in cattle. It is considered a major threat to the cattle industry, which has achieved “brucellosis-free” status in most states after an intensive effort by the U.S. Department of Agriculture. The Yellowstone bison herd probably became infected from cattle that grazed in the park a century ago, Kilpatrick said. Now, cattle ranchers want to keep the bison confined to the park. During severe winters, however, when heavy snow or ice covers grasslands within Yellowstone, many bison move outside the park’s boundaries to graze at lower elevations. To keep them away from areas where cattle graze, state and federal agencies try to herd the bison back into the park by “hazing” them with helicopters, horses, and snowmobiles. When that fails, the bison may be shot or rounded up, tested, and shipped to slaughterhouses. Kilpatrick and his co-authors sought to quantify the risk of brucellosis transmission to cattle under a range of different scenarios. Their study showed that the risk is very low in most years and is periodically high only in certain localized areas.

“There are just a few areas where cattle graze around the park. Compensating ranchers for the grazing rights for those areas would be much more cost-effective than the current management plan,” Kilpatrick said. Efforts to acquire key habitat outside the park for the bison are being pursued, but the process has been lengthy and challenging, he said. Another proposal has been to consider the greater Yellowstone area of Montana as a separate zone from the rest of the state in terms of brucellosis infection status and to provide yearly testing of all cattle within that zone. The cost would be just a fraction of the amount spent by government agencies on the current management strategy, which was estimated in 2000 to be about $2.5 million per year, Kilpatrick said. Similarly, compensating ranchers for the value of all the cattle that graze on public and private lands around the park (assuming they would sell their rights), would cost about half the current yearly amount. “To me, the most interesting result of the study was that in a number of years, the model predicts there will be no risk of transmission at all,” Kilpatrick said. “Even with the bison population at 7,000–the largest population size in our simulations–there was zero risk 10 to 15 percent of the time, because even when some bison leave the park, they don’t always give birth and leave infected birthing materials.”

To transmit brucellosis to cattle, an infected bison would have to enter an area where cattle graze and abort or give birth, leaving infected tissue on the ground, and cattle would then have to contact the infected material while the bacteria in it were still alive. Kilpatrick noted that so far there have been no documented cases of brucellosis transmission from unconfined bison to cattle, although transmission from elk to cattle has occurred several times around feed grounds. Blood tests show that about half the Yellowstone bison herd has antibodies indicating exposure to the brucellosis bacteria, but it’s much harder to determine if an animal is actually infected, he said. Vaccination efforts are currently under way to reduce the prevalence of brucellosis in the bison herd. Eliminating the disease entirely would be very difficult without rounding up all the bison and vaccinating every animal for several years in a row, Kilpatrick said.

Even in the absence of brucellosis, however, management challenges would remain, he said. Without periodic culling, the Yellowstone bison population will continue to grow and could reach 7,000 by 2012. As the population grows, more bison will tend to leave the park, and the massive animals are not particularly respectful of fences and property lines. “Bison used to roam the plains in the millions, and they will try to do so again as their population grows,” said co-author Peter Daszak. “Ultimately, our society will have to decide whether to let bison roam freely or continue shooting them. It’s a tough challenge, but hopefully our analysis provides a way forward for alternative approaches.” There are other bison herds on public and private lands in the United States, but the Yellowstone herd is the only one that has remained free-ranging and unconfined. A record number of Yellowstone bison–about 1,600–were killed last winter. With the herd now reduced to about 3,000 animals, a repeat of that is unlikely this year, Kilpatrick said. But the controversy over how to manage the herd is bound to continue.

Science Daily
January 27, 2008

Original web page at Science Daily

A wireless measuring system, consisting of sensors and transmission units, helps to keep livestock healthier with a minimum use of resources. Gone are the good old days when farmers knew all their cows by name. There is little time left for the animals in today’s dairy industry. And it is easy to overlook the first signs of disease. This situation can now be remedied by a tiny sensor in the cow’s rumen, which monitors the animal’s state of health and raises the alarm in good time. The system determines the pH level and the temperature inside the cow’s rumen. The data are wirelessly transmitted to an external receiver module in the animal’s collar via an encapsulated measuring probe. A network of sensors forwards the signals to a central database. The farmer immediately receives a warning if the readings are above or below a reference value. At present, the pH level in the rumen can only be measured via pharyngeal probes.

Scientists from the Fraunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg have developed the new system, which they can also adapt to numerous other applications in agriculture and forestry. The network nodes contain all of the components needed for connecting sensors and actuators. Radio modules of this kind have a long service life due to their low energy consumption. They are capable of autonomous networking, and do not require supervision or a special infrastructure. The system is a joint development by partners in Germany and the Netherlands. The cross-border project is co-financed by the EU program INTERREG IIIA in the Rhine-Waal region, the Ministry of Economic Affairs and Energy of the State of North Rhine-Westphalia, and the Gelderland province. The new measuring system is slated to go into service as of mid-2008, and will be tested on pilot farms run by the Lower Rhine Chamber of Agriculture and in other research establishments.

Science Daily
September 30, 2008

Original web page at Science Daily

Researchers have demonstrated that protein levels in urine samples can indicate both the presence and progress of Bovine Spongiform Encephalopathy (BSE) disease in cattle. Publishing their findings in BioMed Central’s open access journal Proteome Science, the scientists hope that their discovery might lead to the development of a urine-based test that could prevent the precautionary slaughter of many animals as now occurs when the disease is detected. The discovery of a new human variant of Creutzfeldt-Jakob Disease (vCJD), thought to be transmitted to humans via BSE-infected products, has resulted in many countries instituting extensive BSE testing programs for older animals. Diagnostic testing currently involves the detection of a misfolded “infectious” protein, or prion, in post-mortem brain tissue. BSE has caused significant changes in the way beef products are produced and traded. If a simple and accurate urine test can be developed from this new knowledge, it could be performed on live animals and therefore may provide an alternative to current BSE surveillance procedures. It could also allow for the assessment of the health of breeding stock where post-mortem testing is not an option.
“We are hopeful that the knowledge that we’ve gained from this study will eventually lead to a live test,” says Dr. David Knox, a researcher at the Public Health Agency of Canada’s National Microbiology Laboratory in Winnipeg. “It may be possible to develop similar tests for other species as well, including humans with Creutzfeldt Jakob disease (CJD). A urine test for CJD could assist doctors to narrow down potential diagnoses for people with dementia”. Knox led a team of researchers who have demonstrated that the “protein profile” of cattle urine samples can indicate the presence of a BSE infection as well as how far the disease has advanced. The scientists analysed the proteins in urine samples taken from four infected and four healthy cows of the same age over the course of the disease. The proteins from the healthy and infected samples were compared using a technique called two-dimensional differential-gel electrophoresis (2-D DIGETM). In these preliminary results a single protein was able to distinguish between those infected and control animals. In addition, the relative abundance of a set of proteins could accurately determine how far the disease had advanced. “Our work shows that it is possible to identify biomarkers in urine that could be useful in the diagnosis and monitoring of disease progression in BSE and related transmissible spongiform encephalopathies,” says Knox.

EurekAlert! Medicine
September16, 2008

Original web page at EurekAlert! Medicine

A new study by Newcastle University proves that organic farmers who let their cows graze as nature intended are producing better quality milk. The Nafferton Ecological Farming Group study found that grazing cows on organic farms in the UK produce milk which contains significantly higher beneficial fatty acids, antioxidants and vitamins than their conventional ‘high input’ counterparts. During the summer months, one of the beneficial fats in particular – conjugated linoleic acid, or CLA9 – was found to be 60% higher. The results of this study into UK dairy production are published online in the Journal of Science of Food and Agriculture. ‘We have known for some time that what cows are fed has a big influence on milk quality,’ explained Gillian Butler, livestock project manager for the Nafferton Ecological Farming Group at Newcastle University, who led the study. ‘What is different about this research is it clearly shows that on organic farms, letting cows graze naturally, using forage-based diet, is the most important reason for the differences in the composition between organic and conventional milk.

‘We’ve shown that significant seasonal differences exist, with nutritionally desirable fatty acids and antioxidants being highest during the summer, when the cows are eating fresh grass and clover. ‘As a result, our future research is focusing on how to improve the nutritional composition of milk during the winter, when cows are kept indoors and fed mainly on conserved forage.’ The study, which involved Newcastle scientists working with the Danish Institute for Agricultural Science, is part of the ongoing cross-European Quality Low Input Food project into animal health and welfare, milk quality and working towards minimising the use of antibiotics in dairy production .‘This paper is a major milestone in the project and clearly shows that if you manage livestock naturally then it’s a win-win situation for both us and them,’ said Professor Carlo Leifert, project co-ordinator. The scientists also discovered interesting results from a group of low-input farms in Wales, which are not certified organic but use very similar production methods to organic farms (the main difference was the use of some mineral fertiliser and shorter withdrawal periods after antibiotic use).

To reduce costs, these farmers calved all their cows in spring and grazed them throughout lactation, from March until November, resulting in milk being produced on an almost 100% fresh grass diet. Milk from these non-organic farms also had significantly higher levels of nutritionally desirable fatty acids and antioxidants, which was a direct result of the extensive outdoor rearing and fresh forage intake. ‘These New-Zealand type dairy systems are not common in the UK, as weather conditions in many areas of the country make it unworkable,’ explained Mrs Butler. ‘Therefore, milk from these farms is not available to the public as it’s mixed in with milk from conventional systems during processing. ‘However, including these extremely extensive systems allowed us to clearly link the difference in milk quality to the dairy cows’ diets.’ Gordon Tweddle, of Acorn Dairy in County Durham, is a local supplier of organic milk. ‘We have believed for some time that organic milk is better for us and our customers tell us it tastes better,’ he said. ‘It is satisfying to have the scientific explanation as to why it is also nutritionally better.’

This current research confirms previous studies in the UK, which reported higher concentrations of omega 3 fatty acids in milk from organic production systems than conventional ones. CLA, omega-3 fatty acids, vitamin E and carotenoids have all been linked to a reduced risk of cardiovascular disease and cancer. CLA is hugely popular in the US, where it is marketed as a nutritional supplement. However, synthetic supplements often contain compounds with a different chemical composition (isomer balance) than those occurring naturally in milk, resulting in an equal dose of both ‘good’ (i.e. CLA9, omega-3 fatty acid, vitamin E and carotenoids) and ‘less desirable’ fatty acids (i.e. omega-6 fatty acids and CLA10). ‘Switching to organic milk provides an alternative, natural way to increase our intake of nutritionally desirable fatty acids, vitamins and antioxidants without increasing our intake of less desirable fatty acids and synthetic forms of vitamin E,’ said Mrs Butler. ‘In organic milk, the omega-3 levels increase but the omega-6 does not, which helps to improve the crucial ratio between the two.’

The study involved 25 farms across the UK in two contrasting areas of the UK – South Wales and the North East. The scientists looked at three different farming systems: conventional high input, organically certified, and non-organic sustainable (low-input). The Nafferton Ecological Farming Group at Newcastle University collected 109 milk samples from 25 commercial farms categorised into the three different production systems: conventional high input; organically certified low input; and non-organic, low input. These samples were taken in August and October in 2004 and January, March and May the following year. The group investigated the effects of seasonal and indoor/outdoor feeding differences on the milk’s fatty acid profile, and also compared individual carotenoids, stereo-isomers of alpha-tocopherol (vitamin E) or isomers of CLA. The higher levels of nutritionally desirable fatty acids found in the organic milk were CLA9, omega-3 and linolenic acid and the antioxidants/vitamins were vitamin E and carotenoids. The lower levels of undesirable fatty acids were omega-6 and CLA10.

Science Daily
June 10, 2008

Original web page at Science Daily

Prions that cause disorders such as mad cow disease are notoriously difficult to detect in people or animals before symptoms arise. Now researchers are attempting to develop sensors that can detect prions by having them bind to a tiny ‘tuning fork’ that changes its tune when prions are present. Prions are abnormally structured proteins that are able to convert normal proteins into the abnormal form. They are infectious and cause a number of neurodegenerative diseases. Historically, the only way to accurately detect the presence of prions in people has been to take a blood sample, inject it into a test animal, wait several months and then kill the animal and sample its brain tissue. Aside from being slow, expensive and somewhat grisly, this method is not particularly effective, with a correct diagnosis only 31% of the time. There are concerns that some portion of the population might be harbouring infectious prions, with outbreaks of disease yet to come. A better method of prion detection is important for allaying peoples’ fears, as well as for screening blood banks to ensure they are clear of these abnormal proteins.

Within the past few years, researchers have discovered how to increase prion numbers from the blood of infected hamsters, so that they are easier to detect, and have found a resin that binds hamster prion proteins, allowing them to be physically removed from the blood. But it’s unclear whether this would work with human prions. Even if it did, a test based on boosting prion numbers would still take days to perform. Now a team of biomedical engineers led by Harold Craighead at Cornell University in New York report on a different strategy for detecting prion prescence: nanoscopic resonators1. These small devices function like tuning forks — their resonance frequency changes as mass is added to them. Such devices are already used to detect the presence of bacterial pathogens, but prions are a bigger challenge as they are smaller, lighter and present in low concentrations in the blood. The team made nanoscale resonators coated with commercially available antibodies that adhere to cow prions. They then exposed these resonators to prions in a saline solution. The prions stuck to the antibodies, but because they are so small, they barely changed the frequency of the resonator.

To amplify the effect, the Cornell team exposed the resonator to a second solution containing different antibodies that adhered to the prions already bound to the resonator. Exposure to a third solution, this time of metal-oxide particles, attached these bulky particles to the second set of antibodies. The heavier load of prions-plus-metal resulted in a much larger change in frequency in the resonator — enough to be noticeable. Unlike other tests in development, once this technique is perfected it should provide an instantaneous result. The next step is to get these tests to work in blood rather than a saline solution. Blood contains a host of proteins and other chemicals, and making antibodies that selectively bind only the infectious prions will be tricky, but shouldn’t be impossible: other companies are working on this now. “The real challenge is going to be to build an automated device that can take blood from a cow in the field and give a rapid response as to whether prions are present,” says Craighead. “At the moment we only test cows when they fall over, but that is a late stage of the disease. It would be ideal to test cows a lot earlier. Resonators could be one path to doing this.”

“Since we can only detect prions reliably in the brains of dead people, having one more option available is definitely a good thing,” says neurologist Claudio Soto at the University of Texas Medical Branch in Galveston. “But the researchers need to improve sensitivity dramatically for this to work,” he says. Nano-engineer Thomas Thundat at Oak Ridge National Laboratory, Tennessee, who was not involved with the work, says that shouldn’t be a problem: “Getting more sensitive readings depends on increasing the resonance frequency of these devices, which is a straightforward engineering task that we are more than ready to do.” “The results are very exciting,” he adds. “With this technology at hand we are now about two years away from having a prion detection solution.”

Nature
April 15, 2008

Original web page at Nature

Despite millions of dollars spent on food safety research over the last 10 years, ground beef recalls due to E. coli O157:H7 were higher in 2007 than in 2006, according to researchers from Kansas State University and West Texas A&M University. E. coli O157:H7 has been linked to foodborne illnesses in humans after consuming contaminated beef and produce. “We have been studying the effects of a novel vaccine technology to make beef safer,” said Dr. Dan Thomson, an associate professor at Kansas State University. Thomson worked with Dr. Guy Loneragan, West Texas A&M University, and Dr. T.G. Nagaraja, of K-State, to examine the effects of this vaccine on its ability to decrease E. coli shedding in beef cattle. “We had a decrease in cattle shedding E. coli by 54 percent in our first field study,” Thomson said. “However, we increased the amount of SRP exposure in the second field study and decreased the rate of cattle shedding E. coli by 85 percent.”

Loneragan said, “This tells us that efficacious interventions that predictably reduce the burden of E. coli O157 on cattle entering packing plants are needed. Successful interventions will reduce the burden of E. coli O157 to a level that is within the capacity of in-plant interventions to handle. If this can be achieved, then tremendous progress toward preventing E. coli O157 from ever getting into ground beef has been made. This vaccine appears to fit this purpose and has great promise.” Thomson and his colleagues studied Siderophore receptor and porin — SRP — technology, which was developed by Epitopix, LLC in Willmar, Minn. “Siderophore receptor and porin proteins are utilized by food borne pathogens like E. coli to acquire iron,” Thomson said. “The SRP vaccine technology immunizes animals against these mechanisms and does not allow the bacteria to take up iron. Iron is to bacteria, as oxygen is to humans. Without iron consumption, the bacteria suffocate and can’t grow or replicate.” “We conducted a challenge study, a natural infection study and two large pen field studies at commercial feedyards,” Thomson said. “All studies showed positive results of this vaccine, making an impact on decreasing not only the number of the cattle shedding the bacteria but also decreasing the concentration of the bacteria being shed.” Super shedder cattle are cattle that shed E. coli in very high concentrations. “Our natural field study showed that the SRP technology vaccine reduces the number of super shedder cattle,” Thomson said.

Science Daily
March 17, 2008

Original web page at Science Daily

Many of the world’s indigenous livestock breeds are in danger of dying out as commercial breeds take over, according to a worldwide inventory of animal diversity. Their extinction would mean the loss of genetic resources that help animals overcome disease and drought, particularly in the developing world, say livestock experts. “Valuable breeds are disappearing at an alarming rate,” says Carlos Seré, director general of the International Livestock Research Institute in Nairobi, Kenya, one of the organizations involved in the survey. The entire inventory, compiled by the United Nations’ Food and Agriculture Organization, contains details of some 7,600 breeds of cattle, pigs, sheep, poultry and other animals in 169 countries. The survey reports that 11% of the investigated breeds are now extinct (some having disappeared many decades ago), 16% are currently at risk, 38% are unthreatened, and the security of the remaining 35% is unknown.

Discussing the findings at a meeting of policy-makers, breeders and livestock scientists in Interlaken, Switzerland, Seré called for the establishment of ‘gene banks’ containing frozen sperm and eggs from endangered breeds, similar to the facilities currently being set up to preserve the world’s crop strains. Local breeds, nearly 70% of which are found in the developing world, are often better suited to their environments than commercially marketed animals bred for their high yields and short-term profitability, Seré argues. Red Maasai sheep, for example, are naturally resistant to intestinal parasites, and Uganda’s indigenous Ankole cattle are particularly drought-hardy. Until recently, natural selection allowed animals to adapt, but now a lot of this is falling through the cracks.

But the dominance of big breeding companies, mostly based in industrialized countries, means that these populations are being supplanted by the most common commercial breeds. Holstein-Friesian cattle, the stereotypical black-and-white dairy cow, are now found in more than 120 countries throughout the world. The spread of such animals means that many farmers are now working with livestock that are poorly adapted to their environment, Seré says. “Until recently, natural selection allowed animals to adapt, but now a lot of this is falling through the cracks,” he says. The pursuit of high-yielding animals means that genetic diversity is in crisis even in the established commercial breeds, says Shirley Ellis of the Institute for Animal Health in Compton, UK. She estimates that the roughly one billion Holstein-Friesians in the world were sired by the same few dozen bulls in North America. The advent of cloning for the most prized males will make the inbreeding problem worse still, she says. Exporting strains such as Holstein-Friesians to the developing world is short-sighted, experts point out. “They don’t cope very well with local climate and diseases,” Ellis says.

Gene banks to preserve local diversity should be set up in the areas where this genetic diversity is found, argues Seré. He wants to see an international effort to raise perhaps US$2 million to begin the process of establishing either national or regional centres for storing genetic material. “Many rich countries are already setting up genetic stores, but we don’t have it in the south where it’s needed,” he says. The main threat facing local livestock is the pre-eminence of short-termism in livestock breeding, and the fact that it is controlled by large Western companies, Seré says. But the political volatility of much of the developed world also plays a part, he argues. In the wake of human conflicts such as the Darfur crisis, in which livestock were slaughtered by marauding militias, aid agencies can only replace these animals with Western breeds, Seré points out. But such animals are less valuable to local farmers in the long run. Preserving the genetic heritage of indigenous breeds could also save breeders the trouble of trying to promote traits, such as drought-tolerance, from scratch. “Breeding is sophisticated, but it’s cheaper to spot a breed that can do the job already,” Seré says. “Nature may have already produced what you need.”

Nature
September 17, 2007

Original web page at Nature