Tag: Bovine

Intensive farming practices such as larger herd size, maize growth, fewer hedgerows and the use of silage have been linked to higher risk of bovine TB, new research has concluded.

A study by the University of Exeter, funded by BBSRC and published in the Royal Society journal Biological Letters, analysed data from 503 farms which have suffered a TB breakdown alongside 808 control farms in areas of high TB risk.

Dr Fiona Mathews, Associate Professor in Mammalian Biology, who led the study, said: “TB is absolutely devastating for farming, and it’s essential that workable solutions are found. In the worst hit areas, farms are frequently affected over and over again with crippling consequences. If lower intensity production means better animal health, it offers a sustainable long-term strategy in high risk areas.”

The last few decades have seen radical changes in farming practices. Half of British dairy farmers have gone out of business since 2002. Those that remain have larger herds and greater productivity: average herd size increased from 75 animals in 1996 to 133 in 2014 (a rise of 77%), and the annual yield increased from 5,775 per cow in 1995 to 7,535l per cow in 2013 (a rise of 27%).

The team found that farms with herds of 150 cattle or more were 50% more likely to suffer a bovine TB outbreak than those with herds of 50 or fewer. Patterns of crop production and feeding were also important, with the risks increasing with practices linked with higher productivity systems. For every 10 hectares of maize — a favourite food of the badgers that play a role in transmitting the disease — bTB risk increased by 20%. The feeding of silage was linked with a doubling of the risk in both dairy and beef systems. Landscape features such as deciduous woodland, marshes and hedgerows were also important. For example, on farms with 50km of field boundaries, each extra 1km of hedgerow was linked with a 37% reduction in risk. This is likely to be because there is less contamination of pasture by badger faeces and urine in hedgerow-rich areas. Marshland was associated with increased risk, possibly as a secondary effect of infection with liver fluke — a disease linked with wet environments and which interferes with the diagnosis of bTB in cattle.

Dr Mathews said: “To beat TB, we need to ensure our approach is robust and evidence-based. This is the first large-scale study to link a range of landscape-scale habitat features and farming practices with bTB. All of the effects we have found are additive, so changing several linked aspects of the farming system could potentially make a big difference. Farmers are already aware that biosecurity in the farmyard can help reduce the risk of bTB in cattle. We have now shown that wider environmental management is also important. By finding out more about these links, we hope that we can help eradicate this terrible disease.”

The paper, ‘Environmental Risk Factors Association with Bovine Tuberculosis in Cattle high Risk Areas’, is published online in the journal Biological Letters today.

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

http://www.sciencedaily.com/releases/2015/11/151111055318.htm  Original web page at Science Daily

Scientists at the University of Veterinary Medicine Vienna investigated whether stomach ulcers in cattle are related to the presence of certain bacteria. For their study, they analysed bacteria present in healthy and ulcerated cattle stomachs and found very few differences in microbial diversity. Bacteria therefore appear to play a minor role in the development of ulcers. The microbial diversity present in the stomachs of cattle has now for the first time been published in the journal Veterinary Microbiology.

Gastritis and stomach ulcers in humans are often caused by the bacterium Helicobacter pylori. But other factors, such as stress and nutrition, also play a role in stomach health. In cattle the weather and husbandry in general play an additional role. The etiological role of bacteria in abomasal ulcers was investigated by veterinarian Alexandra Hund of the Clinical Unit of Ruminant Medicine together with microbiologist Stephan Schmitz-Esser of the Institute for Milk Hygiene. “The abomasum is the last of the four stomach compartments in cattle. The three other compartments, the rumen, the reticulum and the omasum, serve to predigest the food. The abomasum is the actual stomach and is similar in anatomy and function to the human stomach. Painful gastritis and ulcers can occur in the abomasa of cattle, potentially weakening the animals, leading to perforations of the stomach and possibly even to cases of death,” first author Alexandra Hund explains.

Microbiologist Schmitz-Esser analysed stomach samples from slaughter cattle. Around half of the samples were taken from healthy cattle, the other half from cattle with low-grade abomasal ulcers. “Very sick animals are barred from slaughter,” says Alexandra Hund. The researchers isolated and sequenced the bacterial DNA from the stomach samples. The DNA sequences were then used to determine the type of bacteria present. “The most common were species of Helicobacter, Acetobacter, Lactobacillus and new strains of Mycoplasma. The bacterium Helicobacter pylori, commonly found in humans, was not present at all. We nearly saw the same bacterial composition in healthy and ulcerated animals, which suggests that bacteria only play a minor role in the etiology of abomasal ulcers,” says Schmitz-Esser. “However, this is something we would like to underpin in future studies.”

Calf stomachs contain a relatively immature microbial biomass. This means that bacterial diversity must still develop. The primary bacteria found in calf stomachs were beneficial lactic acid bacteria. These bacteria enter the stomachs of calves through the milk that forms their main source of nutrition. “Due to the very subtle symptoms of abomasal ulcers, they are very difficult to diagnose for non-experts. The abomasum is the last of the four stomach compartments and therefore not accessible to gastroscopy. We are currently working on a method for the early and rapid diagnosis of those ulcers. In any case, keeping cattle stress-free is one way of preventing stomach ulcers,” Alexandra Hund recommends.

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

http://www.sciencedaily.com/releases/2015/04/150417085224.htm  Original web page at Science Daily

The latest honor to come Lubbock’s way may not sound good at first, but when realizing it’s a breakthrough in biological sciences, it will become something to brag about. Marie Bugarel, a research assistant professor at Texas Tech University’s Department of Animal and Food Sciences in the College of Agricultural Sciences and Natural Resources, has discovered a new serotype of the salmonella bacteria. The new serotype was confirmed by the Pasteur Institute in Paris, the international reference center for salmonella. Because convention calls for a new serotype to be named after the city in which it is discovered, this one will be called Salmonella Lubbock (officially Salmonella enterica subsp. enterica Lubbock). “More important than the name, however, is that this discovery illustrates there is more that needs to be discovered about salmonella and how it interacts with cattle populations,” said Guy Loneragan, a professor of food safety and public health who, along with Kendra Nightingale, are Bugarel’s mentors at Texas Tech. “With this understanding will come awareness of how to intervene to break the ecological cycle and reduce salmonella in animals and in beef, pork and chicken products.” Bugarel, who came to Texas Tech with an extensive background in salmonella research, has worked on developing new tools to detect salmonella, new approaches to distinguish serotypes and ways to understand salmonella’s biology. Her work has led to a patent application that has been licensed to a high-tech biosciences research company. Her invention means it is now possible to simultaneously detect and distinguish specific strains of salmonella by targeting a specific combination of DNA. That will allow for early detection in food while also identifying whether or belongs to a highly pathogenic strain.

In her research for Salmonella Lubbock, the impetus was to reduce salmonella in food and improve public health. She focused on providing solutions to control salmonella in cattle population, which led to a better understanding of the biological makeup of salmonella itself, including its genetic makeup. Through this approach, Bugarel discovered the new strain never before described. The long-held standard way of distinguishing one strain of salmonella from another is called serotyping and is based on the molecules on the surface of the bacterium. Each serotype has its own pattern of molecules, called antigens, and the collection of molecules provides a unique molecular appearance. These antigens interact with certain antibodies found in specifically prepared serum, thus providing the serotype. It is similar to how blood typing is performed. “This discovery reinforces my feeling that the microbiological flora present in cattle in the United States harbors a singularity, which is an additional justification of the research we are doing in the International Center for Food Industry Excellence (ICFIE) laboratories at Texas Tech,” Bugarel said. “Additional research will be performed to better describe the characteristics of this atypical bacterial flora and, more specifically, of the Lubbock serotype.”

With this discovery, Loneragan believes between 20 and 30 percent of two current strains, Salmonella Montevideo and Salmonella Mbandaka, will be reclassified as Salmonella Lubbock. The algorithm used in serotyping has some stopping points, but Bugarel discovered a need to go a step further to get the correct strain name. Therefore some of those strains called Montevideo and Mbandaka are now Salmonella Lubbock. Some of the strains of Salmonella Lubbock fall into the category of serotype patterns that are more broadly resistant to many families of antibiotics, furthering the need for more research on the subject. Human susceptibility to the Lubbock strains remains unknown. “We will continue to develop methods to detect, identify and control the presence of pathogenic microorganisms in food products in order to improve food safety and public health,” Bugarel said. “Kendra and I have been honored to serve as Marie’s mentors,” Loneragan said. “But now, the growth in Marie’s expertise means that she is becoming the mentor to us. Many students, and the citizens of the United States in general and Texas in particular, are benefitting from her commitment to research excellence at Texas Tech. We are very lucky to have her.”

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

http://www.sciencedaily.com/releases/2015/01/150116143835.htm Original web page at Science Daily

Modelling produced by researchers at Queen Mary University of London (QMUL) has found that the only effective potential Bovine Tuberculosis (TB) control strategies are badger culling, cattle testing, controlling cattle movement, and ceasing the practice of housing farm cattle together during winter. The modelling found that in a region containing about 1.5m cows of which 3000 to 15,000 might have TB, badger culling could account for a reduction of 12 in the number of infected cattle. While reducing the testing interval by one month could reduce the number of those infected by 193. The model showed that regular and frequent testing of cattle could eventually lead to the eradication of the disease, whether or not badgers were culled and despite the current test being at most 80% accurate. Badger culling alone, however did not lead to TB eradication in the study and is therefore unlikely to be a successful control strategy. The model also suggested that housing cattle in large sheds over winter could potentially double the number of infected animals in a herd, as under such conditions there is a much greater chance of TB being passed between cows. This is the first large-scale model of TB in cattle and badgers that included the possibility of the infection being passed in both directions between the two species. The model successfully mimicked the changing patterns of TB in the UK, including the changes seen after TB controls were reduced during the foot-and-mouth epidemic of 2002. Researchers Dr Aristides Moustakas and Professor Matthew Evans, of QMUL’s School of Biological and Chemical Sciences, used state-of-the-art computer modelling to understand how the interaction of different factors impacted on infection rates. Such factors included the movement and life-cycles of badgers and cattle; how cattle are moved and housed; how frequently cattle are tested, different types of badger culling; and the infection rates between animals. The research is published online in Stochastic Environmental Research and Risk Assessment. Professor Matthew Evans, Professor of Ecology at QMUL, said: “Of the available Bovine Tuberculosis control strategies we believe that how frequently cattle are tested and whether or not farms utilise winter housing have the most significant effect on the number of infected cattle.” “TB is a complex disease and modelling it is difficult but we’ve successfully used our model to replicate real world situations and are confident that it can be used to predict the effects of various changes in the way we tackle the disease.” “Our modelling provides compelling evidence, for those charged with controlling Bovine TB, that investment in increasing the frequency of cattle testing is a far more effective strategy than badger culling.”

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

http://www.sciencedaily.com/releases/2015/01/150114072705.htm Original web page at Science Daily

Pseudomonas bacteria in soil benefit from manure fertilizer treatments. Treating dairy cows and other farm animals with antibiotics and then laying their manure in soil can cause the bacteria in the dirt to grow resistant to the drugs. But a study now suggests that the manure itself could be contributing to resistance, even when it comes from cows that are free of antibiotics. The mechanism at work is not yet clear, but the finding — published on 6 October in Proceedings of the National Academy of Sciences — suggests a complex link between antibiotic use in agriculture and resistance in human pathogens. Many bacteria in the environment naturally carry antibiotic-resistance genes, probably as defence against the antibiotics produced by some soil fungi and bacteria. Laboratory-made versions of these antibiotics are used to treat infection in humans and animals, and to promote growth in livestock. Because manure itself is known to change the composition of bacterial communities in soil, a team led by microbiologist Jo Handelsman, then at Yale University in New Haven, Connecticut, decided to examine whether it also affects drug resistance. The team treated soil samples with either a nitrogen-based fertilizer or with manure from cows that had never been fed antibiotics. The researchers examined soil bacteria sampled before and after the treatment, searching for genes that encode enzymes called β-lactamases, which break down a class of antibiotic that includes penicillin. Two weeks after treatment, the soil spread with manure contained significantly higher numbers of bacteria producing β-lactamases than did soil treated with only the nitrogen-based fertilizer. By tracing genetic markers in the resistant bacteria, the researchers found that these bacteria came from the soil rather than from the manure, suggesting that the manure treatment had helped these natural bacteria to grow by feeding them or eliminating their competitors. The manure was particularly beneficial for Pseudomonas species, which are common in human infections. But it is unclear how manure creates a better environment for antibiotic-resistant bacteria. Handelsman — now associate director for science at the White House Office of Science and Technology Policy — and her colleagues suggest that certain nutrients or heavy metals in the manure could be responsible, because bacteria with β-lactamases are also more likely to be resistant to metals. The authors say that they plan to test this in the future.

http://www.nature.com/news/index.html  Nature

http://www.nature.com/news/manure-fertilizer-increases-antibiotic-resistance-1.16081  Original web page at Nature

“Increased to levels unprecedented” is how the Intergovernmental Panel on Climate Change (IPCC) described the rise of carbon dioxide, methane and nitrous oxide emissions in their report on the physical science basis of climate change in 2013. According to the US Environmental Protection Agency (EPA), the atmospheric concentration of methane, a greenhouse gas some 28 times more potent than carbon dioxide has been steadily growing since the 18th century and has now increased by 50 percent compared to pre-industrial levels, exceeding 1,800 parts per billion. The EPA attributes one-fifth of methane emissions to livestock such as cattle, sheep and other ruminants. In fact, ruminant livestock are the single largest source of methane emissions, and in a country like New Zealand (NZ), where the sheep outnumber people 7 to 1, that’s a big deal. However, not all ruminants are equal when it comes to greenhouse gas emissions. It turns out that the amount of methane produced varies substantially across individual animals of the same ruminant species. To find out why this is so, a team of researchers led by the US Department of Energy Joint Genome Institute (DOE JGI) deployed high throughput DNA sequencing and specialized analysis techniques to explore the contents of the rumens of sheep in collaboration with NZ’s AgResearch Limited to see what role ruminant “microbiomes” (the microbes living in the rumen) play in this process. The study was published online June 6, 2014 in Genome Research. “We wanted to understand why some sheep produce a lot and some produce little methane,” said DOE JGI Director Eddy Rubin. “The study shows that it is purely the microbiota responsible for the difference.”

To learn why the amount of methane that ruminants produce varies, the researchers took advantage of a large sheep screening and breeding program in NZ that aims to breed low methane-emitting ruminants without impacting other traits such as reproduction and wool and meat quality. The team measured the methane yields from a cohort of 22 sheep, and from this group, they selected four sheep with the lowest methane emissions, four sheep with the highest emissions and two sheep with intermediate emission levels. Rumen metagenome DNA samples collected on two occasions from the 10 sheep were sequenced at the DOE JGI, generating 50 billion bases of data each. “The deep sequencing study contributes to this breeding program by defining the microbial contribution to the methane trait, which can be used in addition to methane measurements to assist in animal selection,” said senior scientist Graeme Attwood of AgResearch Limited, a senior author on the paper. The team then checked to see if there was a correlation between the proportions of methanogens in the eight sheep with the highest and lowest recorded methane emissions. In sheep with low methane emissions, they found elevated levels of one particular species of methanogen (Methanosphaera) while sheep with high methane emissions had elevated levels of another group of methanogens (Methanobrevibacter gottschalkii). Exploring further, the team then identified a methane-producing pathway and three variants of a gene encoding an important methane-forming reaction that were involved in elevated methane yields. While the overall changes to the methane-producing microbial community structure and methanogen abundance across sheep were rather subtle, the team reported that the expression levels of genes involved in methane production varied more substantially across sheep, suggesting differential gene regulation, perhaps controlled by hydrogen concentration in the rumen or by variations in the dwell time of their feed.

“It’s not so much the actual composition of the microbiome that determines emission — which conventional wisdom would suggest — but mostly transcriptional regulation within the existing microbes that makes the difference, which is a concept that is relatively new in metagenomic studies,” Rubin said. The team’s findings suggest new possible targets for mitigating methane emissions at the microbiome level. Screening and breeding for low-methane producing sheep is still underway, and importantly, low-methane lines then need to be tested for stability of the trait, as well as the absence of any impacts on fertility or meat or wool production. Moreover, as Attwood notes, “there needs to be an incentive for farmers to incorporate low methane animals into their flocks, that is, achieving better performance with the low methane animals or being able to claim carbon credits. If everything went well you could expect introduction of the low methane trait to begin in three years, and for there to be slow but incremental changes to the sheep industry in subsequent years.”

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

July 22, 2014

http://www.sciencedaily.com/releases/2014/06/140617121946.htm  Original web page at Science Daily

Cougars may have survived the mass extinction that took place about 12,000 years ago because they were not particular about what they ate, unlike their more finicky cousins — the saber-tooth cat and American lion. Both perished along with the woolly mammoth and many of the other supersized mammals that walked Earth during the late Pleistocene. That is the conclusion of a new analysis of the microscopic wear marks on the teeth of cougars, saber-tooth cats and American lions described in the April 23 issue of the journal Biology Letters. “Before the Late Pleistocene extinction six species of large cats roamed the plains and forests of North America. Only two — the cougar and jaguar — survived. The goal of our study was to examine the possibility that dietary factors can explain the cougar’s survival,” said Larisa R.G. DeSantis, assistant professor of earth and environmental sciences at VanderbiltUniversity, who co-authored the study with Ryan Haupt at the University of Wyoming. For their investigation, DeSantis and Haupt employed a new technique called dental microwear texture analysis. DMTA uses a confocal microscope to produce a three-dimensional image of the surface of a tooth. The image is then analyzed for microscopic wear patterns. The analysis of the teeth of modern carnivores, including hyenas, cheetahs and lions has established that the meals an animal consumes during the last few weeks of its life leave telltale marks. Chowing down on red meat, for example, produces small parallel scratches while chomping on bones adds larger, deeper pits. The researchers analyzed the teeth of 50 fossil and modern cougars, and compared them with the teeth of saber-tooth cats and American lions excavated from the La Brea Tar Pits in Los Angeles and the teeth of modern African carnivores including cheetahs, lions and hyenas.

Previously, DeSantis and others found that the dental wear patterns of the extinct American lions closely resembled those of modern cheetahs, which are extremely finicky eaters that mostly consume tender meat and rarely gnaw on bones. Saber-tooth cats were instead similar to African lions and chewed on both flesh and bone. Among the La Brea cougars the researchers found significantly greater variation between individuals than they did in the other large cats, including saber-toothed cats. Some of the cougars show wear patterns similar to those of the finicky eaters but on others they found wear patterns closer to those of modern hyenas, which consume almost the entire body of their prey, bones included. “This suggests that the Pleistocene cougars had a ‘more generalized’ dietary behavior,” DeSantis said. “Specifically, they likely killed and often fully consumed their prey, more so than the large cats that went extinct.” This is consistent with the dietary behavior and dental wear patterns of modern cougars, which are opportunistic predators and scavengers of abandoned carrion and fully consume the carcasses of small and medium-sized prey, a “variable dietary behavior that may have actually been a key to their survival.”

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

May 13, 2014

http://www.sciencedaily.com/releases/2014/04/140422202047.htm  Original web page at Science Daily

Manure from dairy cows, which is commonly used as a farm soil fertilizer, contains a surprising number of newly identified antibiotic resistance genes from the cows’ gut bacteria. The findings, reported in mBio® the online open-access journal of the American Society for Microbiology, hints that cow manure is a potential source of new types of antibiotic resistance genes that transfer to bacteria in the soils where food is grown. Thousands of antibiotic resistance (AR) genes have already been identified, but the vast majority of them don’t pose a problem when found in harmless bacteria. The real worry is when these genes appear in the types of pathogenic bacteria that cause food-borne illnesses or hospital infections. “Since there is a connection between AR genes found in environmental bacteria and bacteria in hospitals, we wanted to know what kind of bacteria are released into the environment via this route,” of manure fertilization, says Fabienne Wichmann, lead study author and former postdoctoral researcher at Yale University in New Haven, Connecticut. Farmers use raw or composted cow manure on some vegetable crops, which could lead to a scenario where residual manure bacteria might cling to produce and they or their genes might move to the human ecosystem. “Is this a route for movement of these genes from the barn to the table?” asks Jo Handelsman, senior study author and microbiologist at Yale. The first step toward an answer was surveying which AR genes are present in cow manure. Handelsman’s team used a powerful screening-plus-sequencing approach to identify 80 unique and functional AR genes. The genes made a laboratory strain of Escherichia coli bacteria resistant to one of four types of antibiotics — beta-lactams (like penicillin), aminoglycosides (like kanamycin), tetracycline, or chloramphenicol.

Roughly 75% of the 80 AR genes had sequences that were only distantly related to AR genes already discovered. The team also found an entire new family of AR genes that confer resistance to chloramphenicol antibiotics, which are commonly used to treat respiratory infections in livestock. “The diversity of genes we found is remarkable in itself considering the small set of five manure samples,” says Handelsman, who is also a Howard Hughes Medical Institute Professor. “But also, these are evolutionarily distant from the genes we already have in the genetic databases, which largely represent AR genes we see in the clinic.” That might signal good news that AR genes from cow gut bacteria are not currently causing problems for human patients. But, Wichmann points out, another possibility is that “cow manure harbors an unprecedented reservoir of AR genes” that could be next to move into humans. “This is just the first in a sequence of studies — starting in the barn, moving to the soil and food on the table and then ending up in the clinic — to find out whether these genes have the potential to move in that direction,” says Handelsman. AR genes can enter the human ecosystem by two routes — either the bacteria that contain them colonize humans, or the genes are transferred through a process called horizontal gene transfer to other bacteria that colonize humans. Research has already shown that bacteria are transferred from farm animals to their human caretakers. Gene transfer enables genes to jump between microorganisms that are not related, and it occurs in most environments that host bacteria. Some manure bacteria might be pathogenic to humans, so if they acquire antibiotic resistance, they could pose a problem. Alternatively, benign bacteria in manure might transfer resistance genes to pathogens at any point along the path — in manure, soil, food, or humans. “We’re hoping this study will open up a larger field of surveillance, to start looking at new types of resistance before they show up in the clinic,” says Handelsman.

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

May 13, 2014

http://www.sciencedaily.com/releases/2014/04/140422084928.htm Original web page at Science Daily