Tag: Nutrition

Dairy cows that are fed flaxseed produce more nutritious milk, according to a new study by Oregon State University. Their milk contained more omega-3 fatty acids and less saturated fat, the study found. Diets high in saturated fat can increase cholesterol and cause heart disease, while those rich in omega-3 and other polyunsaturated fatty acids may reduce the risk of heart disease, studies have shown. Traditional cattle feed mixtures of corn, grains, alfalfa hay and grass silage result in dairy products with low concentrations of omega-3 and other polyunsaturated fats, according to Gerd Bobe, the lead scientist on the study, which has been published online in the Journal of Dairy Science. Ten pregnant cows at OSU’s dairy were fed different amounts of flaxseed — up to seven percent of their daily diet. Researchers attempted to pinpoint the amount of flaxseed that would maximize the amount of omega-3 in milk and dairy products without negatively affecting their production and texture. “We were looking for a sweet spot,” said Bobe, an expert in human and animal nutrition. “Too much of a good thing can be bad, especially when trying to maintain consistency with dairy products.”

Collaborators in OSU’s food science and technology department assisted in turning milk into butter and fresh cheese, which were then tested for texture and nutritional composition. The study found that feeding cows up to six pounds of extruded flaxseed improved the fat profile without negatively affecting the production and texture of the milk and other dairy products. Extrusion presses raw ground flaxseed into pellets with heat. At six pounds per day, saturated fatty acids in whole milk fat dropped 18 percent, poly-unsaturated fatty acids increased 82 percent, and omega-3 levels rose 70 percent compared to feeding no flaxseed. Similar improvements were observed in butter and cheese. Still, saturated fat accounted for more than half of the fatty acids in the dairy products while the increase in polyunsaturated fats compromised no more than nearly nine percent of the total. Researchers also noted that the refrigerated butter was softer and less adhesive thanks to fewer saturated fatty acids. Also, the cows produced the same amount of milk while eating flaxseed. Although flaxseed costs more than traditional cattle feeds, Bobe hopes that it still could be an affordable feed supplement for cows because products enriched with omega-3 can sell for a premium at the grocery store. “Many consumers already show a willingness to pay extra for value-added foods, like omega-3 enriched milk,” he said. One thing is for sure, he said: Dairy farmers will have no trouble convincing cows to eat flaxseed. “They loved it. They ate it like candy,” he said.

Science Daily
February 19, 2013

Original web page at Science Daily

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

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

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

Science Daily
September 20, 2011

Original web page at Science Daily

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

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

PhysOrg.com
June 28, 2011

Original web page at PhysOrg.com

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

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

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

Science Daily
June 28, 2011

Original web page at Science Daily

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

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

Science Daily
August 3, 2010

Original web page at Science Daily

A new study identifies cattle feed as a possible culprit in the long-standing mystery of why California’s San Joaquin Valley — a moderately-populated agricultural region — has higher levels of ozone (one of the main ingredients in smog) than many densely-populated cities. The report, which explains how fermented cattle feed works with automotive exhausts in forming ozone, is in ACS’ Environmental Science & Technology. Michael Kleeman and colleagues note that high ozone levels in the San Joaquin Valley, which produces 10 percent of America’s food, have puzzled scientists for years. Motor vehicles are the major source of smog elsewhere, but the Valley has fewer motor vehicles compared to big urban areas with similar levels of ozone. Suspicion thus fell on farming activities, and the new study investigated the role of fermented livestock feed. The paper documents emissions of reactive organic gases, which react with combustion emissions and sunlight to form smog, from seven different animal feeds. It shows how fermented feed like silage appears to be the largest man-made source of these organic gases that contribute to ozone formation in the Valley even more than automobiles. The until-now-unrecognized animal-feed factor may account for the failure of traditional vehicle smog control regulations in the Valley, they note.

Science Daily
May 11, 2010

Original web page at Science Daily

Beef farmers can breathe easier thanks to University of Alberta researchers who have developed a formula to reduce methane gas in cattle. By developing equations that balance starch, sugar, cellulose, ash, fat and other elements of feed, a Canada-wide team of scientists has given beef producers the tools to lessen the methane gas their cattle produce by as much as 25 per cent. “That’s good news for the environment,” said Stephen Moore, a professor of agricultural, food and nutritional science at the University of Alberta in Canada. “Methane is a greenhouse gas, and in Canada, cattle account for 72 per cent of the total emissions. By identifying factors such as diet or genetics that can reduce emissions, we hope to give beef farmers a way to lessen the environmental footprint of their cattle production and methane reductions in the order of 25 per cent are certainly achievable.” Using information from previous studies, the researchers compiled an extensive database of methane production values measured on cattle and were able to formulate equations to predict how much methane a cow would produce based on diet.

Science Daily
May 19, 2009

Original web page at Science Daily

Genomics, are developing a grass that will not only cut the amount of methane cows burp up when chewing the cud but also grow in hotter climes. This means that farmers should be able to maintain dairy herds’ productivity and profitability in the face of a changing climate, while cutting down their gaseous burps and reducing their contribution to global warming. Combating greenhouse gas emissions produced by the agricultural industry is a priority. The UK’s DEFRA has just announced a roadmap aimed at helping the dairy industry reduce its potential impact on the environment in line with Britain’s target to cut its greenhouse emissions by 20% by 2010. By 2015 the roadmap plans to have 20-30% of milk producers trialling new technology to cut greenhouse gas emissions. The Inter-governmental Panel on Climate Change (IPCC) calculates that methane makes up 14.3% of humanity’s contribution to global warming and data from the National Oceanographic and Atmospheric Administration (NOAA) in the US shows that atmospheric methane levels may be rising again after a 10 year period of stability. A single dairy cow can produce between 550-700L of methane a day and it has been estimated that methane from cattle in the UK could account for as much as 3% of the country’s total greenhouse gas emissions.

Cows’ production of methane is down to the microflora in their gut that helps them to digest their food. As these microbes break down the grass’ cellulose, methane is produced as a by-product, the majority of which is burped up. David Beever, international nutrition director of Richard Keenan UK, said: ‘You don’t actually hear the cows burp, but they are permanently releasing methane.’ Gramina will use sense suppression technology to prevent the expression of the enzyme O-methyl transferase. Suppressing this enzyme leads to an increase in the digestibility of the grass without compromising its structural properties and therefore less burps and less methane. Gramina has already tested this modification in temperate grasses in the lab and glasshouses and is now planning field trials.

Science Daily
May 27, 2008

Original web page at Science Daily