subject: dairy production

MicroRNAs May Play a Key Role in Heat Stress Responses in Mammary Glands of Lactating Cows

MicroRNAs May Play a Key Role in Heat Stress Responses in Mammary Glands of Lactating Cows

A concern facing dairy farmers as the long, hot days of summer approach is the threat of heat stress in their cows. Experienced at temperatures above 80°F, heat stress affects growth and development as well as milk composition and volume. Heat stress is a major cause of low fertility in dairy cattle. It also increases susceptibility to metabolic disorders, mammary gland pathogens and mastitis. Compared with other livestock, cattle are unable to dissipate their heat load efficiently. Additional heat generated by the fermentation of food in the rumen compounds this problem. Cows’ sweating response is not highly effective, and the animals rely on respiration to cool themselves. Because of their inefficient response, cattle accumulate a heat load during the day that must be dissipated in cooler nighttime temperatures. In extreme weather conditions with overnight temperatures above 70°F, however, this doesn’t happen. Cattle experiencing increasing heat stress will stop feeding and become restless. They will then begin drooling and breathing more rapidly and with increased effort. They will also begin to group together, further exacerbating the problem. If not controlled, severe cases of heat stress will result in death. Economically, decreased milk yield and reproductive losses through hot summer months seriously affect the dairy industry. Increased occurrences of extreme weather conditions caused by ongoing global warming will only worsen these losses. Read More...

Discovery of “Dark Matter” in Livestock Genomes

Discovery of “Dark Matter” in Livestock Genomes

Paradoxes are uncomfortable. They remind us of how little we understand. Worse, it sometimes seems the more we know, the less we understand, and that’s a bitter-sweet paradox in itself. Nowhere are paradoxes more apparent than in our understanding of life, and in particular the scientific understanding of the encyclopedia of life—the genome present in every living cell. Many scientists conclude that without understanding these genomic paradoxes, humans cannot fully exploit the amazing potential of genetics to improve human health and enhance the efficiencies of livestock production systems. The latter occurs primarily through DNA marker-assisted selective breeding of livestock. This process exploits the genetic (DNA) variations present in a large population of a livestock species to help select for the high-performing animals that then go into breeding programs. The aim is to improve animal productivity in each generation. It’s a little like how a savings account grows with each year of interest. Read More...

Measuring Inbreeding Balances Efficient Selection with Sustainable and Healthy Herds

Measuring Inbreeding Balances Efficient Selection with Sustainable and Healthy Herds

Selective breeding has been used for many centuries—initially in a crude form by early farmers, but today using highly sophisticated genome analysis and complex algorithms. However, the goals have remained the same: to improve the efficiency of dairy production. This translates into breeding the healthiest, most productive cows suitable for the appropriate farming system and environment. New technologies have provided the capability to monitor the changes that occur with selection in great detail. Two recent papers explored the most effective methods to accomplish this and investigated changes in North American Holstein and South American Gyr dairy cattle. Read More...

A Cow’s Milk Reveals Her Health

A Cow’s Milk Reveals Her Health

Defense wins games. Ask any coach impatiently striding the sidelines. “The defensive line-up must be ever vigilant and able to rapidly neutralize the attacking incursion, which may come from any direction. You cannot wait for help from the cover defense! Any defensive lapse will be ruthlessly exploited by this opposition and all will be lost,” shouts the coach at spent and cowed players as the bell signals the end of their halftime break. Coaches could learn a lot more about defense from biology. An exemplar defensive strategy par excellence is used by mammals, especially dairy cows, where the defensive system is the animal’s immune system, the best in the league, and the opposition threat is microbial infection. Read More...

Dairy Farmers Prefer Healthy Manageable Cows

Dairy Farmers Prefer Healthy Manageable Cows

Reaping the rewards of the genomic revolution in selective breeding in of dairy cows requires an informed and engaged dairy farmer response. A study published in December 2016 from a Danish group of dairy scientists reports that farmers rank health and management qualities above production traits in their cows. However, this ranking differs depending on whether the farmer is classified as organic or conventional. Read More...

Happy Cows to Reduce Milk Fever

Happy Cows to Reduce Milk Fever

Serotonin is best known to us as a brain factor that affects mood, with high levels associated with euphoria. However, it has much wider effects in the body, influencing gut motility, blood vessels, and osteoporosis. To scientists, this points to an interaction with calcium, and as we all know, calcium is an important component of milk and dairy products. So does serotonin influence milk calcium, and could the mood of cows affect milk production? Recent research by scientists in Wisconsin suggests that serotonin has an effect on regulating calcium in the important transition period from late pregnancy through lactation. Read More...

The Bacterial Diversity in Raw Cow Milk During Its Transport and Storage

The Bacterial Diversity in Raw Cow Milk During Its Transport and Storage

Pasteurization helps make raw cow milk safe for human consumption, but it doesn’t get rid of all bacteria. These remaining bacteria can cause spoilage, thus affecting the shelf life and quality of milk products and leading to wastage. Knowing what bacteria are present in milk before and during milk processing could help identify sources of spoilage and find ways to get rid of them. Read More...

Genomic Selection Accelerates Improvements in Health and Productivity of Dairy Cows

Genomic Selection Accelerates Improvements in Health and Productivity of Dairy Cows

The introduction of genomic selection into dairy cattle selective breeding programs has been greatly anticipated and is a remarkable example of the benefits of genomic technology. Made possible because the systems for selective breeding were already well developed in dairy, and the widespread use of artificial insemination meant that new developments could be delivered quickly. First introduced in the USA in 2008, there has now been sufficient time to generate enough data to assess its impact. Read More...

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