Getting it right for health
The Science and Grace of Animal Nutrition
by Constance Breese
The invitation was welcome. A select group of veterinarians were invited to visit Long View Research Farm
in St. Louis, Missouri and I was one of them. Questions about feeds and nutrition are frequently asked in my veterinary practice. I was more than ready to learn first hand about nutrition and the development of commercial animal feeds and supplements. The seemingly simple goal of raising healthy animals, which in
turn become our healthy meats, is a complex matter.
Our guides brought us to the beef production part of the research farm first. Raising beef cattle is big business, and it is all about getting faster and faster rates of growth and weight gain. At Long View
in 2009 tests were being conducted on calves recently weaned. Separation from the mother cow causes stress and poor digestion in the calf. Feeds were being developed for this short but crucial time in a calf’s life. Other diets target the needs of a cow when she is pregnant, a different formula for when she is nursing, and another for “finishing,” the period of time a steer puts on the desired weight before slaughter.
I learned that the feeds for livestock must be multi-faceted. The food must be nutritionally complete (provide all the essential vitamins, minerals, amino acids, and proteins), digestible, and palatable. The taste testing at the farm is performed by a select group of animals from each species. These animals are the first screeners of a new diet. If they don’t like it, the formula is adjusted and retested. The tasters are chosen for their hearty appetites, but they must be discriminating too.
After a feed passes the taste test and is known to meet the nutritional requirements, it is tested again on a research farm herd. The members of the herd have frequent weigh-ins, measurements are taken monthly, and physiologic and blood tests are done. Some animals are tested on treadmills and have stress test EKGs to see how well their nutritional state supports body function and performance. The animals are followed for generations to measure the nutritional effects on reproduction and birth weights. Learning about the multigenerational studies was reassuring in a way. I was glad to know that a commercial feed producer was looking at long-term effects of diet on health. Clearly a lot of time and money is invested into formulating and manufacturing commercial foods for livestock, including specialized feeds for different
stages of life.
However, many farms are moving away from using a lot of processed feeds and choosing to raise their animals “grass fed.” The idea is appealing: let the livestock graze on pasture until they are ready to go to market. Alas, it is not that simple. Nutrition and good health still require science and testing when animals
are raised primarily on pasture. All pastures are not the same; they can become depleted of important nutrients if not managed properly.
Since 2007 I have been the veterinary consultant for the Nantucket Conservation Foundation. The NCF owns over 8,000 acres of land and a flock of sheep. The sheep are used to graze the land as part of a management plan to study and preserve the local vegetation. No commercial grains are fed to these sheep, because uneaten grain could seed itself and alter the native vegetation that the NCF is studying. Because the animals are exclusively grass fed, I recommended that samples of the plants and grasses being consumed be sent to a lab for analysis. The samples are tested to identify any mineral deficiencies and to assess moisture, protein, and carbohydrate content and other components of feed that ultimately determine health in the animal. Through blood testing and pasture analysis, we established that the NCF sheep (even with their vast amounts of pastureland) needed supplementation with some key vitamins and minerals.
Overall I know now that nutritional requirements differ with age, pregnancy, disease, stress, activity, weather, breed, etc. It’s complicated. The nutritional value and taste of our meat depends on getting it right.