Ed "I MILK!" DePeters Leads Popular Dairy Program

With a license plate given to him by students in one of his classes to commemorate his near obsession with animal nutrition, an "I MILK!" button that his colleagues believe he wears even when he sleeps, and a cadre of current and former students who credit their successes to his interest and caring, Professor Ed DePeters is a dairy nutritionist who exemplifies a faculty member bent on making sure that his teaching, research and outreach to the public make a difference. As a nutritionist working on problems of the state's largest agricultural industry, the dairy industry, Professor DePeters, or “Ed” or “Dr. D.” as he prefers to be called, focuses his research on two important and practical problems: modification of milk protein and fat composition, and characterization of by-product feedstuffs.  

In a nutshell, Ed's research on milk composition aims at determining the effect of dietary intake on milk composition and in using diet to change milk composition. Frequently in his research he uses lactating cows with ruminal and duodenal cannulas that allow samples to be collected during digestive processes. For example, he and his graduate students measured changes in milk protein in response to changes in the processing of cereals fed to dairy cattle. Results from one experiment showed that steam-flaking corn, in contrast to the more typical rolling process, increased ruminal starch digestion and enhanced microbial growth, increased flow of microbial protein into the duodenum and increased milk protein synthesis by the mammary gland. Since milk is a source of high-quality proteins in the human diet, these results are important to not only dairy producers but to consumers in general. He also used the lactating cow model involving ruminal and duodenal cannulas to elucidate the effect of fats in dairy cattle diets on rumen metabolism and milk composition. One interesting finding is that feeding unsaturated fatty acids contributes to the conjugated linoleic acids (CLA) in milk fat; CLA has been shown to possess potent anticarcino- genic properties in vitro and in rodent models. Working with researchers in Food Science and Technology, Ed is developing a feed product that will increase the unsaturated fatty acids available for absorption from the small intestine. The impact will be to increase the unsaturated (omega-6 and omega-3) and decrease the saturated fatty acid contents of milk fat, thus improving the human nutritional value of dairy products. Plus, there is a potential that increasing the absorption of omega-3 fatty acids will improve reproductive performance of dairy cattle, a major problem in the dairy industry. Ed's research program is providing important results that have implications for both dairy cattle nutrition and human health.

Another important focus of Ed's research is utilization of by-product feeds by dairy cattle. More than 300 crops are grown in California. Processing these crops to prepare human-edible food generates enormous quantities of by-products that create a serious waste-disposal problem. Feeding these by-products to livestock converts human-inedible feedstuffs into human-edible foodstuffs (milk and meat). Although widely fed in California, few by-products have been characterized for their variability in nutrient composition. His study measuring the variability in nutrient composition of by-products involved nutrition professionals throughout California and was one of the largest studies of its kind.

The results of these experiments have many practical implications. For example, he showed that feeds containing slowly digested fiber (e.g., soy hulls) are more dramatically impacted by high rates of passage through the digestive system as seen in high-producing dairy cows compared with feed containing rapidly digested fiber (e.g., beet pulp). Ed's research on dairy cattle nutrition was recognized nationally when he received the 1999 Applied Nutrition Award of the American Dairy Science Association.

Ed is also one of the Department of Animal Science's excellent teachers and advisers. He teaches courses on introductory animal management, nutrition and feeding, and dairy cattle production. He received the UC Davis 1998 Distinguished Teaching Award and the 2000 Distinguished Teacher Award given by the American Dairy Science Association. Each year he serves as faculty academic adviser for 40 to 50 undergraduates in Animal Science. His popularity as a faculty adviser stems from his making time to help students in need. In 1993, he received the College's Outstanding Faculty Adviser Award recognizing him as a truly outstanding faculty adviser.