Education

PhD--1984, University of Missouri-Columbia

MS--1978, Southern Illinois University-Carbondale

BA--1975, Luther College, Decorah, Iowa

Professional Experience

2005-present: Professor and Head, Department of Animal and Veterinary Science, University of Idaho

1998-present: Professor, Department of Animal and Veterinary Science, University of Idaho

1991-1998: Associate Professor, Department of Animal and Veterinary Science, University of Idaho

1985-1991: Assistant Professor, Department of Animal Science, University of Idaho

1984-1985: Postdoctoral Research Assistant, Department of Animal Science, University of Nebraska

1980-1984: Graduate Research Assistant, Department of Animal Science, University of Missouri

1975-1978: Graduate Research Assistant, Department of Animal Science, Southern Illinois University

Research Program

In general, the focus of our research program has been to investigate methods which will improve the energy status of ruminants. In particular, the project has focused on factors associated with fermentation of fibrous and starch carbohydrates which yield metabolizable energy for the host animal. Studies have involved examination of inherent differences in the nature of the cell wall from genetically diverse feedstuffs which result in differences in ruminal fermentation and degradability. In addition to inherent genetic differences in plant cell wall, studies have examined various strategies for altering the cell wall by chemical and enzymatic treatments. Both areas of research are intended to increase the bioavailability of energy present in the structural carbohydrates in feedstuffs. Specifically, the research program is structured around the following program activities: 1) evaluation of chemical and enzymatic enhancement of the digestibility of forage, 2) evaluation of fiber quality in forage crops, 3) evaluation of the feed value of barley. Below are descriptions of these research activities.

1. Evaluation of chemical and enzymatic enhancement of the digestibility of forages. A great deal of research has been performed regarding the improvement in the digestibility of low quality forages and crop residues via chemical treatment. The treatment which has shown the greatest promise is ammoniation (treatment of the forage with anhydrous ammonia). We have investigated various treatment alternatives of barley and wheat straw involving method of containment of the ammonia gas, level of ammonia applied, and moisture content of treated forage. In general, we have observed improvements in the digestibility of these crop residues to the level observed for good quality grass or alfalfa hay. Intake of the treated forage is typically less than that of typical forages, therefore the treated straws would serve as partial replacement of the conventional forages in a winter feeding program. Straws can be treated for a total cost of $15 to $18 per ton; therefore feasibility certainly exists where one-for-one substitution of treated straw for conventional hay is possible.

Fibrolytic enzymes which were initially evaluated were commercially available but are more routinely used to enhance ensiling characteristics of forage crops. Our preliminary results were quite promising as direct-fed enzymes improved dry matter digestibility and intake 20 to 25 percent and enhanced milk production by more than 10 pounds per day in lactating dairy cows. Research to date suggests that efficacy of the enzymatic treatment is dependent upon the proportion of cellulase and xylanase activity. Other factors which our results suggest may affect treatment response is ambient temperature, enzyme level and moisture content of the treated forage. The enzyme preparations tested to this point have been equally effective for high and low quality forages; therefore application potentially exist across a wide range of feeding situations. Variables measured in our studies have included ruminal metabolism and degradation, total tract digestibility, beef growth performance, and dairy lactation performance.

Grass seed straw is a major agricultural byproduct available throughout the Pacific Northwest. Environmental concerns have now precluded field burning of most of this crop residue, providing additional incentive to identify methods to improve its value as a feed for livestock. We have recently initiated research to investigate the combined effect of ammoniation and fibrolytic enzymes on digestibility of grass seed straw. Animal performance studies will be conducted contingent upon identifying efficacious treatments.

2. Evaluation of fiber quality in forage crops. This area of research began with evaluation of corn hybrids. Investigations have demonstrated tremendous differences in the fiber content and degradability of corn stover. Corn hybrids have been identified which are indeed quite significantly improved in digestibility. This research has allowed Pioneer HiBred International to provide their customers with digestibility values on their various corn hybrids and has encouraged the company to continue to seek corn genetic lines which have superior digestibility characteristics. We are proceeding in this area of research to evaluate genetic effects on digestibility of stover fractions of both corn and other cereal crops such as wheat and barley. In particular we are identifying characteristics of fiber which are associated with greater digestibility in the rumen. The ultimate goal of the research is to identify forage crops which approach the digestibility, and therefore the energy value, of grains.

A tangential area of research which has now been initiated involves investigation of the effects of processing corn silage with high pressure rollers immediately following field chopping. This processing is intended to fracture mature corn kernels which may escape digestion. Preliminary results show a dramatic benefit from this processing on the digestibility of the entire corn plant. Also, results indicate that magnitude of response to corn silage processing depends on maturity and hybrid.

3. Evaluation of the feed value of barley. Initial experiments determined that large varietal and growing location differences exist for barley in test weight, chemical composition (starch and fiber) and ruminal degradability. Studies are in progress which attempt to equate these differences to differences in the nutritive value of the grain. Starch content has been determined to be a particularly important characteristic associated with the energy value of the grain. Our investigations have also demonstrated that the amount and nature of the cell wall of the hull fraction are important quality factors. This experimentation may lead to development of barley varieties which have greater and more predictable energy values. Our studies have identified relationships between chemical composition (fiber and starch) and energy value which are more predictive of the nutritive value of barley than the commonly used bushel weight measurement.

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