David Marshall

Synthesized analogs of oosporein will be evaluated for their teliospore inducing activity on the oat rust fungus Puccinia coronata in greenhouse and field experiments. Experiments will involve the production and quantification of inoculum of P. coronata, production and inoculation of oat plants, application of treatments, evaluation of rust disease development and data collection, and analysis of experimental results.

Small grains contain large amounts of starch. Starch is a major source of energy to animals consuming grain diets. The content of starch in small grains can be highly variable and the quality (rate and extent of digestion) may impact the form in which energy is made available to the animal. Oats is very palatable containing about 53% starch, The starch in oats is easily digested (83%) by enzymes in the foregut but is more resistant to microbial breakdown in the rumen. Therefore, oat starch doesn?t contribute to starch overload in the hindgut like corn. Corn is the more common grain source in North America and is more energy dense when compared to oats. Most of the starch in corn is not digested in the foregut, unless the corn is ground and pelleted or extruded. Most of the starch (72%) from whole or cracked corn proceeds to the hindgut where it is rapidly fermented. The starch contained in wheat grain is more rapidly fermented compared to the starch in corn grain. Barley contains about 60% starch compared to 72% starch in corn but the rumen degradability of starch in barley is higher than corn. Barley has a hard kernel and when processed can result in greater amounts of ruminal starch degradation. Increased availability of starch in the rumen of animals fed barley or wheat can lower pH and negatively affect animal performance. In some cases, the metabolizable energy content of corn has been shown to be slightly higher than the other grains however differences in protein content make oats, wheat and barley competitive. Balancing the rapid release of energy from starch with available protein will optimize microbial function and minimize nutrient waste. Feeding grains in appropriate amounts can support a greater production of microbial biomass, the major source of the animals? metabolizable protein. Effect of processing grains can have a major impact on energy and protein utilization by animals. Hulled barley has not generally been included in ruminant diets because of the higher fiber content. Limited data on new varieties of hulless barley suggest a modest improvement in crude protein and digestibility when compared to the hulled variety. However, the greater fiber content of hulled barley should promote a more favorable rumen environment by slowing the rate of starch fermentation - a balance of these two components, fiber and starch, is necessary to achieve stable rumen fermentation. There is little known on the fermentation characteristics of these grains and their effect on microbial crude protein production in the rumen. This aspect of ruminant utilization can be achieved through the use of continuous culture fermentors. Experimental Plan The grains that will be used are as follows:Corn grain, Hulless Oats, Rolled Wheat, Hulless and Hulled Barley. Diets will consist of a concentrate mix and alfalfa hay (60:40 wt/wt; DM basis). A total of 5 concentrate mixes will be prepared as outlined below: Ingredient Mix 1 Mix 2 Mix 3 Mix 4 Mix 5 % of DM Oats. hulles 80 --- --- --- --- Wheat, rolled --- 80 --- --- --- Barley, hulless --- --- 80 --- --- Barley, hulled --- --- --- 80 --- Corn, ground --- --- --- --- 80 SBM (49%) 18 18 18 18 18 Premix 2 2 2 2 2 The experiment will consist of five continuous fermentors operated twice (n=2) for a period of 9 days following 2 days of stabilization. Samples will be analyzed for methane, pH, ammonia-N, volatile fatty acids, and long chain fatty acids (LCFA). Digestibility estimates will also be measured. Data from this study will enable livestock producers to evaluate the nutritional value of the different grains and the effect of processing on ruminal fermentation as compared to corn.