HEATHER ANN LYNCH The Effect of Ensiling on Malate Content of Alfalfa, Corn, and Wheat (Under Direction of SCOTT A. MARTIN) Based on our understanding of ruminal fermentation, nutritionists and microbiologists try to formulate diets

The objective of this study was to evaluate the effect of ensiling alfalfa, wheat, and corn on malate content. Samples were grown, collected, and ensiled in 7.5 L plastic buckets with airtight lids. All samples were either ensiled immediately after cutting, or wilted for at least one h between treatments. Sources of corn either were grown in drought conditions or irrigated conditions. No other forages were irrigated during growth. Alfalfa was ensiled at two different cutting lengths. The experimental silos were kept for 6 weeks at 25°C and then opened for analysis. The organic and volatile fatty acids, percent dry matter, and pH were measured. Because soluble nutrient losses are associated with the ensiling process, concentrations of malate were expected to be lower in all silage treatments. Silage samples of all varieties had decreased malate and pH values and increased lactate, acetate, butyrate, propionate, and total VFA concentrations. However, the loss in malate during the ensiling was less than in hay. No common trends based on percent dry matter treatment were observed. Alfalfa had the lowest concentration of malate and corn (drought-stressed) had the highest concentration of malate among all of the plant varieties. Increased dietary concentrations of malate might help reduce problems associated with subclinical acidosis by stimulating lactate utilization by S. ruminantium. Malate concentrations in silage may be sufficient to improve ruminal pH of lactating dairy cattle.