Supplementation of Urea Level and Malate in Concentrate Containing High Cassava Chip on Rumen Ecology and Milk Production in Lactating Cows

Abstract

Four, lactation dairy cows were randomly assigned according to a 2 x 2 Factorial arrangement in a 4 x 4 Latin square design to study supplementation of urea level (U) at 2 and 4 % and malate (M) at 10 and 20 g/hd/d in concentrate. The treatments were as follows U2M10, U2M20, U4M10 and U4M20, respectively. The cows were offered the treatment concentrate at a ratio to milk yield at 1:2.5 and urea-treated rice straw was fed ad libitum . The results have revealed that rumen fermentation and blood metabolites were similar for all treatments. The populations of protozoa and fungal zoospores were significantly different as affected by urea level and malate. In addition, the viable bacteria were similar for amylolytic and proteolytic bacteria. Cellulolytic bacteria were significantly affected by level of malate especially Selenomonas ruminantium and Megasphaera elsdenii while Butyrivibrio fibrisolvens was significantly affected by level of urea supplementation. Yield of milk was greatest in cows fed cassava-based diets with M20U2, but were lowest when receiving M10U4 in diets. In addition, production of 3.5%FCM exhibited similar results for all treatments. In conclusion, the combined use of concentrate containing high level of cassava chip at 75% DM with urea at 4% in concentrate and malate at 20 g/hd/d with UTS as a roughage could improved rumen ecology and microbial protein synthesis efficiency in lactating dairy cows.