Effects of Protein Level in Concentrate and Urea-Treated Corn Silage on Rumen Ecology and Milk Production in Lactating Dairy Cows

Abstract

Four, lactating dairy cows were randomly assigned according to a 2x2 Factorial arrangement in a 4x4 Latin square design to study supplementation of concentrate containing different level of protein at 14 and 18% CP and urea-treated corn silage at 2 and 5% respectively. The treatments were as follows by concentrate containing protein at 14% CP + 2% urea-treated corn silage (T1); concentrate containing protein at 14% CP + 5% urea-treated corn silage (T2); concentrate containing protein at 18% CP + 2% urea-treated corn silage (T3) and concentrate containing protein at 18% CP + 5% urea-treated corn silage (T4), respectively. The animals were offered the treatment concentrate at a ratio to milk yields at 1:2 and urea-treated corn silage were fed ad libitum. The results have revealed that total DM intake (%BW) and ruminal pH were not affected (p>0.05). Likewise, the concentration of ammonia-nitrogen (NH₃-N) and Blood Urea Nitrogen (BUN) were significantly different affected by protein levels in concentrate with urea levels treated corn silage. In addition, rumen microorganism populations such as bacteria, protozoa and fungal zoospores were affected (p<0.05) by different by protein levels in concentrate with urea level treated corn silage. Moreover, the differences of protein levels in concentrate and urea level treated in corn silage were affected to milk yield and composition (p<0.05), especially income over feed highest in dairy cows were received a concentrate containing protein at 18% CP + 5% urea treated corn silage (T4). Therefore, results from this experiment indicated that the differences of protein levels in concentrate and urea level treated corn silage affected on rumen ecology and milk production in lactating dairy cows.