NR 21. Intake and digestibility of whole sorghum (Sorghum bicolor L.) crop urea ammoniated silage

Abstract

In many countries of tropical and subtropical Latin America, sorghum silage has a great potential to be used as supplementary feed for cattle, during the dry season. The objective of this study was to examine the intake and digestibility of a whole crop sorghum silage. Nine steers of 217 kg mean live weight (range 212 to 230) at the beginning of the experiment, were distributed at random to each of the three treatments in a latin square design. The experimental time was 60 days, with 3 periods of 20 days each. The three treatments were the addition of: 2, 4 and 6 % urea on DM basis, applied at ensiling. The sorghum silage was prepared harvesting when it was at about 50 % DM in the grain. The hybrid «Chaguaramas VII» was used. The steers were individually allocated in pens where they received the silage ad libitum. Measurements of DM intake and total collection of faeces was carried out during the last 6 days of each period, they were collected 3 to 4 times per day directly from the floor. The individual daily faeces were mixed and subsampled for drying. The results were: silage intake (kg DM/day); kg DM/100kg live weight and digestibility for the treatments 2, 4 and 6 % urea were: 4.92, 5.91 and 5.99 (P<.01); 2.22, 2.69 and 2.71 (P<.01); 45.2, 54.9 and 55.3 (P<.01) respectively. In spite of the strong ammonnia smell, the intake was height. It was concluded that the increasing addition of urea had a positive effect on intake and digestibility. However the digestibility of the silage was moderate to low.