Effect of different crude protein sources on feed intake, digestibility, rumen parameters and nitrogen
retention of Lai Sind calves from 10-12 months of age 

This experiment was carried out as a 4x4 Latin square design with 4 treatments, 4 Lai Sind calves and 4 periods (2 weeks/period). The treatments were different supplements of coconut oil cakes, extracted oil soybean cakes, fish meal and urea in the basal diet of 85 % Para grass (Bracharia multica) and 15 % Bim Bim vines (Operculia turpethum) in dry matter basis. The aim of experiment was to evaluate effects of the different protein sources on feed
intake, digestibility, ruminant parameters and nitrogen retention on Lai Sind calves from 10-12 months of age. All the treatments the calves were fed at a fixed level of 230 g crude protein (CP) per 100 kg body weight. The results shown that DM and CP intakes were not significantly different (P>0.05) and from 3.05 to 3.37 and 0.42 to 0.45 kg DM/head/day, respectively. After feeding 3 hours, rumen N-NH3 concentration was from 16.1 to 20.7 mg/100ml and total volatile fatty acid concentration was from 72.1 to 81.3 ?mol/l, however, they were not significantly different (P>0.05) among the treatments. The apparent digestibility of DM and CP were not significantly different (P>0.05) among the treatments and they were from 54.0 ± 56.2 % and 69.7 ± 76.0 %, respectively. Nitrogen retention among the treatments was similar (P>0.05) and from 0.730 to 0.885 g/kgW 0.75. The conclusion was that calves from 10-12 months of age fed 85 % Para grass and 15 % Bim Bim vines with supplementation of 4 protein sources, the nutrients and metabolizable energy intakes, digestibility and nitrogen retention were similar among the treatments. However, the diets supplemented with extracted oil soybean cakes and fish meal were rather promissing. 

Keywords: Ruminants, nitrogen sources, supplementation, feed utilization, rumen environment, digestion.