Promkot et al., 2003. Livest. Res. Rural Dev., 15 (11)

The experiment was carried out on four fistulated multiparous Holstein Friesian crossbred (dry period ) dairy cows to evaluate nutritive value of local protein feed resources using the in sacco method and in vitro pepsin -pancreatin digestion. Measurements were made of ruminal degradability, intestinal digestibility of DM and crude protein, and effects of the rumen environment in cattle fed on untreated and urea-treated rice straw. Feeds used were cottonseed meal (CSM), soybean meal (SBM), dried brewer's grain (DBG), palm seed meal (PSM), cassava hay (CH) and leucaena leaf meal (LLM). Each feedstuff was weighed into duplicate nylon bags and incubated in each of the four rumen fistulated cows for 0, 2, 4, 8, 16, 24, and 48 h post feeding. Rumen feed residues from bags of 16 h of incubation time were used for estimation of lower gut digestibility by in vitro pepsin-pancreatin digestion. Ruminal ammonia-nitrogen (NH3-N) concentrations were 4.5 and 12.4 mg% for untreated rice straw and urea-treated rice straw, respectively. Effective degradability of DM of CSM, SBM, DBG, PSM, CH, LLM in cows fed with untreated rice straw and urea-treated rice straw were 41.9,46.7; 56.1,63.3; 30.8,36.1; 47.0,48.3; 41.1,44.1 and 47.5,49.5 %, respectively. Effective degradability of the crude protein in cows fed with untreated rice straw and urea-treated rice straw were 49.6,54.6; 59.2,66.3; 40.9,48.8; 33.5,39.9; 47.3,54.6 and 65.0,70.6 % for the respective feeds. Both DM and crude protein in vitro pepsin-pancreatin digestibility of the same feed sources in cows fed with urea-treated rice straw were higher than in untreated rice straw . Results of crude protein in vitro pepsin-pancreatin digestibility, as ranked from the highest to the lowest, were SBM, CSM, LLM, CH, DBG and PSM for both environments. It is concluded that the nutritive value of protein-rich supplements, in terms of rumen degradable, intestinal and total tract digestibility, was improved when urea-treated rice straw was offered as a roughage as compared with untreated rice straw; and that the lower ruminal ammonia concentration inhibited the degradation rate of the supplements when the cows were fed with low quality roughage (untreated rice straw). SBM and LLM were highly degraded in the rumen, while CH, CSM and DBG were less degraded and hence resulted in higher levels of rumen undegradable protein. These protein sources can be used to improve rumen ecology and rumen by-pass protein supply to ruminants.