EFFECT OF DIFFERENT SUPPLEMENTS ON THE DEGRADABILITY OF ORGANIC-MATTER, CELL-WALL CONSTITUENTS, INVITRO GAS-PRODUCTION AND ORGANIC-MATTER DIGESTIBILITY OF WHEAT STRAW

Samples of wheat straw were suspended in the rumen of animals fed under the different treatments. The disappearance of organic matter and fibrous constituents from the nylon bags suspended in the rumen of animals was not significantly different amongst Groups II, III and IV, but was significantly (P < 0.0 1 ) higher as compared to group I. As a result, rate of degradation of neutral detergent fibre (NDF), acid detergent fibre (ADF) and cellulose in the rumen of animals increased significantly when the basal diet of wheat straw was supplemented with either concentrate mixture or urea-molasses block. Thus, time taken (h) for 50% retention of dry matter (DM) in the nylon bags was significantly (P < 0.0 1 ) higher in Group I (93.61 +/- 2.76) as compared to Groups II (70.25 +/- 3.30), III (74.95 +/- 2.69) and IV (75.46 +/- 3.51 ). The other fibrous fractions such as NDF, ADF and cellulose followed a similar trend. In another experiment, gas production (ml g-1 of wheat straw) was studied using rumen fluid of animals under different treatments. It was observed that gas production was not significantly different during Phase I (first 3 h of incubation when soluble fractions are rapidly fermented) and II (from 4 h of incubation when mainly cell wall fractions are fermented) of incubation amongst groups I (3.01 +/- 0.02; 0.93 +/- 0.06), II (3.03 +/- 0.06; 0.87 +/- 0.03),III (3.06 +/- 0.03; 0.91 +/- 0.03), and IV (2.99 +/- 0.96; 0.88 +/- 0.02). Similarly, in vitro organic matter digestibility of wheat straw determined using rumen fluid of animals under different treatments was non-significantly different amongst Groups I (44.66 +/- 0.28), II (45.18 +/- 0.39), III (45.66 +/- 0.27) and IV (43.87 +/- 0.76). These studies suggest that microbial activity, as indicated by wheat straw degradability from nylon bags, was poor when the animals were fed only wheat straw and increased significantly and at a similar level when supplemented with either concentrate mixture or different urea-molasses mineral block (UMMB) licks.