Impact of Three Categories of Supplements on In Sacco Ruminal Degradation of Urea-Treated and Untreated Straw Substrates

Abstract

The objective of this study was to examine the impact of three categories of supplements on intake and diet induced difference on degradation of straw substrates. Sixteen crossbred cattle fitted with rumen cannula were randomly divided into 4 equal groups. Animals were fed on wheat straw ad libitum without any supplement except mineral mixture (control; T1) or supplemented with concentrate mixture (CS; T2) or green Lucerne (GLS; T3) or urea-molasses block lick (ULS; T4). Total dry matter intake in T2, T3 and T4 was increased by 70, 54 and 49%, respectively compared to T1 which was only 1.55 kg/100 kg B.Wt. Other than control animals, straw intake was less on T3 than T2 or T4. In Sacco degradation of untreated and urea treated wheat or paddy straw in different treatments indicated that the supplements had a significant (p<0.01) impact on rapidly soluble (A) and insoluble but potentially degradable (B) fractions of straw. Urea treatment increased fraction-A but, provision of supplement improved fraction-B also. Effective degradation (ED) of OM was better on T2. Rate of degradation (C) of OM and CWC was dependent on diet and type of straw but hemicellulose and cellulose were related to latter factor only. ED of cell wall carbohydrates (CWC) was similar in T2 and T4 but higher than T3. CS was more effective in improving the degradation of both untreated and urea treated straw while ULS was effective on the former only. CS had more impact on superior quality straw while contrary was true with ULS. Although GLS improved intake and degradability of untreated and urea treated straws, its bulkiness affected the straw intake compared to other supplements. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 2 : 195-204)