Nutrient utilization and rumen fermentation pattern in crossbred cattle fed different planes of nutrition supplemented with urea molasses mineral block

In order to investigate the effect of the plane of nutrition on intake and nutrient utilization from urea molasses mineral blocks (UMMB) and rumen fermentation pattern, sixteen adult crossbred cattle were divided into four equal groups following a completely randomised design and fed individually for 60 days ad libitum with either wheat straw alone (Group I) or with wheat straw with UMMB (Group II) or with wheat straw and UMMB with 50% of energy requirements provided by crushed barley fortified with mineral mixture and common salt (Group III) or with wheat straw and UMMB with 100% of energy requirements provided by fortified crushed barley (Group IV). At the termination of the feeding trial, a metabolism trial of six days duration was also conducted. A fermentation study was carried out on four rumen fistulated adult cattle following a 4 × 4 latin square design. Results showed that intake (except for ether extract) and digestibility of all the nutrients increased significantly (P < 0.01) in the block-fed groups which was further enhanced by energy (barley) supplementation except for digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF) which decreased owing to concentrate supplementation. Total digestible nutrients and digestible protein contents of UMMB were 56.6 and 42.5%, respectively. Significantly increased (P < 0.01) concentrations of total nitrogen and its fractions, except TCA-precipitable-N owing to block feeding were observed. However, it did not influence the TVFA concentration in rumen liquor of fistulated animals. Rumen pH, rumen fluid volume and digesta flow rate were also unaffected. This clearly indicated that supplementing 50% of energy requirements through concentrate on a straw based diet along with UMMB resulted in increased intake of UMMB and better utilization of dietary nutrients in adult crossbred cattle.