Nutrient intake, digestibility and growth performance of Yankasa sheep fed urea-treated or untreated rice straw with supplements

Abstract

A study was conducted at the Abubakar Tafawa Balewa University (ATBU) Research and Teaching Farm between December and May 2006 to determine nutrient intake, digestibility and growth performance in Yankasa rams fed urea-treated (UTRS) and untreated rice straw (URS) with supplementation. Thirty-two (32) Yankasa rams with an average weigh of 17.5kg, and aged 1.5 to 2 years old were alloted to eight (8) dietary treatments with four (4) rams per treatment in a 2 x 4 factorial design. The two basal feeds were urea0treated rice straw (UTRS) and untreated rice straw (URS). The supplements were maize bran (MB), MB + sun-dried poultry litter (MB + SDPL), MB + ensiled poultry litter (MB+ EPL) and MB + cotton seed cake (MB + CSC). Total dry matter intake (TDMI), daily basal feed intake (DBFI) were significant (P<0.05) across dietary treatments. Animals on supplements MB and MB+CSC for both UTRS and URS recorded the lowest and highest DBFI. The digestible crude protein intake (DCPI) and digestible organic matter intake (DOMI) were high for rams on UTRS and the values ranged from 17.72 to 28.36g/d and 288.81 to 482.66g/d for DCPI and DOMI respectively. Nutrient digestibility was improved by treatment of straw and supplementation. However, crude protein digestibility was similar for animals fed URS but, significantly (P<0.05) lower compared to those fed UTRS which were also similar across supplements. Average daily weight gain ranged from 53.58 to 91.18g/d across dietary treatment with animals on supplement MB recording the lowest (53.58 and 61.43g/d for URS and UTRs respectively) and those fed supplement MB+CSC the highest (81.38 and 91.18g/d fro URS and UTRS respectively) irrespective of straw treatment. Feed conversion ratio (FCR) was least for animals on supplement MB+CSC for both URS and UTRs, indicating that this supplement (MB+CSC) influenced feed utilization more positively. From the results of this trial, it may be concluded that straw treatment and/or supplementation can enhance crop residue utilization by sheep. however, mixed supplements especially MB+CSC were more efficient in enhancing the utilization of the straw and consequently animal performance.