Effect of food allowance on intake, digestibility and selection of wheat straw by Barbari goats

Abstract

The selective consumption of cereal straws may affect the quality and quantity of ingested feed according to the level of feed offered. Wheat straw (WS) was offered at levels of 75, 100, 125 and 150% ad lib. Barbari bucks (16) were divided into 4 homogeneous groups of 4 animals and each group was offered feed at different levels. DMI increased significantly from 27.20 to 39.24 g/kg W^0.75. The increase in DMI at higher levelsof DMO (P<0.01) followed a curvilinear relationship (R² = 0.62). The calculated level of WS refusals for obtaining upper limit of intake (m = 38.93) was above 30% of DMO. In the range of feed offered, the nutrient digestibility was not depressed at higher levels of DMI. Consequently intake (g/ kg W^0.75) of DCP, TDN, DDM and DOM increased with the increase in amount of WS offered up to WS 125. Concentration of ADF and lignin was significantly lower and CP was higher (P<0.05) in food ingested relative to food offered/refused in response to increasing allowance of WS. The results suggest that DMI and quality of ingested straw would improve with higher rates of offer because of the greater opportunity afforded for selective feeding.