In vitro Evaluation of Critical Supplementation of Wheat Straw with Graded Levels of Various Sources of Cobalt

Wheat straw was supplemented with graded levels of cobalt from three sources, namely cobaltous chloride, cobaltous sulphate and cobalt acetate to study the effect on in vitro gas production parameters by Hohenheim gas test (HFT). The 24 hr gas production was not significantly affected by supplementation of cobalt as cobaltous chloride or cobaltous sulphate supplementation caused general decrease in gas volume. True substrate degradability of wheat straw in terms of DMand NDF significantly improved up to 6 ppm of cobalt as cobaltous chloride where as similar picture was not evident with cobalt as cobaltous sulphate or cobalt acetate. In vitro microbial biomass production increased when cobalt was supplemented as cobaltous chloride up to 6 ppm, while no such effect was evident from other two sources. Neither level nor source of cobalt supplementation affected the partition factor or ME content of wheat straw significantly in the present study. The results indicate that supplementation of wheat straw with cobaltous chloride up to 6 ppm appears to be effective as a divalent cation in enhancing microbial attachment to fibre particles, there by increasing the in vitro substrate degradability and microbial growth.