Supplementation of cobalt and copper on wheat straw utilization by in-vitro and its influence on the performance of calves

Abstract

This study examined the interaction between cobalt and graded levels of copper for enhancing the utilization of wheat straw in vitro and in calves. Wheat straw supplemented either with 1 ppm cobalt (Co1) or graded levels (5, 10 and 15 ppm) of copper (Cu5, Cu10 and Cu15) and their combinations (Co1Cu5, Co1Cu10, Co1Cu15) were evaluated by in vitro gas production technique. Wheat straw without any supplement served as control. The validation of in vitro findings was undertaken in 15 crossbred growing calves divided equally into 3 groups in a completely randomized block design. The calves in control group were offered wheat straw ad lib. and supplemented with concentrate mixture to meet their requirements for maintenance and growth. However, the calves in Co1 and Co1Cu15 treatments were supplemented either with 1.0 ppm cobalt or 1.0 ppm cobalt plus 15.0 ppm copper of the total experimental diet, respectively. The average gas volume (24th) did not differ significantly irrespective of levels of cobalt and/or copper supplementation. However, TDOMR (%), MBP (mg/200mg), EMP (mg/100 mg TDOMR) and PF (mg TDOMR/ml gas volume) significantly improved when wheat straw substrate was supplemented with either 1.0 ppm cobalt, graded levels of copper (5.10 and 15 ppm) or their combinations. The improvement was highest in the dietary group Co1Cu15 as compared to other treatments. Intake (g kg/W0.75) of dry matter, DCP, TDN, and digestibility coefficient of various nutrients did not differ significantly (P<0.05) irrespective of dietary treatments. Net-retentions (g/d) of nitrogen, calcium, phosphorus and various blood-biochemical parameters in crossbred calves were also observed to be statistically similar. It may be concluded that supplementation of wheat straw with 1.0 ppm cobalt and a mixture of cobalt and copper (1:15 ppm) exerted beneficial effect on fermentation variables in vitro but did not impart any positive effect on the performance of growing calves.