Effect of Cobalt Supplementation on Performance of growing Calves

Fibrous crop residues especially cereal straws form an integral part of the ruminant feeding under the prevailing livestock production systems in India. The abundance of these fibrous crop residues to the tune of 425 million tonnes (Banerjee, 1998), however, is constrained by their poor nutritional quality in terms of digestible nutrients and minerals. Promising approach appears to be the critical supplementation with limiting nutr ients like various macro and micro minerals, nitrogen or energy which would help in maximizing the ruminal fermentation and thereby better utilization of this low quality roughage. It has been postulated that divalent cations could act as bridges between bacteria and plant cell walls as both of them tends to be negatively charged (Somers, 1983). Therefore, the difficulty in attachment between the similarly charged rumen bacteria and plant cell walls could be overcome by providing freely available divalent cations such as cobalt and copper to serve as a link. Of these (divalent trace elements), cobalt appears to be a better choice because it is also an essential trace element required exclusively by rumen microorganisms for the biosynthesis of vitamin B12. The supplementation of cobalt above minimal requirement therefore may be beneficial during rapid rumen fermentation for increased growth and activity of microbes (Saxena and Abstract