author(s)
AK Singh, SK Rajak, Priyaranjan Kumar, Shilpi Kerketta and RK Yogi

abstract
With the advent of artificial insemination in cow and buffalo, the need of fertile bulls with good quality semen doses get much more importance now a days. Bull fertility depends upon various factors such as genetics, environment, season and nutrtion. Among these nutrition plays significant role to maximize the potential of bull fertility. Balanced nutrition during pre-weaning and post-weaning stages of male calves has a significant impact on testicular steriodogenesis and gonadotropins releasing hormone which ultimately determine the bull fertility. Hence, level of different nutritional requirement in bull at various stages and their effect on puberty, sexual maturity and fertility need to be elucidated.