G. K. Das

Contents: The present review addresses summer anoestrus in buffaloes. The condition is a major impediment in the improvement of reproductive as well as productive efficiency in buffalo. Factors affecting summer anoestrus include environment, nutrition and management. The environmental factors especially longer day length and increased temperature with high humidity pre‐dispose to the condition when the nutritive status of buffaloes is poor. Buffaloes with summer anoestrus fail to exhibit oestrus as a result of aberration in the endocrine profile leading to ovarian inactivity. Increased day length with high environmental temperature causes hyper‐prolactinaemia, suppressing the secretion of gonadotrophins, which leads to an alteration in ovarian steroidogenesis. Heat stress produced during summer also affects folliculogenesis, follicular fluid microenvironment and oocyte quality. A large number of hormonal regimens have been used with varying degree of efficacy in terms of oestrus induction and conception rate. A combined strategy of improvement in environment, nutrition and management is pre‐requisite for hormonal manipulation in order to improve productivity in summer anoestrus buffaloes. A brief description of summer anoestrus with special reference to factors responsible, endocrinology, deleterious effects on reproductive system and possible remedial measures is presented in this review.