Seasonal alterations in the serum prolactin and LH levels in the water buffaloes

It has hem established that buffaloes come to heat during summer months (low breeding period) but do not exhibit clear cut heat symptoms. Because of this, many good animals remain unmated during summer. Hence, it was felt essential to study the endocrine physiology of buffalo, which is the main dairy animal in this country. By using radioimmunoassay technique, serum prolactin and LH levels in Surti breed of Indian water buffaloes were determined. Blood samples were collected at specific phases of the estrous cycle throughout the year and the samples were divided into three categories namely, medium breeding (monsoon), peak breeding (winter) and low breeding (summer) periods. Large fluctuations in prolactin activity were observed at different phases of the estrus during monsoon and winter but not in summer. Specifically, during monsoon and winter seasons a sharp fall in prolactin levels after ovulation was noted.