SINGH, PAWANSATPUTE, TEJESHWARI2023-11-062023-11-062021https://krishikosh.egranth.ac.in/handle/1/5810200403Artificial insemination has been proved as the most rapid and cost effective method to improve the productivity of livestock including buffaloes, as a result the demand for frozen semen of elite bull is increasing day by day in the country. The quality semen from high genetic merit bulls is imperative in improving the productivity of buffaloes. In tropical and sub-tropical regions heat stress is the major constraint for buffalo bull’s performance, which is contributed by number of factors like temperature, humidity, rainfall, photo-period etc. However, how heat stress affects buffalo bulls performance is not understood yet, therefore, the present study was planned to investigate the effect of season on testicular temperature, hormonal profile and semen quality in Murrah buffalo bulls. The experimental period was divided into three seasons- winter (15th December to 15th February), spring (16th February to 30th April) and summer (1st May to 30th June). For that 14 mature Murrah buffalo bulls of 3-4 yrs age were selected. Physiological responses and surface temperature (Infrared thermal imaging) at eye, forehead, flank, rump and scrotal surface were recorded during morning and afternoon hrs. Semen was collected twice a week and sexual behaviour was recorded at the time of collection. Semen quality parameters were evaluated two times during peak of each season. Blood for hormone estimation was collected on the day of semen collection. Data so generated was analysed by one-way analysis of variance (ANOVA) using SPSS software. The results showed that the ambient temperature and THI was higher during summer season as compared to winter and spring. The rectal temperature (°C) and respiration rate in morning and afternoon hours was least during winter and higher (p<0.05) in summer season. Body surface temperature (eye, Forehead, flank and Rump region) showed difference (p<0.05) among seasons, being lowest in winter and highest in summer. The testicular temperature gradient (°C) was higher (p<0.05) in the morning during spring season than summer season. Activity of thyroid gland in terms of T3, T4 and TSH concentration was lower (p<0.05) in summer as compared to winter and spring season. Conversely, testosterone concentration was higher in summer season; however, cortisol concentration did not vary significantly among seasons. The bulls have shown short reaction time and higher libido score during spring season as compared to other seasons. Higher (p<0.05) values of sperm concentration, mass motility, individual motility and HOST reacted spermatozoa was obtained in spring and lowest during summer except for acrosome integrity. So from this study, it can be concluded that the season has significantly influenced the physiological and endocrinological responses, sexual behavior and overall semen quality of Murrah buffalo bulls.EnglishThesis