EFFECT OF SEASON ON TESTICULAR TEMPERATURE, HORMONAL PROFILE AND SEMEN QUALITY IN MURRAH BUFFALO BULLS
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Date
2021
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Publisher
ICAR-NDRI, KARNAL
Abstract
Artificial 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.