COMPARISON OF THERMAL STRESS ALLEVIATION METHODS FOR MURRAH BUFFALOES IN HUMID TROPICS
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Date
2019
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College of Veterinary and animal Science,Mannuthy
Abstract
A study was conducted to compare the different thermal stress alleviating methods for
Murrah buffaloes in humid tropics. Twenty-four lactating Murrah buffaloes were randomly
selected from University Livestock Farm and Fodder Research Development Scheme,
Mannuthy and grouped into four treatments with six animals each namely, T1 as control, T2
was allowed to wallow, T3 was provided with THI based automated foggers and T4 was
provided with THI based automated wetting and forced ventilation and were studied under two
seasons with different THIs (low – 76.93 ± 0.53) and high – 82.55 ± 0.35). The mean rectal
temperature (°F) was 102.04 ± 0.02, 102.08 ± 0.02, 101.96 ± 0.02 and 100.89 ± 0.02 in T1, T2,
T3 and T4 respectively during high THI season. The mean pulse rate (beats per minute) was
57.92 ± 0.15, 55.71 ± 0.15, 56.33 ± 0.15 and 55.23 ± 0.15 in T1, T2, T3 and T4 respectively
during high THI season. The mean respiratory rate (breaths per minute) was 17.92 ± 0.15,
16.48 ± 0.15, 17.08 ± 0.15, 15.28 ± 0.15 in T1, T2, T3 and T4 respectively during high THI
season. The respiratory rate, pulse rate and rectal temperature were found to be lowest in T4
with a significant difference with all other treatment groups in both seasons. On analysis for
cortisol, no significant difference was observed in low THI season but significant difference
was observed within the treatments in the high THI season. In high THI season, cortisol level
in T4 group was significantly higher than the control group. Even though there was no
significant difference, a substantial increase in milk yield was found in T4 when compared to
control group in both the seasons. It may be concluded that animals in T4 group experienced
relatively mild heat stress when compared to control group. Among the three thermal stress
alleviating measures, T4 (automated wetting and forced ventilation) was the group that
exhibited lowest heat stress during high THI which was evident by the lower values in
physiological and biochemical parameters. So, it could be suggested that in tropical humid
climate, automated wetting and forced ventilation with respect to dynamic variation in
temperature and relative humidity maybe preferred in comparison to other thermal stress
alleviating measures for Murrah buffaloes.