Influence of Temperature and Humidity on Pregnancy Rate of Murrah Buffaloes under Subtropical Climate.

Soumya Dash,N Kashyap,A K Chakravarty,V Sah,R Behera,V Jamuna,B Deshmukh

doi:10.5713/ajas.14.0825

Abstract

Heat stress has adverse effects on fertility of dairy animals. Decline in fertility is linearly associated with an increase in combination of both temperature and humidity. The purpose of this study was to investigate the relationship between temperature humidity index (THI) and the pregnancy rate of Murrah buffaloes in a subtropical climate. The effects of genetic and non-genetic factors viz., sire, parity, period of calving and age group at first calving were found non-significant on pregnancy rate. The effect of THI was found significant (p<0.001) on pregnancy rate of Murrah buffaloes calved for first time and overall pregnancy rate. The threshold THI affecting the pregnancy rate was identified as THI 75. The months from October to March showed THI<75 and considered as non heat stress zone (NHSZ), while months from April to September were determined as heat stress zone (HSZ) with THI≥75. The lowest overall pregnancy rate (0.25) was obtained in July with THI 80.9, while the highest overall pregnancy rate (0.59) was found in November with THI 66.1. May and June were identified as critical heat stress zone (CHSZ) within the HSZ with maximum decline (−7%) in pregnancy rate with per unit increase in THI. The highest overall pregnancy rate was estimated as 0.45 in NHSZ with THI value 56.7 to 73.2. The pregnancy rate was found to have declined to 0.28 in HSZ with THI 73.5 to 83.7. However, the lowest pregnancy rate was estimated as 0.27 in CHSZ with THI value 80.3 to 81.6.

Highlights

Buffaloes are generally reared in the subtropical region where they are exposed to wide range of temperature and humidity
The genetic and non-genetic factors like sire, parity, period of calving and age group at first calving had no significant effects on the pregnancy rate of Murrah buffaloes
The effect of THI was highly significant (p

Summary

Introduction

Buffaloes are generally reared in the subtropical region where they are exposed to wide range of temperature and humidity. The district Karnal belongs to Haryana, a home tract of Murrah buffaloes in India where the climatic parameters like temperature in summer reach up to 47°C and decline to the extent of 1°C during winter. In tropical and subtropical climate, high ambient temperature is the major constraint on animal productivity (Marai et al, 2008). They exhibit a seasonal variation in display of oestrus, conception rate and calving (Sing and Nanda, 1993). Few buffaloes exhibit postpartum oestrus during April and May due to maximum air temperature (Abayawansa et al, 2011).

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