Effect of simulated summer environment on growing lambs under hot semi-arid tropical region

Abstract

An extended hot summer is a major constraint in animal production in the semi-arid tropical region. However, the adult native sheep is well-adapted to this climatic condition. Nonetheless, the adaptability of growing lambs in summer conditions is yet to be explored for sustainable sheep production. Therefore, the present study was carried out to assess the effect of simulated summer environment on the growing lambs in hot, semi-arid regions. For this purpose, 16 Malpura weaner lambs of 3-4 months of age were selected and equally distributed into two groups, control (C) and thermal exposure (T). The lambs of T groups (n = 8) were kept inside the psychometric chamber in different temperature and humidity schedules simulated with the summer average temperature and humidity of the last 10-year of the semi-arid tropics. The lambs of C groups (n = 8) were kept inside the pen in a thermocomfort environment with the same space availability of T group lambs. The lambs of both the groups were provided with ad libitum feed and water. The general linear model procedure was applied to analyze the data. The water intake, respiration rate, pulse rate, rectal temperature, and skin temperature of T group lamb were significantly (P < 0.05) higher as compared to C group lambs. The summer exposure (T) reduced (P < 0.01) the feeding and rumination time whereas increased (P < 0.01) the panting in lambs as compared to C group. The endocrine profile did not vary (P > 0.05) with the simulated summer exposure of semi-arid region in lambs. The present study reflected that the native Malpura growing lamb modifies their behavior and thermoregulatory responses to counter the extreme summer of the semi-arid region.