Adaptability and growth of Malpura ewes subjected to thermal and nutritional stress

摘要

A study was conducted to assess the effect of combined stresses (thermal and nutritional) on physiological adaptability and growth performance of Malpura ewes. Twenty-eight adult Malpura ewes (average BW 33.56 kg) were used in the present study. The ewes were divided into four groups, viz., GI (n=7; control), GII (n=7; thermal stress), GIII (n=7; nutritional stress), and GIV (n=7; combined stress). The animals were stall-fed with a diet consisting of 60% roughage and 40% concentrate. GI and GII ewes were provided with ad libitum feeding, while GIII and GIV ewes were provided with restricted feed (30% intake of GI ewes) to induce nutritional stress. GII and GIV ewes were kept in climatic chamber at 40pC and 55% RH for 6 h/day between 1000 and 1600 hours to induce thermal stress. The study was conducted for a period of two estrus cycles. The parameters studied were feed intake, water intake, physiological responses (viz., respiration rate, pulse rate, and rectal temperature), body weight, and body condition scoring (BCS) of ewes. Both thermal and combined stress significantly (P<0.05) affected the feed intake, water intake, respiration rate, and rectal temperature. The feeding schedule followed in the experiment significantly (P<0.05) altered the body weight and BCS between the groups. The results reveal that when compared with thermal stress, nutritional stress had less significant effect on the parameters studied. However, when both these stresses were coupled, it had a significant influence on all the parameters studied in these ewes. It can be concluded from this study that when two stressors occur simultaneously, the total cost may have severe impact on biological function.