Effect of water restriction on physiological responses and certain reproductive traits of Malpura ewes in a semiarid tropical environment

Abstract

Other than high temperature and feed shortage, water scarcity is a major problem in semiarid tropical region during summer. Water is considered as an essential nutrient and is involved in every metabolic function of the body. Considering its importance in sheep productivity, twenty-eight nonpregnant Malpura ewes were randomly and equally divided into 4 groups, viz., GI (control; ad libitum water), GII (20% less than ad libitum water intake), GIII (40% less than ad libitum water), and GIV (ad libitum water on alternated day) to see the effect of water restriction on physiological responses and certain reproductive traits of Malpura ewes in semiarid tropical environment. This study was conducted for a period of 35 days covering 2 estrous cycles. All the animals were provided with ad libitum feed consisted of 70% roughage and 30% concentrate. All the ewes were synchronized for estrus at the starting of the experiment and reproductive parameters were recorded. The feed intake of all the ewes was recorded individually daily during the study period. All the ewes were weighed individually every week before morning feeding. Physiological responses were recorded twice daily at 0700 h and 1400 h on weekly basis. Blood samples were collected at weekly interval. The feed intake was lower (P 0.05) during afternoon. All the water-restricted groups showed a trend of lower respiration rate and pulse rate both in morning and afternoon compared with GI, although the difference was not significant. Hemoglobin, packed cell volume, glucose, cholesterol, and chloride level were significantly (P < 0.05) lower in GIV compared with GI. The glucose and cholesterol levels were (P < 0.05) lower in GIII compared with GI. Estrus percentage was lower (85.7%) in the water-restricted ewes compared with control (100%). Estrogen level was significantly (P < 0.05) lower in GIII and GIV compared with GI, whereas progesterone level showed a reverse trend. The present study reveals the effect of water stress on biological functions of Malpura ewes during summer. The results suggest that Malpura ewes can adjust their physiochemical response and reproduction up to 20% of water restriction during hot summer.