The effect of water-restriction on various physiological variables in intensively reared Lacaune ewes

The effects of water restriction on rectal temperature, respiratory rate and selected blood variables in intensively reared Lacaune ewes were evaluated. The tests were carried out over the course of 28 days in spring on 30 lactating sheep divided into three groups of 10 animals each, matched by lactation status and body weight and allocated into individual boxes. The animal groups were as follows: control group W100 with drinking water for the whole day (24 h/24 h), while the two experimental groups each received 80% (W80 group) and 60% (W60 group) of the water ration of the control group, respectively. The feed, in according with physiological and production needs of the animals, was administered in three daily meals (08:00, 14:00 and 20:00 h). Water intake was recorded three times per day (at 08:00, 14:00 and 20:00 h) and the daily feed intake at 08:00 h, while the rectal temperature, respiratory rate were measured and blood samplings were carried out on Day 0, Day 14 and Day 28. In water-restriction groups (W80 and W60) a lower (P < 0.01) feed intake of meadow hay, and a lower ingestion of alfalfa hay pellet in the W60 group compared to W100 group were observed. In addition, the water restriction regimen resulted in a significant decrease of respiratory rate (P < 0.05) and an increase in serum total protein, urea, creatinine, sodium, chlorine, reactive oxygen metabolites, cortisol, haemoglobin and mean corpuscular haemoglobin concentration (P < 0.05), red blood cell counts, and haematocrit (P < 0.01). These results show the important role of water, as limiting factor for animal breeding in low-water availability environments. Where possible, the management of low-dairy breeds should be well adapted to support the productive performance.