Effects of dehydration, rehydration, and hyperhydration in the lactating and non-lactating black Moroccan goat

The effects of water deprivation, rehydration and hyperhydration were investigated in the black Moroccan goat (Capra hircus). Mean daily water intake was 46 +/- 5 ml/kg in lactating and 36 +/- 4 ml/kg in non-lactating black Moroccan goats, and milk production 21 +/- 1 ml/kg. Mean urine excretion was 8 +/- 2 ml/kg body weight in both groups, and the daily water losses via evaporation and feces were estimated at 23 +/- 3 ml/kg during lactation and 28 +/- 4 ml/kg during non-lactation. Forty-eight hours of water deprivation caused a body weight loss of 9% and 6% in lactating and non-lactating goats, respectively, and a drop of 28% in milk production with only a slight decrease in food intake. After rehydration, the elevated plasma osmolality as well as Na and total protein concentrations returned to basal values within 2-3 hr, indicating a rapid absorption of the ingested water, but urine excretion did not increase. After hyperhydration (10% of body weight), 46% of the load was excreted by the kidneys within 6 hr. In conclusion, black Moroccan goats have a low water turnover, and they can retain water upon rehydration but not store excess water after hyperhydration.