EFFECTS OF DEHYDRATION, REHYDRATION, AND HYPERHYDRATION IN THE LACTATING AND NONLACTATING 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.