Renal performance in relation to water and nitrogen metabolism in bedouin goats during lactation

Abstract

1. 1. Black Bedouin goats (16–24 kg body wt) at 4–5 months post partum produce daily in the laboratory 50 g milk per kg body wt. Similar yields were recorded at mid-summer in goats herded in the desert where food is meagre, low in protein and water is scarce. 2. 2. Urine concentration in lactating goats was higher than in goats before gestation but urine urea concentration was only a third that in the non-lactating ones. The increase in urine volume in the lactating goats was less pronounced than the increase in drinking and water turnover rates or in food consumption. 3. 3. Daily renal reabsorption of urea in lactating goats amounted to 588 mmol compared to only 361 in non-lactating ones. Urine urea loss in lactating goats was 25% less than in the non-lactating ones. 4. 4. Urea entry rate in lactating goats was 65% higher than in non-lactating goats. 748.6 mmol urea were recycled daily in lactating goats compared to only 277 mmol in non-lactating ones. 5. 5. The role the kidney plays in economizing both water and nitrogen metabolism in goats lactating in the desert is assessed and discussed.