Influence of the concentration and volume of saline water on the food intake of sheep, and on their excretion of sodium and water in urine and faeces

Abstract

The intake of food and the excretion of urine and faeces by 15 Merino sheep were recorded while they were given fixed volumes of fresh or saline (1 -5 and 2.0% sodium chloride) drinking water. The food intakes of the sheep increased as the volumes of either fresh or saline water were increased from 0.5 to 6.0 l/day. The addition of sodium chloride to the water decreased the food intake, but the decrease was restored by an increase in the volume of water given of c. 50 % for 1.5 % sodium chloride, and c. 100% for 2.0% sodium chloride. However, on 2.0% sodium chloride, no further increase in the intake of food occurred with volumes above 3.0 l/day, and maximum intakes were only 6045% of the maximum intakes on fresh water. When the lower volumes of saline water were given, the amount of food eaten for a given volume of water was decreased at higher temperatures and slightly decreased by a higher potassium content of the diet. High volumes (4.0-6.0 l/day) of 2.0% sodium chloride depressed food intake when the ration was oaten chaff, but not when it was lucerne chaff. The increased intake of sodium arising from the addition of sodium chloride to the water was excreted in the urine, and there was no change in the sodium content of the faeces. The concentrations of sodium and potassium in the urine declined as the amount to be excreted was increased. The volume of urine excreted was related to the amount of sodium and potassium to be excreted, while the amount of water lost in the faeces was related to the quantity of faecal dry matter excreted and the type of diet.