The effect of high salt intake or restricted water intake on diet selection by sheep

Abstract

1. In three experiments sheep were offered a choice of two rations: one high in NaCl (7.5 or 15%) and one low in NaCl. The intake of each ration was recorded when fresh water was freely available, when increasing amounts of NaCl were added to the drinking water and when the amount of fresh water available was restricted.2. Low levels of NaCl in the drinking water or mild restriction of available water were without effect on the diet selected. At higher levels, total food intake was reduced and the reduction was sustained entirely by the high-salt ration. The intake of the low-salt ration remained the same or increased, so that the selected diet then contained an increased proportion of the low-salt ration. The effects of adding NaCl to the drinking water and of water restriction were similar.3. It was concluded that sheep with a choice of high- and low-salt rations can partly avoid the stress of saline drinking-water or restricted water supply by changing the proportion of each ration eaten.