Studies on salt tolerance of sheep. V. The tolerance of sheep for mixtures of sodium chloride, sodium carbonate, and sodium bicarbonate in the drinking water

Abstract

Six groups, each of six sheep, were fed in pens for 15 months on a ration of chaffed lucerne and wheaten hays. One group was offered rain-water to drink, another group was offered 1.30% sodium chloride, whereas the others were offered one of the following mixtures of sodium chloride, carbonate, and bicarbonate: 1.26 + 0.015 + 0.025, 1.21 + 0.04 + 0.06, 1.12 + 0.08 + 0.13, and 0.95 + 0.161+ 0.25%. The intake of all saline solutions was higher than that of rain-water, ranging from 150% above for 1.30% sodium chloride to 60% above for the highest level of carbonates; the mean daily intakes for the entire experiment by the six groups were 2.6, 6.6, 4.8, 5.7, 5.8, and 4.2 l. respectively. The intake also increased in all groups with temperature, being 40–70% higher in the hottest months than in the coldest months.Weight increase was less from 6 months onward in the group receiving 1.30% sodium chloride, and was less at certain times only in the experiment in the groups receiving 0.04 or 0.10% carbonates, than in that receiving rain-water (control group). There were no differences in weight increase between the control group and the groups receiving the highest concentrations (0.21 and 0.41%) of carbonates The saline drinking waters had no effect on the concentrations of sodium, potassium, calcium, magnesium, or chloride in the blood plasma. The concentration of carbon dioxide was higher, for the last year of the experiment, in the blood of the control group, and, for approximately one-third of the experiment, in that of the group receiving the highest level of carbonates in its drinking water, than in that of any of the groups receiving lower levels of carbonates. There were differences in blood carbon dioxide on one occasion only between the control group and that receiving the highest level of carbonates. None of the solutions used in the experiment had any adverse effect on the general health, food consumption or wool production of the sheep.