Studies on salt tolerance of sheep. VII. The tolerance of ewes and their lambs in pens for drinking waters of the types obtained from underground sources in Australia

Groups of eight or 10 ewes were fed in pens on a ration of chaffed lucerne and wheaten hays and oats and were offered various solutions as drinking waters. In two experiments these comprised: (1) reservoir water (control group); (2) synthetic water containing salts in the proportions found in many underground waters in South and Western Australia ("chloride water") with a total salt concentration of 1.30%; or (3) synthetic water resembling the waters obtained in Queensland from the Great Artesian Basin ("bicarbonate water") with a total salt concentration of 0.50%. In a third experiment the total concentration of salts in the chloride water was only 1.00%, that of the bicarbonate water again being 0.50%. The ewes were mated, they lambed, and they reared their lambs on the experimental regime until the lambs were weaned at the age of approximately 10 weeks. The weaned lambs were continued on the treatment for a further 5 months, the total duration of each experiment being 13 months. The commencement dates of the experiments were separated by intervals of approximately 6 months; by this arrangement pregnant ewes, lactating ewes, and weaned lambs received, in at least one experiment, the saline waters during the months of high environmental temperatures, with the associated high water intakes. There was some indication in one experiment of a poorer reproductive performance by the ewes receiving either chloride (1.30% total salts) or bicarbonate water as compared with the control group. The intake of saline waters in all experiments was higher than that of reservoir water, the increases ranging from 20 to 50%. The body weight increases during early pregnancy of the ewes receiving saline waters were identical with those of the corresponding control groups. Significantly lower body weights, as compared with the control group, were observed at one period only in one group of treated lambs receiving chloride water with a concentration of 1.30% total salts. Reductions in the sodium, potassium, and chloride concentrations in the plasma occurred in some groups receiving saline water. No effect was observed on concentrations of calcium, while the effect on magnesium was variable. No adverse effects were observed on health, food consumption, or wool production of the ewes and lambs as a result of drinking any of the saline waters. It is suggested that under the conditions of the experiment, ewes and their lambs could tolerate drinking water of either the chloride type with 1.00% total salts or the bicarbonate type with 0.50*#37; total salts.