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

Abstract

Groups of 50–60 ewes grazing sown pastures near Adelaide, S.A., 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%; (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 one group received reservoir water and another group received a chloride water containing I .00% total salts.

The ewes were mated, they lambed, and they reared their lambs in the paddocks while receiving the various waters. In at least one experiment, pregnant ewes, lactating ewes, and weaned lambs received the saline waters during the months of high environmental temperatures, with associated high water intakes.

The chloride water with a total salt concentration of 1.30% led to a reduction in the percentage of ewes that lambed in one experiment, but not in the other. It also led to decreased body weight gains of the lambs in both experiments, and in addition to diarrhoea and increased mortality in one experiment. Chloride water with 1.00% total salts led to decreased body weight gains and reduced wool production, without apparently adversely affecting the health of the lambs. Bicarbonate water with a total salt content of 0.50% had no adverse effect on the lambs in either experiment, but in one of these experiments it did lead to a reduction in the percentage of ewes that lambed.

The implications of the findings in relation to the use of saline drinking waters under field conditions are discussed.