Effect of salt water ingestion on pregnancy in the ewe and on lamb survival

Abstract

The addition ot sodium chloride, to provide concentrations of 1.0 and 1.3&337;, to the drinking water of pregnant ewes caused distress at parturition to some of the ewes and neonatal mortalities in their lambs. The effects were more evident in older sheep (aged 7 years) than in younger (3-year-old) animals and were associated, in general, with ewes which carried twin lambs.

Progesterone levels in the blood plasma of sheep were higher in twin-bearing ewes than in ewes with single lambs, both for control ewes drinking fresh water and for ewes drinking saline. Drinking 1.3% saline augmented the increase in progesterone levels in older ewes bearing twins. Cortisol levels were normal in all ewes.

Plasma levels of potassium and chloride were significantly higher and calcium and magnesium levels lower in pregnant ewes which received saline.

It is suggested that the adverse effects of salt water ingestion in twin-bearing pregnant ewes could be due to an excessive retention of potassium and chloride, brought about by a disturbance of normal sodium homeostatic mechanisms associated with the pregnant state of the animals.