EFFECT OF COLD EXPOSURE ON LIVEWEIGHT AND BODY FLUID COMPARTMENTS IN SHEEP

Abstract
Effects of cold exposure on liveweight and body fluids were studied in 12 six-month-old wethers. Six sheep were offered feed ad libitum and six sheep were restricted to a near maintenance level of intake of a pelleted concentrate ration. The sheep were individually caged in controlled temperature chambers for two preliminary and four consecutive experimental (I-IV) periods of 10 days each; the preliminary periods and period I at 21 °C air temperature, periods II and III at 0 °C and period IV at 21 °C. In general, the responses to the cold were more pronounced during period II than period III, and more pronounced in the sheep on restricted feed than in the sheep on ad libitum feed. The sheep receiving feed ad libitum were able to maintain or increase their liveweight and body solids throughout the experiment. The sheep receiving a restricted ration lost 2.53 kg during the first 8 days of period II. Their total body water (tritiated water space) was reduced by 1.68 L representing 66% of the weight loss, and their body solids were reduced by 0.85 kg. The reticulo-rumen fluid volume (51Cr EDTA space) was reduced by 1.32 L; the interstitial fluid volume (SCN space-T-1824 space) by 0.39 L and the plasma volume (T-1824 space) by 0.13 L. There was no reduction in absolute intracellular fluid volume with cold exposure.