The nutrient status of sheep grazing on a dry Mitchell grass pasture association in central-western Queensland.

Abstract

The lambing performance of a group of ewes grazing a dry Mitchell grass pasture association in central-westem Queensland was recorded and found to be very poor. A portion of the ewe flock received a urea-molasses supplement those ewes did not exhibit an increase in lamb or ewe survival and it is likely that most did not consume the supplement. One week prior to the ewes' expected date of lambing, intact wethers and other wethers with oesophageal fistulas or rumen and abomasal cannulas were grazed on the pasture and the intake and digestion of nutrients by these animals were determined. Extrapolating the results from the wethers to the ewes indicated that the major limiting nutrients for the ewes were energy and, at least during the latter stages of lactation, rumen digestible nitrogen. Other nutrients that may have been deficient in the diet were copper and zinc.