The efficiency of utilization of grass by lactating ewes

Abstract

1. A study of grazing intake and efficiency was carried out on eighty-one ewes suckling twin lambs during early lactation.2. A method of estimating comparative grazing intake is described involving the administration of Cr2O3 and sampling from the pasture with the minimum of labour. The results indicated that reasonable precision was achieved with a method suitable for studying large numbers of animals. 3. The efficiency of production of lamb up to 5 weeks of age was not associated with the body weight of the ewe nor with the wither height. It was, however, negatively associated with grass intake by the ewe and to some extent with the gain in body weight by the ewe during lactation. Only in two of the four experiments was efficiency associated with lamb production up to 5 weeks.