Effect of Three Levels of Grazing Nutrition upon Calving and Subsequent Performance in Hereford Heifers

There were no significant differences in calf birth weight and size between treatments in s ite of diet-induced differences in mean heifer liveweight of up to 81 e+ 7.4) kg 24 hours post-calving. There was a significantly higher incidence of stillbirth in the poorest-fed Rhodes grass heifers and two of these died as a result of dystocia compared with no dystocia or mortality in the other treatments. Pelvic size between treatments was similar and it is inferred that the inferior calving performance was associated with reduced calving endurance in the poorestfed Rhodes grass heifers. These animals subsequently reared calves which were significantly lighter in liveweight and grew at inferior rates throughout the pre-weaning period.