Protein and roughage supplements for pregnant and lactating ewes fed wheat for survival

Abstract

Wheat-based diets were supplemented to provide additional protein and/or roughage to meet nutrient and energy requirements of Merino ewes in late pregnancy and early lactation. Protein sources were soybean meal, meat and bone meal, and lupins; safflower meal was used as a source of both protein and roughage, while barley straw provided roughage alone. Treatments received adequate vitamin A and mineral supplementation, including calcium, sodium, sulfur, magnesium, potassium, copper, cobalt, iodine and selenium. Management of ewes in late pregnancy was complicated by metabolic disorders, in particular hypocalcaemia. Lamb birth weight was increased with supplements of protein or roughage which had not been pelleted. A nutritional myopathy associated with vitamin E deficiency resulted in the sudden death of 5% of the lambs born alive. Although ewes receiving wheat alone showed increased liveweight following lambing, the growth rate of their lambs was inadequate for survival. Treatments receiving protein alone initially had higher lamb growth rates than those given roughage, but this difference was not maintained over the 6-week feeding period. In treatments given both protein and roughage, lambs tended to have higher growth rate and ewes lost more liveweight.