PROTEIN SUPPLEMENTATION IMPROVES THE PERFORMANCE OF PARASITIZED SHEEPFED A STRAW-BASED DIET

A study was made of the benefits of protein supplementation for parasi tised and non-parasitised lambs. Sixty, 5-month-old crossbred wether l ambs were placed in individual pens indoors for 9 weeks. Half of the a nimals were experimentally dosed with 1500 Haemonchus contortus larvae per head per week and were fed ad libitum and the other half were wor m-free, pair-fed controls. Diets were formulated to be iso-energetic ( 9.0 MJ of calculated metabolisable energy per kg dry matter) with five levels of protein (10, 13, 16, 19 and 22% crude protein). These diets were based on oaten chaff, with barley, cotton-seed meal, urea and mi neral mix (except for the 22% crude protein diet which did not contain barley). Dietary crude protein content increased live-weight gain, fe ed intake, rumen fluid ammonia-N, packed cell volume, eosinophil count s and antibody responses to H. contortus L3 antigen and decreased faec al worm egg counts significantly. Infection did not significantly affe ct packed cell volume of animals on diets with 16, 19 and 22% crude pr otein content. We conclude that extra dietary protein can prevent the adverse effects of H. contortus infection on animal production. (C) 19 98 Australian Society for Parasitology. Published by Elsevier Science Ltd.