INFLUENCE OF DIETARY-PROTEIN ON PARASITE ESTABLISHMENT AND PATHOGENESIS IN FINN DORSET AND SCOTTISH BLACKFACE LAMBS GIVEN A SINGLE MODERATE INFECTION OF HAEMONCHUS-CONTORTUS

The influence of dietary protein on parasite establishment and pathogenesis of H. contortus in lambs of 2 breeds Finn Dorset and Scottish Blackface was examined. The lambs were introduced to high protein (170 g crude protein (CP) kg-1 dry matter (DM)) or low protein (88 g CP kg-1 DM) diets at 3 mo. old and infected 1 mo. later with 125 larvae (kg body wt)-1. Blood and fecal samples were collected for analysis and body wt recorded weekly. The lambs were killed 20 wk after infection. A 2nd experiment was conducted in Blackface lambs solely to determine the influence on parasite establishment of the high and low protein diets following infection with 125 larvae kg-1. These lambs were killed 5 or 14 wk after infection. In Scottish Blackface lambs dietary protein did not significantly influence the establishment of H. contortus. In Finn Dorset lambs dietary protein may have influenced parasite establishment since lambs on the low protein diet had a higher fecal egg output 4 wk after infection and more severe clinical signs than infected lambs of the same breed on a high protein diet.