The influence of breed on the susceptibility of sheep and goats to a single experimental infection with Haemonchus contortus.

Four breeds of sheep and three breeds of goats, maintained on both high and low planes of nutrition were given a single infection of 350 Haemonchus contortus larvae per kg. Although animals on a low protein diet had much higher faecal egg counts than those on the high protein diet the pattern of relative susceptibility was similar in both cases. It would appear that the nutritional status of the host influences its resistance to H contortus infection. Of the breeds studied the indigenous Red Masai was the most resistant breed of sheep while the exotic Saanen was more resistant than the the two indigenous breeds of goats.