Abstract:
Six of 10 lambs previously given two doses of irradiated (60 kr) Haemonchus contortus larvae showed solid resistance to an experimental challenge with 10,000 larvae. The remaining four lambs in the group developed moderate infections. Nine of 10 lambs previously given two doses of irradiated (80 kr) Trichostrongylus colubriformis larvae showed solid resistance to an experimental challenge with 30,000 larvae. The 10th lamb was moderately resistant. Doses of X-rays within the range 40