The effects of transfer factor, parasitic antigen and precipitated immunoglobulin treatments in lambs infected with Haemonchus contortus.

Significant reductions in adult worm burdens in lambs less than six months old infected with 5000 third stage Haemonchus contortus larvae were achieved following the combination of a single transfer factor treatment with multiple parenteral treatments of adult parasitic antigen and precipitated immunoglobulin. Specific cellular responses in the abomasa associated with individual treatments were discernible in all the experimental groups and quantitative differences in these responses reflected the varying treatment levels and treatment combinations. The reactions associated with transfer factor were similar to immediate type hypersensitivity responses and their role as possible effector mechanisms in correcting partial immune incompetency in lambs is discussed.