Protein supplementation in the first 100 days of gestation fails to enhance resistance of weaned Merino lambs against Haemonchus contortus

The aims of this study were to investigate the effects of a high-protein maternal diet on the fetal immune system development, and subsequently on resistance to the abomasal blood sucking parasite Haemonchus contortus in lambs after weaning. Merino ewes (n=39) of mixed age and parity were fed either a normal protein diet (12% CP) or a high-protein diet (21% CP) for the first 100 day of their 150 day gestation. The lambs were weaned at 3 months old and infected at 6 months of age with 10,000 L3 H. contortus larvae. No significant differences were found between the groups fed a normal protein diet and a high-protein diet in any of the variables measured in lambs (birth weight, fleece weight or fecal parasite egg counts) However, there were differences in hematological variables, except lymphocytes and monocytes, between lambs born to ewes fed 12% or 21% protein during the first 100 day of gestation. Fetal exposure to a maternal high-protein diet during the first 100 day of gestation did not appear to influence lamb susceptibility to experimental H. contortus infection in Merino lambs.