Evaluation of protection in grazing lambs immunised with different doses of Haemonchus contortus gut membrane glycoproteins in Southern Brazil

•Faecal egg count reduction in Haemonchus antigen treated lambs was of 59.3 % vs controls.•Antigen had a dose-dependent effect on packed cell volume.•Drenching was needed in 88 % of control lambs and in 16.7 % of vaccinates.•Antibody response was not related to antigen dose.