Effect of management factors on fecal egg counts of Haemonchus contortus in pastured sheep and goats in Northern New England

Abstract

Haemonchus contortus (HC) is a subtropical parasite whose pasture-based larval stages are reduced significantly by severe Northern New England winters. Consequently, HC-contaminated northern pastures experience a winter die-off of infective larvae, with re-colonization of pastures occurring as temperatures moderate each spring. The cold winter environment of northern New England provides sheep and goat producers with an advantage over southern farmers because HC-infected fields may be managed each spring to minimize recontamination of pastures, and there is a short grazing season that limits the build-up of infective larvae on pastures. Management data were collected and HC concentrations in pooled feces were measured during the grazing season on 73 farms in Maine, New Hampshire and Vermont. Our objective was to determine the effect of farm type and management strategy on the abundance of H. contortus during the grazing season on northern New England farms.