Trials with the Haemonchus vaccine, Barbervax ® , in ewes and lambs in a tropical environment: Nutrient supplementation improves protection in periparturient ewes.

•Vaccination of grazing ewes and lambs against Haemonchus contortus.•The nutritional status affects the outcome of the vaccine against haemonchosis.•Vaccinated animals received less precautionary treatments with anthelmintic.•Protective effect between vaccination and improved nutrition against haemonchosis.•Barbervax® can afford high level of protection against haemonchosis in young lambs.