Little anthelmintic drenching required for lambs finished over winter and spring on annually re-established irrigated pasture on the Highveld of Gauteng province, South Africa

afrique du sud agneau anthelminthique anthelmintics cordero haemonchus contortus hiver invierno lambs ostertagia ovin ovinos pastizales pastures primavera printemps sheep south africa spring trichostrongylus colubriformis trichuris winter