The availability of the infective stages of nematode parasites to sheep in early spring.
D000818:Animals; D006632:Histamine / Q000662:veterinary*; D009348:Nematoda; D010271:Parasites; D012621:Seasons; D012756:Sheep; D012757:Sheep Diseases
D006632:Histamine
NEOANTERGAN/veterinary; SHEEP/diseases