Wool production of sheep chronically infected with Haemonchus contortus.
A chronic infection was established in a group of twenty 18-month-old non-reproductive Merino ewes by oral administration of 3000 infective H. contortus larvae twice weekly for 12 weeks. Their live-weights and wool production were compared with those of 20 uninfected ewes grazing the same pasture. In the infected sheep, faecal egg counts increased over a period of 9 weeks to reach a mean of 5000 eggs per gram, accompanied by small, but significant effects on packed-cell volume and live-weight. The effects of infection on wool growth were also small, and not statistically significant, although there was evidence of a faster seasonal decline in wool growth in infected sheep. It was concluded that mortality induced by acute infection is the most important economic effect of this parasite.
D000818:Animals; D001835:Body Weight; D002908:Chronic Disease; D005243:Feces / Q000469:parasitology; D005260:Female; D006188:Haemonchiasis / Q000469:parasitology / Q000503:physiopathology / Q000662:veterinary*; D006400:Hematocrit / Q000662:veterinary; D008297:Male; D010270:Parasite Egg Count / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology / Q000503:physiopathology*; D014252:Trichostrongyloidiasis / Q000662:veterinary*; D014935:Wool / Q000254:growth & development*