Variation in resistance to haemonchosis: selection of female sheep resistant to Haemonchus contortus.
Seventy female lambs (6-7 months old) which were exposed to natural infections of Haemonchus contortus were designated as responders or non-responders on the basis of 10 weekly cumulative faecal egg counts. Selected responder and non-responder lambs were treated with ivermectin, housed separately and 6 weeks post-housing, seven lambs from each group were given a trickle infection of Haemonchus contortus at 1000 L3 daily for 5 days per week up to 2 weeks and examined weekly for 10 weeks after first infection. Analysis of data revealed significantly lower mean faecal egg counts and non-significantly less weight loss in responder than non-responder lambs. Mean values of haemoglobin, packed cell volume, total serum protein and peripheral eosinophil counts were significantly higher in responders than non-responders. In contrast, serum pepsinogen concentration was significantly less in responders than in non-responders. At 10 weeks post-infection, there were fewer pathological lesions and significantly lower worm burdens in responders than in non-responders. These results demonstrate a distinct resistance in responders to Haemonchus contortus infection.
Hooda
V
V
Department of Veterinary Parasitology, Haryana Agricultural University, Hisar, India.
Yadav
C L
CL
Chaudhri
S S
SS
Rajpurohit
B S
BS
D000818:Animals; D001947:Breeding; D005243:Feces / Q000469:parasitology; D005260:Female; D006188:Haemonchiasis / Q000276:immunology* / Q000469:parasitology / Q000662:veterinary*; D006189:Haemonchus / Q000302:isolation & purification; D007113:Immunity, Innate; D010270:Parasite Egg Count; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology* / Q000469:parasitology