Resistance of exotic and domestic lambs to experimental infection with Haemonchus contortus.

摘要: Abstract Resistance to primary and secondary infections with H. contortus was compared in St. Croix, 3/4 Florida Native, Barbados Blackbelly domestic crossbred lambs. On the basis of worm counts, fecal egg counts packed cell volumes, Croix lambs were most resistant infections, Native intermediate resistance, least resistant. Breed differences highly variable during infection. pronounced prior puberty, susceptible infections. After better able resist Age apparently had little or no effect on parasite resistance exotic breeds. Sex significant only after puberty when ewe more infection than ram In one three experiments hemoglobin genotype AB BB terms volumes proportion ‘responder’ ‘nonresponder’ but not although subtle may have been detected because small numbers