1. The value of circulating eosinophil count as a selection criteria for resistance of sheep to trichostrongyle parasites.
- Author
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Woolaston RR, Manueli P, Eady SJ, Barger IA, Le Jambre LF, Banks DJ, and Windon RG
- Subjects
- Analysis of Variance, Animals, Female, Haemonchiasis genetics, Haemonchiasis immunology, Haemonchiasis veterinary, Immunity, Innate genetics, Leukocyte Count, Male, Parasite Egg Count, Predictive Value of Tests, Sheep, Sheep Diseases genetics, Trichostrongyloidiasis genetics, Trichostrongyloidiasis immunology, Trichostrongylosis genetics, Trichostrongylosis immunology, Trichostrongylosis veterinary, Eosinophils, Selection, Genetic, Sheep Diseases immunology, Trichostrongyloidiasis veterinary
- Abstract
In merino sheep bred for either increased or decreased resistance to Haemonchus contortus, faecal worm egg counts (FEC) were lower in the resistant line (6,831 vs 17,645 epg, P < 0.01), and circulating eosinophils (EOS) were higher, but not significantly so (3.40 x 10(4) ml(-1) vs 1.40 x 10(4) ml(-1), P = 0.1 1). Another flock was artificially infected with Trichostrongylus colubriformis and significant genetic variation was found in both FEC (heritability 0.40 +/- 0.11) and EOS (0.19 +/- 0.08). In a third flock comprising tropical sheep breeds, a natural challenge with T. colubriformis resulted in significant sire effects on FEC (heritability 0.20 +/- 0.10) but not EOS (heritability inestimable). We conclude that EOS offers no advantage over FEC as it selection criterion for resistance.
- Published
- 1996
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