title: Estimation of genetic parameters for resistance to gastro-intestinal nematodes in pure blood Arabian horses.
abstract: Equine internal parasites, mostly cyathostomins, affect both horse welfare and performance. The appearance of anthelmintic-resistant parasites creates a pressing need for optimising drenching schemes. This optimization may be achieved by identifying genetic markers associated with host susceptibility to infection and then to drench carriers of these markers. The aim of our study was to characterise the genetics of horse resistance to strongyle infection by estimating heritability of this trait in an Arabian pure blood population. A population of 789 Arabian pure blood horses from the Michałów stud farm, Poland were measured for strongyle egg excretion twice a year, over 8 years. Low repeatability values were found for faecal egg counts. Our analyses showed that less than 10% of the observed variation for strongyle faecal egg counts in this population had a genetic origin. However, additional analyses highlighted an age-dependent increase in heritability which was 0.04 (±0.02) in young horses (up to 3 years of age) but 0.21 (±0.04) in older ones. These results suggest that a significant part of the inter-individual variation has a genetic origin. This paves the way to a genomic dissection of horse-nematode interactions which might provide predictive markers of susceptibility, allowing individualised drenching schemes.
authors.affiliation: Department of Zoology and Ecology, University of Agriculture of Krakow, 30-059 Krakow, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Kornaś
authors.affiliation: INRA, UMR1282 Infectiologie et Santé Publique, F-37380 Nouzilly, France; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France. Electronic address: Guillaume.Salle@tours.inra.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Sallé
authors.affiliation: Department of Zoology and Ecology, University of Agriculture of Krakow, 30-059 Krakow, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Skalska
authors.affiliation: INRA, UMR1388 Génétique, Physiologie et Systèmes d'élevage, F-31326 Castanet-Tolosan, France.
authors.forename: Ingrid
authors.initials: I
authors.lastname: David
authors.affiliation: INRA, UMR1313 Génétique Animale et Biologie Intégrative, F-78352 Jouy-en-Josas, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Ricard
authors.affiliation: INRA, UMR1282 Infectiologie et Santé Publique, F-37380 Nouzilly, France; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, F-37000 Tours, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Cabaret
mesh_terms: D000818:Animals; D060467:Disease Resistance; D005243:Feces / Q000469:parasitology; D005260:Female; D006736:Horses; D008297:Male; D010270:Parasite Egg Count; D011044:Poland; D019655:Quantitative Trait, Heritable; D013319:Strongyle Infections, Equine / Q000235:genetics / Q000276:immunology* / Q000469:parasitology*
keywords: Genetic resistance; Heritability; Horse; Nematode; Repeatability