Monday, 28 August 2017

The genetic basis for the selection of dairy goats with enhanced resistance to gastrointestinal nematodes

Parasite. 2017;24:32. doi: 10.1051/parasite/2017033. Epub 2017 Aug 9. Heckendorn F1, Bieber A1, Werne S1, Saratsis A2, Maurer V1, Stricker C3. Author information 1 Research Institute for Organic Agriculture (FiBL), PO Box, CH-5070 Frick, Switzerland. 2 Laboratory of Parasitology, Veterinary Research Institute, Hellenic Agricultural Organization Demeter, Thermi, 57001 Thessaloniki, Greece. 3 agn Genetics GmbH, Börtjistrasse 8b, 7260 Davos, Switzerland. Abstract Gastrointestinal nematodes (GIN) severely affect small ruminant production worldwide. Increasing problems of anthelmintic resistance have given strong impetus to the search for alternative strategies to control GIN. Selection of animals with an enhanced resistance to GIN has been shown to be successful in sheep. In goats, the corresponding information is comparatively poor. Therefore, the present study was designed to provide reliable data on heritabilities of and genetic correlations between phenotypic traits linked to GIN and milk yield in two major dairy goat breeds (Alpine and Saanen). In all, 20 herds totalling 1303 goats were enrolled in the study. All herds had (i) a history of gastrointestinal nematode infection, (ii) uniform GIN exposure on pasture and (iii) regular milk recordings. For all goats, individual recordings of faecal egg counts (FEC), FAMACHA© eye score, packed cell volume (PCV) and milk yield were performed twice a year with an anthelmintic treatment in between. The collected phenotypic data were multivariately modelled using animal as a random effect with its covariance structure inferred from the pedigree, enabling estimation of the heritabilities of the respective traits and the genetic correlation between them. The heritabilities of FEC, FAMACHA© and PCV were 0.07, 0.22 and 0.22, respectively. The genetic correlation between FEC and FAMACHA© was close to zero and -0.41 between FEC and PCV. The phenotypic correlation between FEC and milk yield was close to zero, whereas the genetic correlation was 0.49. Our data suggest low heritability of FEC in Saanen and Alpine goats and an unfavourable genetic correlation of FEC with milk yield. © F. Heckendorn et al., published by EDP Sciences, 2017. PMID: 28792887 PMCID: PMC5550108 DOI: 10.1051/parasite/2017033 Free PMC Article Share on FacebookShare on TwitterShare on Google+