Submitted to: American Association of Veterinary Parasitologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 29, 2006
Publication Date: July 14, 2006
Citation: Gasbarre, L.C., Sonstegard, T.S., Li, R.W., Araujo, R., Van Tassell, C.P. 2006. Resistance to Gastrointestinal nematodse of cattle: Identification of genomic regions affecting resistance and potential mechanisms [abstract]. American Association of Veterinary Parasitologists Proceedings. Technical Abstract: Gastrointestinal nematode infections remain a major economic drain on the efficient raising of cattle throughout the world. The recent demonstrations of the appearance of drug resistance in these parasites underscores the problems associated with a complete reliance on anthelmintics to control economic loss. A number of years ago we began the development of a resource population of Angus cattle to map and identify important bovine genes that affect resistance to these parasites. The pedigree of this population encompasses over 600 animals and approximately 500 of these have been completely characterized for their resistance to natural challenge by the parasites. Over the period of this work, we have seen the segregation of resistant and susceptible phenotypes and can now predict with about 80% accuracy the phenotype of calves prior to actual testing. The development of these animals has allowed us to begin to identify the areas of the genome that contain genes important in determining the resistance phenotype of individual animals, and also provided us with animals in which we can begin to determine the actual mechanisms of resistance, To date, we have identified 8 regions on 6 chromosomes that affect resistance to the parasites. In terms of mechanism(s) of resistance, it appears that resistant animals are more efficient in the generation and maintenance of inflammatory responses at the actual site of infection, i.e. the gut mucosa. The pending release of the bovine genome sequence and associated SNP HapMap will greatly facilitate the identification of the actual structural genetic polymorphisms that render animals resistant or susceptible to the parasites.