|Vantassell, Curtis - USDA BELTSVILLE MD|
|Padilha, Terezinha - USDA/EMBRAPA MD|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 30, 2002
Publication Date: November 13, 2002
Citation: GASBARRE, L.C., SONSTEGARD, T.S., VANTASSELL, C.P., PADILHA, T. IDENTIFICATION OF QTL AFFECTING RESISTANCE TO GASTROINTESTINAL PARASITES OF CATTLE. PLANT AND ANIMAL GENOME ABSTRACTS. pp. 218, 2002. Technical Abstract: Overall parasite transmission in cattle herds can be reduced by identifying the few individuals responsible for most of the gastrointestinal (GI) nematode transmission. We initiated a genome-wide scan of linebred Angus populations selected for resistance to GI parasites to identify quantitative trait loci (QTL) related to parasite infection. This unique population has a closed pedigree, where the 383 parasite-challenged calves were derived from 43 sire families, and most of these families were paternally descended from a single sire born in 1944. Genotypes were generated for 218 microsatellite markers using 432 animals including the parasite-challenged animals, their parents, and historic sires from the extended pedigree. Phenotypic traits analyzed were mean and peak numbers of nematode eggs/gram of feces and mean and final serum pepsinogen levels. GenoProb, a program that implements multilocus iterative allelic peeling to calculate probability of allele inheritance for each meiosis in the pedigree, was used to determine inheritance probabilities. These inheritance probabilities were used to identify QTL. Models for analysis included sex of calf, age of dam at calving, age of calf, calving season, and sire. In a sire family model, within-sire regression was done based on the probability of inheriting one of the two QTL alleles from the sire. For identity-by-descent analysis, phenotypic residuals were calculated in SAS, and marker associations were detected on a partial pedigree (N=373) using the TWOPOINT option of SOLAR. Together, putative QTL were identified on bovine chromosomes 1, 3, 5, 6, 8, 11, 12, 13, 14, 15, 19, and 26.