ARS | Publication request: Identification of QTL affecting a piglet’s ability to acquire and absorb gamma-immunoglobulin from colostrum

Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: December 19, 2012
Publication Date: March 1, 2013
Citation: Rohrer, G.A., Rempel, L.A., Miles, J.R., Keele, J.W., Vallet, J.L. 2013. Identification of QTL affecting a piglet’s ability to acquire and absorb gamma-immunoglobulin from colostrum [abstract]. Journal of Animal Science. 91 (Supplement 2):63-64 (Abstract #O189).

Technical Abstract: Consumption of an adequate amount of colostrum is critical to a piglet’s survival and productivity. The immunocrit is an inexpensive rapid measurement of the amount of gamma-immunoglobulin absorbed by a piglet. Genetic analysis of immunocrits on 5,312 piglets indicated that the heritabilities (se) for direct and maternal effects were 0.13(0.06) and 0.53(0.08), respectively. To identify QTL for direct genetic effects, piglets with the highest and lowest immunocrits from litters of eight or more were selected from 470 litters. The second highest and second lowest piglets in 24 litters were also selected. Pools were assigned based on sire of the litter. Six sets of high and low pools were created by mixing equal quantities of DNA of ~100 piglets. Pools 1 through 5 were unique and pool 6 contained a subsample of piglets from pools 1 and 2 from litters with the greatest variation. The 12 DNA pools were applied to SNP60 BeadChips. Normalized X and Y values were evaluated with three different methods and the 25 highest ranking SNP were selected from each evaluation for further study. In addition, 10 regions were studied based on a 5-SNP window approach. Selected SNP were individually genotyped in the 988 piglets included in pools as well as 524 piglets that had intermediate immunocrits. Association analyses were conducted fitting an animal model and using genetic parameters previously estimated. Twenty-five SNP were associated (P < 0.01) with immunocrit values and 10 remained significant (P < 0.05) after Bonferroni correction. These 25 markers were located in 18 genomic regions on 14 different chromosomes. In conclusion, the pooling strategy employed reduced the cost to scan the genome by more than 80% and identified genetic markers that can be used to improve a piglet’s ability to acquire gamma-immunoglobulin from colostrum. USDA is an equal opportunity provider and employer.