Many traits financially important to hog producers are either expensive or time-consuming to measure or difficult to successfully select animals for based on low heritability of the targeted traits. Feed efficiency and sow longevity are examples of such traits. If genetic markers can be used successfully in marker-assisted selection (MAS) to improve these traits, producers would see a large impact on their profits.
The objectives of this study were to: 1) use the newly developed porcine SNP chip to genotype animals from the NPB funded feed efficiency and longevity trials; 2) complete association analyses to determine which markers are associated with the traits of interest; and 3) inform producers of how to utilize this genetic information in selection programs.
Feed efficiency and its relationship to growth and backfat were assessed in this genetic marker association study by analyzing residual feed intake (RFI – a measure of the difference between what an animal actually consumes and the average amount of feed required for that animal’s level of maintenance and growth), average daily feed intake (ADFI), average daily gain (ADG), and backfat (BF). Sow longevity depends significantly on the structural soundness of sows’ feet and legs. Many feet and leg structure traits, such as overall leg action and front leg pastern conformation, were analyzed to address this objective.
All traits were analyzed in Yorkshire and/or Landrace x Yorkshire crossbreds with a total of 1550 animals genotyped, 250 more animals than planned in the original proposal. The SNP chip genotyped 64,232 genetic markers (almost 15,000 more than originally planned) in each animal at a cost of approximately 0.3 cents per genotype. Genetic effects of these markers were estimated using an advanced statistical method developed by Drs. Dorian Garrick and Rohan Fernando at Iowa State University.
Many well-known and newly discovered regions of significance were identified throughout the pig genome during analyses for each of these traits. An example of a well-known gene is MC4R which was again found to be associated with ADFI, ADG, and BF in the current study. Hundreds of new regions of significance were also identified which will require more in-depth research to confirm their effects. More detailed results are given in the final reports on NPB grants #08-011 and #08-012. Overall, the findings from this study look very promising. Validation of these results may prove that utilization of some of these markers in MAS can decrease production costs by several dollars per pig in the near future.
For additional information, contact Dr. Rothschild at [email protected] or call (515) 294-6202.
