Genetics play a big role in feed efficiency. The Pork Checkoff-has funded research to identify genes that impact feed efficiency in pigs.

The research was designed to identify genetic markers for producers to use in marker-assisted selection programs to improve feed efficiency. Because feed-intake data is expensive to collect on individual finisher pigs, the Pork Checkoff made this investment so producers would have such trait data available to them.

About 10 years ago, Iowa State University (ISU) started selection for residual feed intake, which measures the difference between what an animal actually consumes and the average amount of feed required for that animal’s maintenance and growth. To do this, ISU established two lines, a selection line for residual feed intake and a control by randomly splitting litters. For this study, 730 animals from the first seven generations of these lines were genotyped.

To improve the speed and reduce the cost of genotyping, a tool known as the PorcineSNP60 BeadChip (SNP chip) was developed with the assistance of ISU’s Dr. Max Rothschild and other researchers. The single nucleotide polymorphism (SNP) chip simultaneously genotypes 64,232 genetic markers in a single pig at a cost of about 0.3 cents per genotype.

Study Yields Promising Results
The SNP chip works extremely well in many populations. Statistical analyses identified numerous genetic markers for residual feed intake, average daily feed intake, average daily gain and backfat. A currently unmapped genetic marker had a large effect on backfat, accounting for more than 3 percent of the genetic variance in the trait.

By selecting animals using genetic markers associated with residual feed intake, producers could reduce feed costs without the expense and difficulty of measuring feed intake and without reducing growth rates. Taken together, selection for the various markers identified in this study could reduce cost per pig produced in the near future.

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