Dairy Genetic Diversity Concerns Highlighted
A recent segment produced by Iowa Public Television Service (PBS) featured the issue of minimal genetic diversity in the Holstein breed. The feature, shown on the Iowa PBS program “Market to Market,” noted that 99.75% of today’s Holstein sires are descendants of just two bulls.
Pennsylvania State University Associate Professor of Animal Science, Chad Dechow, and his research team have studied the issue of narrow genetic diversity in Holsteins in great depth. “It’s kind of the running joke in the industry that, ‘if it works, it’s line breeding; if it doesn’t, it’s inbreeding,’” said Dechow.
One Holstein sire born in 1962, Pawnee Farm Arlinda Chief, sired 16,000 daughters, 500,000 great-granddaughters, and more than 2 million great-granddaughters. But as descendants of Chief started showing up on both sides of pedigrees, a genetic recessive trait emerged. The APAF1 mutation, discovered by researchers at the University of California-Davis in 2016, causes mid-term fetal death and abortion, and is estimated to have cost the dairy industry $420 million.
Andy Snyder, a representative for GENEX in eastern Iowa, said producers are mindful of the Holstein breed’s lack of genetic diversity, yet still are driven by production and profitability demands. “They’re constantly looking for that outside bull, but he has to measure up,” said Snyder.
The piece also features Wayland, Iowa dairy producer Doug Roth, and how he is using beef crossbreeding and genomics to manage his herd’s genetic program. You can watch the full segment here.
