Initial success achieved in ending surgical swine castration

Project successfully deletes gene that triggers release of hormones necessary for sexual maturation.

Castrating male piglets is currently practiced to improve the quality of meat for consumers, but from an animal welfare standpoint, the practice has caused concern, as it is usually preformed without pain management.

Today, Recombinetics/Acceligen and Hendrix Genetics announced that they have successfully used a genome editing method to create swine that remain in a prepubertal state, thus eliminating the need for surgical castration.

The first litter of castration-free prototype piglets using commercially relevant genetics confirms that the methodology is working, the companies reported.

In 2017 the Foundation for Food & Agriculture Research (FFAR) awarded a grant to Recombinetics Inc. to end surgical swine castration. Since then, Recombinetics/Acceligen and Hendrix Genetics -- pioneering companies in swine genetics, responsible farm animal breeding and precision breeding technologies -- formed the Alliance to End Surgical Castration of Swine. The venture developed an approach that prevents sexual maturation in swine without introducing any foreign material into the genes of pigs.

“This first litter of permanently prepubescent piglets is a huge success,” FFAR executive director Sally Rockey said. “Not only does the industry benefit, but once this technology is deployed commercially, we can eliminate an animal welfare issue while maintaining a quality product for consumers.”

An issue with intact male pigs is “boar taint,” which causes an unpleasant odor and unsavory taste in the resulting meat. Male pigs are castrated young to prevent boar taint, but pain relievers are rarely administered. Castrated piglets show an acute physiological stress response to castration, including increased stress hormone levels, elevated heart rate and demonstrated indicators of pain that can last for four days following the procedure. The European Union has banned the practice of swine castration, but the ban has been delayed amid challenges with implementation costs.

The new project has successfully deleted the gene that triggers the release of hormones necessary for sexual maturation in the piglets’ DNA, preventing them from reaching puberty and, thus, negating the need to castrate the pigs. The next step in this research is determining the commercial viability of castration-free pigs. Since these prototype pigs were created to be permanently prepubescent, the alliance is determining how to breed these pigs without comprising traits like feed efficiency and meat quality. The alliance comprises some of the largest pig genetic companies in the world, possessing the capacity and capabilities needed to supply these permanently prepubescent pigs to pork producers worldwide.

Research is being led by principal investigator Dr. Tad Sonstegard, chief executive and scientific officer of Acceligen, the agriculture division of Recombinetics.

“The birth of these castration-free prototype piglets using commercially relevant genetics is just another example of how Acceligen is working to deploy our breeding technologies to help producers better meet the demands of consumers and producers to improve food animal well-being,” Sonstegard said.

Further, Sonstegard said the technical expertise and support provided by industry partners and FFAR gives the alliance the capability to meet the demands with the highest standards.

“Together we will bring the castration-free trait to market and provide solutions to benefit the pork industry,” he added.

Luis Prieto Garcia, managing director swine of Hendrix Genetics, said, “At Hendrix Genetics, we are very excited about the birth of the first castration-free piglets. This is an important step to end one of the biggest concerns of the swine industry regarding animal well-being. Within Hypor, Hendrix Genetics’ swine business unit, we are continuously exploring new opportunities to support the pork value chain with innovative and sustainable genetic solutions.”