Pork producers now have a new option for temporary immunological castration and reduction of boar taint in intact male pigs intended for pork. The veterinary-prescription product Improvest (gonadotropin releasing factor-diphtheria toxoid conjugate) from Pfizer Animal Health has received U.S. Food and Drug Administration approval for the United States.

Improvest is a protein compound that uses the pig’s own immune system to provide the same effect as surgical castration, but much later in the male pig’s life.

By eliminating the need for surgical castration, the animal grows with all the inherent advantages of intact males until the second dose. Studies confirm that intact-male pigs eat less feed and produce more meat, increasing feed efficiency by 6 percent to 10 percent, along with a typical improvement of 2 percent to 2.5 percent higher cutout yield. Since male pigs given Improvest are not surgically castrated, the risk of infection or death is eliminated, decreasing mortality by 1.6 percent.

“Improvest creates an opportunity to capture more value from male pigs,” says Jim Bradford, DVM, Pfizer Animal Health. “Male pigs are given Improvest later in the finishing phase to manage boar taint, so they’re able to grow to their full intact-male potential, and do it more efficiently.” 

Improvest is administered by injection. The first dose primes the system and should be administered no earlier than 9 weeks of age. The second dose should be administered at least four weeks later.

Pigs should be sent to market no earlier than four weeks after the second dose to allow adequate time for reduction in the compounds responsible for off-odor in pork. Marketing pigs on the Improvest program more than eight weeks after the second dose may increase the risk of off-odor in pork. Only trained, certified technicians will be permitted to administer the product as part of the quality assurance program. 

As the product is gradually introduced, Pfizer Animal Health will work with veterinarians and their producer clients to help them adopt nutritional guidelines and best handling practices to optimize growth for intact males. “This provides the time needed to ensure a coordinated food-chain effort, and gives processors and packers time to integrate and optimize it into their systems,” Bradford says. “We want to ensure the best Improvest program experience for everyone — from farmers to meat packers, processors and retailers, and, ultimately, to consumers.”

Improvest should not be used with female pigs, barrows or male pigs intended for breeding. Special care should be taken to avoid accidental self-injection during administration. There is no risk to any individual who consumes pork from pigs given Improvest.

Additional product information is available at PfizerPork.com/Improvest.