Research Note
Immunological Strategy:
Improving Growth, Feed Efficiency, Carcass Quality
It’s an ongoing quest — to improve feed efficiency and resource utilization in swine production systems. Immunological castration of male pigs and immunological suppression of estrus in female pigs may be one of the most effective tools available to swine producers.
The product is a gonadotropin-releasing factor (GnRF) analog-diphtheria toxoid conjugate, marketed by Zoetis Inc. in the U.S. and Canada as Improvest and under other tradenames such as Improvac and Vivax in other countries. It’s a two-dose injectable approved by the U.S. Food and Drug Administration in 2011 and used in the European Union and other countries for more than 15 years. The manufacturer reports that no country restricts imports of pork raised with the product and there currently are no trade barriers for pigs managed with the product. Nonetheless, use of the GnRF product in the U.S. remains below that of other pork exporters, including Canada and Mexico, and far below that of Brazil.
“This product represents one of the most unique technologies I have encountered for the swine industry,” says Ohio State’s Dr. Benjamin Bohrer, “and it has meaningful economical and sustainability impacts to swine producers and the packing industry.”
In terms of production benefits, Bohrer says, producers can expect males managed with immunological castration to have 1-2 percentage unit advantages in pre-weaning mortality and 8-12% improvements for feed efficiency during the grow-finish period when compared with castrated barrows.
“For market gilts,” Bohrer says, “producers can expect immunized females to have more consistent feed intake during the late stages of finishing and 3-5% greater average daily gain during the entire grow-finish period. Effects on feed efficiency are minimal compared with non-immunized gilts.”
In terms of carcass benefits, Bohrer says, packers can expect heavier carcasses (3-8 lb. advantage) and greater carcass cutting yields (1.2 percentage unit advantage) for immunologically castrated males when marketed at the same age as physically castrated barrows.
“For market gilts, packers can expect heavier carcasses (6 to 12 lb. advantage), greater levels of group uniformity (less light weight gilts), greater levels of fat thickness, thicker bellies, and improved iodine value (2-3 unit improvement) for immunized females when marketed at the same age as non-immunized gilts.
Bohrer and his research collaborators have investigated the effects of various nutrition strategies for pigs managed through immunological castration of males and immunological suppression of estrus in females. Strategies include feeding low energy diets to males and female pigs and diet dilution strategies for the post-second treatment period — when feed intake levels are increased due to suppression of gonadal activity.
In addition, Bohrer says optimization of dose timing strategies to balance live performance and carcass benefits of pigs managed with the product are an ongoing area of research emphasis.
“Future areas of importance,” Bohrer says, “are related to the optimization of dose strategies for pigs raised to older ages and marketed at heavier weights.”
Questions?
Email FeedInsight 4Swine