Improvest Program Earns Status Upgrade

The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) has issued a directive regarding on-farm protocols for using Improvest (gonadotropin releasing factor analog - diphtheria toxoid conjugate). This protocol accreditation helps to ensure operational consistency for packers and their producer suppliers who adopt Improvest that product protocols are comprehensive and will remain stable over time.  


The previous FSIS Notice acknowledged that hogs presented at harvesting facilities with the Improvest Quality Assurance Certificate are to be classified as barrows; and therefore, do not warrant testing for off odors during inspection. The classification change to directive signals that protocols for using Improvest are no longer subject to annual review, although Zoetis will continue to audit and refine those protocols as necessary.


"It's important that our processes for using Improvest meet the highest standards on the farm and at the processing plant," said Gloria Basse, vice president, U.S. Pork Business Unit, Zoetis. "As we continue to work with packers on processing pigs raised using Improvest, this FSIS status upgrade further validates Improvest as a production option for the entire pork industry."


Improvest is approved by the U.S. Food and Drug Administration (FDA) for the temporary immunological castration and reduction of boar taint in intact male pigs intended for pork. Improvest had been under FSIS notice classification since January 2013. The status upgrade is the latest in a series of protocol accreditations detailed below.


Timeline of protocol accreditations for IMPROVEST




Marketing definition established for pork raised using IMPROVEST

May 20, 2011

USDA Agricultural Marketing Service (AMS)

Intact male pigs receiving IMPROVEST, as per FDA-approved label instructions and before sexual maturity, should be considered barrows at the time of slaughter by pork processors.

USDA verifies the IMPROVEST Quality Management System

Nov. 12, 2012


Livestock, Poultry and Seed Program



Third-party audit assures that IMPROVEST is administered properly on the farm through a closely audited process. The IMPROVEST Process Verified Program documents and records farm employee training, and tracks and certifies all steps involved in administering IMPROVEST. 

FSIS issues Notice classification

Jan. 8, 2013


Hogs presented at harvest with the IMPROVEST Quality Assurance Certificate are to be classified as barrows; and therefore, do not warrant testing for off odors during inspection. This classification alleviates questions about any biological variation in the testes or the secondary sex organs that may be observed at slaughter.

FSIS issues Directive classification

Oct. 29, 2013


FSIS status for IMPROVEST upgraded from Notice to Directive.


"We're pleased the USDA, AMS and FSIS have recognized that our current on-farm protocols are thorough and allow producers and packers to produce high-quality pork," said Gary Kahle, Improvest Quality Operations manager, U.S. Pork Business Unit, Zoetis. "Producers who choose to use Improvest to manage off odors in pork can be confident processes will remain stable and that the product they supply will meet federal inspection standards at the processing house."


About Improvest

Improvest is an FDA-approved veterinary prescription product that is a safe and effective alternative to physical castration. It is a protein compound that works like an immunization to protect against unpleasant aromas that can occur when cooking pork from some intact male pigs. It uses the pig's own immune system to provide the same effect as physical castration, but much later in the male pig's life than physical castration is traditionally done. For more information on how Improvest works, visit