Finding the Right Diet Balance

Case study demonstrates the impact of diet on performance of intact males

The relationship between feed and nutrition programs and producer profitability is significant. A small adjustment to a pig’s diet may increase feed costs, but can also improve efficiency, yielding a greater financial benefit for producers. As research, better management and technology are applied at the farm, it’s important for producers to continuously evaluate their feed and nutrition programs.

This is particularly true as more producers, veterinarians and nutritionists implement immunological castration (IC) as an alternative production technology on pig farms. IC barrows have the potential for greater lean deposition, greater average daily gain (ADG) and superior feed conversion compared to physically castrated (PC) barrows.

“There are many advantages to IC barrows,” said Daniel Nelson, PhD, PAS, Senior Nutritionist, Pork Technical Services, Zoetis. “For producers to fully reap the economic benefits of raising IC barrows, it’s important that they manage these pigs differently than PC barrows and gilts. This means understanding that these animals have different nutritional requirements.”

IMPROVEST® (gonadotropin releasing factor analog-diphtheria toxoid conjugate) involves a two-dose regimen, during which the male pig experiences physiological changes resulting in a shift in protein and mineral requirements as well as feed intake.

Maximizing performance through increased lysine supplementation

Recent studies by Iowa State University and the University of Illinois suggest IC barrows have the potential to improve ADG and feed efficiency compared with PC barrows by as much as 15% with increased lysine and phosphorous supplementation.1

Managing IC barrows

To get the most return on your investment from raising IC barrows, it’s important to manage them differently from gilts to ensure they are receiving the proper nutrient requirements to optimize their potential.

IC barrows should be penned and fed separately from gilts to ensure they receive diets containing the correct lysine and phosphorus concentrations. This requires separate-sex housing by barn or site.

As the pork industry adopts new, more-sustainable technologies such as the use of  IMPROVEST as an alternative to physical castration, Zoetis will continue to research management and marketing practices that make this technology more  profitable to producers. The 2014 Nutritional Guidelines for Immunologically Castrated Male Pigs provides a complete overview of the new research and nutritional recommendations for IC barrows. For more information on IMPROVEST, contact your local Zoetis representative or visit

For more perspective on this topic, visit Pork Perspectives where you will find “Get out what you put in: Balancing pig diets for optimum performance” by Dr. Nelson. For more conversations on important industry topics, news, and information on animal health technology, subscribe to Pork Perspectives from Zoetis.

IMPORTANT SAFETY INFORMATION: Pregnant women should not administer IMPROVEST. Women of childbearing age should exercise extreme caution when administering this product. Exercise special care to prevent accidental self-injection because of negative effects on reproductive physiology in both men and women. However, there is no risk associated with consuming pork from animals administered this product. IMPROVEST should not be used in female pigs, barrows, or male pigs intended for breeding. See full Prescribing Information.


IMPROVEST is a Food and Drug Administration-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 when physical castration is traditionally done. For more information on how IMPROVEST works, visit

About Zoetis

Zoetis (zō-EH-tis) is the leading animal health company, dedicated to supporting its customers and their businesses. Building on more than 60 years of experience in animal health, Zoetis discovers, develops, manufactures and markets veterinary vaccines and medicines, complemented by diagnostic products and genetic tests and supported by a range of services. In 2014, the company generated annual revenue of $4.8 billion. With approximately 10,000 employees worldwide at the beginning of 2015, Zoetis serves veterinarians, livestock producers and people who raise and care for farm and companion animals with sales of its products in 120 countries. For more information, visit

For Further Information,Contact:

Christina Lood

Betsy Rado
Bader Rutter

[1] Elsbernd AJ, de Lange CFM, Stadler KJ, Karriker LA, Patience JF. Determining the SID lysine requirement of immunologically and physically castrated male pigs during three growth phases and feed intake pattern characterization in immunologically castrated pigs following their second injection [thesis]. Ames: Iowa State University; 2014. 

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