October 06, 2013

The benefits of immunological castration

Photo credit: Zoetis Inc.

This month, Animal Frontiers shifts some of its focus to a topic that is controversial across the globe.

Certain countries, such as Ireland and the United Kingdom, have passed laws making physical castration illegal on the grounds it is a serious animal welfare offense. Soon to follow their example, the European Union is expected to have a voluntary ban on physical castration in 2018.

Animal health experts Dr. James Bradford and Dr. Martha Mellencamp write about the controversies surrounding physical castration and discuss viable alternatives in an article titled “Immunological control of boar taint and aggressive behavior in male swine.”

Bradford and Mellencamp describe the process of physical castration as being done in a “clean, but non-surgical manner.” Incisions are made in the scrotum, the testes are removed and the spermatic cords are detached during physical castration within the first few weeks of life.

Bradford and Mellencamp write, “It is painful, increases death losses and results in pigs that grow less efficiently.”

Anesthetics and analgesics may be used in an attempt to relieve the pain of physical castration, but they have not been proven to completely relieve the stress associated with the procedure.

Even though the authors mention a number of alternative options, this article focuses on immunological castration in pigs.

The process of immunological castration involves two injections given 3 to 10 weeks before market. First, an initial priming dose is given to ready the memory cells of the animal’s immune system. The second dose is administered four weeks later to boost immune function and suppress testicular function.

Although immunological castration is temporary, producers can still benefit from using immunological castration over physical castration.

In swine, immunological castration has been shown to reduce the sexual and aggressive behaviors that can be problematic during transport.

Boar taint, an unappealing odor present in pork from male pigs, is also eliminated through immunological castration.

“The two primary compounds that contribute to this offensive odor are androstenone and skatole,” write Bradford and Mellencamp. “Androstenone is a testicular pheromone that functions as a female attractant. It has a urine-like odor. Skatole is produced by bacterial breakdown of tryptophan in the hind gut and has a fecal-like odor.”

These compounds are found in the fat of male pigs at puberty, but are reduced in the fat of castrated pigs.

Another benefit producers can gain from immunological castration is increased feed efficiency, finishing weights and lean meat yield.

Castration tends to decrease feed efficiency and overall carcass productivity gains. Because immunological castration is not performed until later in life, production efficiency in immunologically castrated pigs tends to be greater than in physically castrated pigs.

Yet another advantage of this castration process is fewer greenhouse gas emissions from hog farms.

The authors write, “If one-third of the 53.3 million male pigs raised annually in the US were immunologically castrated, then approximately 508,000 metric tons of greenhouse gas emissions would be avoided each year.”

For more information on immunological castration, the article titled “Immunological control of boar taint and aggressive behavior in male swine” can be read in full at animalfrontiers.org.

Scientific contact:
James Bradford

Media contact:
Samantha Walker
ASAS Communications