Test to Increase Sheep Productivity

ARS researchers and collaborators developed a test to help identify high sexually performing livestock males, particularly sheep. The test measures testosterone response in sires using a naloxone injection, which blocks certain hormones to stimulate testosterone release. When a male mammal is given a naloxone injection, his testosterone response to the injection predicts whether or not he is sexually active or inactive. The test is based on the premise that libido is more closely linked to the ability to secrete testosterone. This tests could impact the U.S. Sheep industry by helping identify up to 30 percent of high performing male sheep, thus increasing reproductive potential. This could offer a savings of 5 to 15 million dollars in replacing nonproductive males, depending on whether rams are replaced yearly or every three years. The potential of using this technology in other livestock species is high and could increase its impact dramatically.

Companies that develop diagnostic kits could use this invention. Developing such a test kit will help the sheep industry, and potentially other livestock industries as well.

Please refer to U.S. Patent Number 6,193,949, "Method of Sire Selection Using Naloxone Challenge Test and Kits Thereof," which issued on February 27, 2001.