Sex-sorted Semen for Beef Cattle
Technology is most practical in situations where one gender is more valuable than the other.
by Troy Smith, field editor
SIOUX FALLS, S.D. (Dec. 4, 2012) — For a few years now, bull studs have been offering sexed semen, affording producers using artificial insemination (AI) the opportunity to choose the gender of calves with considerable accuracy. During the Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium Dec. 3-4 in Sioux Falls, S.D., attendees heard how sexed semen is produced and how it might be used practically in a cow-calf operation.
“It’s a terrible method,” said Colorado State University reproductive physiologist George Seidel in describing how sperm cells are sorted, with up to 95% purity, with an instrument called a flow cytometer/cell sorter.
“It’s amazing that it works at all,” he added, noting that sperm are stained with a dye, zapped with a laser and spun in a centrifuge. “It does work, but sperm suffer numerous insults, and fertility is lower.”
According to Seidel, a flow cytometer costs about $500,000 and is capable of sorting close to 15,000,000 sperm cells per hour. It’s an expensive process. It’s too expensive for resulting product to be packaged in normal AI doses, so sexed semen doses contain half as much — just 2 million sperm. Most bull studs merchandise sexed semen sorted for 90% accuracy, but some companies also market semen of lower purity.
“Use of sexed semen requires excellent management. Still, its use can result in 70% pregnancy rates,” stated Seidel. “It works best after heat detection and is not recommended for fixed-time AI.”
Seidel said the use of sexed semen is most practical in situations where one gender of animal is more valuable than the other. That makes it appealing to seedstock breeders who market bulls. It’s also applicable to producers who specialize in marketing registered or commercial replacement heifers.
Seidel spoke during Tuesday's ARSBC session focused on advancing technologies. Visit the Newsroom at www.appliedreprostrategies.com to listen to his presentation and to view the accompanying PowerPoint and proceedings paper.
Comprehensive coverage of the symposium is available online at www.appliedreprostrategies.com. Compiled by the Angus Journal editorial team, the site is made possible through sponsorship by the Beef Reproductive Task Force and LiveAuctions.tv.