Tips for Using Sexed Semen

Use of sexed-semen is practical if female is showing estrus.

by Troy Smith, field editor

BROOKINGS, S.D. (June 18, 2019) — It’s a fairly common occurrence in the beef industry: Application of a technology usually lags well behind its research and development. So it is with artificial insemination (AI). According to South Dakota State University (SDSU) Reproductive Physiologist George Perry, as AI technologies continued to advance, adoption by the dairy industry far outpaced that of beef producers. That has been true for use of sexed semen, too.

George Perry
South Dakota State University Reproductive Physiologist George Perry said, due to the increase price of bulls for natural service, he expects more commercial cow-calf producers to embrace AI, and many of those may consider the use of sexed semen. [Photo by Troy Smith]

However, things could change. Perry said as much during the June 19 National Association of Animal Breeders (NAAB) Symposium hosted in conjunction with the 2019 Beef Improvement Federation (BIF) Convention in Brookings, S.D. Perry said economics favor serious consideration of AI, citing a 60% increase in the average price of breeding bulls, between 2009 and 2016, compared to a 23% increase in the price of frozen semen for AI.

Noting how bull prices have continued to creep upward, Perry pondered, “How can producers afford the bull power they need for natural service, especially when they want different bulls for heifers than for cows, and different bulls to produce replacement females than those used for a terminal cross?”

Perry said he expects more commercial cow-calf producers to embrace AI, and many of those may consider the use of sexed semen. Sometimes called gender-sorted semen, this technology allows the breeder to choose the gender of calves resulting from mating cows to AI sires for which sexed semen is available.

Perry admitted that a challenge exists. Several studies have reported 38% lower pregnancy rates when using sexed semen, as compared to AI with conventional semen. Best results have occurred when insemination occurs after heat detection. Accordingly, use of sexed semen for timed AI often is discouraged since, at the time of mass-insemination, not all synchronized females will be fully expressing estrus. For these females, sexed semen may not survive the wait between insemination and ovulation. The reason is that sorting sperm cells by gender involves extra physical stress that can lessen sperm survivability.

Perry described a research study involving nearly 900 heifers and cows. The study was designed to compare results of insemination with sexed semen vs. conventional semen following estrous synchronization using a popular timed AI protocol (CoSynch plus CIDR®). Of the females inseminated with sexed semen, 52.4% became pregnant, compared to 67.2% of the females inseminated with conventional semen.

Also observed were differences among females inseminated with sexed semen related to the females’ expression of estrus. Though synchronized for timed AI, all females had worn heat-detection patches that provide evidence of mounting activity associated with females coming into heat. According to Perry, 69% of females with fully activated patches became pregnant, as well as 65% of females with partially activated patches. These two groups represented females fully expressing estrus and those for which estrus was just beginning, respectively. Forty-five percent of females with nonactivated patches – those not expressing estrus — became pregnant.

“What we saw was a big semen type by estrous expression interaction,” stated Perry, cautioning breeders that heat detection is important to success with sexed semen. “There definitely is a place for sexed semen and it is very practical to use. But it should be used in females showing estrus.”

The 2019 BIF Annual Convention was hosted by South Dakota State University and the South Dakota Beef Breeds Council June 18-21 at the University Comfort Suites and Convention Center in Bookings. ANGUS MEDIA® provides comprehensive online coverage of the event at www.BIFconference.com. Visit the Newsroom for summaries, proceedings, PowerPoints, video and/or audio of the sessions and the Awards page for announcements and photos of award winners.

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