MADISON, Wis. — Whether dairy producers are breeding cows for commercial production or eye-catching show appeal, the viability and cost-save analysis of using sexed semen is still a big question mark.

However, many of those questions were answered during a World Dairy Expo seminar sponsored by ABS, a sire selection company. The Oct. 3 seminar, presented by Joe Dalton, an extension dairy specialist and professor at the University of Idaho in Caldwell, explained the history of sexed semen, the process of selecting sperm based on sex, opportunities with sexed semen and challenges with its use.

According to Dalton, the USDA developed and patented flow cytometer technology during the late 1980s to separate sperm based on sex, either male or female. This USDA innovation was further developed by a company called XY and researchers at Colorado State University, he added.

“Today, this sexing technology provides sorting needs for companies such as ABS, Select Sires, Alta Genetics, Genex and many more,” said Dalton.

He explained that companies use the technology on specific bulls by treating the collected sperm from a bull with a fluorescent dye. Through the flow cytometer technology, the X-chromosome-bearing sperm glow brighter than the Y-chromosome sperm.

According to Dalton, sperm selected for X will produce an XX or in other words, a heifer. Sperm selected for Y will produce an XY or a male dairy animal.

During the age of artificial insemination, producers are now able to purchase sexed semen from sire companies based on whether they’d like to have a male or female offspring, he reported.

He said the biggest advantage to using sexed semen is to breed heifers to have heifer calves to decrease the incidence of dystocia, otherwise known as calving difficulty.

“Perhaps more important for some dairy producers, however, will be the ability to heavily use sexed semen to enable closed herd expansion,” he insisted, further explaining the advantages to using sexed semen.

“Closed herd expansion will virtually eliminate biosecurity risks normally present due to the introduction of purchased animals.”

Another opportunity for producers to use sexed semen comes from research that focused on the use of sexed semen in lactating cows. “Although initial results are promising, caution must be exercised as conception rates in lactating cows following artificial insemination with sexed semen are likely to be unacceptably low,” he said.

In fact, in one research study, the conception rate in lactating cows using sexed semen was at an “unacceptably low” 21 percent versus conventional semen at 46 percent, which is an achievable success rate in most commercial herds.

Besides using this sexing innovation on lactating cows, which envitably Dalton did not recommend; he also indicated numerous challenges using sexed semen to breed heifer calves at 13 to 15 months of age.

“Numerous research trials using sexed semen have reported conception rates in dairy heifers that were 70 to 90 percent of unsexed controls,” he explained. “Therefore if you currently achieve a 70 percent conception rate in your heifers with conventional semen, you can only expect to achieve a conception rate between 49 to 63 percent with sexed semen.”

Meaning, producers will achieve a more consistent and dependable conception rate using conventional semen for either heifer calves or lactating cows, as opposed to pay a higher price for sexed semen. He said that the cost of sexed semen ranges from $30 to $55 dollars per dose versus $10 to $20 for conventional semen. Another disadvantage to using sexed semen, he said, is that it requires an extra active and accurate heat detection program, and well-trained inseminators will be mandatory to maximize fertility. “Consequently the use of sexed semen in herds struggling with reproduction is not recommended,” Dalton concluded.

To determine the viability of sexed semen on herds small or large, Dalton offered a link to an Microsoft Excel spreadsheet available at www.wdmc.org2007fetrow.pdf

“The key to the value of sexed semen lies not in the opportunity to simply have more heifers, but it lies in the opportunity to have better heifers,” closed John Fetrow, professor of veterinary population medicine at the University of Minnesota, specializing in sexed semen research.

This farm news was published in the Oct. 10, 2007 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.