Marketers have consistently maintained that sex sells, but what about “sexed”? Within dairy’s A.I. industry, the word seems to be proving the slogan is still true. During the last six months, A.I. companies have rolled out sexed semen offerings one after the other. Each of the new programs have clever names. But beyond the fancy titles, there are some suggested do’s and don’ts for using sexed semen products. “My sense is that sexed semen is here to stay. That it’s a technology that we hope will mature. But even in its present state, there are definitely places where people should be using it,” says John Fetrow, a University of Minnesota researcher.
Most A.I. companies are using flow cytometry technology that was first developed in the 1980s to separate X- and Y-bearing sperm for their products. After separation, sexed semen straws are loaded with about 2 million sperm, whereas nonsexed semen straws are typically loaded with about 20 million sperm. Because sexed semen straws have fewer sperm per straw, fertility rates can be reduced by as much as 30 percent.
For this reason, Fetrow says his economic analysis of dairies using sexed semen shows dairies should selectively use sexed semen with heifers to find success.
“There are a lot of dairies that can rank the quality of their virgin heifers in such a way that they can go in and breed on the top end some proportion of their heifers with sexed semen and find it is profitable,” Fetrow says.
An occasionally rare opportunity to use sexed semen in cows may exist, Fetrow says. But most often it won’t be profitable in adult Holstein cows. “For the moment, in milking animals, it is a special-case use and not a general management tool,” Fetrow says. “In virgin heifers, I can see it being part of a lot of dairies’ standard management in some small subset of their best heifers.”
John Metzger, dairy product manager for Trans-Ova genetics, says the inherent reduced fertility of current sexed semen technology requires producers to pay close attention to reproductive management protocols, if using a sexed semen product.
Metzger says dairymen who are using sexed semen products should closely monitor heat detection and breed on the a.m.-p.m. rule. He wouldn’t recommend using sexed semen with a timed A.I. protocol. He also says semen handling will be extremely important, including protecting the semen against cold shock.
Without these measures, fertility could be compromised even more than 30 percent.
Fetrow believes dairymen who use sexed semen will want to know the genetic merit of their animals.
“It does put productive pressure on the industry for dairymen to begin to pay more attention to knowing the genetic quality of their animals, not just how much milk their mother produced,” Fetrow says.
“That means writing down bulls, keeping things organized and getting the genetic evaluations done on their females. Previously, that was information many commercial dairymen looked at and said, ‘I don’t know what to do with this because I am going to breed everybody and keep everybody.’ Now it is information that potentially has value. So perhaps we will see a bigger portion of the industry paying attention to the genetic merit of its dams.” PD
