The earliest research on semen sorting was done in the 1980s and the first calves produced by sexed semen were born in the early 1990s. This technology has been continually improving; today a cattle producer can figure that at least 90 out of 100 calves produced by use of sexed semen will be of the desired gender—and it’s usually closer to 99 percent.
The dairy industry has been using sex-sorted semen for many years to produce heifers from their best cows. Willie Altenburg, who raises registered Simmental and Angus cattle near Fort Collins, CO, works for Select Sires and says sorted semen revolutionized the dairy industry—using it on valuable cows and heifers to create more dairy heifers.
Use of sexed semen in the beef industry has been slower to catch on, but today is steadily increasing—especially in seedstock herds—to produce calves of the desired sex as well as the genetics for certain traits.
Depending on their needs, breeders can tweak their calf crop ratio to have a higher number of bull calves from their best cows. Seedstock breeders want more bulls to sell, and some commercial cattlemen want more steers to market. Some producers breed their best cows with heifer semen to create more high-quality replacement heifers.
A producer can breed heifers to calving-ease bulls with high growth and good maternal traits (and keep replacement heifers from that group) or breed certain cows to a valuable bull to produce high-dollar bull calves.
“If you are in the bull business, you can produce males and sell $5,000 to $10,000 bulls instead of $2,000 heifers,” Altenburg said.
A commercial cattleman might breed cows to a high-performance bull or terminal sire for bigger calves to sell or to make more money on retained ownership through the feeding phase.
Altenburg says sexed semen may become more affordable in the future as the sorting technology improves. During the sorting process some sperm cells are always lost, and all cells of the undesired gender are discarded, leaving fewer total sperm cells from the semen collected from a bull. The lower sperm concentration can adversely affect fertility, resulting in lower conception rates. Sorted semen at this point still has a lower conception rate than regular AI semen, but does give very good results on the sex.
“Sexed semen allows you to do several things,” said Altenburg. “If you are breeding heifers you can use heifer semen to reduce dystocia (since heifer calves tend to be smaller at birth than bull calves), and you can keep replacements out of your heifers because hopefully those will be your best genetics. There are many positive ways that it can work for various breeders.”
He also said that for some reason, registered breeders west of the Mississippi tend to want to produce bull calves with sexed semen, and breeders east of the Mississippi are using more sexed semen to produce heifer calves.
“Today there is slightly better conception rate with sexed semen than we had in the past, and more use of sexed semen when doing embryo transfers. Conception rate reduction is not as detrimental with embryo transfer because you take that loss up front (you either have a live embryo or you don’t). In other words, if you have a loss, you know it immediately. If you have a live embryo, then it’s good to go,” he said.
Many registered breeders are using sorted semen with conventional flushes (cheaper than in vitro fertilization with an egg and sperm), and getting embryos produced at reasonable cost. “This is working pretty well; it’s a way to produce embryos of desired sex, which can make a big difference in the value of that calf, especially for seedstock producers who want bull calves. I do this quite a bit with my own cows and I’ve had great success with it, to produce bulls,” said Altenburg.
Some commercial producers who are already doing AI are now trying sexed semen on their best cows, to produce high-quality replacement heifers. “They may also be using heifer semen on their heifers, not only for the genetics they want for replacements, but also for calving ease. Heifer calves tend to be smaller than bull calves and you almost never have calving difficulty with a heifer that’s bred to have a heifer calf—as opposed to having a big bull calf.”
This is a win-win situation. The heifer produces a replacement with desired genetics, and won’t have dystocia. This makes sexed semen cost effective because it reduces the risk for losing calves or ruining a heifer (or having her breed back late) because of a calving problem. Avoiding these losses more than pays for the use of sexed semen.
“You can synchronize heifers and breed early in the breeding season—so if you do get a slightly lower conception rate you are not losing much time. You can still get a calf from that heifer when bred by a bull during her next heat cycle,” said Altenburg.
One of the questions often asked is whether semen from any bull can be made available for use as sexed semen or if only certain bulls’ semen is available in sorted form. Usually only certain bulls are offered by various semen companies, because not all bulls’ semen goes through the sort with optimal results—but many companies do offer this service on any bull the rancher might want to try.
At first there were not many beef bulls available for sorted semen, but today more AI companies are offering sexed semen. “More of their better bulls—the ones with better conception rates with sexed semen—are now available,” Altenburg said.
Most semen companies have the capability to sort semen on any bull desired. There are always some exceptions, but basically if a customer wanted this service on a certain bull, and agrees to buy everything collected from that bull, this will work—as long as that bull’s semen will freeze and go through the sexing process. Thus a producer could purchase sexed semen (choosing male or female) from just about any bull.
“If you are in the bull business, you can produce males and sell $5,000 to $10,000 bulls instead of $2,000 heifers.”
The cost for sexed semen depends on the base cost for the semen from each individual bull, with an additional charge for the sexing. Sexed semen costs more than regular semen, just because much of the semen is wasted when sorted.
“The important thing is a bull’s conception rates. As we learn more about the bulls, there are more of them becoming available for this use,” said Altenburg. As time goes on, there will be more advances in use of sorted semen, and more producers trying it.
As a general rule, conception rates are about 10 percent lower with sexed semen than with conventional semen. AI conception rates vary from ranch to ranch, depending on who is doing the AI work, the condition of the cattle, etc. Some ranchers get only 40 to 50 percent conception while others get 70 percent conception rates with conventional AI. You can usually figure that sexed semen rates will be about 10 percent lower than that ranch’s typical AI conception rate.
For best results, producers should carefully follow the published guidelines for semen thawing and handling, and use highly experienced and trained professionals for the inseminations. — Heather Smith Thomas, WLJ correspondent
