Horse Breeding

Colt Or Filly?

October 16, 2009

The technology and implications of choosing the gender of your foal.

colt or fillyFrom The American Quarter Horse Journal

At Moondrift Farm in Fort Collins, Colorado, equine specialist Allison Lindsey does more than choose the parents of future foals. She decides whether those foals will be colts or fillies.

Moondrift’s parent company, the international genetics firm XY Inc., specializes in sex selection research in non-human mammals and is applying the techniques at Moondrift’s 50 acres. XY Inc. Allison and her team perfect techniques to produce the desired gender using a “MoFlo” – a flow cytometer that sorts X- and Y-bearing sperm – and artificial insemination of both fresh and frozen semen.

Gate Sorting

Of Moondrift’s 27 foals, 93 percent show gender selection success.

The sperm separation depends on differences in DNA content – sperm carrying the X chromosome contain more DNA, Allison explains. That difference varies between species; in horses the X chromosome carries 3.8 percent more DNA, and in humans, it’s 2.8 percent more.

Are you considering breeding your mare? Let AQHA help with our FREE Mare Care: Breeding Tips report. Learn all you need to know about breeding your mare and taking care of her while she is in foal.

Sperm stained with a dye that binds quantitatively to the DNA run through a cytometer in a stream about the size of a human hair. When excited by a laser beam, they fluoresce, the X’s more brightly than the Y’s. The computer puts a positive charge on drops of one brightness level and a negative charge on drops of the other brightness level. Drops are separated by a field of elecromagnetic plates; 90-percent pure samples of X or Y sperm can be collected.

Initially, XY Inc.’s commercial operations will be small, due to the time constraints of the procedure: at CSU, sperm run through cytometers at 5,000 per second. The sorted sperm are delivered to Moondrift and into the mare’s utero-tubal junction (where the oviduct meets the uterus) via a video endoscope. At this location, sperm bind immediately to the oviductal wall, while those sperm deposited at the cervix by natural breeding or artificial insemination must arrive at the junction on their own power – only about 5 percent do so.


What’s good for the breeder might not be good for the breed or the species, cautions medical bioethicist Arthur Kaplan, director for the Center for Bioethics at the University of Pennsylvania in Philadelphia.

“Any technology that narrows the diversity present in the genes of animals is a problem,” Arthur says. “Everybody is keenly aware from experience with dogs and cats that narrowing the pool and inbreeding are not helpful in the long run to the viability of a species, so you are going to skew breeding by using fewer valued males or trying to eliminate one sex or the other. There is already a smaller base of diversity and animals are pretty well inbred.”

Second, diseases linked to the X or Y chromosome can spread much faster by sex selection and breeding to a particular male, he says.

“What might pose a risk in previous times of creating sick animals on a small scale could end up being produced on a larger scale if this technology is not carefully handled,” he cautions.

“Third, there are various claims about the ability to sort gametes for animals and people, but who is checking? You might go through a whole generation of animals, pay money and find you didn’t get the sex you want, or somebody who’s not scrupulous could sell sperm and close up shop. Oversight of standards and regulations and good lab practices should be the start of animal breeding.”

Whether or not you choose the sex of your foal, you need to know how to care for its mother. Check out our FREE Mare Care: Breeding Tips report to learn all that you can do to prepare for breeding your mare.

Other ethicists are less worried. Peter Singer is the Ira W. DeCamp Professor of Bioethics at Princeton University’s Center for Human Values.

“I don’t see anything wrong with selecting sperm in general for animals or in some circumstances for humans to avoid sex-linked diseases,” Peter says. “This issue doesn’t seem to be a big one in animal welfare.”

Whether or not the procedure poses ethical questions, the cost might be a deterrent to widespread use, says Patricia Sertich, associate professor in large animal reproduction at the New Bolton Center of the University of Pennsylvania.

Professor Irwin Liu in equine reproduction at the University of California at Davis agrees with Patricia that this could be a valuable tool, but disagrees that it is too costly.

“Five thousand dollars isn’t very much when you figure embryo transfer costs that much,” he says. “So it’s competitive, and the price will come down, but I see merit for it for the select few at the moment.”

Big Incentive

Invest. Perform. Earn. It’s that simple when it comes to participating in the AQHA Incentive Fund.

In a nutshell, the Incentive Fund was created as a way to reward and encourage AQHA members for showing their American Quarter Horses. If you nominate your American Quarter Horse stallion to the AQHA Incentive Fund by October 31, 2009, you’ll be eligible to win a John Deere trimmer.

Stallions are enrolled on an annual basis for each breeding season, making their offspring eligible to be enrolled as well. The available money in the Incentive Fund is divided by the number of points earned by the enrolled horses in the open and amateur divisions of AQHA competition throughout the year, making each point worth a certain amount of money. The point value is then multiplied by the number of points earned by the horse to determine the accumulated amount for the year.

The 2008 show season saw a record-high in total points — 147,864 — earned by nominated horses, which is 10,066 more points than in 2007. The point value in 2008 was $22.35, which resulted in a 2008 payout of $3,305,489.51.

“I tell all of my customers that if they’re raising horses that will compete in AQHA shows, they’ve got to enroll them in the AQHA Incentive Fund. A majority of buyers won’t even look at show horses that aren’t in the Incentive Fund. That’s how important it is to the industry,” said Mike Jennings of Professional Auction Services in Leesburg, Virginia.

Season of Champions Newsletter

Fall is here and it’s that time of year again … time for the Season of Champions.

Starting October 19, the American Quarter Horse Journal will bring you weekly email updates on happenings in the Quarter Horse world from the All American Quarter Horse Congress to the National Cutting Horse Association Futurity to the Bank of America Racing Challenge.

And November 7-22, subscribers will receive the Season of Champions newsletter daily to get a close-up on the happenings at the 2009 AQHA World Championship Show from winning runs to behind-the-scenes stories.

The Season of Champions newsletter will return to weekly delivery November 23 with a preview of the National Reining Horse Association Futurity and will conclude December 14 with a wrap-up on the Wrangler National Finals Rodeo and NCHA Futurity.

Make sure you don’t miss out on any of the important details and stories during the Season of Champions. Sign up for the Journal’s special e-newsletter today!

Special Event

“Out Here with Horses”

Join Tractor Supply Co. on Saturday, October 24 for special deals, giveaways, activities and learn more about horse ownership. Go online to find out if any of the TSC stores in your area are hosting an “Out Here with Horses” event this month.