The foals run side by side in the pasture, their gait a bit wobbly. Stride for stride, they match one another in their private race. Both are stout and leggy, with the promise of making a fine horse in upcoming years.
To the naked eye, it is impossible to tell that the beginnings of these foals’ stories are incredibly different. One came from natural coverage, the other the result of equine intracytoplasmic sperm injection (ICSI), a relatively new reproductive technology that is starting to take the equine industry by storm.
ICSI has been utilized in the equine world for more than 20 years, but the procedure has started gaining traction at the commercial level in recent years. Dr. Rob Foss of Equine Medical Services in Columbia, MO, said though he knew ICSI would receive interest because of its ability to help produce animals from matings that otherwise wouldn’t be possible, the technology’s surge in popularity has surprised him.
“It has exceeded what I expected,” he told WLJ. “At this point, it’s still in the process of growing in use, popularity and availability. I think it’s going to be around for quite some time and be quite productive.”
Equine Medical Services is one of about six facilities in the country that offers ICSI to breeders. Foss said ICSI foals have proven to be just as functional and healthy as their naturally produced peers. He expects the number of ICSI foals each year to continue to grow as more operations embrace the opportunity to produce valuable genetics.
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In Fort Collins, CO, Jake Dahl has seen the benefits of ICSI firsthand—in his own barn and in those of his clients. He is the co-owner of Vista Equine Colorado, a full-service equine reproductive facility.
About five years ago, Dahl started getting his feet wet in the ICSI world. His facility has seen the number of ICSI clients double each year since the technology was first introduced. Dahl now works with Foss to provide the service to clients. He expected to see about 140 ICSI embryos produced at Vista Equine Colorado by the end of 2022.
ICSI process
Mares are brought to the Colorado facility, and their cycles are checked before the females are aspirated. The aspiration process occurs prior to ovulation. A needle is guided through the flank or with the use of ultrasound to reach the anterior vagina. Once the needle finds the ovary, an oocyte (egg cell) from the donor’s follicle is collected.
Dahl ships the oocyte to Foss’ lab. Once the oocyte has been cultured to maturity, it is fertilized with a single sperm cell. The oocyte should start to divide and become an embryo within 24 to 30 hours after the sperm has been injected.
The embryo is moved to an incubator and should reach the blastocyst stage seven to 10 days later. Foss said there’s a relatively short window after the blastocyst stage where the embryos should either be frozen or placed in a recipient mare to be carried to birth. Similar to frozen semen, embryos should be able to last indefinitely when stored in liquid nitrogen, he added.
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In the past, Foss said mares who couldn’t successfully have an embryo collected through traditional methods were turned out to pasture. Options like in vitro fertilization that proved fruitful in other species were not successful with horses because of sperm capacitation, he said. Oocyte transfer in mares was available and had good levels of success, but Foss described the process as labor intensive, and he said multiple embryos were not typically produced.
Thanks to ICSI, producers now have a chance to produce more embryos using less semen.
It’s a success story Dahl said he’s seen in a multitude of clients. The process can extend the reproductive life of older mares and create a chance for “tough mares” to pass their genetics on to the next generation.
Dahl has encouraged breeders to consider ICSI as a cheaper option than continuing to throw Hail Mary passes on females who aren’t getting bred. He said the costs of cultures, antibiotics and semen can add up, and ICSI has the potential to result in one or two embryos at a lower cost.
The technology provides a solution for difficult stallions as well. For subfertile studs or those who have produced a limited amount of semen, Dahl says ICSI is a viable option, as only a single sperm cell is required rather than an entire straw of semen.
A time and a place for the tech
Along with all its benefits, however, Dahl has a word of caution for breeders. He urges producers not to rely entirely on the technology. Dahl proudly echoes the lesson he was raised with—the backbone of the equine industry is animal husbandry. Horses are livestock and partners, not pieces of equipment.
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“Mares should not be treated like a factory,” he explains. “I’m still a horseman. I hope people don’t abuse (ICSI) and just suck all the oocytes out of mares because we can.”
He sees the benefit of the technology but doesn’t mind admitting that he’s pretty picky about which clients he recommends ICSI to rather than traditional methods of producing an embryo.
“I don’t think every mare needs ICSI done to her,” he said. “I think there’s a time and place for ICSI.”
When used correctly, Foss confirms ICSI is a safe and typically effective reproductive tool. Most mares respond well, and foals are born whole and healthy. There is an increase of loss in the early embryonic stage, but Foss says ICSI has otherwise proved itself in the field.
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Breeders are just now getting comfortable with the technology in Dahl’s eyes. He estimates that the industry is split in half right now when it comes to acceptance of the technology.
Though he’s in support of the practice, Dahl admits he thinks it’s been adopted by a few too many breeders. He predicts as it continues to find its place in the industry, a new checks-and-balances system will be established. He compares the future of ICSI to the story he saw in 2002 and 2003 with the surge of embryo transfers in the equine industry.
“I think it’s going to follow the economy,” he says. “Horse prices are high. People are probably going to be doing more procedures like ICSI. If that market goes down, you’re dang sure going to see a correlation where people are down a bit with spending.”
As the years roll by, both Dahl and Foss expect ICSI to become more common. The industry will continue to grow and evolve, and each individual hopes the genetics of the livestock behind the breeders will reach new heights.
Today, Dahl has performed ICSI on two of his mares and has a total of seven ICSI foals on the ground—all “healthy, good-legged” individuals, he said. Out in Dahl’s pasture, the ICSI foals can’t be picked out from foals who were carried by their own dams.
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The youngsters all have the same wobbly gait as they run side by side in the pasture, ready to find their own place as a productive, effective individual in upcoming years.
