A Surprise Follicle and a Date with Knicks Go: Lady Dyanaformer is Heading to the Breeding Shed
Lady Dyanaformer and Lady Calliope (Callie) in the field today before Dyana’s scheduled bath
The team at Horse Husband Stables had a surprise twist in their breeding plans this week—and it came from none other than Dyana, one of the farm’s cornerstone mares. While everyone expected Audi to be the first of the two to cycle, a routine ultrasound revealed that Dyana was more than ready for her breeding appointment.
During a visit from their veterinarian, both mares were checked to evaluate follicle development and timing. To everyone's surprise, Dyana was already sporting a 49mm follicle, which meant her ovulation was imminent and the breeding needed to happen right away. Thankfully, the booking team at TaylorMade Farm was able to secure a next-day appointment with Knicks Go, and the farm’s go-to transporter, Campbell, was available to make the trip.
Why Timing Is Everything in Thoroughbred Breeding
Unlike many other breed registries, The Jockey Club requires live cover for a foal to be registered as a Thoroughbred in North America. That means the stallion and mare must physically breed—artificial insemination (AI), embryo transfer, or frozen semen are not allowed.
While live cover has a solid success rate, it also comes with logistical challenges, especially around timing. The Thoroughbred breeding season typically runs from mid-February through early July, so stallions can only accommodate a limited number of mares during that window. If a mare is ready to ovulate but the stallion is already booked, that opportunity may be lost.
With AI, semen can be collected and stored in advance, allowing breeders to match insemination precisely with ovulation. But with live cover, the mare and stallion must both be ready—at the same time—making veterinary monitoring and flexibility essential.
Live Cover vs AI: What the Research Shows
Despite the tighter logistics, live cover remains a highly effective method, with an average conception rate of 60–70% per cycle when managed well.
For context:
Cooled/shipped semen: 50–60%
Frozen semen: 30–50%, and more technically demanding
While AI gives breeders flexibility and control over timing, live cover holds its own in terms of success, provided everything is timed just right.
Understanding Follicles, Ovulation, and Why 49mm Was Just Right
Mares experience estrous cycles roughly every 21–22 days, with ovulation typically occurring during the last day or two of heat. As ovulation nears, one dominant follicle matures—usually reaching between 35–50mm before release.
Dyana’s follicle measured 49mm, placing her right at the high end of the normal range. This is not unusual for a larger-framed Thoroughbred mare, who may naturally ovulate at the higher end of the spectrum. But size alone doesn’t determine timing. Dr. Growette also evaluated other key signs, including:
Uterine edema, seen on ultrasound as a classic “wagon wheel” pattern
Cervical relaxation, indicating readiness to accept a pregnancy
Behavioral cues suggesting strong estrus
All signs pointed to imminent ovulation, making the next-day breeding ideal. The plan is to ultrasound Dyana again one day post-breeding to confirm ovulation occurred. If so, a pregnancy check will follow at 14 days.
🧠 Foal Circle Fact: Occasionally, a follicle grows too large (over 55mm) and becomes what’s called a persistent anovulatory follicle. These follicles may luteinize but don’t release an egg, so even if a mare is bred, she won’t conceive. Monitoring with ultrasound helps catch and avoid these situations.
Audi wasn’t quite ready this week, but the team will check her again soon to see if her follicle is progressing.
Pre-Breeding Prep and Foal Development
Before her trip to TaylorMade, Dyana will receive a much-needed bath (after a predictable mud roll). But this wasn’t just about looking good for her date—it will also create a valuable opportunity for a little independence practice for her foal, Callie.
At just over six weeks old, Callie has already experienced a few short separations while Dyana received hoof trims or took short walks in the barn aisle. During these moments—and during the bath—a member of the Horse Husband Stables team stays with Callie, helping her remain calm and connected to people.
These short separations help young foals become more adaptable and confident, and they give human caregivers a chance to build trust and communication. Dyana went through this same routine last year with her colt Paycasso, and both handled it beautifully—Callie is well on her way to doing the same.
We'll be keeping an eye on Dyana’s follow-up check to see if her timing was successful—and if all goes well, there may be a Knicks Go x Dyana foal arriving in early 2026. Stay tuned as we continue following the journey from foal to forever with the team at Horse Husband Stables.
