When it comes to raising horses, technology has given us many options, from traditional methods to sub-fertile mares producing foals by long-deceased stallions. Here’s the breakdown of what you should know before beginning your rope horse breeding journey.
Table of contents
- The natural versus artificial breeding process
- What does flushing embryos mean?
- What is ICSI?
- What pre-breeding prep does your mare need?
- What you need to know about heat cycles
- When is breeding season for horses?
- How do you monitor cycles?
- How do you order horse semen?
- What’s the mare owner’s responsibility?
The natural versus artificial breeding process
It’s not uncommon for larger ranches to turn a stallion out with a specific band of mares for pasture breeding, simply letting mother nature take its course.
Hand-breeding, the careful preparation of the mare and stallion for monitored live cover, is largely exclusive to the Thoroughbred racing industry; however, it’s often the method of choice for “local” stallions that only cover a handful of outside mares each year.
The most common method today is artificial insemination via cooled or frozen semen. For this process, the stallion’s semen is collected and shipped to the mare’s location. It’s important to note that stallions aren’t collected every day; rather, they have an every-other-day collection schedule. This makes monitoring a mare’s cycle extremely important.
Frozen semen is generally offered on deceased stallions, those still performing or those with extremely full books. While it does make it more accessible in reaching the mare’s breeding facility, frozen generally adds to your veterinary fees because it’s more labor intensive.
“Your window for conception has to be more precise,” says Matt Randall, DVM, of Waller, Texas. “That means you’re palpating the mare more often, sometimes three, even four, times a day or night if that’s what the mare’s cycle dictates.”
What does flushing embryos mean?
Embryo transfer is the process of flushing an embryo from one mare (the donor) to another (a recipient). It’s used frequently to allow performance mares to continue their careers while taking advantage of their fertile years. It’s also an option for older mares and mares with high demand for their offspring. It also allows mare owners to get multiple foals by different stallions during the same year.
Shortly after the mare is bred, her uterus is flushed before the embryo can cleave to her womb. The embryo is observed for viability and then implanted in a recipient mare.
The key is to have your donor and recipient’s cycles synchronized to make it more likely that the flushed embryo will cleave to the womb of the recipient. That’s why the larger reproductive facilities that specialize in embryo transfer have large herds of recipient mares. It makes the odds of finding one synchronized with the donor more likely.
Embryos can also be flushed and vitrified, the process of using rapid cooling to freeze the embryo without the formation of crystals. The frozen embryo can then be transported and stored until needed.
What is ICSI?
Intracytoplasmic Sperm Injection (ICSI) is a specialized assisted reproductive process that’s often used on mares with fertility issues or ones where multiple foals are desired. Some stallions, particularly those deceased with limited frozen semen available, are only offered through the ICSI process.
The process starts with the aspiration of oocytes or “eggs” from a mare’s ovaries. After harvesting, the eggs are incubated for 24 hours and injected with a sperm cell when ready. They’re once again incubated for a period of days, and those injected oocytes that mature into embryos are placed into recipient mares or vitrified.
Due to the complexity of the process, it’s one of the more expensive procedures available. Mare owners should research facilities carefully as it is easy to spend several thousands of dollars without having a foal to show for it. (The largest U.S. ICSI lab is based in Purcell, Oklahoma: genetechvet.com.)
When compared to buying a top-tier prospect, breeding can seem cheap. In reality, it’s as expensive as you’re willing to make it. Flushing embryos or using ICSI increases your cost over letting a mare carry her own foal.
What pre-breeding prep does your mare need?
A cost that often adds up quickly is repeated shipments of semen. With each shipment costing $400 to $450, it’s important to start with a mare in good reproductive health.
The best odds for conception come from using mares during their peak reproductive years, from 4 to 12. Typically, at 10 to 12, a mare’s reproductive efficiency starts to decrease, especially in maiden mares.
Prior to breeding, a mare should have a reproductive assessment that may include uterine cultures and biopsies to check for potential infections or problems that may affect their ability to conceive.
“Cultures typically aren’t needed in younger maiden mares,” said Randall, referring to mares that have never been bred or exposed to a stallion. “It is very rare for a maiden mare that’s never been exposed to or serviced by a stallion to have an infection, but it can happen. On older mares, it’s not a bad idea to culture them, especially if they’ve had problems getting in foal in the past.”
Older mares, particularly those that are difficult to settle (get in foal), may need an endometrial biopsy, where a piece of the interior wall is taken for laboratory analysis. This biopsy is used to evaluate a mare’s ability to get and stay in foal.
Ideally, the earlier a mare is checked for issues, the earlier they can be resolved if able. Treating an infection in the fall will increase the odds of conception during the first cycles of the year rather than missing one or two due to treatment.
What you need to know about heat cycles
Estrus, a mare’s reproductive cycle, runs 21 days on average. The seven-day period that leads up to ovulation is estrus, more commonly called “heat.” Mares typically cycle during the spring through early fall but will go into an anestrous period where they don’t cycle at all during the winter months.
Since heat cycles are triggered by lengthening days, like in the spring, mares can be manipulated into starting their cycles earlier in the year by adding artificial light to trick them into thinking the days are longer. They need 16 hours (natural and artificial combined) for 60 to 90 days to kick-start estrous, but no more as 24 hours of light can cause problems. For example, if you want to breed in February or March, you need to start adding additional light no later than Dec. 15.
Artificial light needs to be bright enough to read a newspaper in the darkest corner of a stall. Special masks, like the Equilume, also work to manipulate estrous through additional light without having to have the mare confined to a lighted barn or corral.
Signs of heat are urine squirting, winking of the vulva and generally more squealing and crankiness than normal. Knowing the signs that your mare is coming into her heat cycle is important if you’re hauling her to and from a facility for any reproductive work.
When is breeding season for horses?
Breeding season typically starts late winter and runs through mid-summer with a little variation depending on geography. It often starts sooner in the warmer climate and a little later in the northern states and Canada.
“We start collecting and shipping in March,” said Bill Myers of Myers Performance Horses in St Onge, South Dakota. “We used to start in February, but now we’re in March and go through the middle of July.
“It starts getting hot, especially for southern mares, and things don’t work as good. Being too early up here (in South Dakota) is just as bad as being too late down there (southern states) for your success rate ratio.”
When you start trying to get a mare in foal is also very important, especially if you’re looking to raise one for futurities or that market. The further you go into summer, the later the foal will be born as horses have a gestation period of 340 days, on average.
“With the futurities, you can have a six-month difference in foals, say from a foal born in February to one born in the middle of July,” Myers noted. “That’s a lot of time in a horse’s life, especially when they’re growing. There’s a reason in the racehorse world they like those early colts because they’re more mature by the time they run them.”
How do you monitor cycles?
Veterinarians and reproductive specialists monitor a mare’s reproductive readiness through palpation and ultrasound examination of her ovaries through her rectum.
Where a mare is at in her cycle determines how often she’s palpated. The closer she is to coming into heat, the more frequently she’s monitored for impending ovulation.
“Typically, you’ll check mares once or twice a week until they come in,” Randall said. “Once they’re coming into heat, they’ll be checked daily or at least every other day. The mares dictate the timing of everything. There’s little we can do to influence that, so for the most part, she’s calling the shots. We have to work around her schedule.”
Because timing is of the essence and totally dependent on the mare’s schedule, owners have to decide if they want to haul their mares back and forth to the repro or veterinary facility, or if it’s easier for them to leave the mare onsite.
“The easiest way is to drop the mare off and pick her up when she’s in foal,” Randall said. “You have to decide what your time’s worth versus the board fee. With diesel prices what they are, it’s not much more expensive to leave them for two weeks versus hauling them back and forth.”
How do you order horse semen?
Whomever is doing your mare’s reproductive work should have a copy of the breeding contract, with specific obligations that must be met to be eligible for possible rebreeds (trying again next season) if the mare fails to conceive, or a live foal guarantee—which means the foal is born healthy and stands and nurses without medical intervention.
The contract also has the stallion’s collection schedule and the process of ordering semen.
The person handling your mare has the best idea of when they will need semen and, unless told otherwise, it’s best to let them handle the ordering and receiving of the semen shipment.
“Owners get excited about getting their mares bred, and sometimes when you say, ‘She’s getting close,’ they hear, ‘it’s time to order semen’ and do so before the mare has reached the window,” Randall said.
It’s also important to have a credit card on file with the stud farm.
“If you’re getting shipped semen, they will not collect and ship semen if they don’t have payment up front,” Randall warned.
Mares that will carry their foals to term will have their pregnancy confirmed around day 15 and again at days 30 (the heartbeat check) and 45.
What’s the mare owner’s responsibility?
For open mares, the breeding process starts over within a few days from that first pregnancy check. In the event the mare fails to conceive, you may be entitled to a rebreed the following season, depending on your breeding contract.
“Rebreed is for the following year only as listed in the contract,” noted Myers. “Most people now charge a rebreed fee to collect the horse to offset the cost of the help you need to do it.”
The bottom line is mare owners need to be diligent and give themselves the best chance at getting a foal. “If you bring a mare in at the end of the breeding season and she just has one cycle to try to get bred, that’s not being diligent,” Myers said. “You need at least two cycles to give her a legitimate chance to get bred.
If you’ve tried diligently, you’ve got an automatic rebreed for next year.”
Myers says it’s best if mare owners do their homework and stay ahead of the game.
“They save money because they usually won’t have to pay for multiple shipments,” he said. “We want to do it for them as cheaply as possible, but a lot of the responsibility is on them.” TRJ
2024 Breeder’s Guide
With the explosion of the Ariat World Series of Team Roping’s payouts and the growth of the rope horse futurity industry, the demand for high-caliber horses has never been higher. Searching for ways to maximize horsepower, ropers across the globe are turning to breeding and raising their own. If you’re interested in getting into the rope horse breeding game, you’ll definitely want to page through the 2024 Breeder’s Guide.