Tuesdays with Tony

Breeding & Foaling

Thank you to everyone who came out to my Breeding Seminar last Thursday. You didn’t see me because I was inside. In my bed. Where it was warm. Obviously. Why would I go out in the freezing cold to huddle around a space heater just to learn about how baby horses are made? I did, however, lay on the computer while the docs were working on their powerpoint presentation, so I am intimately familiar with the information they presented. Oh, you want a recap you say? Well, I’m happy to oblige!

Where do baby horses come from?

Well kids, when a daddy horse and a mommy horse love each other very much…their owners run genetic tests to make sure they don’t have any heritable diseases, pay lots of money to have semen collected, ship it cross-country, time the mare’s ovulation, artificially inseminate the mare, patiently wait 14 days, confirm the presence of ONE embryo, monitor the pregnancy with at least 4 more ultrasounds and Rhinopneumonitis vaccines, measure the mare’s milk pH to determine when she’s going to foal, and voila! That’s where baby horses come from.

It may sound simple, but a problem at any of these steps has the potential to create a roadblock to your hopes and dreams of having the perfect foal. Let’s start at the beginning: choosing the parents. Stallions may look sexy in their ads, but remember to look at their offspring’s conformation and performance records, their First Heat Conception Rate (a marker of fertility), and make sure they are free from any breed-associated genetic disorders, such as HYPP, PSSM, HERDA, OLWS, or SCID. If you want to know what these letters stand for, or if your breed of horse is at risk for them, ask one of the docs. I’m just a cat; you’re lucky I know the letters. If you are the stallion owner, it’s time to think about training him to the phantom, and scheduling a blow-out collection and semen evaluation prior to breeding season.

The next roadblock usually comes from FedEx. We here at Springhill have a love/hate relationship with FedEx. Most stallions are collected on Monday/Wednesday/Friday. Unfortunately, those Friday collections require overnight shipping on a weekend. Semen doesn’t live very long in a box with an ice pack. That means any shipping delays on the stallion end translate to a missed breeding opportunity on the mare end, and we have to wait another 2-3 weeks before trying again on her next heat cycle.

Even once the docs have gotten the semen into the mare, there is a chance her body will have an inflammatory reaction to the semen and excrete fluid in her uterus (really, it is a wonder these things ever successfully reproduce in the wild). Barring that scenario, you still have to make sure there is one and ONLY one embryo at the 14-day check. If there are twins, the docs have between Day 14 and Day 16 to pinch one of them while keeping the other alive (this is much easier said than done).

What do I do with my preggo mare?

Now that you have worked so hard to get that beautiful 14-day-old baby embryo, you may as well put in the work to make sure she keeps it. On your part, that means making sure to schedule her 30-day, 60-day, 90-day, and 7-month ultrasounds, as well as Rhinopneumonitis (a.k.a. Pneumabort) vaccines at 3, 5, 7, and 9 months of pregnancy. You may think this is just my way of seeing you more often in the hopes that you might give me snacks; but in actuality these are all aimed at making sure your mare doesn’t drop/slip/abort/lose or otherwise spit out her foal before it’s due date!

Even if you ate a tub of Ben & Jerry’s single-handedly every night of your pregnancy, this does NOT mean you need to fatten up your mare just because she has a baby on board. In fact, depending on her weight and body condition score when she became pregnant, you may not need to increase her plane of nutrition at all until the last few months of her pregnancy. The true calorie demand will come while she is nursing her foal, but that’s a topic for another day.

When is the stork coming?

When the docs tell you your mare’s ESTIMATED due date, that’s exactly what it is- an estimate based on 340 days past her date of conception. In real life, she can foal anywhere from 320-360 days of gestation, and it’s not unusual for a mare to carry over a year! So, how do you know when your cute little bundle of joy is going to hit the ground?

In our opinion, the best way to tell when your mare is going to foal is by measuring the pH of her milk once a day until it reaches a magic number. Here’s what you need to know: If her pH is >6.4, there is a 99% chance she is NOT going to foal that night. If her pH is <6.4, there is a 97% chance she WILL foal within the next 3 nights. And now you know when to start sleeping in the barn aisle/watching cameras/checking your mare every hour, or whatever it is you are doing to make sure you don’t miss the big event.

If I haven’t talked you out of breeding your horse yet, remember that I offer Breeding Packages at a very reasonable set price per cycle. And if you buy your package before Valentine’s Day, you will receive 1 free night of board for your mare…our little secret! We also perform stallion collection, semen evaluation, phantom training, and semen shipment right here at the clinic. I quite enjoy the extra company around breeding season.

Happy baby making!



Tuesdays with Tony is the official blog of Tony the Office Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. For more information, please call us at (352) 472-1620, visit our website at SpringhillEquine.com, or follow us on Facebook!

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