Tuesdays with Tony

Somehow, it’s that time of year again. No, not Christmas or New Years, but breeding season. Well, not quite yet, but it’s just around the corner, which means it’s time to start prepping now. And if you are just starting to prep now, you may even be a little late to the game depending on when you plan to breed your mare. Don’t fret, I’m here to get you back on track and discuss the ins and outs of breeding your mare.

I just love breeding season, because it means I get to see my docs all the time! It’s like they never leave the clinic, so I get to spend all my time outside which is my favorite place to be. It also means my docs are working double time with their usual appointments along with trying to get these mares bred, which is yet another reason to be prepared when it comes to breeding. I’ve said it before, and I’ll say it again: breeding is not for the faint of heart. Yes, foals are adorable, and most mares are wonderful moms, but breeding is not without its pitfalls and heartaches.

Before You Breed

Did you know that even before you start the breeding process there is a lot of homework you have to do? First, and fairly obviously, you have to have a mare. Whether it’s your mare or a mare you are leasing/borrowing, you can’t make a baby without a mare. The next step to know your mare. Know her history, know what she’s done as a performance horse, know if she has any prior injuries or surgeries, and know her breeding history. Knowing all these things will help the docs help you make informed decision prior to breeding.

Once you know what mare you plan to breed, your next step is to set up an appointment with your veterinarian for a pre-breeding examination. During this exam, your veterinarian will go over the ins and outs of breeding your mare and what to expect. They’ll examine your horse in several different ways, starting with a brief physical exam, listening to her heart, lungs, abdomen, and looking at her overall state of health and conformation.

Springhill Equine Veterinary Clinic

Next, they’ll do a speculum examination. This is odd if you ask me, but basically they take a sterile paper towel roll and gently insert it into your horse’s vagina. Then they look through the paper towel roll with a bright light and inspect the inside of the vagina for abnormalities. They inspect the cervix for discharge or scarring, and get an overall idea of the status of your horse’s vagina.

Next comes a rectal exam with an ultrasound. This way they can visualize the entire uterus, both ovaries and the cervix. The uterus is assessed for any evidence of infection or any uterine cysts that might be present. Both ovaries are examined for abnormalities and to determine where your horse is in her cycle.  After the ultrasound your veterinarian should get a sample of cells from your horse’s uterine wall. The cells are examined for abnormalities, bacteria and/or white blood cells which could indicate infection. Fluid is also obtained from your horse’s uterus to culture the cells and determine if there is a uterine infection. If the culture comes back positive, this allows the veterinarian to determine a best course of treatment. The pre-breeding exam is extremely important to perform early, so if your horse does require treatment, it can be completed prior to the start of breeding season.


If you think this sounds like a lot, just wait, there’s more! In case you forgot, you have to have a stallion to make a baby. Finding the right stallion for your mare is not as easy as it seems. The stallion you pick should complement your horse’s conformation, and he should also fit your performance goals.

Once you have your stallion picked, you have to communicate with the stallion owner. A breeding contract should be drawn up and agreed upon by both parties. I can’t begin to tell you how important this contract is. The contract is your lifeline to getting your mare bred. It tells you exactly how much you should expect to spend on stud fees, collection fees, shipping fees, etc. It also gives you essential information that your veterinarian will need when it comes time to breed your mare.

Knowing what stallion you are going to breed to, if he performs live cover, or if cooled semen or frozen semen is shipped out, and what days semen is shipped is essential for owners and veterinarians to know. All this information allows your veterinarian to make decisions when it comes to breeding your mare to give her the best chance of conceiving.

The Breeding Process

So you’ve done your homework, you’ve had your mare checked over carefully by a veterinarian and you have all of the I’s dotted and T’s crossed with the stallion owner. You may think it’s going to be easy now, but it’s not! The breeding process is far from easy and far from simple. Rather than a one and done thing, it often takes up to 3 times of inseminating to get a mare pregnant. That means 3 collection fees, 3 shipping fees, 3 insemination fees and more. Breeding adds up financially very quickly.

Timing is of the essence when it comes to breeding, especially when it comes to cooled shipped or frozen semen. Often, my docs like to have the mare they are breeding at the clinic for several days to several weeks. This allows them to check where the mare is in her cycle daily, follow the development of follicles on the ovaries, and administer medications to induce ovulation in conjunction with when semen is available for shipment. The timing of ovulation is key. Mares should ovulate within 24 hours of insemination with cooled shipped semen. This is why my docs spend all of breeding season with me: they are constantly checking your mare and constantly stressing over when semen will arrive. It’s an extremely stressful time, but it’s also very rewarding.

Insemination is pretty simple: clean the mare up, put the semen in and wait. The wait is sometimes the hardest part. From the time of ovulation to the first pregnancy check is 14 days. Two weeks, that just seems like forever to wait. Two weeks after ovulation an ultrasound will be performed and everyone will be looking for that little black dot. Once that little black dot is seen, you may think the hard part is done. But, no, there is more.

The Follow-Up Checks

Two weeks after the first pregnancy check is when we can see the baby’s heartbeat. The twenty-eight day check is an essential check. It allows your veterinarian to ensure your horse is indeed pregnant, and to find the fetus’ heartbeat. Surely, we must be done now, right? Wrong. The next ultrasound is at 60 days of pregnancy where your veterinarian will assess fetal development.

Another ultrasound is performed at 90 days of pregnancy. This ultrasound is another check on fetal development and to check for signs of early embryonic death. At the 90-day visit, your horse will also receive her first pneumabort vaccination which reduces the risk of abortion caused by herpes virus. Pneumabort vaccinations are given at 3 months, 5 months, 7 months, and 9 months.

The 7-month ultrasound is extremely important. That’s when your veterinarian will check for signs of placentitis. Placentitis can lead to abortion of the fetus, so catching the early signs is essential. Whew, it has been a ride so far and we are only at 7 months! After the 9-month pneumabort vaccine, you’re in the home stretch. At 10 months, your mare will receive her pre-foaling vaccinations and you get to start getting ready for foaling. The excitement builds for the final event.

Foaling and after-foaling is a whole process of its own, so stayed tuned for my upcoming blog about foaling and your foal’s first few months of life.

Until next week,


P.S. The humans have several podcasts on breeding, if you’d like to listen to hours of in-depth information presented in an easy-to-digest manner. Just jump over to the Podcast Page of my website and start scrolling through the episodes.

Tuesdays with Tony is the official blog of Tony the Clinic Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! 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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