Tuesdays with Tony

Pregnant Mare Care 

Congratulations! You’ve got a bouncy baby horse coming in about 11 months! In my experience watching the humans around here, it’s a very long 11 months. There are important things to do during that time to make sure the baby arrives happy and healthy. In my experience, humans are really good at getting the heartbeat ultrasound check at 30 days, but not so good at the rest of it. Read on for Tony’s words of equine wisdom regarding pregnant mare care.


These are just so freakin cool! You get to see that baby go from a black dot on the screen at 2 weeks to having a heart beat at 30 days. At the 60 day ultrasound there are legs and something resembling a head! They grow so fast. My Docs are checking way more than just the baby when they’re ultrasounding, though. They are also checking the entire uterus and ovaries to make sure they’re doing what they should.

The most important thing they are checking is where the cervix and placenta meets. This is where the outside world meets the uterus, and it’s where problems often start. My Docs will check to be sure the placenta is tight up against the cervix, along with measurements to be sure it’s not too thick. A thick placenta can be an indication of infection. If infection is spotted early, it can be easily treated with antibiotics. On young mares who don’t have a lot of exposure to other horses, ultrasounds should be done at 5, 7, and 9 months to check for infection. On older mares (over 12 years), problem mares, or mares who see lots of other horses all the time, the Docs recommend ultrasounds at 3, 5, 7, and 9 months.


Rhinopneumonitis vaccines are super, super, super important for pregnant mares. Most humans call this a Pneumobort shot. Rhinopneumonitis is a Herpes virus. Herpes viruses are nasty little buggers. Once a horse has the virus, they’ve got it for life, and most horses are infected in their first year of life. The virus spends most of its time hibernating, but stress (I hear pregnancy is definitely stressful) can make it wake up. Frequent vaccinations keep the immune system on high alert for this virus. This means that if it does wake up, the immune system is right there to tackle it.

Rhinopneumonitis vaccines follow the same rules as ultrasounds. If your mare doesn’t meet new horses often, she can get a vaccine at 5, 7, and 9 months. If she is a social butterfly, she should get vaccinated an additional time at 3 months. This vaccine can be what my Docs call hot (horses often get a mild to moderate vaccine reaction from it). The Docs recommend some Bute beforehand to help reduce the reaction if you’re worried.

At around 10 months of pregnancy, your mare will need all her “regular” vaccines. For most mares this is Eastern and Western Encephalitis, Tetanus, Influenza, West Nile Virus, and Rabies. This makes sure the baby has great protection against these viruses when it gets here.


Don’t. Ha! That was easy. Seriously though, see my numerous blogs on deworming. Watch an entire presentation by my Docs about deworming here: Deworming Seminar  Fecal egg counts and targeted deworming is the way to go. Don’t go deworming all willy nilly like you humans are prone to doing.


Don’t go crazy. Again, easy! Have your mare on a good feed. If she gets skinny easily, then a mare and foal feed may be necessary. If she’s an easy keeper, then good quality hay and a ration balancer may be all she needs. This is not the time to get her fat. It won’t make foaling easier on you or her.


Yes. Of course they tell me that too, but I don’t like exercise, so I don’t. Pregnant mares can go out and do what they did before they were pregnant with a few guidelines in place.

  1. Don’t do more than you did before she was pregnant. If you went for 5 mile trail rides, great. Don’t sign up for the 50 mile endurance ride.
  2. Watch how hot she gets in the early stages of her pregnancy. Being really hot can be really, really bad for embryos younger than 90 days.
  3. Listen to your mare. At some point, later in her gestation, she’s going to tell you she doesn’t want to work anymore. Respect that.

Before you know it, 11 months will have flown by and you will be anxiously awaiting your foal. Spend the time wisely by thinking up perfect baby names, and keeping your mare up to date on all her prenatal care! Bring her into the Clinic for her happy mom check ups and I’ll even throw in a free CAT scan by yours truly.

Now be a good human and subscribe to my blog. Scroll down a tiny, tiny bit. So easy a human can do it.

Springhill Equine Veterinary Clinic

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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