Second Trimester Care

If you bred your mare in the spring, she will likely be in or close to her second trimester at this time. The second trimester is defined as day 114-210 of gestation. Management isn’t much different from a non-pregnant mare but there are some considerations to keep in mind. Always consult with your vet for specifics regarding your mare and your situation. But here are some general guidelines for the second trimester.

Many people think a pregnant mare is fragile and must be handled carefully. But they need exercise and as long as there aren’t any extenuating circumstances, you can saddle up and ride. In most instances, mares can safely participate in more rigorous activities like cantering, jumping, and competitions up to about month five of gestation. Light riding is fine up to about month 8, though you may need to adjust saddle fit to accommodate her growing shape. At a minimum make sure your mare has plenty of time turned out in a pasture, paddock, or dry lot. 

It is always a good idea to provide high-quality feed but a pregnant mare’s nutritional demands are not much higher than normal during this time. In fact, you must be careful not to overfeed at this stage. Many people think they should feed for two once the pregnancy is confirmed. But excess nutrients above what is needed will not help improve foal growth but will instead go to the mare. Carrying this additional weight can be detrimental for the mare resulting in conditions like laminitis. Excess fat stored around the pelvis can narrow the birthing canal which can make the foaling process more difficult. Try to keep your mare’s BCS around a 5 or 6 during pregnancy. Your vet can help you assess your mare’s body condition score and help with nutrition recommendations.

Consult with your vet for help with preventatives like dewormers and vaccines. Most dewormers are safe for pregnant mares but check the label carefully. During this time, you can vaccinate for EHV-1, which is Equine Herpes Virus-1. Both the first and second shot should be given during the second trimester. Fetal sexing can be done at this time to determine the foal’s sex.

The second trimester is fairly simple in terms of management. Changing up her exercise or feeding routines likely isn’t necessary unless there are extenuating circumstances. Taking care of your mare now helps set her up for a successful third trimester and foaling.