Now that she’s pregnant….

Nathan Voris, DVM
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As the breeding season has come to an end on many farms, the focus shifts from getting your mare in foal to maintaining pregnancy and optimizing her chances of delivering a healthy foal next spring. While the general care for a broodmare early in gestation is similar to that of any other horse, there are some special needs to consider as the foaling date approaches.


Pregnant mares during early to mid gestation require little if any special changes to their diet if they are in good body condition. During the last 3 months of gestation, the foal will gain more than half of it’s eventual birth weight, therefore, a gradual increase in quantity and/or quality of feed will be required to enable the mare to continue consistent weight gain throughout her pregnancy.

Additionally, it is important to remove the mare from all sources of fescue during the last 3 months of gestation. Most fescue contains a fungus that causes prolonged gestation, thickening of placental membranes and inhibits milk production.

Vaccination and deworming

Preventive health care measures are important for optimal performance in all types of horses. Maintaining a current vaccination and deworming schedule for your broodmare is vital to ensure the health of both the mare and foal during gestation and the immediate post-parturient period.

Rhinopneumonitis is caused by a Herpes virus-one of which causes abortions. Maintaining adequate protection against “rhino” requires inoculations during the fifth, seventh and ninth months of gestation. Broodmares should be vaccinated for Eastern and Western Encephalitis, Tetanus, Influenza and West Nile one month prior to foaling to insure that colostral antibody levels are adequate for passive transfer.

While regular deworming is recommended (every 6-8 weeks), it is not advisable to deworm your mare during the first 60 days of gestation when the fetal organs are forming, nor during the last 30 days of gestation.

A recommended gestational timeline is summarized in the table below.

Month of Gestation Action Required
5th Month Deworm, 5-month Rhino shot
7th Month Deworm, 7-month Rhino shot
8th Month Remove mare from fescue
Provide adequate nutritional support to maintain gradual weight gain through the remainder of gestation.
9th Month Deworm, 9-month Rhino shot
10th Month Eastern/Western Encephalitis, Tetanus, Influenza and West Nile Vaccination


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