When quality feed is provided, additional vitamins and feed additives are usually not necessary. Climate exposure can influence the nutritional requirements. The weather pregnant mares can withstand depends upon what the mare is acclimated to. Any time an animal reaches the extreme of its thermal neutral zone, excessive energy is required to increase or decrease the animal's body temperature. Though you should be able to palpate the ribs, they should not be visible on a well-conditioned horse.
Exercise can keep the excess weight gain down.
Protecting the mare from parasites protects the fetus. Age, housing, and exposure all contribute to the continual health threat of parasites. Always read labels and check with your veterinarian before deworming. Certain products are not safe for the various stages of pregnancy. Dr. Rowley has some additional tips about controlling mare exposure to parasites.