Gestation in the mare is approximately 11 months. It must be known that from conception to the 6th month of gestation the growth and development of the embryo and then of the fetus remain weak. The fetus reaches barely 17% of its birth weight at 7 months of gestation. So during the first 8 months, the mare does not need an extremely richer feed, it just needs to be regular.
From the 9th month (up to the 11th month) the level of needs increases (they double) because more than 50% of the birth weight is obtained during the 10th and 11th month. The mare needs more energy and demands more nutritional needs
The most important part in food needs is from foaling (almost 3 times the maintenance base) !! Then there is the "peak of lactation" it is a rather long period or the food must remain the same (if one wants, one can gradually lower the quantities.) The period when there is weaning is a The nutritional needs of the mare decline fairly rapidly, so pay attention to this period so that there is no loss of weight or anything else.