Twelve Facts About Pregnant Mares #3

Twelve Facts About Pregnant Mares

So much is written about mares during pregnancy, perhaps a few selected facts may be of interest as we head into winter and wait for the spring delivery of the new foals.

Pregnancy Facts

  1. The most common mistake during pregnancy is overfeeding protein and energy.
  2. The second most common mistake is overfeeding over-the-counter vitamin and mineral supplements.
  3. Mares are not ‘eating for two’ during early pregnancy.
  4. The ideal Body Condition Score (BCS) for pregnancy is not less than BCS 5.5 and is closer to a BCS 6, which is moderately fleshy.
  5. A foal fetus does not grow at a constant rate throughout the 11 months of pregnancy. By the 7th month of pregnancy, the foal fetus is approximately 20% of its weight at birth.
  6. A developing fetus has the ability to store trace minerals such as Fe, Zn, Cu and Mn in the liver during pregnancy since the mare’s milk is low in these elements during early lactation.
  7. The foal fetus is approximately 20% of its weight at birth at the seventh month of pregnancy. Additional nutrients from a balanced formula are needed to support the developing fetus. Integrity Mare & Foal has the protein, calcium, phosphorus and the other essential macro- and micro-nutrients that are required during the latter stages of pregnancy.
  8. Over the entire pregnancy, mares can expect to gain 12-15% of their non-pregnant weight. For example an 1100 lbs mare can expect to gain between 130 – 165 lbs.
  9. 65 – 70% of a mare’s body weight gain occurs in the final 100 -110 days of pregnancy
  10. Average daily body weight gain during the final 90 days of pregnancy ranges from 0.8 – 1.1 lbs per day
  11. For an 1100 lb mare, the foal’s birth weight will be about 106 lbs.
  12. If energy/nutrients are inadequate during late pregnancy, mares with a good BCS will use body tissues and nutrient stores to support the development of the fetus, causing weight loss.