The Best Time of the Year, Pregnant Mares – The Chance for a Champion!

Many broodmares are in the last one third of gestation at this time of the year and some have already foaled. The latter part of gestation is one of the most important development periods in the life of a foal when the foal is developing in the uterus of the mare. The importance of this period was recognized in the Nutrient Requirements of Horses, Sixth Edition, when the Committee established that the nutrient requirements of the mare start increasing at the 6th month of gestation, earlier than previously believed.  During the last three months of gestation, the foal may be gaining a pound per day.

The key elements of managing the pregnant mare are the following:

  1. Maintain appropriate body condition score. Mares should be at about a body condition score 6 when they foal so that they have sufficient energy reserves for early lactation as well as to maintain condition for re-breeding.  We are already thinking about re-breeding before she foals!
  2. Adequate protein/amino acid intake. Lysine, methionine and threonine, the first 3 limiting essential amino acids, need to sufficient in the diet for placental and fetal development.
  3. Adequate macro mineral, trace mineral and Vitamin intake. The mare needs to be receiving adequate calcium, phosphorus, magnesium, copper, zinc, manganese and selenium to provide minerals for the development of the foal and to build the foals own trace mineral reserves. Trace minerals are also critical for immune support. Vitamins A, D, E and B-Vitamins are all essential and should be included in a balanced diet.
  4. Vaccinations and deworming. A regular vaccination program should be developed in conjunction with a veterinarian so the mare is protected herself and can also produce the appropriate antibodies to protect the foal when it nurses and receives the colostrum that contains maternal antibodies. This is what protects the foal until it can be vaccinated and develop its own antibodies. The mare should also be dewormed as needed prior to foaling to make certain the environment of the foal is as “clean” as possible to reduce parasite contamination. Selective worming based on fecal count monitoring is becoming more and more important to reduce the risk of parasite resistance developing.

Good quality pasture or forage may provide sufficient energy thru late gestation, but may NOT provide adequate amino acids and minerals for optimal fetal development. A well designed ration balancer product may be used from month 5 to about month 10 or 11 of gestation to provide the missing nutrients. A well designed feed for broodmares and foals should be introduced prior to foaling so that the mare is on the feed before she foals to avoid the need for a sudden change in feed at foaling. This feed can then be increased after foaling to provide both the increased energy and the increased nutrients that are required for lactation, as well as providing nutrition for the foal when it starts to nibble on feed. Fresh clean water and free choice salt should also be available at all times.

Feeding the broodmare properly can help reduce the risk of developmental problems for the foal and help insure that the mare can be rebred in a timely manner to produce another foal the following year.

Inside the Broodmare’s Belly…

Lactation demands a lot from a broodmare!

Are you anxiously awaiting that first foal of the spring? Do you have the foaling stall ready, the vet on speed dial, and the video camera on the battery charger? While you’ve been busy prepping, here are some of the amazing changes that have taken place (or are about to take place) in your mare:

  • 6 Month Mark: During 2nd half of pregnancy, 60 – 65% of fetal growth occurs!
    • Energy requirements of the mare go up almost 30% over a normal maintenance horse – from 16.7 Mcal DE per day to 21.4 Mcal DE per day.
    • Her protein requirements will increase 32%, and vitamin and mineral requirements also increase significantly during this time.
    • The mare needs to be receiving adequate calcium, phosphorus, magnesium, copper, zinc, manganese and selenium to provide minerals for the development of the foal and to build the foals own trace mineral reserves.  Trace minerals are also critical for immune support. 
    • Adequate protein/amino acid intake is essential – lysine, methionine and threonine, the first 3 limiting essential amino acids, need to sufficient in the diet for placental and fetal development.
  • Last Trimester: The average foal fetus will grow by 1 pound per day!
  • Lactation: After the foal has been born the real work for the mare is just beginning.
    • The normal mare will produce around 24 lbs (3 gallons) of milk per day. During an average 150 day lactation, this equals 450 gallons or 1.75 tons of milk!
    • During lactation, a mare’s energy needs are easily doubled over her maintenance needs – from 16.7 Mcal DE per day to 31.7 Mcal DE per day!
    • While a mare is producing milk for her offspring, her water consumption can exceed 50-100% that of a maintenance horse.
    • Around 13-24 weeks after the mare has given birth, her milk production will decrease from 3% of her body weight to around 2%.

With all that effort going into producing a darling new foal for your farm, be sure to give your mare an extra pat on the neck, and of course, make sure you are feeding her properly!