2003, Issue #2

  from your Pioneer Sales Representative:  Kingston Feed & Farm

Feeding the Late Gestation Mare

Kasia Miedzinska, PhD

Certified Equine Nutritionist

It’s February and it’s cold. I feel as if I’ve been shivering since New Years. I look out at the paddocks and all I see is snow and ice. I can visualise spring. Late. Wet. Mud up past the pasterns. I just can’t see summer in my mind yet, much less mares and foals out on lovely green fields. It’s not the mares and foals I have difficulty with, it’s the green fields.

The mares and foals are a joy to look forward to, and yes, we have to start thinking about it now. Research over the last ten years or so has verified that the last three months of gestation and first three months after birth are the most important six months of life in terms of preventing developmental joint diseases. In other words, start feeding the foal now, through the mother.

Feeding the late-gestation period mare is both an art and a science, because the demands the foal is putting on her are changing day by day.  During the early-gestation period the foal was growing at a rate of about 0.2 lb/day. In late-gestation fetal development is much more rapid at about one pound or half a kilogram per day. A good portion of this is due to bone and muscle development. Bones need five main minerals (calcium, phosphorus, copper, zinc and manganese). The majority of mineral retention by the foal occurs in the tenth month. The requirement for calcium and phosphorus goes up a whopping 80 to 100%.  If we don’t add it to the feed for the mare, she will leach them out of her own bones in order to provide for the foal. You may have a healthy foal at the end, but the mare may well have been ruined for life.

At the same time the mare needs 20% more energy or calories (up from 16 to 20 Mcal/day), and about 30% more protein to sustain the life she carries within her. Raising her feed volume can certainly take care of these issues as long as she doesn’t explode from the sheer volume. However trying to raise her mineral intake to the amount required by raising the amount of normal feed is virtually impossible. Supplementation with a mineral is possible, but not always practical. Help is at hand with a wide variety of “mare and foal” feeds that are designed for this purpose.

In late gestation a mare should receive from 1.5 to 2% of her body weight in total feed daily. Her new body weight that is, as she is no longer sleek and svelte. This weight includes the foal. As the foal grows and continues to take up more space in the mare’s body, you may find that she will taper off her hay consumption to only 1% of her body weight. The rest will have to be made up by the grain.

In early gestation a mare will consume 90-100% of her food intake as hay, and only up to 10% as a grain ration. By late gestation the ratio changes to 65-75% hay and 25-35% grain. Depending on the quality of hay (alfalfa/legume vs grass) this would mean the grain should range from 10% in crude protein if feeding alfalfa, to 16% in crude protein if feeding grass hay. Broodmare feeds come in such a range, and are often formulated for easier digestion. The best way to ensure that you are choosing the right mare feed is to know the quality of hay you have available. That’s right, my favourite topic rises again – hay sampling!

In about the tenth month the mare will begin to make milk. By foaling time about 3% of her body weight is milk. Throughout that last period her energy requirements will rise again, up to 28 Mcal/day. Upon foaling her feed will need to be raised by about 75%, but not until the foal is at least 7 days old.

Ah, but feeding the lactating mare and foal is for the next instalment, when those foals are ready to burst onto the scene. In the meantime, I’m back to contemplating my not-so-green fields.