EQUINE - Five tips for feeding the pregnant mare

1 Nov 2017

Issued date November 2017

Feeding a pregnant mare should be straight forward; use the following tips as a guide to keep your mare and unborn foal happy and healthy.

  1. Learn how to body condition score your mare.

If you’re not proficient at body scoring, then it is time to learn! As pregnancy advances, the mare will inevitably gain weight, mostly in her abdomen. Key points of fat deposition, such as crest, tail head, shoulder pads and ribs however, should remain similar throughout the duration of her gestation. A pregnant mare should be kept at a condition score of 3-3.5 throughout her pregnancy.  Body condition scores of 4 and above only add unnecessary weight to the mare’s limbs, and this could be difficult for any mare that has potential for soundness issues due to arthritic changes from a past performance career.  Pregnant mares shouldn’t ever be allowed to become fat.  Researchers from the USA found that the nutritional status of the fat/obese mare can affect the unborn foetus:

  • Reduced sensitivity to insulin.   Offspring born to overfed dams have a decreased response to insulin. Later in life, insulin sensitivity could worsen. In horses, insulin resistance is an important risk factor for equine metabolic syndrome and laminitis.  Researchers noted that  “In addition, alterations in foetal insulin sensitivity could impact the health and athletic performance of foals born to obese mares, which are both associated with negative economic and welfare-related issues
  • Decreased colostrum quality. Mares fed as little as 20% more energy than recommended by the National Research Council in the 110 days before their expected foaling date had lower IgG concentrations in their colostrum. Although no evidence of failure of passive transfer was observed, maternal over nutrition could potentially impact a neonatal foal’s ability to fight infection.

With the above findings in mind it is crucial for the unborn foal’s health and ability that the mare is never allowed to become obese.

  1. Provide vitamins and minerals.

For the first seven or eight months of pregnancy, the mare requires no increase in levels of energy fed. She does, however, need sufficient intake of high-quality feedstuffs to maintain moderate body condition. The primary feedstuff should be good-quality forage in the form of pasture or hay, and a source of essential vitamins and minerals. Vitamins and minerals can be provided via a compound feed, a balancer pellet or a vitamin and mineral supplement. If the mare needs the extra energy from a compound feed to maintain her weight, be sure she consumes the recommended amount as provided by the feeding instructions. This way, her vitamin and mineral needs will be satisfied, as will those of her developing foetus.  If she is receiving less then please do top up with a vitamin and mineral supplement.

  1. Resist the temptation to overfeed.

A common management mistake, among well-meaning mare owners, is overfeeding during the first seven to eight months of pregnancy. The foetus does not grow at an even rate during pregnancy; in fact, most foetal growth occurs in the final three months of gestation. Because of this, energy needs of the pregnant mare do not increase greatly until then. Keeping the mare in good body condition and supplying appropriate vitamin and mineral nutrition are the most important management tips during early pregnancy and mid-pregnancy. Mares should never be obese, because as well as the reasons already mentioned, this can make delivery more difficult.

  1. Reconsider energy levels in late pregnancy.

During the last trimester of pregnancy (from nine months to foaling), the nutrient requirements of the foetus and therefore the mare increase. During these last three months the foetus will gain 60% of its final birth weight and be growing at 350—450g/day!  A point also to be aware of is that 90% of foetal bone development takes place during this period so calcium and phosphorus requirements also increase dramatically. Compared to early gestation, energy and crude protein requirements increase by up to 20% and 30% respectively.  Even if your mare is a very good doer some sort of supplementary feeding will be necessary, and balancer pellets are ideal for the good doer. Try to find a special stud balancer or use calcium and phosphorus supplement as extra.  In mares that are not good doers, now would be the time to start using specialised stud feeds. The majority of stud feeds are formulated with thoroughbreds in mind so ask advice before selecting which feed would be best for your mare and unborn foal’s situation.  There are a few good reasons for starting to feed your mare at this stage (apart from the obvious increased nutrient needs of the foetus). During the later stages of pregnancy the digestive capacity of your mare can decrease, due to the sheer size of the foal and uterus restricting space. Her intake therefore will be lower which means that what she does eat needs to be nutrient dense and this is where hard feeding comes in.  Also, it gives the mare time to adjust to the new feeding system gradually before lactation is upon her. Remember all changes should be made gradually; the last thing you want is colic in a heavily pregnant mare!

  1. Salt and Water

As with all horses, provide a pregnant mare with free-choice access to a fresh, clean water source and a salt block or add extra salt to her feed.

Feeding the pregnant mare should be a straight forward exercise but should you have any queries or there are any issues that arise please do make sure that you contact a qualified nutritionist for advice.

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