Pregnant Mare Nutrition
Proper feeding and management of broodmares is a key factor in the production of healthy foals. Horse owners invest a great deal of time, money and feeling into the selection of breeding stock. Management and nutrition should be planned to give the foals the opportunity to achieve full genetic potential.
Any time after January 1, mares are foaling in many barns. Broodmare nutrition can be broken down into three categories:
1. The first 2/3 of pregnancy
2. The last 1/3 of pregnancy (110-115 days)
The first 2/3 of pregnancy is the least demanding. Mares should be maintained at a body condition score of about 5 or slightly above. During early gestation, the weight of the fetus is small relative to the weight of the mare. Mares should be fed according to their requirement for maintenance and activity level. This will require 1% to 1-1/2 % of body weight fed in hay or equivalant fiber source plus sufficient grain concentrate to maintain weight. If alfalfa hay is used, a properly formulated grain containing 10%-12% protein and guaranteed levels of lysine, methionine, calcium, phosphorus, copper, zinc and vitamins will be appropriate. If grass hay is being used, a properly formulated 12%-14% concentrate is suggested. Grain concentrate levels should be adjusted to maintain desired body condition. Adequate water and free choice salt must be available.
The last 1/3 of gestation places additional demands on the broodmare. The fetus may be gaining 1 lb per day as bone growth and body development take place.The NRC (National Research Council) shows an increase of about 20% in DE (Digestible Energy) from maintenance requirements to the 11th month of gestation requirements. An appropriate 14%-16% concentrate will provide the increased amounts of key amino acids such as lysine and methionine as well as calcium, phosphorus, copper, zinc and other trace minerals and vitamins required for proper growth of the foal in utero. A recent research trial has documented that proper mineral supplementation of broodmares improves cartilage quality in foals at 150 days of age. (World Equine Veterinary Review, Volume 2: No. 4, p. 36, 1997.)
The most dramatic increase in nutrient requirements for broodmares occurs in early lactation. According to NRC data, the energy requirement increases by about 70% and the protein requirement more than doubles, with comparable increases in minerals. If nutrient intake is not sufficient, mares will loose weight and remove minerals from their body, thus reducing their chances of re-breeding. These early lactation mares will consume 2.5-3.0 lbs of hay and grain per 100 lbs of bodyweight. The grain concentrate portion of this ratio may be brought up gradually to 1-1.5 lb per 100 lbs of bodyweight to maintain milk production and body condition. Free access to water and salt are mandatory. Decreases in body condition score indicate negative energy balance with potential negative effects on production and re-breeding.
Late gestation and lactation are key periods in the life of the broodmare (and the owner). Proper veterinary health care (de-worming, dental work, vaccinations) and proper nutrition are essential to the development of this year's foal, and next year's as well.