Feeding Orphaned Foals

From Dr. Holly Bedford, DVM University of Minnesota
Original Article here https://www.extension.umn.edu/agriculture/horse/nutrition/feeding-orphaned-foals/

Mare's colostrum (first milk) is a rich source of antibodies that protect the foal from infection until the foal's immune system is fully developed. Unlike humans, horses do not receive any antibodies through the placenta prior to birth and therefore are dependent on colostrum. Absorption of colostrum from the foal's gastro-intestinal tract peaks within 6 to 12 hours after birth. By 18 to 24 hours of age, absorption is minimal. In general a, 100 pound foal requires a minimum of 2 to 3 quarts of colostrum within the first 6 to 8 hours of age. Foals should have an IgG test performed within 24 hours of age in order to ensure that they have absorbed adequate antibodies. In the event that equine colostrum is unavailable, intra venous administration of hyperimmunized equine plasma by your veterinarian is the best alternative to provide adequate protective antibodies to foals. Other alternatives to mare's milk include milk replacers, goat's milk, and cow's milk.
The best and most economical alternative to mare's milk is equine milk replacers. These replacers are specially formulated to meet a foal's nutritional needs and are the closest in content to mare's milk. Acidified milk replacers are preferable because acidification enhances nutrient digestibility and allows the reconstituted milk to stay fresh longer.
Goat's milk is the next best alternative to mare's milk. While the fat content is higher than mare's milk, it is highly emulsified and easier to digest than the fat found in cow's milk. Disadvantages of feeding goat's milk include the small packaged volume, the expense, and the greater risk of constipation.
While cow's milk can be fed to foals, it is lower in sugar than mares' milk and has twice the fat content, which can lead to diarrhea due to poor digestibility. If cow's milk is fed, it is best to feed 2% milk (lower in fat) and add dextrose (easily digestible type of sugar) to the milk to increase the carbohydrate content to match that of mare's milk. This can be accomplished by adding 40 millimeters of 50% dextrose solution to each quart of milk, or by adding a 2 ounce package of jam/jelly pectin to every 3 quarts of milk. Honey, corn syrup, or table sugar should not be used to increase the sugar content as these types of sweeteners contain sucrose which is poorly utilized by the foal and can cause diarrhea and colic. Non-pasteurized milk should be heated to 160 F for 15 seconds and allowed to cool prior to adding dextrose and feeding.
Calf milk replacers can be used for foals. When choosing a calf milk replacer, carefully read the ingredients list and only opt for products containing all milk proteins (skim milk, buttermilk, whey, casein) and avoid products containing soy protein, fish proteins, meat solubles, yeasts, or flours, and distiller's grain byproducts. Additionally, check the crude fiber, protein, and fat content. Appropriate levels for foals are: crude fiber < 0.2%, crude protein 20%, and fat 15%.
Foals should be feed 20 to 25% of their body weight per day (not per feeding). It is important to weigh the foal daily and adjust the daily feeding volume accordingly as the foal grows. Gradually, the volume of milk fed can be increased, while the frequency of feeding may be decreased. The average foal should gain approximately 2 pounds per day. If the foal fails to gain weight, the volume of milk or frequency should be increased. A general guideline for feeding normal healthy foals is to feed every 2 hours during the day and every 3 hours through the night for the first 2 weeks (make sure to divide the total amount needed-about 25% of body weight - by the feeding frequency). Once the foal is consuming the calculated milk volume readily, the feedings can be spaced out to every 3 to 4 hours during the day, and 4 hours at night for another 1 to 2 weeks. By 1 month of age, most foals can be fed every 6 hours.