Feeding for Breeding

Breeding and foaling season may be the most special and most important time of the year for the mare owner. To have a successful breeding program, however, all aspects of the horse's health and management must be considered. A thorough physical examination should be performed by a veterinarian because it is important to ensure that the mare has a functional reproductive tract and is capable of becoming pregnant and carrying a foal to term. It's much better to discover and treat problems before sending the mare off to be bred than to invest time and money, only to learn months later that the mare is incapable of reproducing.

Preparation for breeding is essential. Brood mares lead a different lifestyle from other horses; the brood mare actively progresses through many internal changes during conception, gestation, and lactation. Keeping a mare healthy and fit year round is the most sensible thing to do, because it takes time for the body to rebalance itself, to adjust to changes in nutrition, and to achieve a healthy weight. Mares will cycle and conceive more readily if they are kept in good physical shape and receive the best in nutrition.

Well in advance of breeding time (several months, not weeks), open mares must be on a nutritionally complete diet. The reproductive performance of the mare and the health of her offspring depend on the health level of the mare, and health depends primarily on proper nutrition. Pregnancy will take its toll on the body if it is not in good health, so a mare must be properly nourished. With balanced nutrition, a mare can build up her strength and resistance to diseases. The added strain of pregnancy may aggravate any existing conditions, so they also should be dealt with well ahead of time.

Nutrition and exercise are needed to maintain the proper condition of the mare. The mare's weight is an important factor in fertility. Being of correct weight is important because generally, overweight or thin mares do not conceive well. Ideal weight differs with each animal, but as a general guideline, mares should be in moderately fleshy condition, with flesh covering the ribs. There should be just enough flesh on the last three ribs that they can still be felt, but not seen. Getting the weight down or up should be attempted well in advance of breeding, not after the mare is bred.

Keeping a mare healthy also involves hoof care and dental care. The hooves must be trimmed and properly balanced, and in most cases, left unshod. Any sharp edges on a mare's teeth should be removed to improve the ability to chew and digest feed, which ultimately affects the ability to conceive.

A good, basic feeding program must meet the requirements for the five nutrient classes (which support different body functions): energy, protein, minerals, vitamins, and water. It must also meet the needs of the horse - there is no single best way to feed all horses, so this will vary depending on the horse's weight, age, and activity level.

Energy, or calories, is the fuel for all physical activity, growth and repair, and milk production. A deficiency of energy will cause slow growth, reduced activity, general weakness, and poor condition. Excess energy becomes body fat. Digestible Energy (DE) is the amount of energy that is actually available to the horse in a digestible form. Carbohydrates, abundant in plant feeds, are the horse's major source of energy.

Protein is needed for growth and repair of body tissues, muscle development, skin and hair development, reproduction, and lactation. If energy in the diet is low, protein can also be converted to energy. Good quality protein contains essential amino acids. The average recommended protein levels for mares are: First eight months of gestation, 8%; 9th and 10th months, 10%; 11th month, 13%; lactation, first three months, 13%; after third month, 11%.

Vitamins and minerals are also essential to the body for many functions and they act as catalysts for metabolism. A proper balance is necessary. While only small amounts of each may be needed, deficiency can cause problems once the reserves are used up. In general, a good balanced diet of fresh (properly cured) green hay, some grain if needed, and sunlight will provide sufficient amounts of vitamins for the average horse. Vitamin and mineral supplements are available, but should only be used when needed.

Access to fresh, clean water, a most essential nutrient, must be provided at all times. The average horse will consume 10 to 20 gallons per day. Water intake is affected by air temperature, exercise, lactation, and especially dry matter consumption. Without adequate water, horses are more prone to colic and impaction, and they will eat less dry matter. Also, water intake is essential to body temperature regulation.

Pasture and hay may very well provide all the necessary nutrients up to the last trimester. Fortunately, nature's timing is such that the increase in grazing quality and quantity helps to signal the mare to reproduce, and the following year, optimum grazing occurs when the mare needs it most, during late gestation and lactation. Carefully maintained and monitored pastures provide the most natural food for a horse. Good pasture is abundant in energy, protein, vitamins, minerals, micronutrients, enzymes, trace minerals, fiber, and moisture. Grazing allows for a more natural feeding stance, proper wear on incisors and hooves, and proper function of the entire system, from head to tail. It also provides the opportunity for exercise, socialization, and sunshine.

Pasture and grass hays may be supplemented with the more robust legume hays, such as alfalfa, if necessary. Diets need not be supplemented with grains unless forage is inadequate.

The need for any added grains can be determined by a lab test. Forage testing is available for finding out the nutrient compositions of various grasses and hays. If they don't measure up, then grains and other supplements should be added to the diet. Good quality forage will have above 8% crude protein and below 40% acid detergent fiber. The protein content in the forage will then be used to determine the protein content needed in the feed. The protein demand for the average adult horse or open mare is fairly low. Too much grain could lead to colic and founder. Grains (and all other feeds) should be fed by weight, not volume. Because nutrients are measured per pound of feed, it is necessary to know how many pounds are being fed.

For mares, the same feeding program that is being used before breeding can be continued through the first eight months of gestation. The slow growth of the fetus does not yet put extra demands on the mare, because less than half of his growth occurs during this 8 months. During the last three months of gestation, 60% of fetal growth occurs. The mare's protein, vitamin, mineral, and energy requirements increase at this time as the foal's growth increases from less than 3 ounces a day to 1 pound per day in an average sized horse. Hay for open mares should be fed at the rate of 1 to 1.5% of body weight, e.g., a 1000 pound horse should get 10-15 pounds of hay per day. Avoid fescue hays and sorghum or sudan hays because of possible toxins to broodmares.

Getting the right amounts of nutrients into your mare does take some time, effort, and investigation. To increase your mare's chances to conceive and become a productive broodmare, take time this fall to begin to properly prepare her.


See Fertile or Fallow, Premier Issue, for supplemental herbs in preparation for breeding.