The life stage of the horse largely determines its nutrient needs. Generally, the greater the activity of the horse, whether it be late pregnancy, lactation, rapid growth, or heavy work, the greater its nutrient needs will be. Also, during late pregnancy, lactation, and periods of rapid growth, the range of nutrient adequacy is narrower, and a marginal diet is more likely to result in problems. As a first approximation, horses eat to meet their needs for energy. Horses use energy to maintain the metabolic processes that sustain and perpetuate life. It is convenient to consider the horse’s total energy (and other nutrient) needs in relation to its maintenance energy needs. Maintenance energy needs are mostly the sum of the energy required to meet the basal needs and the needs of normal daily activity.
Basal energy needs are for basic physiologic functions, digestion, absorption, and assimilation of food, and to maintain body temperature in excessively cold or warm environments. Because most horses used for recreation are adults at maintenance, we begin by describing them.
Mature horses that are not being used for hard work or reproduction can live very well on grass or a good quality grass hay without any grain. When they are worked, extra energy is required and can most easily be supplied by increasing the amount of hay or adding a concentrated energy source to their diet.
Mares in good flesh or in a gaining condition at breeding conceive with the least difficulty.
During gestation, foal mass does not actually develop much until the last three months of pregnancy. Therefore, the mare can be fed as a mature horse until that time. Pregnant mares can be ridden or worked as a nonpregnant animal until the seventh month of pregnancy. Work during the seventh to ninth months should not include jumping, hard gallops, or other excessive stress. During the last two months, exercise should be limited to walking.
When a mare is ready to foal, she should be slightly fat (body condition 6—7) if you want to have the best success getting her in foal again. Producing milk for her foal is a large drain on the mare’s nutrient stores, and if she is a little fat at foaling she can better handle the stress of lactation, as well as start to feed the next foal inside her. (Mares, unlike cows, do not have difficulty giving birth if they are overweight.)
After foaling, mares need a large increase in energy, protein, and minerals in the ration to provide for lactation. Most mares can meet these needs if turned out on a good quality pasture. (It is wise to offer trace-mineralized salt and dicalcium phosphate free choice to the mare at all times.) If the grass is not good, grain may need to be added to the ration. However, if a mare needs grain to maintain lactation, it is probably time to wean the foal since it is cheaper to feed the grain to the foal than to run it through the mare to make milk.
Usually mares will start to lose weight in July and August when the pastures are not producing enough, and the foal needs more nutrition than the mare can supply. So the foal is weaned then at about four months of age. Foals may stay on the mare to six months if it is not detrimental to the health of the mare.
At weaning time the mare is separated from the foal and put on a ration for a mature idle horse unless she is thin and needs grain to get back in good flesh. Her udder will enlarge and become firm and tender to the touch. It is the pressure of the milk in the udder from the cessation of milk removal that will cause milk production to cease, so milking the mare to relieve the pressure only slows the process.
It takes at least 30 days for the udder to stop producing milk and regress to a non-producing state. Do not put the mare back with her foal for at least that long. It is recommended that you avoiding putting foals with mature horses if it is not necessary.
Lactation in the mare peaks by two months after foaling and by four months will only provide about 50% of the energy and protein and about 30% of the calcium and phosphorus needed by the foal. Therefore, creep feeding – providing feed where the mare cannot eat it – should begin early in the foal’s life.
The first solid food a foal will eat is the mother’s manure. This is thought to be important in inoculating the gut of the foal with microorganisms that are necessary for normal digestion. Expect to see the foal develop diarrhea at about two weeks of age, when it begins to eat roughage. If the foal does not have an elevated temperature or appear ill, you may allow the diarrhea to correct itself, which usually takes one to two weeks. If you want to help stop the diarrhea (if it persists), you can give 60 cc of Kaopectate twice a day until the diarrhea stops, but for no longer than three days. Do not give Kaopectate after the diarrhea stops. If this treatment does not work, have a veterinarian evaluate the foal for other problems.
Creep feeding can begin as early as one week of age. Foals learn to eat grain more quickly when they eat with their mothers first. You can also help start them by putting some grain in their mouths. Be sure the creep feeder is near to where the mare likes to loaf so the foal will be encouraged to enter the creep and eat. The creep feed should contain at least 16% protein, be of high quality, and be very palatable. Pelleted feeds work best for creep feeds because they do not spoil quickly and ensure that all of the nutrients are eaten. Feeds bound together with molasses are more likely to mold, and the minerals and protein can still settle out in the fines and not be consumed by the foals.
Foals usually eat only about a pound of feed a day during the first month, but consumption will gradually increase to as much as 10 pounds a day by weaning time. At weaning, be sure there is always good clean feed available in the creep feeder. There have been cases of foals overeating after weaning or when creep feeders were refilled after being empty for some time, resulting in colic or a ruptured stomach. If the foal is getting fat on free choice creep, you may want to limit the amount fed each day. By one year of age, foals are usually taken off free choice feed.
If at all possible, get at least two pints of colostrum (the milk secreted by the mare for the first 24 hours after foaling) into the foal within the first two (ideally) to 18 hours of life. This milk contains antibodies that protect the foal from disease until his own system can produce antibodies. If colostrum from the mother is unavailable, colostrum from another mare can be used. If no colostrum is available, a veterinarian should be consulted. There are commercial colostrum-like preparations that can be used, and the vet can develop an antibiotic and vaccination program to help protect the foal.
There are milk replacers available for horses, but they may be hard to find on the spur of the moment. Therefore, to feed the foal until one can be found, you can use a calf milk replacer as long as it contains iron (do not use veal-calf milk replacer). If you are not able to get a calf milk replacer, you can mix four teaspoons of jelly pectin (dextrose) to one quart of 2% milk to use until a replacer can be found.
You do not need to feed the foal out of a bottle, and you do not need to warm the milk. Teach the foal to drink by sticking your finger into its mouth until it begins to suck. Then, as the foal sucks your finger, lower its head into a pail of milk until it is drinking. If you have a hard time getting the foal to suck, rubbing the roof of its mouth briskly will often start the sucking instinct.
Once the foal is drinking the milk, put the pail in a location in the stall that will allow the foal easy access. Using a bucket with a bright color that contrasts to the stall wall will help the foal to find it. Change the milk twice a day. Each time put into the bucket about the amount of milk the foal will drink until it is time to change the bucket again.
A second bucket containing a very palatable pellet of at least 18% protein should be placed beside the milk bucket. Place a few pellets of the feed in the foal’s mouth each day until it starts to eat on its own. Also limit the foal to five gallons of milk per day to encourage it to eat the pellets. Fresh water should also be available in the stall along with a flake of high quality hay.
After six weeks, decrease the milk by one gallon per week to increase dry feed intake. By 10 weeks the foal should be fed totally on dry feed. Continue providing the pellets and supply high quality hay free choice. Follow the guidelines for feeding weaned foals.
You should also expect orphan foals to develop diarrhea at about two weeks of age, which can be treated as explained in the section on feeding foals.
Weanlings and yearlings are still growing and therefore need a higher concentration of nutrients than mature horses. Tables 1, 2, and 3 give some of the required nutrient levels. Most weanlings and yearlings will require high-quality roughage and some grain to meet their needs. A common problem with weanlings and yearlings is that they often look pot bellied. If this is the case, they are either wormy, in which case they should be dewormed, or the quality of their feed is not sufficient to meet their needs without stuffing themselves, in which case supplying a better quality feed will take care of the problem.
During the breeding season, the energy level of the ration will need to be increased to cover the stallion’s increased level of activity. Most owners think they need to increase the protein level in the diet also, but this is not necessary. There are only about three pounds of protein in all the sperm a stallion will produce in one breeding season.
It is wise to have the stallion in good physical condition and in good flesh (a body condition score of 6 or 7) as he enters the breeding season.
Maintaining weight on an older horse is important as getting an older horse to gain weight can be very difficult.
Occasionally old horses cannot chew their feed well due to problems of the mouth, such as excessively worn or missing teeth. These animals may require ground food or a complete pelleted feed. Complete pelleted rations for normal healthy horses can be fed, but horses often become severe wood chewers, cribbers, or weavers as a result. The reason is simple. They can eat the pellets very quickly and are bored for something to do. Pellets also do not have enough bulk to keep a horse feeling full, so they feel constantly hungry.
Older horses may have impaired digestive systems and will need higher quality feed than normal, with particular emphasis on protein, phosphorus, and fiber. If they have kidney or liver problems, though, do not feed high protein diets, including legume hays. Older horses are also more prone to tumors. A pituitary tumor is fairly common and causes the horse to have a long, shaggy haircoat that does not shed properly. The horse also loses weight even though it has a good appetite. A drug treatment program is available to help them maintain a normal weight.
The general recommendation for aged horses is to provide 12% protein and 0.3% phosphorus in their diets. Energy intake should be adjusted to maintain a 5—7 body condition score. They may also need to be fed individually if younger horses chase them away from their feed.
Performance can be broadly described as falling into three categories – endurance (long-term work), middle-distance (work of 75—95% of maximum for several minutes), and sprint (short-term, all-out effort).
Besides adequate water and salt (electrolytes), the most important dietary factor is energy. High-energy feeds such as grains and fat will allow the horse to meet its energy requirements. At least 50% of the diet should still be roughage, though. Added fat in the diet will increase the energy concentration without increasing the total feed volume. Feeding fat results in lower heat production during digestion and metabolism than does feeding added roughage or protein and can result in increased glycogen stores in the muscle.
A slight increase in protein is appropriate; however, excess protein is not. The excess can impede performance by increasing body heat production, and increasing water and electrolyte losses as the body eliminates the excess nitrogen. It does not improve performance.