by Steven Haughen, DVM
Age is somewhat relative in the horse, with some horses being “old” by the time they are 8 years of age and others going strong at 25 years of age. These differences can sometimes be attributed to breed, genetics, health care and the type of work during previous years. After a horse is mature it is sometimes said that one year of a horse’s life equals three years of a human’s. So, the 20-year-old horse is comparable to the 60-year-old human.
The physical signs that the older horse shows may vary but will often include the following:
- Loss of muscle tone, resulting in a flabby or “pot-belly” appearance
- Change of weight distribution; they may deposit fat in one place yet appear skinny in others
- Change in facial appearance, such as drooping of the lower lip and deepening of the pockets above the eye
- A hair coat changing color and/or rough, dull, long hairs that don’t shed out properly
The older horse is more likely to encounter medical problems, which may include:
- Dental problems: Poor teeth result in difficulty in properly chewing and digesting food. The horse’s teeth constantly erupt, with each year wearing off a certain amount of the tooth until eventually there is no longer any tooth left. For many horses the loss of their teeth and inability to chew is what limits their lifespan. A yearly examination of the teeth is important. Floating the teeth removes sharp points on the premolars and molars and enhances the horse’s ability to chew and digest. In the very old horse the teeth may have very little root left to hold the tooth into the gum and jaw. By floating loose teeth it is possible to loosen these teeth further and have them fall out sooner. By examining and floating these horses before they get too old, we can avoid these problems from occurring.
- Liver and kidney problems: These problems can show a variety of signs. The animal may be dull, listless, stumbling or dragging the back feet. They may also have a poor or excellent appetite but be unable to gain weight. They may drink excess amounts of water and urinate excessively. A blood screen can help diagnose these problems, and treatment includes diet changes and sometimes medication.
- Hormone problems:
- Horses with a hypo thyroid are often overweight and lack energy. A blood test can determine if there is a problem, and the horse’s feed can be supplemented with medication.
- The adrenal gland is a small gland by the kidney. Adrenal glands sometimes are exhausted after a bad winter or period of stress, resulting in a horse that drinks large quantities of water and is a hard keeper no matter what it is fed.
- Tumors of the pituitary gland (a gland located in the brain) can result in the adrenal gland producing too many hormones. These horses will have a long, rough, curly coat, which usually never sheds. They may also have a greater loss of muscle tone, resulting in a more pronounced swayback.
- Weight problems: The obese horse may be seen in the more geriatric horse due to feeding too much, thyroid problems or lack of exercise. The extra weight puts additional stress on the horse with lung and heart problems and aggravates arthritis, laminitis and navicular disease. Lipomas or fatty tumors are more likely to be found in the older fat horse. These fatty tumors are generally inside the horse and often look like a large mushroom. They can wrap around intestines, causing blockages, circulation collapse, colic and even death.
Sometimes people think that they do not feed their horse anything, and yet it is still fat. Many horses’ metabolic rates will slow down as their feed is decreased. This allows the horse to conserve its energy stores when feed is not available. Sometimes the only way to get this type of horse to lose weight is to start them on an exercise program to increase the metabolic rate.
Too much weight loss can also be a problem in more geriatric horses. As the horse ages, there is often a reduced efficiency in the digestive system. It is believed that the older horse may need a 10% to 20% increase in feed to make up for the loss of efficiency. Researchers have determined that older horses need higher-quality protein, more digestible energy and increased minerals as compared to the maintenance requirements of the adult horse. Horses over 20 years of age often have the same requirements as yearlings. Once an older horse loses weight, it is more difficult to return it to good body condition. Sometimes no matter what is fed, the horse does not gain weight, but clients have reported good results with a variety of feeds and supplements.
Horses that still have good incisors (front teeth) can benefit from being allowed to graze throughout the day. If the incisors are in poor condition, however, the horse will have difficulty grasping grass. The back teeth consist of 24 premolars and molars for grinding the food. If these are not in good condition, the horse will have trouble chewing. It may be necessary to crack, crimp or make gruels from the grains, and roughes may have to be chopped or made into soft cubes or pellets. Sometimes a complete feed is ground and mixed into the consistency of oatmeal for horses that cannot chew. Unfortunately, horses can choke from pellets, and the lack of stem fiber often leads to colic. A high-energy supplement such as corn oil can be added to the feed.
- Vitamins: The older horse may have certain medical problems that require vitamin supplements. However, administering large doses of vitamins beyond those recommended for the yearling horse are not always beneficial. Because of the metabolism in the older horse, it is not able to deal with an excess of vitamins, and over supplementing may result in liver and kidney damage or failure.