Generally, a horse is classed as a veteran when it reaches 14-15 years of age and, with the advances in equine nutrition, health and welfare, we are seeing more horses and ponies leading active lives into their 20's and 30's. Usually one of the first signs of growing old is the state of the horse's teeth. These become worn causing sharp edges and, at worse, loose or even missing, making chewing long fibre very difficult. Regular 6 monthly visits from the dentist or vet will help to correct uneven wear. The long fibre part of the diet is very important to keep the gut healthy and functioning, aid digestion and keep the horse warm, so it may be necessary to consider alternative fibre sources if your horse has a dental problem. There are many chopped fibre sources available or complete mixes containing chopped long fibre such as Saracen Fibre Mix. If even these present a problem, then high fibre cubes such as Saracen Super Fibre Pencils, soaked in water will produce a soft mash, which will require minimal chewing and reduces the risk of choke.

The older horse loses his ability to digest and utilise protein efficiently so a diet containing good quality protein sources is important. A good quality protein will contain Lysine, an essential amino acid that forms part of the protein molecule. The horse is unable to synthesise Lysine itself so it must be supplied in the diet. Alfalfa is a rich source of lysine and it is a good idea to look for this as an ingredient when choosing a suitable veteran diet. A diet of between 14-15 % protein in a veteran ration will help to prevent against the loss of top line and aid cell and tissue repair.

Vitamins and minerals are essential elements in all equine diets, and although required in minute quantities, they are necessary for all bodily functions. With age these are not absorbed as efficiently so higher vitamin and mineral levels are required to compensate for a less efficient gut. There is reduced absorption of phosphorous, which is involved with the strength and resilience of bone as well as maintenance of cellular functions. When increasing the level of phosphorous the level of calcium should be adjusted to maintain the correct Ca:P ratio. A reduction in the gut microflora also compromises the ability of the horse to manufacture his own B vitamins, which are normally produced in abundance, as well as vitamin C, which is important for the horse's immune function. A healthy horse manufactures sufficient quantities of his own vitamin C but many older horses that suffer from pituitary dysfunction show low blood levels of vitamin C, which might make them vulnerable to viral infections.

In most veteran diets you will find a higher oil content than in a typical feed designed for light to medium work. Oil is an excellent source of slow release energy which, together with digestible fibre sources, will provide some of the energy for maintenance and work without oversupplying the hind gut with soluble carbohydrates. This will therefore reduce the likelihood of causing digestive upsets, sometimes associated with high cereal diets. Oil will also help to keep the older horses coat in good condition and help with mobility.

Yeasts can also be a beneficial part of his diet. These line the gut and help to promote a healthy environment by reducing the fluctuations of pH, which can lead to problems such as laminitis and colic. Yea Sacc in particular may increase the digestibility of the forage cell wall, hence increasing energy supply as a result of an increase in the products of fermentation. There is also an increase in phosphorous absorption, the benefits of which should now be apparent. They can also help to boost the immune system and reduce stress levels.

Unfortunately, even with proper nutrition and management, illness may still develop. Liver disease and Cushings disease are just a couple of examples. Liver disease will cause weight loss and is often due to ragwort poisoning. Liver disease can be detected from a blood sample and if detected, dietary adjustments can be made to support the remaining liver function. Feed small amounts of high carbohydrate feed and moderate to low protein feed. This may prevent surges in gluconeogenesis, insulin release and enteric ammonia production.

A tumour in the pituitary gland causes equine Cushing's Disease. The pituitary gland is located at the base of the brain, which secretes and stores hormones that regulate most basic body functions. In Cushing's disease, the pituitary gland secretes abnormal levels of these hormones, which causes the following symptoms to show:

Retention of a thick winter coat, which usually becomes curly.
Increased susceptibility of recurrent laminitis.
Lethargy
Occurrence of minor infections.
Excessive thirst. The normal amount a horse will drink is between 36-45 litres per day, but a horse with Cushing's may consume between 50-80 litres per day.
' Excessive urination.
' A pendulous abdomen and loss of weight in spite of having a ravenous appetite.

Most of these symptoms are brought about by the over stimulation of the adrenal glands by Adrenocorticotrophic Hormone (ACTH). The adrenal glands lie next to the kidneys and when stimulated, produce corticosteriods, hence the other name for Cushing's Disease, Hyperadreno-corticism. Cortisone is used to regulate blood glucose levels and its excretion of excess glucose in to the urine, protein metabolism, and electrolyte levels, so confirmation of the condition is usually confirmed by a urine analysis.

The thyroid stimulating hormone, TSH, is responsible for controlling the metabolic rate, and disturbances of its release can alter tissue metabolism and result in lethargy, often associated with Cushing's disease. Excessive thirst and urination are brought about by the action of the anti-diuretic hormone ADH, which regulates the retention and output of water from the body.

As we are aware, the prolonged use of cortisone drugs can cause laminitis, hence this is why horses suffering from Cushing's disease are more susceptible to laminitis. Laminitis is a very painful disease where the laminar bonding that is normally strong and suspends the pedal bone inside the hoof, become loose and causes the pedal bone to sink down into the hoof. Along with this there is also a shortage of blood to the laminae causing excruciating pain. Attention to the diet will help to control the laminitis so the following precautions should be taken:

Do not allow the horse to become overweight.
Provide a diet that is low in calories but high in fibre.
Get the horse correctly shod and trimmed every six weeks.
Provide a diet containing good quality protein for cell and tissue repair e.g. Alfalfa.
Seek veterinary advice.

So why do the tissues fail to recognize the circulating hormone levels? In normal hormone systems the body is able to self regulate the levels of hormones released, increasing or decreasing the levels as required. However in Cushing's disease, this self-regulating system breaks down because the abnormal hormone differs from its normal composition, so that the body does not recognize it and therefore does not respond in the correct way.

There is at present no known cure for the disease and veterinary treatment may cost up to £20.00 per day. Correct management is obviously very important and correct feeding will help manage the laminitis, but recognizing the symptoms early on can be very helpful.