The majority of horses today are kept for leisure and recreational purposes and can really be considered as pets. The love and devotion that owners develop for their pets means that they will offer them a home for life. This contrasts with attitudes in the past when the horse was primarily a working animal and once it had reached the end of its working life it was of little or no value to anyone. Research has increased our understanding of the physiology of the horse which has improved standards of horse care. Advances in Veterinary science have improved the diagnosis and treatment of diseases removing or reducing the severity of their debilitating effects. All of these factors have contributed to the average horse living longer.

FACTORS THAT AFFECT AGEING
The most fundamental factor that determines a horse's natural life span is its breed, which is related to its size. Smaller ponies such as Shetlands and Welsh Mountain ponies often live into their late twenties and thirties. A heavy horse such as a Shire or Suffolk Punch is much less likely to reach twenty years of age as their bodies have to cope with greater stresses and strains. A heavy work load can age horses prematurely as the greater stresses and strains placed on their bodies can cause joints, limbs and organs to fail at an earlier age. Many competition horses that have been kept in peak fitness throughout their lives do not adapt well to retirement. Their condition can quickly deteriorate even though the stress to their bodies has been reduced. The standard of care that the horse experiences also influences how well he thrives in later years. Good management helps to reduce the risk of injury and disease throughout the horse's life. Injuries will become increasingly debilitating as the horse gets older and many diseases such as laminitis, are more likely to occur again once the horse has had them once.

WHEN IS A HORSE CONSIDERED OLD?
Horses age at different rates and so it is difficult to determine the exact age at which a horse becomes old. Insurance companies tend to classify horses from 15 years and over as old which is reflected by higher premiums as they are considered to be a greater risk. However, there are many horses who are still leading very active lives in their late teens and twenties. When the horse no longer seems to thrive we consider him to be showing his age and this is probably the time that we can consider him to be old. It will be a gradual process in most horses and typical signs might be that the horse starts to become a bit stiff or needs more feed to keep his weight on in the winter. These are indications that his body just isn't as effective as it used to be.

THE EFFECTS OF OLD AGE
Dentition :Impaired chewing ability due to loss of teeth or poor tooth condition is the problem most commonly associated with old age. All horses will eventually wear their teeth down to the root if they live long enough. The root is softer than the crown which is the part of the tooth normally used for chewing in the younger horse. Once the root tissue is exposed the horse's chewing function will be impaired and the implications of this can be quite distressing for both horse and owner. If a horse can not grind feed down in to small enough pieces to swallow comfortably it may cause him to choke. Partially digested food that manages to progress further through the digestive system may result in blockages causing the horse discomfort that would be exhibited as colic symptoms. Both of these problems may cause the horse to lose weight and condition and are costly in terms of time and money to the owner as treatment from a Vet is likely to be necessary. They are problems that will continue to occur unless addressed. Poor dentition may also mean that it is actually painful for the horse to eat. This is likely to reduce the horse's appetite preventing him from taking in all the nutrients he requires which can result in weight loss and poor condition.

EFFICIENCY OF THE DIGESTIVE SYSTEM
Research has shown that as horses get older they are less efficient at extracting nutrients from the feed. There are certain nutrients that the horse is particularly less efficient at absorbing. Sarah Ralston VMD, PhD, ACVN from Rutgers University in New Jersey conducted research to establish the differences in digestive efficiency between young and old horses. The research compared horses over 20 years with 5 to 6 year olds.
The results showed a reduction in fibre digestion efficiency is probably due to two contributing factors. Firstly, horses with impaired chewing function will not be able to chew forage as effectively, resulting in larger pieces being ingested. Secondly, the population of micro organisms in the hind gut that the horse relies on for fibre digestion are less varied and less efficient. As fibre is such an important nutrient source to the horse it should make a significant contribution to the total diet. Therefore, a reduced fibre intake and less efficient fibre digestion can result in a horse losing weight and condition.

WORM DAMAGE
Most horses carry a worm burden. The use of de-worming pastes and granules (wormers) controls the size of the worm population and allows the horse to thrive. However, even in an apparently healthy horse low grade worm damage can be occurring to the wall tissue of the intestine. The damage results in the formation of scar tissue which is not as absorbent as normal, healthy tissue. It is the cumulative effect of the damage that results in an increasing amount of scar tissue and a decrease in absorptive areas. Reduced nutrient absorption will result in a loss of condition.

COUNTERACTING THE EFFECTS OF OLD AGE}
The most important objective is to provide feed that is easily broken down and digested so that the risk of choke and colic is reduced and nutrient absorption is enhanced.
Forage: Use a soft, leafy forage; the more stalky and spiky a forage looks the more indigestible material it will contain and the more difficult it will be to chew and digest. Fibrous forages generally also contain fewer nutrients due to the lower leaf content. Haylage can be a useful fibre source for the older horse as it is generally less dusty than hay. COPD (Chronic Obstructive Pulmonary Disease) is a disease that can affect the older horse and so a cleaner forage will be beneficial. As haylage has a lower dry matter content than hay, the same weight of haylage would provide less fibre than hay. A lack of fibre can result in a build up of gas and so it is important when using haylage to ensure that you are feeding enough of it. If a horse's teeth are particularly bad he may not be able to manage long stem forage like hay or haylage. If you do not have the time or inclination to chop your own forage there are several alternatives available which are generally termed "hay replacers". Short stem fibre sources will be easier for the horse to chew and can be used to replace hay or haylage if required. Improving the population of bacteria and micro organisms in the hind gut may help the older horse to digest fibre more efficiently. Yeast culture supplements help to enhance the existing population whereas probiotic supplements actually contain bacteria and help to re-establish a healthy population in the horse's gut. Probiotic supplements are particularly beneficial after any incident that may have disrupted the normal population of micro organisms such as a course of antibiotics, stress, travelling and competing, illness or diarrhoea.
Concentrates:
There are several compound feeds produced specifically for veterans that should contain very digestible ingredients. Any cereals included in the feed should be cooked either by micronisation or extrusion to improve digestibility. Minerals should also be chelated, which basically means that they are attached to other molecules to make it easier for the horse to absorb them. Some feeds for older horses will also contain yeast culture which will help to keep the micro organism population in the hind gut healthy.
There are feeds that are not necessarily designed specifically for older horses that may be appropriate for some individuals. Feeds that are finely ground such as cooked cereal meals can be made into mashes that are very easy for the horse to chew and swallow, greatly reducing the risk of choke. They are also effective at promoting weight gain but are not balanced feeds and so a broad spectrum vitamin and mineral pellet should be added. For older horses and ponies that are over weight there are low calorie feeds available that will provide a balanced diet without promoting further weight gain. As long as the availability of the nutrients contained in these feeds is good they can be fed to the older horse or pony.

MANAGING THE OLDER HORSE
It is important to remember that all horses are individuals and so require diets to meet their particular requirements. There are some general management tips that can help to keep your older horse well and healthy.  Older horses will become less dominant and may be bullied away from food and shelter by younger horses. Ensure older horses have the opportunity to finish their feed and can escape the elements. The older horse can often become quite fussy. Use feeds with added herbs for improved palatability, particularly if the horse has any medication. If softening the feed use warm water to aid palatability. Implement the rules of feeding as extensively as possible.  Implement an effective de-worming programme and have teeth checked regularly by a professional.   Act quickly on evidence of changes in condition and behaviour. The sooner you get your horse on to a more suitable feed the less weight he will lose.

If you have any queries about the nutritional requirements of your older horse contact a nutritionist.