Small packages: pony health

It's not just about the height! We take a look at some of the differences between horses and ponies when it comes to their health

A horse is a horse, of course, of course… unless he stands under 148cm and is therefore a pony. But the difference between a horse and a pony is not simply height. In fact when you start to look into it, there is a range of interesting information.

Firstly, it’s not strictly true that every equine under 148cm is a pony. There are some breeds that are considered horses, even though they are usually pony height, such as the Icelandic horse and the Fjord horse. 

In general though, there are a range of differences between horses and ponies; from the way they look (these are called phenotype differences) and to their genetic make-up (genotype differences). 

Think about a typical pony’s head, for example. Small, neat ears come to mind, along with a wider forehead and shorter length. Ponies usually have a thicker winter coat that most horses, and a thicker mane and tail, too. These are determined by genes. 

Ponies are, in general, stockier with shorter, wider, legs – they are often stronger for their size and have lots of stamina. Ponies are known for being resilient, tougher, less prone to certain diseases (although on the other hand there are some diseases they are more prone to), having hardier feet and also for being quite smart and a bit cunning. 

Over the centuries, ponies have been used to work in a whole range of jobs including as pit ponies in the mining industry, and for driving, for farm work and as pack ponies. 

Obviously they are great for children and adolescents to ride, but there may be advantages that a pony has over a horse for adults too (as long as the rider is not too heavy, of course) and they can have a positive influence on a breeding programme for a certain type of equine. 

Thrifty genotype

Ponies, particularly native breeds, as described as having thrifty genotype. This means that ponies may be genetically better adapted to survive in harsh conditions, as they can get enough nutrition from pasture that a horse would struggle on. The converse side of this is that when there is a plentiful supply of feed, ponies are prone to becoming overweight and this can lead to medical problems. Wild/feral ponies will put on weight and condition during the seasons with good grass growth, but they then use these extra reserves to help them survive over winter, when they will lose weight and condition. It is an annual cycle of weight gain and loss which usually averages out, and doesn’t usually cause any problems. It is when ponies are allowed to keep on gaining weight (and not lose it) that problems are likely to occur. 

The advantages of a pony with a thrifty genotype for the owner, of course, is that they are very easy keepers and won’t need lots of money spent on hard feed!

When it comes to their feet, while there is a wide range among individuals of any breed, ponies do tend to have strong hooves with a good conformation. Problems do arise, of course, when regular hoof trimming hasn’t taken place. Especially with some of the smaller ponies (eg. Shetlands) they can become very overgrown rapidly at certain times of the year, and they can also grow in an abnormal shape quite quickly and need drastic trimming to correct them. Other problems with hooves are due to laminitis which is more common in ponies (and will be discussed further under veterinary conditions) although of course it is a disease horses can suffer from, too.

Temperamental matters

There are a wide range of temperaments found in both horses and ponies, so it is certainly not possible to say that horses always behave one way and ponies another. In general, however, ponies tend to be a bit less easily startled and more docile than horses. They tend to be smart, and this may come from genes relating to survival, and they may be quite wily about getting their own way.   

In general, ponies have a longer expected lifespan compared to horses. In addition, they also often have a very active and useful life for a lot longer than a horse (of course, there are always exceptions to this). A lot of ponies live well into their thirties and ponies hold many of the records for the longest-living equines.

Health conditions

There are certain veterinary conditions that are more likely to occur in horses compared to ponies, and there are also some that are more often occur in ponies. Some examples are below:

Ponies are less prone to certain lameness problems, such as navicular syndrome. This debilitating disease is much more commonly seen in horses, which is likely related to the usual shape of the hooves of horses compared to ponies, and how this affects the stress and strain on the internal structures. 

Ponies are also much less prone to becoming a typical ‘roarer’  – a condition called laryngeal hemiplegia which is when there is a degree of paralysis to the larynx. This affects airflow to the lungs and reduces the maximum exercise the horse can do. The term roarer comes from the noise the turbulent air makes, which can be quite loud. Taller equines are more prone to this condition than smaller ones, and this is thought to be due to the length of the nerve involved.

On the other hand, ponies are more prone to certain conditions, including equine metabolic syndrome and hyperlipaemia. 

Equine metabolic syndrome (EMS) usually shows up as laminitis (pain and inflammation in the feet) and is to do with high levels of insulin in the blood. To explain this in a simple way, there are genes which make a pony (or horse, as it can affect horses too) more prone to developing laminitis and these are related to the thriftiness genotype discussed earlier, together with access to high-sugar grass, obesity and not enough exercise. It is a lot more complicated than this, but it is easy to understand how ponies are more likely to develop insulin problems and laminitis if they are not managed well. 

Hyperlipaemia is a condition which is much more common in ponies, miniature horses and donkeys than other horses (although it is not a common problem, it is something to be aware of it you have ponies, miniature horses or donkeys).  It can be a disease in itself, but it can also happen if there is another disease problem going on, eg. a worm problem, dental disease, colic. Sometimes, pregnancy and lactation or even stress can trigger it. It is very serious and involves breakdown of the pony’s body fat into the blood stream. The increased fat in the blood causes all sorts of problems, can damage the kidneys and liver and makes the pony go off their food, which in turn makes the problem worse as more body fat will get broken down. If a pony, miniature horse or donkey become quiet, dull and off their food, seek veterinary attention urgently.

Wounds and healing

The difference between wound healing in ponies compared to horses is very interesting. Studies have shown that leg wounds in ponies heal significantly faster than the same size wound in a horse, there is less swelling and the wound quickly contracts and fills in with an even layer of granulation tissue (the pink tissue that fills in a wound before the skin grows over). 

In a horse, the wound does not contract as much (so stays larger for longer), there is more swelling of the leg, and the granulation tissue is more irregular and oozing (irregular protruding granulation tissue is what we know as proud flesh, and it is very difficult/impossible for the skin to grow over when it is sticking out). 

When this difference was studied in more detail it was found that in ponies, a wound caused a very strong initial inflammatory response which attracted lots of useful cells to the area. This response was rapid but only lasted a short time (three weeks) then settled back down. With horses, there was not such a strong response in the beginning, but the lower level of inflammation stayed for much longer. It is these internal differences which cause the much quicker and better healing of ponies.

Summary

Ponies and horses have their similarities and differences, each with their own advantages and drawbacks. It is interesting to know that it is more than height that determines the difference, there are genetic differences which even affect things like wound healing. Genes are being studied and advances made all the time and the more we learn about this, the better we will be able to breed for the positives and learn how to manage the downsides. 

  • This article was first published in the October 2020 issue of NZ Horse & Pony magazine