In an article titled Feeding Show Horses and Ponies, by Dr Jennifer H Stewart BVSc BSc PhD MRCVS Dip BEP AAIM, she says:
Ponies are not just small horses - Although horses which stand less than 148cm or 14 hands are generally labelled as 'ponies', to a zoologist, 'ponies' are those small horses which evolved from the wild euids that inhabited the cold, harsh Isles of Great Britain some 40,000 years ago. Freezing conditions selected for thicker coats, an insulating layer of subcutaneious fat and the ability to withstand periods of poor nutrition and sub-zero temperatures. To survive extremes in temperature and lack of food over winter, ponies developed metabolic and physical characteristics different to those found in the Arabian and Thoroughbred rootstock that evolved in warmer regions of Africa and Asia.
Ponies, regardless of height, need less feed to maintain themselves compared to horses; have altered hormone responses to eating; are pre-occupied (obsessed!?) with eating and have 'shunts' in the blood vessels in their feet - periodic opening and closing prevented excessive cooling while maintaining blood flow.
These features favoured survival, but they are also the reasons why ponies are more susceptible than horses to diseases such as hyperlipaemia and laminitis.
By Marty Adams, Ph.D:
Although ponies belong to the same species as horses, they generally
developed in harsh conditions and are recognized for their hardiness and
easy-keeping characteristics. These traits also make them easy to overfeed,
and ponies are known to have higher rates of obesity, colic and founder.
Fat Pony Founder
by Dr Marjorie Orr, veterinarian and lifestyle farmer, Dunedin & Michelle
Ponies think fat is sexy! Ponies think fat is fun! Ponies are the sumo
wrestler champions of the equine world. And they don't need chocolate bars
and fish and chips to pile on the weight - some ponies seem to get fat on
the smell of an oily rag! Sadly though, the enormous stresses on a pony's
body caused by overfatness lead to a serious risk of founder or laminitis,
and as responsible owners we have a duty to prevent it.
Laminitis (founder) is an acutely painful inflammation of the lining (called
laminae) in the feet, mainly the front feet, and it's one of the major
causes of lameness in ponies in New Zealand.
Laminitis can be recognised by the 'lean-back' stance of the affected pony,
as it tries to relieve the pain in its forefeet by leaning back so that most
of its weight is carried on its hind feet.
Veterinary advice and treatment at an early stage are essential, because
apart from being very painful, laminitis can lead to permanent crippling and
distorting damage to the feet.
Feet that have had laminitis for a while grow ridged and distorted horn, and
it can be very difficult if not impossible to treat them effectively once
the condition has reached this stage.
Occasionally, laminitis is caused by acute inflammation such as womb
infections after foaling, but in the great majority of cases it's the result
of an over-rich diet, ie too much grass.
With careful management of your pony's food and its weight, you can
dramatically reduce the risk of it developing this condition in the first
The spring grass is romping away, and if your pony is at all plump, it
should be on a diet. This might involve stabling or yarding, or simply
fencing off a small area of the paddock with electric fencing so that it can
continue to hang out with the other horses. The important point to remember
is that you must restrict the pony's access to pasture.
You should offer a slice of hay morning and evening, but you have to impose
a strict weight-watchers regime.
Remember that all ponies need ready access to clean drinking water at all
times, especially in warm weather.
Don't give your dieting pony any hard feed, like concentrates or grain. This
can cause laminitis too.
Your plump little pony certainly won't thank you for keeping it off pasture,
and will probably make a point of sucking in its cheeks and staring at you
reproachfully each time you pass. But when laminitis is a risk, you have to
be tough to be kind.