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Hamilton Stud




•Framlingham Country Show

IP13 9EY  9th & 10th April

•Hertfordshire Country & Craft Show

Lee Valley, Waltham Cross, EN91DB

•Robin Hood Show

Brentwood Centre 1st &  2nd May

•Lloyd Park Country CR0 5RA

•Stradsett Country & Craft Show

PE33 9HA 11th & 12th June

•Mill Hill Park Country & Craft Show

NW7 2BD 18th & 19th June

•Nonsuch Park Country Show

SM3 8AB 25th & 26th June

•Elvedon Country Show

IP24 3TJ 9th & 10th July

•St Albans Country Show

AL4 0RE 16th & 17th July

•The Enfield Town & Country Show

EN2 4LE 24th & 25th September

•The British Pet Show

South England Show Ground 8th & 9th October

•Trinity Park, Robin Hood Country Show

Ipswich 15th & 16th October


For a fun filled day for all the family!!!


We now know why some horses have an extra gait.


In all mammals locomotion is controlled by a central pattern-generating circuitary of spinal interneurons which are established during development to co-ordinate the movement of limbs. They include the alternating left-right movement of limbs and the co-ordinated activation of the flexor and extensor muscles.


In August 2013 research from Upssala University  in Sweden discovered that DMRT3 plays a pivotal role in configuring the spinal circuits controlling stride in vertibrates and that a change or mutation in DMRT3 is responsible for the ability of horses such as the Rocky Mountain to perform the fifth gait.


CC  3-GAITED HORSES (Walk, Trot, Canter)


CA  4-GAITED HORSES (Walk, Amble, Trot, Canter)


AA  5-GAITED HORSES (Walk, Amble, Trot, Pace, Canter)


Testing has shown that traditional 3-gaited horses such as sport horses, draft horses and thouroughbreds are homozygous for the C-variant (CC).

Horses that can perform intermediate gaits have the A-variant.


Some gaited horses can only perform 4-gaits (CA) yet few gaited horses can perform 5-gaits (AA).


Selective breeding in most gaited breed associations prefer to only breed with 4-gaited horses (CA) because the “pace” gait disturbs the training of gaited horses, particularly the gaited mountain horses and Icelandic’s, where the horses are strictly judged on the four- beat intermediate gait. The

gait is smoother for a rider than the 2-beat trot or pace. The four-beat intermediate gait can be sustained for a long period of time and (if trained) at speed creating a smooth gliding gait for many riders such as the elderly or physically disabled rider.


On the other hand in harness racing, the pace and trot produced from the mutation of the dmrt3 gene is extremely desirable.

The horses have the ability to trot or pace without breaking into a gallop. The American Standard bred horse was selectively bred for harness racing. Since the 18th century there are 2 divisions of competition. The selective breeding was based on preferred gait which created 2 populations within the breed, PACERS and TROTTERS. These are both homozygous for the mutation DMRT3.


The mutation found in the American Standard bred was not as commonly found in the Swedish standard bred, maybe due to other breeds such as the French trotter influences (CA). With intense research and examinations held on the effect of the DMRT3 mutation gene, racing performance has impacted hugely on standard bred and racing breeders.


A genetic test is now available to horse breeders that breed specifically for gait performance.




View the publication in Nature on DMRT3 mutation, click here to read.




Hamilton stud farm is open to all colour combinations of horses. If we don’t have what you require, then we can certainly source it from other professional breeders in the United States, Europe and Australia.


When colour is mentioned with particularly the Rocky Mountain Horse, many people think about vision problems and ASD.


ASD (Anterior Segment Dysgenics) This is an eye condition spoken about by many admirers to the breed. ASD is an ophthalmic abnormality caused by a dominant gene found in some horse breeds not just Rockies. ASD is not a degenerative eye disease; it is an inherited defect in the formation and development of the eye. The horses with ASD have problems in the anterior (front) part of the eye which was not developed normally. In some cases abnormalities appear in the posterior (back) part of the eye, this is an inherited genetic condition. Horses that are considered normal and exhibit no sign of eye abnormalities could be carriers of the genetic defect.

Most horses with ASD have acceptable vision which will not worsen with time. The most striking colour of the gaited horse breeds are chocolate with white/flaxen mane and tail. Now, because the colour is produced from the presence of the silver dapple gene.

Some Rocky mountain horse admirers choose to just dream about this colour horse rather than risk purchasing a blind horse.

Some people wonder why rocky mountain horse ranches and breeders are still producing silver dapple horses. So here are some horse breeds that exist in the UK and Europe that process the ASD and carry the silver dapple gene, as it is NOT unique to just Rocky Mountain Horses.

Shetland Pony, Miniature Breeds, Rocky Mountain Horse, Kentucky Mountain Saddle Horse, Morgan, Mountain Pleasure, Bashkir-curly, Narragansett Pacer, Haflinger and Icelandic. These are just some to name.

Dr David T Ramsey, an ophthalmic researcher from Michigan State University who has conducted the ASD investigations for over a decade, states that the analysis of the above horse breeds have ASD which is just as commonly present in these breeds as well as the Rocky Mountain Horse.

The ASD has only been studied intensely in the Rocky Mountain Horse because it was the RMHA (Rocky Mountain Horse Association) that recognised it and was proactive to determine whether the abnormality was a severe defect.

An excerpt from Dr David T Ramsey’s publicised article states “The most abnormal trait that was documented was the cysts that arise from the ciliary body (inside the eye). These cysts are never painful, do not limit vision and are therefore of no consequence to the eye of the horse”.

In experienced breeders can generate badly affected ASD horses if breeding programs are not generated properly with the attention to breed detail and gene/colour testing.


Breeding for colour, temperament and conformation requires a lot of knowledge and detail. When breeding rocky mountain horses, genetic testing is key to generate the best possible match between two horses.

Here at Hamilton stud we have genetic testing performed on all our horses to help ensure we do not produce an undesirable result in our breed plan. Cassey Morris explains “breeding for colour can sometimes cause problems when breeding horses where coat colour and pattern can have effects on the health of the horse. It is imperative that a breeder of such breeds should be educated in the specific breed and to know about the health risks and how to prevent unhealthy stock.”

Colour is a big deal to some equine owners and some equine owners may say that colour is nothing it’s how the horse can perform. Colour is an important part to a horse as many breed studbooks have colour codes and limitations on markings and set rules. There is a lot of colour variety in the different horse breeds because throughout the years the colour breeders try to create a desirable colour to enhance marketability because a buyer will nearly always prefer to purchase a good looking horse.

Caution must be made when choosing to purchase a rocky mountain horse because there are some inexperienced breeders that inbreed certain breed lines to keep colour or temperament. The breed line becomes abused with results that deteriorate the breeds reputation.

As well as breeding for colour, other major characteristics must be bred for at the same time. It comes down to having specifically selected stock that has conformation, temperament and colour. It is important that you do not focus too much on colour and lose focus on the other characterises that are extremely important.

Here at Hamilton stud, we specifically selected our horses for breeding, incorporating five star stallions that have proven results for passing on their traits. Our colour breeding does not intensely focus on the colour but on the temperament, conformation and performance. We only offer to sell our best produce of our Quality stock.

Colour breeding and breeding with the silver dapple gene provides beautiful colours in horses and when bred correctly, the result is breath taking beauty, temperament and conformation. The ultimate healthy, enchanting, magical dream horse is available to you at Hamilton stud.





Part of our breeding and performance programme will include checking performance results from Endurance, Show Jumping and Dressage against the genomes and DNA especially looking for indicators that improvements may also affect humans.

Taking The Science Forward



Cassey regularly attends various Mountain horse shows in the USA and recommends

Kentucky Horse Park for all equestrian world breeds.