Type of paper: Literature review. Subject: Equine Physiology. Topic: Dorsal metacarpal disease in horses. The MARKING TEMPLATE is on one of the documents attached, please make sure yo read them ... Th

Running Head: EQUINE PHYSIOLOGY

Dorsal Metacarpal Disease

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EQUINE PHYSIOLOGY 2

Equine Physiology

Various breeds of horses are suitable for multiple equestrian disciplines than others.

However, the competitive use of horses raises some concerns in public concerning their

health and welfare. There is an economic impact of the horse industry on a country from

activities such as racing, horse shows, recreational activities, and employment opportunities

(Beck, 2014). The sector further generates $39 – $102 billion in direct economic impact to

the US economy while still supporting 4 million jobs daily.

Notwithstanding, equestrian sport is rapidly growing in China, Australia, and the

Middle East. In the United Kingdom, equestrian sport is more popular as compared to cricket

or rugby. From this, we can conclude that this sport is a global activity (Allen, 2013). Some

horses take part in recreational activities, which is the most common type of activity. Others

are horses are involved in horse shows, which is the second most common activity for horses

while others are ‘working horses’ and are used for farming, in ranch work, police work,

rodeos or in polo (Berget, 2018).

As equestrian sport is rapidly growing worldwide, it is vital that a horse meet

individual requirements and demands of the specific game. Various disciplines require the

horse to perform certain tasks or movements either in hand or under saddle. The way the

horse is used, however, dictates the ideal physical or behavior it should be subjected to as to

accomplish the needed tasks (Cantin, 2015). Due to this, there are specific breeds, which are

best suited for such disciplines. For this reason, there is a need to manage these equine

athletes.

Maintaining a horse’s health especially in their tissues and bones is essential to

their health during these exercises (Bachi, 2014). Though mammals are warm-blooded,

horses are either hot, cold and warm-blooded as per their breed, characteristics, and genetics.

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Coldblooded horses are used to pull heavy loads. They weigh close to 200 pounds and

include the Friesian and shire Belgium. They are also used in vaulting competitions and

driving, and determine how fast they can haul a load and over what distance. Hot-blooded

horses include thoroughbred and Arabian and are known for their speed and agility. They are

more fine-boned compared to the cold-blooded horses and are more agile with a lighter body

mass often usually around 1000 pounds.

Disciplines requiring speeds as track and barrel racing, use a thoroughbred which

has stamina and can travel for a mile and a half, at speeds of 45 miles per hour. Its

competitor, still a hot-blooded horse, is the quarterback that can outrun the thoroughbred in

short race matches. It is heavily muscled, intelligent and agile, making it the best type for

quick movement races and competitions. Warm-blooded horses are a mix of the hot and cold-

blooded horse breeds and have large bones, agility and the swiftness of the hot-blooded

breeds. This breed is best suited for equestrian discipline as cross-country events, dressage

and in show jumping. They are becoming more frequent and gaining popularity in the driving

and vaulting disciplines too.

Horses are different in stature and agility as well as ability, as not all the breeds can

handle the activities involved in these vigorous disciplines. It is therefore essential to take

care of their soft tissues and their bones for their mental and physical health (Becky, 2014).

Their hearts, lungs a digestive tract also need to be well taken care of to minimize chances of

illnesses or weaknesses. As the disciplines are of various categories, it means that multiple

parts are affected during intense training. Such subject looks at the horse’s performance, gait,

the track being used and what the instructor asks of the horse. Though there many things to

consider, such as breed, discipline, character and the health of a horse, the review looks at all

horses taking part in the equestrian disciplines.

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Producing the best thoroughbred to win in competitions or maintain their stamina,

means finding the right ingredients which are vital for their physiological well-being. The

most important thing to first look at a horse is athletism and balance. While they come in at a

young age, there is always room for growth and physical improvement. What is to be

maintained is the neck, strong square shoulders, the limbs, which are proportional to its body,

a deep middle and the girth. The horse should also not be too long and needs to have a well-

developed backside. It is particularly important as a horse is a horse due to its engine that

from the back which ought to be well-formed.

All in all, horses do incur injury to their bones and soft tissue because of the strenuous

physical exercise they have to go through. Dorsal metacarpal disease, also called DMD

affects young horses and is among the common bone injury. It affects close to 70% of

Thoroughbred while in training. It involves a broad range of pathologic changes on the

metacarpal bone as well as the periosteal bone that is forming. It also affects the focal lysis

found in the dorsal cortex and involves fractures. Treatment ranges from nonsteroidal anti-

inflammatory drugs (NSAID), controlled exercise, internal fixation, periosteal scraping, and

pin firing.

In performance horses, the relatively new treatment – extracorporeal shockwave therapy

treats musculoskeletal injury (Cantin, 2015). Though this low-energy radial shock wave and

high-energy focused device is used to treat a horse’s lameness, there is little evidence of

shock wave effectiveness as a treatment on a horse’s tissues. Radial Shock Wave Therapy

(RSWT), when used with appropriate training regimes, was successful yet safe. Its success

rate is estimated to be at 90% with most of these thoroughbred racehorses back to racing after

their treatment (Ewing, 2017). This non-evasive adjunctive DMD treatment has seen a

decrease in horse lameness cannot be wholly said it is on the treatment using RSWT. It is

because usually when a horse with DMD is removed from training their lameness improves

EQUINE PHYSIOLOGY 5

within eight weeks. Healing will, however, rely on the degree of the injury. Though stress

fractures take three to five months to heal after treatment, it is not unheard of for some stress

fractures taking only two months to heal completely.

Also, thoroughbred stress fracture healing took a shorter time when cortical fenestration

and internal fixation were used. After treatment, horses resumed racing after eight months.

Healing in such cases also depend on whether the horses had had previous treatment before

the RSWT. Treatment does not affect performance as horses who returned did so with the

same levels of efficiency as before the injury (Griffiths, 2016).

Dorsal metacarpal disease, also going by the name bucked shins, is one of the things that

cause trainers to lose a lot of time with these two-year-olds. Changing of diet, to something

like triacton, reduces cases of bucked shins significantly. Given that there is a relationship

between bone density degradation and DMD, it can also be used on horses with a chronic

bone problem. This supplement is made to support a horse’s digestive health and improve

bone density. Such diets include vitamins and minerals essential in a horse’s skeletal

development as well as maintaining it. It also offers for optimal gastrointestinal tract

functioning. Not only does such a diet increase bone thickness and density, but it also

improves hindgut buffering and health (Pilsworth, 2014).

It is however recommended that no matter how well veterinary check and evaluate the

horse owner should be able to assess further and use specific techniques to know what is

going on or what certain things mean. For a lame horse, an owner needs to do a baseline

assessment first. It includes walking the horse to see the extent of lameness in a horse – subtle

or obvious. Some history is also required to know if it is something persistent, for how long it

has been going on and if it is just seen under style or a particular gait or is it very persistent

and high grade.

EQUINE PHYSIOLOGY 6

As close to 80% of all lameness will be on the foot, that is the first place to look at. For

how severe the injury is, the horse can trot or move back and forth to know which leg is

involved. The leg is then isolated, and in a standing position, the leg is evaluated for any

noticeable abnormalities such as swelling on joints, wounds, punctures, sensitivity in the

tendon areas. It goes on until the hoof where the coronary region examined. It helps in ruling

out anything obvious but if there isn’t, then an owner can work on the sesamoid region up to

the horse's tendons especially the superficial deep and the suspensory. By pushing and

applying pressure on these areas, should a place be sensitive then a horse will show.

In evaluating the foot, the sole area is cleaned, and care is taken to prevent any further

damage or to take off excess tissue. The goal is to clean the surface so that hoof testers are

put. Looking for any defects in the sole is essential. It includes a lodged rock or nails. When

it comes to hoof testers, it should be applied to all areas of the foot. This method tries to elicit

some form of response from the horse. If a horse has an injury to the navicular bone, most

horses will respond

When evaluating lameness, especially in the foot region which is at the back just above the

sesamoids, it is required that an owner gently rub a finger through on the chord-like structure

underneath, inside the medial surface and on the lateral surface. This network of arteries,

veins, and nerves do not usually have any pulsation. However, horses with problems say

abscess, their pulse is elevated and is very prominent (Beck, 2016). Such vibrations help

localize the pain in specific regions. In cases where the horse does not perform to their

optimum levels, shows signs of discomfort or palpation in the dorsal metacarpus, it is likely

that biomechanical stress leads to rapid modeling in the horse’s foot. In Type I, cyclic loading

leads to the foot’s loss of stiffness leading to the fast production of periosteal bone due to the

repeated stress. Type II is usually due to continued track exercise in which causes pressure on

EQUINE PHYSIOLOGY 7

the medial side . the horse will, therefore, experience callus formation. Type III is the

weakening and fracture of the dorsolateral cortex

Factors as fast exercises, running on hard tracks, traditional training methods cause stress

on the dorsal cortex of metacarpus. It in turns leads to the loss of the leg’s stiffness and the

rapid production of periosteal bone and microfractures, which is painful to the horse. If stress

continues, then the dorsal cortex undergoes fatigue fracture (Pilsworth, 2014). Such

incidences, however, increase with long periods of fast exercises and when on harder surfaces

as compared to dirt tracks. As a result, it is a cause for wasted trained time and poor

performance.

With the goal being to strengthen bones, especially the cannon bone, a horse needs

rest as well as other forms of treatment. Total rest is discouraged and exercise should be

gradual to allow the bone to heal. Also, not resting enough could lead to more serious injuries

to the horse. It can be frustrating to have two-year-olds with dorsal metacarpal disease but it

should be noted that proper treatment and rest help in bone healing.

EQUINE PHYSIOLOGY 8

Reference

Stauffer, C. (2016). Leadership skills through equine-assisted learning: The participant’s

perspective. 21(3), 87 -88

Allen, K. (2013). Are pets a healthy pleasure? The influence of pets on blood pressure.

Current Directions in Psychological Science, 12(6), 236-239

Bachi, K. (2014). Equine-facilitated psychotherapy. 2(4), 298-312.

Beck, G. (2016). Use of animals in rehabilitation. Psychological Reports, 58, 63-66

Becky, S. (2014). Cognitive behaviour therapy: Basics and beyond, 23(1), 98 – 102

Berget, O. (2018). Animal-assisted therapy with farm animals 4(9), 1-7.

Cantin, S. (2015). Examining the literature on the efficacy of equine assisted therapy. 8(1),

51-61.

Chandler, C. (2014). Animal assisted therapy in counselling. 43(2), 90 – 98

Christian, J. (2015). All creatures great and small: Utilizing equine-assisted therapy to treat

eating disorders. 24(7), 65-67.

Pilsworth, R. (2014). Incomplete fracture of the dorsal aspect of the proximal cortex of the

third metatarsal bone as a cause of hind limb lameness in the racing Thoroughbred. 24, 147-

150.

Ewing, J. (2017). Equine-facilitated training for two-year old Thoroughbred. 36(5), 59-72.

Griffiths, J. (2016). Improving the predictability of performance by prerace detection of

dorsal metacarpal disease in Thoroughbred racehorses. 78(4), 466-467