Everyone acknowledges the strength and stamina of horses because whatever can carry a human must relatively be strong. Some other animals can also do this, but horses offer speed to a reasonable extent which is why they have been more widely kept than others.
Have you ever questioned how four skinny legs could carry the weight of the horse itself and a rider?
The importance of every horse and its relevance to man lies in the legs – be it for speed (race), riding, or farm work. Hence, proper leg conformation is essential for every horse and all its endeavors.
Hind leg problems in horses often happen as a result of improper leg conformation. Proper leg configuration helps to reduce the tension at the joints and makes the impact of each hoof on the ground bearable.
A foal’s crooked leg can easily be worked on by extensive therapeutic shoeing and procedures. In a proper environment with modern science, there is a solid chance of recovery but a horse with a leg injury at adulthood hardly gets its leg recovered.
Also, there is no certainty that a horse without leg issues will produce a foal without leg issues but with hereditary, the horse with leg issues most likely will produce a foal with leg complications.
A horse can also have a proper leg conformation, but with factors such as overexertion or injury, issues may arise.
Propulsion is a major function carried out by the hind limb. A good horse used for riding or racing needs to have a proper hind leg conformation to carry out the task soundly.
The strength of the rear limb is also an advantage but generally, the hind limb must be strong enough to support a good portion of the weight of its body. Proper leg conformation is no certainty that the horse will never take lame steps, but it reduces the chances to the minimum. (1)
Lameness in horses
The major hind limb problem in horses can simply be tagged lameness. Lameness is the abnormality in a horse’s movement due to pain which ranges from mild to severe.
Lameness can be caused by a wide variety of factors ranging from overexertion to injuries, bruises, fractures, contusions, lacerations including inflammation. Lameness is also affected by breed, type, leg conformation, the intensity of activity, and the surface upon which they are used.
Most of these categories of lameness are obvious in the stifle and hock joint. The stifle is a joint under the massive muscle at the top of the hind leg where the leg nearly meets the belly.
The joint is supported by several ligaments and a nutrient-rich joint fluid that serves as a lubricating pad which aids lubrication to keep the joint motion smooth. A cartilage pad also serves as a shock absorber for the joint. The hock joint is a hinge joint about midway the horse’s hind limb.
This joint is made up of six small different bones around which there is no muscle. Also, the cannon bone and splint bone can be felt while only supported by tendons and ligaments (2).
Pain is therefore a major signal to check for lameness which can be properly classified into
- Degenerative problems
- Traumatic problems
- Deformities
Degenerative problems
a) Bone Spavins: This is commonly seen in standardbred and also often results from cow hock or sickle hock in adult horses. The bone spavin at the lower hock joint is the enlargement on one or more of the hock bones.
You will hardly find any swelling at the early phase and often only lameness makes one realize its existence. Veterinary attention is required for x-ray and sometimes surgery. It results in permanent lameness as a treatment to become normal is hardly attainable. (3)
b) Cow Hocks: This is a problem that arises from the strain and irritation of the medial side of the hock joint. It is a trigger to bone spavin, hence needs immediate attention when observed.
c) Sickle Hocks: If observed in a foal, it requires urgent attention as it eventually leads to curb while it results in bone spavin in adult horses. This has been observed over time and concluded to be heritable, hence proper management and attention are to be given during breeding.
d) Thoroughpin: Immediately you notice a swelling or an enlargement above the hook joint, it is important to check out for this. An injury or excessive use of a tendon above the hook joint results in thoroughpin and inflammation. This is often related to the flexor tendons but also used to regard the extensor as well. It may be found in foals but the cause remains unknown. Where no pain is noticed in adult horses, lameness will not result.
e) Curb: This results from the damage to a ligament which helps in the stability of the hock joint. In foals with sickle hocks, there is a high possibility of resulting in a curb. You may only observe a thickened appearance. An additional bone is often produced around the ligament. (4)
f) Capped hock: This is also observed as a large fluid swelling on the hock joint caused by overused ligaments and tendon. This hardly results in lameness as thick bedding resolves issues.
g) Bog Spavin: When you carefully look at the hock joint, this is observed as swelling or accumulation of fluid due to wear and tear of the joint. Many horses still carry out their activities with them but negligence often leads to lameness and inflammation.
This is the permanent swelling in the soft tissues of the hock joint. It is obvious at the front of the joint and often does not result in lameness but may reoccur.
h) Jack Spavin: Jack spavin is noticed inside the hock joint, which results in the push of tendons, resulting in pain. An observation of the horse dragging the leg may be an indication for you.
i) Acute and Septic arthritis: Arthritis generally begins with the inflammation of a joint capsule to an erosion of cartilage, then fusion of the joint. This can easily be stopped when pain is observed as the horse moves. It eventually results in lameness and affects both the young and adult horses.
Acute arthritis hardly results in degenerative joint disease as it is either caused by stress or injury. You will observe swellings at the joint but there are hardly any signs for septic arthritis aside from observed pain. Septic arthritis results from infection by bacteria in the blood which leads to irreversible damage.
Traumatic problems
a) Stringhalt injury: If you observe high steps or sudden upward jerk of the hind leg by the horse when moving, it is advisable to check for Stringhalt injuries. It results from over flexing of the hind leg and is accompanied by involuntary flexion of the hock during the forward movement.
There are diverse forms of Stringhalt that range from unilateral to bilateral and false Stringhalt. Also, there is Australian Stringhalt which is acclaimed to be a toxic weed.
b) Bursitis: This is a trauma caused to bursa (a cushion at moveable points often joints). Acute bursitis causes lameness. Septic bursitis is the inflammation with either bacteria or fungi which requires immediate treatment to minimize complications. (5)
Deformities
a) Congenital limb’s deformities
These are the deformities that arise from the complications of pregnancy. As much as everyone will not purchase a horse that is deformed during breeding, your horse may give birth to a foal which is.
It results from the wrong positioning of limbs in the uterus, even nutritional imbalances in the mare, unequal growth between two long bones of both sides, and neonatal hypothyroidism.
Often veterinarian treatments are essential but some get better though hardly normal with proper care. Knocked knees, bowlegs, sprung, popped knees or benched knees are some of the angular knee deformities.
It is advisable to employ immediate professional attention to avoid permanent complications.
b) Flexural limb deformity
These are deformities that become obvious or can result within the period of birth and 18months. The knee joint, coffin joint, or fetlock joint are prominent points where this can occur.
The causes are still not known but it has been observed that this is due to the rapid growth of bones which is matched with the slow growth of tendons. Osteochondrosis is one of the flexural limb deformities.
c) Treatments of Hind leg problem
The treatment for any hind limb problem is advisable to be done by a veterinarian. Treatment ranges from simple thick bedding to rest and some mild exercise while others require therapy.
Where excess fluid has gathered (bog spavins), it should be properly drained and corrective shoeing may be required for bone spavins and sometimes surgery. Some of these hind leg problems do not require treatments at all but this risk should not be taken, except advised by a veterinarian. (6)
A final note on hind leg problems
The proper leg conformation remains a major part of what makes the horse carry out its task and useful to man. Hind leg problems may affect the kind of task a horse can carry out, but every horse can still carry out one task or the other despite the complications.
Glossary:
(2) Lameness in the horse: an owner’s overview.
(3) Common Leg Faults of Horses III: Hindlimb.
(5) Causes of Equine Lameness.
(6) Hind leg problems in horses.
