Horses often exhibit congenital anomalies and hereditary diseases which are usually diagnosed only during the life of the animal. Some of these may be contracted during fetal development, others may be hereditary. In this article we explain what they consist of.
Congenital diseases of the autoimmune system
There are several genetic abnormalities very common in horses. A condition called severe combined immunodeficiency, or SCID, which is caused by a genetic defect, can occur in Arabian foals. Affected animals can develop infections and die between 4 and 5 months of age.
Another inherited disease, called neonatal iso-erythrolysis, destroys red blood cells in the newborn foal. Good results can be achieved with early diagnosis and therapy.
The horse may exhibit some congenital eye and ear anomalies such as the coloboma, a defect in the development of the eye or eyelid that can cause corneal irritation and other ocular abnormalities, such as congenital cataract.
Possible cardiac abnormalities may be holes or defects present in the atria or ventricles, as a result of poor fetal development.
Regarding congenital diseases of the gastrointestinal system, we can talk about the blockage of the intestinal tract. This condition is rare in foals: affected animals have abdominal cramps in the first 24 hours of life.
Another disease, called brachignatia, causes malocclusion between the mandible and the maxilla. Mandibular brachignathy is more common and causes abnormal shortening of the jaw.
Other congenital diseases in horses
Concerning congenital diseases of the musculoskeletal system, there areangular or rotational deformities of the limbs and anomalies in flexion of the fetlock.
Another pathological condition is the dislocation of the patella, which usually occurs in miniature horses and Shetland ponies. Dislocation occurs laterally when the patella can be displaced or moves towards the outside of the knee, due to trochlear and femoral dysplasia and thinning of the infratrochlear nerve. In newborn horses it is evident when the foal tries to get up, but fails, then the animal remains in a squatting position.
In addition, the horses may have …
- Skeletal malformations in the nose
- Stiff neck
- Spina bifida
- Digital malformations
- Phalangeal hypoplasia
Malignant hyperthermia syndrome can occur, which causes a progressive increase in body temperature, muscle stiffness and metabolic acidosis, which causes rapid death.
On the other hand, in some breeds, such as the Standardbred and in some draft horses, inguinal hernias are more frequent, especially in males, which show the typical symptoms of colic. In cases where the animal shows signs of colic or when the edema appears in the inguinal / abdominal area, it is advisable to intervene surgically.
Another pathological condition is dwarfism, which is a growth defect. It can be caused by a growth hormone deficiency or abnormal levels of thyroid hormone. The latter causes a delay in bone development, a head larger than normal, a silky coat, drooping ears and mandibular brachignathy.
Respiratory diseases include …
- Tympanism, which is a swelling in the throat.
As far as sexual disorders are concerned, horses can often be intersexual, hermaphroditic and pseudohermaphroditic due to an abnormality of the sex chromosomes. The disorders include: gonadal hypoplasia, which causes abnormal development of the testicles or ovaries (small in size).
Other defects can be rupture of the bladder, which occurs more often in male foals, at birth. These animals may be suffering from metabolic disorders. Clinical signs include lethargy, abdominal bloating, decreased appetite and slight signs of colic. They must be treated surgically.
Finally, there is also ectopic ureter. There is no predisposition for sex or race. It may go unnoticed for years, or the foal may show signs of urinary incontinence. In some cases, surgery has been successful.