This muscle disease, which was only discovered in recent years, occurs primarily in Quarter Horses and cold-blooded animals and is characterized by the storage of excessive amounts of glycogen (animal starch stored in cells) in the horse's muscles. It is known as polysaccharide storage myopathy (PSSM).
As the disease has not been known for very long, its causes have not yet been fully researched. Since the disease was initially only detected in Western horses, it was long considered to be a breed-specific condition. It is now known that all other breeds can also suffer from this metabolic disorder.
The muscle cells of affected animals show increased insulin sensitivity, which means that significantly more glucose (sugar) can be transported from the blood into the muscle cells and stored as glycogen. The breakdown and consumption of glycogen proceed normally.
Two different types of the disease can be distinguished in terms of occurrence and heritability:
This form mainly affects heavily muscled horse breeds such as Quarter Horses, Paints, Appaloosas, Haflingers, some cold-blooded breeds, but also ponies and heavy warmbloods. A hereditary predisposition (= genetic predisposition) has been proven for this type, which occurs in 90% of cases. With the help of a genetic test, it is now possible to determine exactly to what extent a horse is a carrier and transmitter of the PSSM gene. However, a positive test does not mean that the affected horse will necessarily develop PSSM; with appropriate feeding and husbandry, there is only a predisposition to develop the disease.
The exact triggers of this form of PSSM are still largely unknown. It occurs in about 10% of cases in lighter breeds (thoroughbreds, Arabians, light warmbloods) and no hereditary link has yet been proven.
With a low-carbohydrate and low-grain diet, affected horses can remain symptom-free for a long time. Sick animals often have a high proportion of easily digestible carbohydrates in their diet due to sugary feed such as carrots, apples, molasses, broken grains, or similar. For this reason, the disease often only occurs when young horses are broken in and suddenly receive large amounts of concentrated feed.
The first signs of the disease usually appear within 10 minutes of the start of exercise. Affected horses refuse to move, sweat profusely, and tire quickly. In mild cases, only a stiff gait and a stretched posture can often be observed. More severe cases are characterized by anxiety, muscle cramps and stiffness, or even recumbent posture in recurring episodes. If movement is not stopped immediately, the symptoms worsen, leading to colic (see corresponding article) and colic symptoms (see corresponding article). Severe fluid loss can also lead to kidney damage.
A general examination and a detailed preliminary report from the horse owner can provide the veterinarian with valuable information about the disease.
However, as the symptoms are similar to those of various other muscle diseases, a definitive diagnosis can only be made with the help of further tests. In acute cases, a blood test is advisable, as specific muscle enzymes are already significantly elevated even at rest. A second blood sample taken after light trotting shows massively elevated enzyme levels, which are a clear indication of PSSM but do not yet provide definitive proof.
Only a muscle biopsy (removal of muscle tissue) can clearly diagnose both type 1 and type 2 PSSM. However, the biopsy cannot prove heredity. After staining, excess glycogen appears as a dark area in the muscle fibers. The muscle tissue of affected animals has 1.5 to 4 times the glycogen content of healthy horses.
A genetic test for PSSM type 1 has been available for some time, but is currently only performed by one laboratory in Germany. However, the test only detects genetic predisposition and not the clinical disease. This test is already mandatory in some horse breeding associations.
If an acute attack occurs, the horse should be stopped immediately, covered warmly, and placed in a stall. Painkillers should be administered if the horse is in severe pain. Dehydration and fluid loss should be compensated for with appropriate infusion solutions to protect the kidneys. The next step in treating a horse with PSSM must be a change in diet. A high-fat diet that is free of rapidly available carbohydrates can prevent excessive glucose uptake into the muscle cells.
The prognosis is favorable if the feeding and training regimen is adhered to for life. With an appropriate change in diet and additional regular exercise, up to 90% of all affected horses can return to their original performance level.
Syncope refers to fainting or circulatory collapse that occurs suddenly without warning and leads to a temporary loss of consciousness in animals. The dog collapses suddenly and shows no signs of life. After a short time, it regains consciousness and behaves as it did before the syncope.
Ectropion is a malposition of the eyelid that mainly affects the lower eyelid. The outer edge of the eyelid is turned outward and hangs down, which is why it is also referred to as a "drooping eyelid." This malposition prevents the eyelid from closing normally, leaving the eye permanently slightly open.
Tracheal collapse is a condition in dogs that causes the windpipe (trachea) to collapse. It mainly affects small breeds such as Yorkshire terriers, miniature Spitz, poodles, and Pekingese. The condition often manifests itself in the first few months of life, sometimes with severe breathing problems.
The tendons are part of the musculoskeletal system and act as the connecting links between the muscles and the skeleton. They consist of strong, flexible tissue, transfer energy from the muscles to the bones, and thus enable targeted movement. Their special structure, consisting of parallel connective tissue fibers grouped together in bundles, gives them enormous tensile strength and elasticity. The flexor tendons of the front legs are particularly exposed to extreme stress in horses, as more than half of the body weight has to be carried by the forehand. Tendon damage is one of the most common causes of lameness, especially in sport horses. In most cases, the structures affected on the front leg are the superficial flexor tendon, the deep flexor tendon, the suspensory ligament, and the fetlock joint (see diagram). As there are very few nerves and blood vessels in the tendon tissue, healing is very slow.
Myiasis is the medical term for fly maggot infestation in rabbits, which occurs primarily in the warm summer months and in injured or weakened animals. The disease is often underestimated, but can be life-threatening for rabbits.
The puppy has moved in and everyone is thrilled! This is an exciting time, when your new family member has a lot to discover and learn. Of course, as a new dog owner, you also have a responsibility to ensure a good start to a happy future together. One of the most important tasks is to house-train your dog as quickly as possible.
Just like in humans, the lung tissue of dogs can become inflamed. Medically referred to as pneumonia, this condition is also a serious illness in dogs and can lead to death if left untreated.
Heatstroke occurs when the internal body temperature rises above 41 degrees Celsius, which can cause life-threatening physical damage. Sunstroke, on the other hand, refers to heat accumulation in the area of the meninges caused by intense sunlight on the animal's head, which can also lead to the death of the patient in severe cases. The body temperature does not necessarily have to be elevated in sunstroke.
Neoplasms of the mammary gland account for more than half of all cancers in female dogs. These benign or malignant tumors occur primarily in older, unspayed female dogs and initially appear as small, nodular changes along the entire mammary gland, which can later become very large. Different types of mammary tumors can occur.
Most horse owners are now familiar with Cushing's syndrome and its symptoms in horses. A disease with very similar symptoms is equine metabolic syndrome (EMS). In its early stages, it is therefore often confused with equine Cushing's syndrome. But what is the difference?
Toxoplasmosis is an infectious disease that primarily affects cats but can also be transmitted to humans, which is why it is classified as a zoonosis. Humans are considered intermediate hosts, although clinical symptoms do not usually occur. It only becomes truly dangerous when pregnant women come into contact with toxoplasma for the first time and the pathogen infects the unborn child.
The air sacs of horses are part of the upper respiratory tract. They develop in foals as a mucous membrane protrusion on both sides of the Eustachian tube (the connection between the middle ear and the nasopharyngeal cavity), each with a capacity of approximately 300 ml. Air sacs are found exclusively in equines and some other odd-toed ungulates, making them a unique feature. There are various theories about the function of the air sacs. The most likely is that they serve to cool the brain. There is a connection between the horse's throat and the air sacs, which is why infections of the upper respiratory tract can also spread to the air sacs. The most important diseases of the air sacs are described below.
