The thyroid gland in dogs weighs an average of just one and a half grams, but without the mini organ, almost nothing functions in the entire organism of the four-legged friend. The tiny gland uses its two hormones thyroxine (T4) and triiodothyronine (T3) to stimulate a wide range of processes in the body and drive all organs to work. In young animals, the thyroid hormones are the driving forces for growth and development. Virtually all body functions in the adult dog are dependent on the health of the thyroid gland.
Hereditary diseases, injuries, inflammation, and the development of a tumor can damage the dog’s thyroid. In addition, other diseases – such as diseases of the pituitary gland – also have an impact on the health and functionality of the thyroid gland
By far the most common thyroid disease in dogs is an autoimmune disease in which the body’s own defense cells attack and destroy the thyroid tissue (autoimmune thyroiditis). It is not known why the immune cells attack the thyroid gland. As a result of the autoimmune processes, the damaged thyroid can hardly or no longer produce any hormones. So-called underactive thyroid (hypothyroidism) occurs. Hypothyroidism has serious consequences for the entire dog’s body.
Since the destruction of the thyroid gland by the autoimmune processes is usually slow, the production of thyroid hormones can be sustained for quite a while.
Symptoms only appear when around three quarters of the thyroid gland has been destroyed:
In the further course of the disease, the affected dogs also show skin and coat changes. If the thyroid is underactive, water is retained in the subcutaneous tissue. This makes the skin appear thick, doughy, and puffy. Dogs’ faces are often puffy and look sad.
The following physical changes can also occur:
Affected dogs usually only get going when it comes to food. © Denis Aglichev – stock.adobe.com
Diagnosing hypothyroidism is complicated because all of these symptoms can also occur in other diseases in dogs. The measurement of the thyroid values in the blood does not always provide clear results, because hormone values are subject to fluctuations even in healthy dogs.
In addition, the normal values for thyroid hormones are also different depending on the breed. The thyroid values of completely healthy Salukis, for example, are often below average.
Since the thyroid tissue is usually irreversibly destroyed by the autoimmune processes, the missing hormones have to be replaced for life. This happens through replacement hormones, which the dog receives once or twice a day, depending on the preparation or clinical picture. It is important that the hormones are always given at the same time, if possible. In this way, the organism can better adapt to it. The required dose of the hormone varies from dog to dog, so it may take a while for the veterinarian to determine the right dose.
If the underactive thyroid is discovered in good time and everything goes well, the animals feel much better one to two weeks after the start of therapy, they are much more active and livelier again. Dogs’ skin and coat take approximately eight weeks to recover.
In recent years, the trend towards raw meat feeding has repeatedly resulted in cases of hyperthyroidism (overactive thyroid gland) in the appropriately nourished dogs. The reason for this was the feeding of large quantities of gullet meat that still contained thyroid remains and thus the thyroid hormones from the animals for slaughter.
This led to a dangerous oversupply of hormones. The dogs suffered from palpitations and showed symptoms such as nervousness, weight loss, panting, great thirst and increased urination. As soon as the gullet was removed from the rations, these symptoms also stopped.
Raw meat, especially throat meat, can lead to an overactive thyroid. © mfotohaus – stock.adobe.com