Thyroid gland is one of the most important of all the glands in the body. It can be considered as the metabolic seat. Various hormones are being secreted by this gland that plays a very vital role in carrying out the normal physiological functions in the body. But some times due to some abnormalities or by various other causes this gland produces lesser amount of thyroxin. This condition is known as hypothyroidism. This condition can be very serious and can lead to a lot of serious metabolic disorders.
The thyroid gland produces the thyroid hormones that are significant in maintaining the normal metabolic rate. This is the process in which the body converts nutrient energy into energy of the body. If the thyroid gland deteriorate or becomes inflamed, it can no longer produce enough quantities of hormones. As a result, cells do not convert the nutritional energy it needs in natural state.
The symptoms of hypothyroidism are generally insidious or slow in onset. Below are some of the signs that can make us bit doubtful for the normal working of the thyroid gland.
- Weight gain
- Letharginess
- Lack energy
- Hair loss
- Dryness of skin
- Constipation
- Slow heart rate
- Infertility
Veterinary doctors treat hypothyroidism by recommending supplemental thyroid hormone, which the pet owner must give it orally once or twice daily. These treatments are primarily prescribed according to the weight of your pet. Doctor will strictly observe your pet in the early stage of treatment by re-testing the thyroid level- T4- to make sure the animal is getting the appropriate dosage. 
Less amount of hormone would not alleviate the signs, while large amount can lead to development of hyperthyroidism (excessive thyroid hormone causing agitated and overactive behavior, weight loss, excessive drinking, and excessive urination). Once thyroid- hormone levels have steady within a normal range, your doctor will likely check the levels every 6 months to every year. The dose levels of medication used to treat this disease in pets is much higher than the rate use to treat hypothyroidism in people.
Once medication begins, most hypothyroid dogs are ever more active and show fewer behavior troubles within a week. Hair growth typically speeds up in about a week, too, although bare spots may take months to fully grow in. Most dogs begin to lose over weight within two to four weeks of starting medication.