Hypothyroidism is when the dog's thyroid produces insufficient thyroid hormones. Symptoms can include lethargy, dull and dry coat, obesity or weight gain, and a thinning coat. The dog may seek warmer areas. Hypothyroidism can cause infertility in intact males and females.

Some forms of hypothyroidism may be hereditary, so it is inadvisable to breed a hypothyroid dog. Your veterinarian can diagnose hypothyroidism through a blood test. If your rottweiler is hypothyroid, your veterinarian may prescribe a form of thyroid hormone.