[header] How to diagnose hypothyroidism in golden retrievers [title] Be aware of how hypothyroidism develops in your golden retriever. [step] Hypothyroidism is caused by a low amount of thyroid hormone in your dog's body. Your dog's thyroid glands sit on your dog's neck on either side of his windpipe. 
They produce the thyroid hormone, which helps to control your dog's metabolic rate. If your dog's thyroid glands are underactive, the thyroid will be attacked by your dog's immune system, leading to health issues.