A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and tells the thyroid gland to make and release the hormones thyroxine (T4) and triiodothyronine (T3). See also: 1  T3 test.  T4 test.
Best Answer: Female cats typically have their first heat around the age of six months, which usually lasts for 5 to 7 days. Cat's heat cycles are light dependent and they usually have heat cycles every 9 to 13 days from January through October, though some indoor cats exposed to constant light times will cycle all year. I advise unless you want kittens to keep her in at these times.
Once in heat, the fertile part of the cycle can last for anything between five and ten days, and as mentioned, the cycle will repeat on a regular basis unless the cat is spayed or conceives. How to tell when your cat is in heat. All cats are different, but it is usually fairly obvious when a female cat is in heat, as they will display a distinctive set of mating behaviours and often, undergo personality and temperament changes for the duration.