1 Cats: Cats normally have their first estrous cycle between 4 and 6 months of age, with the average age around 5 months. 2  The female cat has 2-4 estrous periods every year, each lasting 15-22 days. 3  If she is bred, estrus seldom lasts more than 4 days.
Lactate dehydrogenase (LD or LDH) is an enzyme involved in energy production that is found in almost all of the body's cells, with the highest levels found in the cells of the heart, liver, muscles, kidneys, lungs, and in blood cells; bacteria also produce LD.actate dehydrogenase (LD or LDH) is an enzyme involved in energy production that is found in almost all of the body's cells, with the highest levels found in the cells of the heart, liver, muscles, kidneys, lungs, and in blood cells; bacteria also produce LD.
Lactate dehydrogenase test. The lactate dehydrogenase (LDH) test measures the amount of LDH in the blood. A blood sample is needed. Your health care provider may ask you to stop taking certain medicines that may affect the test.