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.
Lactic Acid Dehydrogenase (LDH). Guide. Lactic acid dehydrogenase (LDH) is an enzyme that helps produce energy. It is present in almost all of the tissues in the body and its levels rise in response to cell damage. LDH levels are measured from a sample of blood taken from a vein.