[Review article: factors influencing the estrogen and progesterone concentration in the blood of cows in late pregnancy].

This review describes the factors influencing the estrogen und progesterone levels in late pregnant cows. The various endogenous and exogenous factors (breed, calf birth weight, sex of calf, number of fetuses, season, nutrition and stressors) influence particularly significant estrogen and progesterone concentrations in peripheral blood and may lead to high variations of hormone values between cows. The possible mechanisms of influence on the estrogen und progesterone levels are discussed.