The aim of this paper was to present the relationship between different kinds of stress and the milk yield, its chemical composition, and disorders of reproductive functions in high-yielding dairy cows. Failure to satisfy adequately the demand of cows for nutrients, in combination with inappropriate conditions of maintenance, causes substantial disorders in their metabolic processes, described as stress. This leads to the premature culling of cows as a result of such diseases as mastitis, laminitis/lameness, displaced abomasum, endometritis, retained placenta, dysfunction of ovaries, infertility, clinical ketosis, acidosis, etc. The literature indicates that these negative phenomena are associated with various kinds of metabolic, oxidizing, thermal, or psychological stress. Each kind of stress has an adverse effect on the health status, on the yield and quality of the milk and on the reproductive traits of high-yielding dairy cows. An excessive generation of reactive forms of oxygen damages luteal cell membranes and affects progesterone production. This condition may lead to a failure in embryo development, increasing days open and extending calving intervals. Adverse effects related to stress can be reduced or totally eliminated by adapting the general conditions of the external environment (especially feeding and maintenance) to the requirements of high-yielding dairy cows.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.