[Quantitative dynamics of zinc in the coat of cows during pregnancy].

An atomic-absorption spectrophotometer AAS1 was used to evaluate the content of zinc in the coat of cows of the Bulgarian Black-and-white breed during the period of pregnancy. It was found with the advancement of pregnancy the amount of zinc in the hairs dropped almost twice as compared to the initial content of zinc prior to the impregnation of the cows. The weight of the fetus correlated negatively with the content of zinc in the coat of dams. After calving the level of zinc rapidly came back to normal. The method of the spectrophotometric analysis employed was shown to be rational when used with a great number of animals of a herd in order to obtain a general idea of zinc dynamic in the animals' coat of this same herd.