The purpose of this study was to analyse the effect of the application of oxytocine in the early stage of the oestrous cycle on the levels of serum progesterone and plasma vitamin A and ß-carotene during the cycle. Five Swiss-Brown cows were used during two oestrous cycles. Blood samples were collected during the first cycle starting after synchronization and then a total daily dose of 100 I.U. oxytocine was applied subcutanously as a half dose at 12 hour intervals on days on 4, 5 and 6 of the second cycle. During the same cycle, blood samples were again collected, from which serum and plasma were extracted. The levels of serum progesterone and plasma vitamin A and ß-carotene were determined from each sample and the correlations between these parameters were investigated. A statistically significant negative correlation was present between serum progesterone and plasma ß-carotene levels during the second cycle in cows (P

The purpose of this study was to analyse the effect of the application of oxytocine in the early stage of the oestrous cycle on the levels of serum progesterone and plasma vitamin A and ß-carotene during the cycle. Five Swiss-Brown cows were used during two oestrous cycles. Blood samples were collected during the first cycle starting after synchronization and then a total daily dose of 100 I.U. oxytocine was applied subcutanously as a half dose at 12 hour intervals on days on 4, 5 and 6 of the second cycle. During the same cycle, blood samples were again collected, from which serum and plasma were extracted. The levels of serum progesterone and plasma vitamin A and ß-carotene were determined from each sample and the correlations between these parameters were investigated. A statistically significant negative correlation was present between serum progesterone and plasma ß-carotene levels during the second cycle in cows (P