This study was carried out on 18 calved dairy cows, near the town of Curitiba -PR- Brazil. The animals were submitted weekly to a rectal palpation of the genital tract and the uterine involution and ovarian activity were considered. The rectal palpations began from the 7th day postpartum till the 49th day. At the same time milk samples from the first morning milk were taken on the 9th day till the 7th week. The progesterone (P4) level determination of the milk was established by radioimmunassay. The findings of the research showed: the first postpartum oestrus was observed at the 28.5th day and the corpus luteum (CL) was detected on the 34.5th day. The period from oestrus to the first high progesterone level post partum was 5.5 days. The uterine involution period was carried on the 24.1th day. The progesterone dominant period was shorter and had duration of 11.5 days on the first oestrus cycle post partum. The progesterone concentration from the 1st Corpus luteum post partum was low (1.9 ng/ml milk). The anoestrus rate until the 49th day postpartum was 33.3% and the silent heat rate reached 61.1%.
Puerperium; Progesterone; Radioimmunoassay; Cows
