PLASMA B-ENDORPHIN PROFILE DURING EARLY, INTERMEDIATE AND LATE PUERPERIUM IN FRIESIAN DAIRY COWS

Document Type : Research article

Authors

Abstract

This investigation was performed on 28 pluriparous dairy Friesian cows during the Ist, the 2nd and the 3rd weeks of puerperium in addition during the postpartum (PP) estrus cycle (Follicular and luteal stages). Blood samples were collected in heparinized Vacutainer tubes, plasma was obtained by cooling centrifuge and kept frozen at-20°C until hormonal assay. A special radioimmunoassay technique was adapted for detemination of plasma B-endorphin levels. The results revealed highly significant rise (P<0.01) of B-endorphin profile in postp < /strong>artum cows at the 1st week (70.31+3. 88 pg/ml) when compared with the 2nd week (57.37+ 4.96 pg/ml) and the 3rd. Week (36.38+ 3. 17 pg/ml). Highly significant increase was observed in the follicular phase (53. 46+ 5.32 pg/ml) at the Ist estrus when
compared with the luteal phase (35.03+ 3.68 pg/ml) .. in the same estrus cycle of the studied animals.