PATTERNS OF PLASMA PROLACTIN IN POST-PARTUM SUCKLED COWS
- 1 September 1981
- journal article
- research article
- Published by Bioscientifica in Journal of Endocrinology
- Vol. 90 (3) , 391-396
- https://doi.org/10.1677/joe.0.0900391
Abstract
Blood samples taken on alternate days through indwelling jugular venous catheters from 12 suckled cows between days 14 and 48 post partum contained significantly less prolactin than samples collected on intermediate days by jugular venepuncture. Samples taken through the catheter every 2 h for 72 h periods revealed a repetitive daily biphasic pattern of prolactin secretion with low concentrations at 09.00 and 19.00 h and high concentrations at 13.00 and 23.00 h. In two groups of cows, one group calving at the beginning of March (increasing photoperiod) and the other calving during June (decreasing photoperiod), there was a significant negative correlation between stage of lactation and plasma prolactin concentrations in samples taken by venepuncture.This publication has 1 reference indexed in Scilit:
- Prolactin Response to Duration and Wavelength of Light in Prepubertal Bulls*Endocrinology, 1979