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Foetal and maternal hormonal changes preceding normal bovine parturition.
Acta Endocrinologica
|March 1, 1977
Summary
Hormonal shifts in pregnant Jersey cows were monitored. Fetal corticosteroids and maternal estrogens increased, while progesterone decreased before calving, indicating key physiological changes.
Area of Science:
- Veterinary Endocrinology
- Reproductive Physiology
Background:
- Monitoring hormonal changes during late gestation is crucial for understanding calving processes.
- Previous studies have focused on specific hormones, but comprehensive analysis in Jersey cows is limited.
Purpose of the Study:
- To investigate plasma hormone level changes preceding calving in Jersey cows.
- To correlate hormonal profiles with the calving process in this breed.
Main Methods:
- Chronic cannulation of fetal and maternal blood vessels in five Jersey cows (days 240-260 gestation).
- Assay of fetal corticosteroids, and maternal prostaglandin F, progesterone, oestrone, and oestradiol-17beta via competitive protein-binding and radioimmunoassay.
Main Results:
- Fetal corticosteroids increased significantly towards term. Maternal utero-ovarian estrogens (oestrone, oestradiol-17beta) rose sharply 1-4 days before delivery.
- Maternal progesterone levels declined towards term, with a rapid decrease preceding calving and a surge during labor. Fetal estrogens remained low.
Conclusions:
- Plasma hormone profiles provide insights into the physiological events leading to calving in Jersey cows.
- Distinct patterns of fetal corticosteroids, maternal estrogens, and progesterone correlate with the onset and progression of labor.