What question did this study set out to answer?

To measure sequential changes in peripheral plasma progesterone in cows across the estrous cycle, gestation, parturition, and the postpartum period.

December 1, 1972Canadian Journal of Animal ScienceOpen Access

Sequential Changes in Plasma Progesterone in the Cow During the Estrous Cycle, Pregnancy, at Parturition, and Post-Partum

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Authors

HRHamish RobertsonQueensland University of Technology

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Implication

Longitudinal study reveals dynamic peripheral plasma progesterone profiles across reproductive stages in cows, indicating that luteal activity precedes normal estrous behavior.

Key Points

To measure sequential changes in peripheral plasma progesterone in cows across the estrous cycle, gestation, parturition, and the postpartum period.
Measured sequential peripheral plasma progesterone concentrations in individual cows across complete estrous cycles, pregnancy, parturition, and postpartum intervals.
Compared baseline cycle concentrations against control plasma progesterone levels measured in three ovariectomized cows.
Progesterone was lowest near estrus (0.1–0.4 ng/ml), peaked at 3–6 ng/ml on days 11–13 of the cycle, and dropped to basal values 24–72 hours prior to the subsequent estrus.
Early pregnancy levels mirrored luteal phase peaks before declining between days 90–150, then gradually fell over 35–70 days to <2.0 ng/ml the day before calving.
Postpartum concentrations remained at <0.5 ng/ml for 20 to >60 days until cyclicity resumed, with findings indicating behavioral estrus requires preceding luteal activity.

Cite This Study

Hamish Robertson (1972) studied this question.

synapsesocial.com/papers/6a8dbb8223326f78e47dd5b2 https://doi.org/10.4141/cjas72-076

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Implication

Longitudinal study reveals dynamic peripheral plasma progesterone profiles across reproductive stages in cows, indicating that luteal activity precedes normal estrous behavior.

Sequential Changes in Plasma Progesterone in the Cow During the Estrous Cycle, Pregnancy, at Parturition, and Post-Partum

Discussion

Member takes

Implication

Key Points

Cite This Study

Sequential Changes in Plasma Progesterone in the Cow During the Estrous Cycle, Pregnancy, at Parturition, and Post-Partum

Discussion

Member takes

Implication

Key Points

Cite This Study

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