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dc.contributor.authorYoung, William McFerrin
dc.creatorYoung, William McFerrinen
dc.date.accessioned2015-04-01T13:42:13Zen
dc.date.available2015-04-01T13:42:13Zen
dc.date.issued1976en
dc.identifier.urihttp://hdl.handle.net/10150/348035en
dc.description.abstractThe object of this investigation was to measure the changes in plasma corticoids and progesterone, at two different levels of energy intake during the postpartum period in beef heifers and to assess their relationship to breeding efficiency. Blood samples were taken using a tail bleeding method from 26 first calf crossbred heifers within 24 hours postpartum. Sampling was continued twice weekly until each animal was diagnosed pregnant. Plasma samples were analyzed for progesterone and corticoids using competitive binding techniques. Progesterone levels increased from .5 ng/ml postpartum to 3.7 ng/ml following first ovulation. These levels remained high if conception occurred (5.0 + ng/ml) or returned to minimum levels for repeat estrous cycle. Due to the necessary manipulation of the animals, postpartum plasma levels of corticoids fluctuated widely (10 ng/ml to 70 ng/ml) for each animal. Corticoids means were lower during the postpartum anestrum than during subsequent estrous cycles. No significant correlations were found between plasma corticoids and progesterone concentrations. Providing more than NRC recommended energy intake had no influence on breeding efficiency.
dc.language.isoen_USen
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.subjectProgesterone.en
dc.subjectAdrenocortical hormones.en
dc.subjectPostpartum.en
dc.titlePlasma progesterone and cortisol in postpartum beef heifersen
dc.typetexten
dc.typeThesis-Reproduction (electronic)en
dc.identifier.oclc701940196en
thesis.degree.grantorUniversity of Arizonaen
thesis.degree.levelmastersen
thesis.degree.disciplineAnimal Scienceen
thesis.degree.disciplineGraduate Collegeen
thesis.degree.nameM.S.en
dc.description.noteThis item was digitized from a paper original and/or a microfilm copy. If you need higher-resolution images for any content in this item, please contact us at repository@u.library.arizona.edu.en
dc.identifier.bibrecord.b64850456en
dc.identifier.callnumberE9791 1976 456en
refterms.dateFOA2018-09-01T05:58:50Z
html.description.abstractThe object of this investigation was to measure the changes in plasma corticoids and progesterone, at two different levels of energy intake during the postpartum period in beef heifers and to assess their relationship to breeding efficiency. Blood samples were taken using a tail bleeding method from 26 first calf crossbred heifers within 24 hours postpartum. Sampling was continued twice weekly until each animal was diagnosed pregnant. Plasma samples were analyzed for progesterone and corticoids using competitive binding techniques. Progesterone levels increased from .5 ng/ml postpartum to 3.7 ng/ml following first ovulation. These levels remained high if conception occurred (5.0 + ng/ml) or returned to minimum levels for repeat estrous cycle. Due to the necessary manipulation of the animals, postpartum plasma levels of corticoids fluctuated widely (10 ng/ml to 70 ng/ml) for each animal. Corticoids means were lower during the postpartum anestrum than during subsequent estrous cycles. No significant correlations were found between plasma corticoids and progesterone concentrations. Providing more than NRC recommended energy intake had no influence on breeding efficiency.


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