Effects of dietary lasalocid during late pregnancy, postpartum period, and sex of calf on profiles of progesterone, estrogen, 13-14-dihydro-15-keto-prostaglandin F2alpha and follicular patterns in Brahman cows /
Mature Brahman cows were utilized to evaluate the effects of dietary lasalocid (LAS) and sex of calf (SC) during the precalving (n=75) and postcalving periods (n=73) on pre and postpartum hormonal profiles, changes in body weight and condition, follicular populations and postpartum interval (PPI)....
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=737708721&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Mature Brahman cows were utilized to evaluate the effects of dietary lasalocid (LAS) and sex of calf (SC) during the precalving (n=75) and postcalving periods (n=73) on pre and postpartum hormonal profiles, changes in body weight and condition, follicular populations and postpartum interval (PPI). Plasma concentrations of 13-14-dihydro-15-keto-prostaglandin-F2. (PGFM) and progesterone (P4) were higher (P< .05) and the estrogen:P4 ratio was reduced in cows fed LAS during the precalving period. Prepartum changes in BW and BCS were similar (P > .10) between treatments and SC. Calves of LAS cows were heavier (P < .05) than calves of control (CON) cows. SC did not affect (P >.10) birth weight of calf. Hormonal profiles during the postcalving period were not affected by the combined pre and postcalving treatments; therefore, postcalving endocrine data were pooled. Plasma PGFM, estrogen and P4 were not influenced (P > 10) by diet or SC during the early postpartum period. Plasma P4 was higher (P < .08) in LAS cows than CON cows on days 6 and 12 after estrus. Postpartum changes in BW and BCS in dams and BW in the calves were not affected (P <.10) by diet or SC. The number of medium (4.0 to 7.9mm) follicles was greater (P<.05) in LAS cows compared with CON cows during the first 49 days postcalving. Follicular populations were not influenced (P >.10) by diet or SC during the three week period before first estrus. The interval from calving to the first > 10mm follicle, and intervals from calving to: behavioral estrus, formation of a CL, and estrus with a subsequent CL were shorter (P< .01) in LAS cows than CON cows. The cumulative frequency of return to estrus by day 55 after calving was higher (P < .05) in LAS cows than CON cows. Dietary lasalocid fed to late pregnant cows did not improve reproductive efficiency. The greatest improvement in reproductive performance was found when cows received the ionophore antibiotic in the diet following calving. |
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| Item Description: | Vita. "Major Subject: Physiology of Reproduction". In title, symbols are used. |
| Physical Description: | xii, 119 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 88-118. |