Estrous cycle characteristics of postpubertal gilts approaching anestrus due to limited dietary energy intake
Twenty-nine Duroc X (Yorkshire X Landrace) gilts, approximately 9 mo of age and each having experienced at least three estrous cycles, were allotted randomly to five dietary treatments. Each treatment provided a different daily intake of metabolizable energy: 0.25, 0.5, 0.75, 1.0 Mcal (severely rest...
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Published in | Journal of animal science Vol. 71; no. 2; p. 436 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.02.1993
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Subjects | |
Online Access | Get more information |
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Summary: | Twenty-nine Duroc X (Yorkshire X Landrace) gilts, approximately 9 mo of age and each having experienced at least three estrous cycles, were allotted randomly to five dietary treatments. Each treatment provided a different daily intake of metabolizable energy: 0.25, 0.5, 0.75, 1.0 Mcal (severely restrictive [RES]; chosen to cause cessation of estrous cycles) or 3.4 Mcal (control; designed for maintenance of estrous cyclicity). Blood samples were drawn by venipuncture every 3 d and sera were assayed for progesterone (P4) concentration. Estrous cycle length was estimated by defining d 0 as the last day when serum P4 concentrations were 1 ng/mL before increasing to 1 ng/mL. Gilts were considered acyclic when serum P4 levels remained 1 ng/mL for four consecutive samples (9 d). Anestrus occurred after 78.7 +/- 6.1 d in all RES gilts (n |
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Bibliography: | 9409578 L53 |
ISSN: | 0021-8812 1525-3163 |
DOI: | 10.2527/1993.712436x |