Causes for decreased fertility in out-of-season mated ewes
| Autor: | S.E. Echternkamp, D.D. Lunstra |
|---|---|
| Rok vydání: | 1978 |
| Předmět: |
Estrous cycle
endocrine system urogenital system Equine media_common.quotation_subject Serum gonadotropin Fertility Exogenous hormones Biology Andrology Human fertilization Food Animals Reduced fertility Animal Science and Zoology Decreased fertility Small Animals Luteinizing hormone reproductive and urinary physiology media_common |
| Zdroj: | Theriogenology. 10:65-71 |
| ISSN: | 0093-691X |
| DOI: | 10.1016/0093-691x(78)90081-x |
| Popis: | The interval from onset of estrus to preovulatory luteinizing hormone (LH) release, conception and fertilization rates, and number of accessory spermatozoa per ovum at 48 hr postmating in untreated cyclic ewes and in progestogen-pregnant mare serum gonadotropin (PMSG) treated, anestrous ewes were compared in efforts to identify sources of lowered fertility for matings induced in anestrous ewes with exogenous hormones. Blood samples for LH determination were collected at 0, 2, 4, 6, 8, 10, 12, and 24 hr after the onset of estrus. Conception and fertilization failure rates were determined at 48 hr, 12 days, or parturition. The progestogen-PMSG treated ewes had a shorter interval from onset of estrus to preovulatory LH release, lower conception rates, and fewer accessory spermatozoa than cyclic ewes had. Conception failure, rather than embryonic mortality, was the major cause of reduced fertility for the out-of-season mated ewes and apparently resulted from insufficient viable spermatozoa in the oviducts to fertilize the ova. |
| Databáze: | OpenAIRE |
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