Deep anestrous mares under natural photoperiod treated with recombinant equine FSH (reFSH) and LH (reLH) have fertile ovulations and become pregnant
| Autor: | M.C. Loud, Janet F. Roser, Geraldine A. Meyers-Brown, John C. Hyland |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Ovulation
medicine.medical_specialty endocrine system media_common.quotation_subject Photoperiod Estrous Cycle Human chorionic gonadotropin Andrology 03 medical and health sciences Follicle Follicle-stimulating hormone 0302 clinical medicine Food Animals Induced ovulation Pregnancy Internal medicine Medicine Animals Horses Small Animals Insemination Artificial media_common Estrous cycle 030219 obstetrics & reproductive medicine Equine business.industry 0402 animal and dairy science 04 agricultural and veterinary sciences Luteinizing Hormone medicine.disease 040201 dairy & animal science Recombinant Proteins Pregnancy rate Endocrinology Animal Science and Zoology Female Follicle Stimulating Hormone business |
| Zdroj: | Theriogenology. 98 |
| ISSN: | 1879-3231 |
| Popis: | The most common equine breeding practice to decrease the time to the first ovulation of the year is to use artificial lights starting December 1 in the Northern Hemisphere. It can take 60–90 d for this lighting regimen to induce a fertile ovulation. The success rate for pharmaceutical compounds to carry out the same process has been variable. One compound that did induce an early ovulation was recombinant equine follicle stimulating hormone (reFSH), but neither pregnancy nor cyclicity was established in that study. Starting on December 1, 20 deep-anestrous mares of light horse breeds (4–15 y old) with follicles ≤ 20 mm in diameter and progesterone 4 ), estradiol-17β (E 2 ) and immunoreactive (ir)-inhibin were analyzed by radioimmunoassay (RIA). When the largest follicle reached ≥32 mm in diameter, reFSH treatment was discontinued in both groups while reLH treatment continued in the reFSH/reLH group until a cohort of follicles reached ≥35 mm in diameter. Human chorionic gonadotropin (hCG) was administered intravenously (iv) to induce ovulation, and mares were bred to a fertile stallion every other day until ovulation. Mares receiving either reFSH or reFSH/reLH developed follicles ≥35 mm within 5–6 d of treatment compared with 15.8 ± 3.4 d in the control group. Both reFSH and reFSH/reLH induced ovulation in 100% of the mares within 10 d after treatment resulting in an 80% conception rate and a 70% pregnancy rate for both groups. Conception and pregnancy were designated as either presence of a 14 d old embryo (n = 16) or a fetal heartbeat at 24 d (n = 14), respectively. Only three mares in the control group ovulated within the same treatment period. Later ovulations in the control group resulted in 100% conception and pregnancy rates. At 25 d post-conception, treated mares that were pregnant (n = 7 per group) were administered prostaglandin (PGF2 α ) to terminate the pregnancy and later returned to estrus. Treatment with reFSH or reFSH/reLH given to deep-anestrous mares under natural photoperiod induced fertile ovulations that resulted in pregnancy and cyclicity when pregnancies were terminated. |
| Databáze: | OpenAIRE |
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