Human chorionic gonadotropin (hCG)-induced ovulation occurs later but with equal occurrence in lactating dairy cows: comparing hCG and gonadotropin-releasing hormone protocols
| Autor: | Chao-Chin Chang, Tsung-Ching Liu, Jacky Peng-Wen Chan, Chia-Tang Ho, Kuang-Po Li |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Ovulation
endocrine system medicine.medical_specialty Time Factors media_common.quotation_subject Prostaglandin Gonadotropin-releasing hormone Chorionic Gonadotropin Human chorionic gonadotropin Gonadotropin-Releasing Hormone 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Induced ovulation Internal medicine Animals Humans Lactation Human chorionic gonadotropin (hCG) Medicine Insemination Artificial Progesterone reproductive and urinary physiology 030304 developmental biology media_common Estrous cycle 0303 health sciences 030219 obstetrics & reproductive medicine Gonadotropin-releasing hormone (GnRH) urogenital system business.industry Reverse order Dairying Treatment Outcome Endocrinology chemistry Ovulation time Cattle Female Original Article Animal Science and Zoology Estrus Synchronization business hormones hormone substitutes and hormone antagonists Hormone |
| Zdroj: | The Journal of Reproduction and Development |
| ISSN: | 1348-4400 0916-8818 |
| DOI: | 10.1262/jrd.2019-037 |
| Popis: | This study assessed the effects of two hormones, human chorionic gonadotropin (hCG) and gonadotropin-releasing hormone (GnRH), on ovulatory responses during different diestrous stages in lactating dairy cows. Estrous cycles of 21 cows were synchronized and were enrolled in stage 1 of the experiment. The cows were treated with a prostaglandin (PG) F2α analog either 9 to 10 days [mid-diestrus (MD) group] or 5.5 to 6.5 days [early-diestrus (ED) group] after synchronized ovulation (day 0 = first PGF2α administration). On day 2, the cows were administrated 250 μg GnRH or 3000 IU hCG. Ovulation was determined every 2 h from 24 to 36 h after GnRH or hCG administration, and then every 4 h up to 72 h until ovulation. Cows in stage 2 were administered these treatments in the reverse order. The results indicated that average ovulation times in cows treated with GnRH in the MD group (GnRH-MD group) and cows treated with GnRH in the ED group (GnRH-ED group) were 30.0 ± 1.0 h and 28.8 ± 0.4 h, respectively. However, ovulation times for cows treated with hCG in the MD group (hCG-MD group) and cows treated with hCG in the ED group (hCG-ED group) were 35.8 ± 4.6 h and 32.8 ± 2.2 h, respectively, and ovulation occurred significantly later in the hCG-treated groups than in the GnRH-treated groups. In summary, we found that hCG-induced ovulation occurred later than GnRH-induced ovulation regardless of different diestrous peroids; however, the two treatments did not differ in terms of percentage of ovulation. |
| Databáze: | OpenAIRE |
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