Effect of GnRH on ovulatory response after luteolysis induced by two low doses of PGF2α in lactating dairy cows
| Autor: | Chia-Tang Ho, Tsung-Ching Liu, Chen-Fei Chiang, Jacky Peng-Wen Chan |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Ovulation
0301 basic medicine medicine.medical_specialty medicine.medical_treatment media_common.quotation_subject Luteolysis Gonadotropin-releasing hormone Dinoprost Gonadotropin-Releasing Hormone Andrology 03 medical and health sciences Follicle Food Animals Internal medicine medicine Animals Lactation Small Animals Saline media_common Estrous cycle Equine business.industry Artificial insemination 0402 animal and dairy science 04 agricultural and veterinary sciences 040201 dairy & animal science 030104 developmental biology Endocrinology medicine.anatomical_structure Cattle Female Animal Science and Zoology business Corpus luteum |
| Zdroj: | Theriogenology. 105:45-50 |
| ISSN: | 0093-691X |
| DOI: | 10.1016/j.theriogenology.2017.09.013 |
| Popis: | This study investigated the effect of gonadotropin-releasing hormone (GnRH) on ovulatory response after complete luteolysis induced by two low doses of prostaglandin (PG)F2α in lactating dairy cows. Cows (n = 18) ranging between 45 and 65 days in milk were recruited for synchronization by a modified Ovsynch-48 protocol (GnRH-7 days-375 μg PGF2α-1 day-250 μg of PGF2α-1 day-GnRH) over a total of 23 estrous cycles. Synchronized cows (n = 16) were randomly assigned to GnRH and Saline groups in stage 1 of the experiment after 9-10 days of ovulation in synchronization. On days 0 and 1 (day 0 = first PGF2α administration), cows were treated with 375 and 250 μg PGF2α, respectively. On day 2, cows in the GnRH and Saline groups were administered 250 μg GnRH or 2.5 mL of 0.9% saline, respectively. Serum progesterone (P4) levels were measured and changes in the corpus luteum (CL) were ultrasonically monitored daily from day 0-3 to assess complete luteolysis. Preovulatory follicle diameter and ovulatory response were evaluated by ultrasonography. In stage 2, cows were treated in a manner converse to that in stage 1. The synchronization rate was 69.6% (16/23). In stages 1 and 2, cows showed complete luteolysis with P4 concentration |
| Databáze: | OpenAIRE |
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