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Human chorionic gonadotropin (hCG)-induced ovulation occurs later but with equal occurrence in lactating dairy cows: comparing hCG and gonadotropin-releasing hormone protocols.

Abstract

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 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, indicating that 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.

Authors+Show Affiliations

Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31619595

Citation

Liu, Tsung-Ching, et al. "Human Chorionic Gonadotropin (hCG)-induced Ovulation Occurs Later but With Equal Occurrence in Lactating Dairy Cows: Comparing hCG and Gonadotropin-releasing Hormone Protocols." The Journal of Reproduction and Development, 2019.
Liu TC, Ho CT, Li KP, et al. Human chorionic gonadotropin (hCG)-induced ovulation occurs later but with equal occurrence in lactating dairy cows: comparing hCG and gonadotropin-releasing hormone protocols. J Reprod Dev. 2019.
Liu, T. C., Ho, C. T., Li, K. P., Chang, C. C., & Chan, J. P. (2019). Human chorionic gonadotropin (hCG)-induced ovulation occurs later but with equal occurrence in lactating dairy cows: comparing hCG and gonadotropin-releasing hormone protocols. The Journal of Reproduction and Development, doi:10.1262/jrd.2019-037.
Liu TC, et al. Human Chorionic Gonadotropin (hCG)-induced Ovulation Occurs Later but With Equal Occurrence in Lactating Dairy Cows: Comparing hCG and Gonadotropin-releasing Hormone Protocols. J Reprod Dev. 2019 Oct 17; PubMed PMID: 31619595.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Human chorionic gonadotropin (hCG)-induced ovulation occurs later but with equal occurrence in lactating dairy cows: comparing hCG and gonadotropin-releasing hormone protocols. AU - Liu,Tsung-Ching, AU - Ho,Chia-Tang, AU - Li,Kuang-Po, AU - Chang,Chao-Chin, AU - Chan,Jacky Peng-Wen, Y1 - 2019/10/17/ PY - 2019/10/18/entrez KW - Gonadotropin-releasing hormone (GnRH) KW - Human chorionic gonadotropin (hCG) KW - Ovulation time JF - The Journal of reproduction and development JO - J. Reprod. Dev. N2 - 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 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, indicating that 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. SN - 1348-4400 UR - https://www.unboundmedicine.com/medline/citation/31619595/Human_chorionic_gonadotropin_(hCG)-induced_ovulation_occurs_later_but_with_equal_occurrence_in_lactating_dairy_cows:_comparing_hCG_and_gonadotropin-releasing_hormone_protocols L2 - https://dx.doi.org/10.1262/jrd.2019-037 DB - PRIME DP - Unbound Medicine ER -