scholarly journals Influence of ipsilateral coexistence of the first wave dominant follicle and corpus luteum on ovarian dynamics and plasma sex steroid hormone concentrations in lactating dairy cows treated with human chorionic gonadotropin

2020 ◽  
Vol 66 (3) ◽  
pp. 265-269
Author(s):  
Ryotaro MIURA ◽  
Nobu MATSUMOTO ◽  
Shingo HANEDA ◽  
Motozumi MATSUI
Keyword(s):  
Dairy Cows ◽  
Corpus Luteum ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Steroid Hormone ◽  
Sex Steroid ◽  
Dominant Follicle ◽  
Sex Steroid Hormone ◽  
Lactating Dairy Cows ◽  
Ovarian Dynamics

scholarly journals The ovulatory response to human chorionic gonadotropin administration on day 4 post timed artificial insemination improved fertility in repeat breeder cows

2021 ◽  
Vol 90 (1) ◽  
pp. 15-20
Author(s):  
Gulnaz Yilmazbas-Mecitoglu ◽  
Ahmet Gumen ◽  
Ebru Karakaya-Bilen ◽  
Abdulkadir Keskin ◽  
Baris Guner ◽  
...  
Keyword(s):  
Beneficial Effect ◽  
Dairy Cows ◽  
Corpus Luteum ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Control Group ◽  
Timed Artificial Insemination ◽  
Repeat Breeder

This study focused on determining the success of inducing endogenous progesterone source (by formation of accessory corpus luteum) by human chorionic gonadotropin (hCG) administration on day 4 post timed artificial insemination (TAI) and on evaluating the effect of the day of hCG administration (day 4 or 5 post TAI) on pregnancy rates in repeat breeder cows according to their responses to hCG administrations. Non-pregnant cyclic lactating Holstein dairy cows with more than three services despite no clinical reproductive abnormalities were enrolled in the study. All cows (n = 192) received the Ovsynch protocol (GnRH-7d-PGF2α-56h-GnRH-16/18h-TAI) and hCG administration (1500 IU, i.m.) was performed in group hCG4 (n = 64) on day 4 and in group hCG5 (n = 68) on day 5 post TAI. The control group (CON, n = 60) did not receive any hCG treatment. The responses (ovulation rate) to hCG (~64%) were similar on days 4 and 5 post TAI. Pregnancy per AI (P/AI) at 31 days was similar among the groups (48.3% in CON, 48.4% in hCG4, and 42.6% in hCG5). Regardless of the day of the treatment (hCG4 + hCG5), the cows had an ovulatory response to hCG (54.1%), and a greater P/AI (P = 0.007) at 31 days than those without a response (29.8%). The administration of hCG on either day 4 or 5 post TAI did not increase overall pregnancy rates, however, the ovulatory response to the post TAI hCG administration on day 4 improved fertility in repeat breeder cows. Further studies are needed with a larger number of animals to reveal this potentiallly beneficial effect.

Follicular dynamics, corpus luteum growth and regression in lactating dairy cattle

1991 ◽  
Vol 71 (1) ◽  
pp. 61-68 ◽  
Author(s):  
C. Taylor ◽  
R. Rajamahendran
Keyword(s):  
Dairy Cows ◽  
Corpus Luteum ◽  
Estrous Cycle ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Lactating Dairy Cows ◽  
Ovulatory Follicle ◽  
Second Wave ◽  
Lactating Dairy Cattle ◽  
Follicular Dynamics

Ultrasound imaging and progesterone (P4) profiles were used to characterize follicular and corpus luteum (CL) growth and regression in 10 cycling dairy cows. Thirteen of sixteen cycles were characterized by two waves of follicular growth, the second wave giving rise to the ovulatory follicle. The remaining three cycles had three waves. There was no difference between two- and three-wave cycles with regard to the day of emergence of the first or second dominant follicle (day 2.5 ± 0.9 vs. day 2.4 ± 1.2 and day 12.4 ± 1.6 vs. day 12.0 ± 2.0, respectively) or the onset of regression of the first dominant follicle (day 12.5 ± 1.5 vs. day 12.3 ± 1.5). In two wave cycles, estrous cycle length was shorter (20.8 ± 1.7 d vs. 29.7 ± 4.9 d), the first day of decline in P4 (day 16.2 ± 1.5 vs. day 23.7 ± 5.5) and the onset of CL regression (day 17.1 ± 1.3 vs. day 24.3 ± 5.5) was earlier. It is concluded that two waves of follicular growth in an estrous cycle is the norm in lactating dairy cows. The presence of an additional wave is due to a prolonged luteal phase. Key words: Follicle, corpus luteum, estrous cycle, dairy cow

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