Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8404118 | Animal Reproduction Science | 2018 | 8 Pages |
Abstract
Two experiments in Nelore cows subjected to timed artificial insemination (TAI) were designed to compare the influence of the antral follicle count (AFC/AFCs) on (1) ovarian follicular dynamics and (2) conception rates. First, multiparous cows with high (â¥45 follicles; n = 43) or low (â¤15 follicles; n = 32) AFCs were selected to undergo a TAI protocol to monitor ovarian follicular dynamics. Second, the AFCs of 962 cows also subjected to TAI were determined and classified as groups of high (G-high; â¥45 follicles; n = 194), intermediate (G-intermediate; â¥20 â¤Â 40 follicles, n = 397) or low (G-low;ââ¤15 follicles; n = 243) AFCs. In study I, the ovarian measurements (diameter, perimeter and area) were greater (P â¤Â 0.05) and there was a greater consistency in number of antral follicles during the period of synchronization for TAI in the high than low group. Effects of the AFC and ultrasonic evaluation interval on the follicular diameter were observed (P â¤Â 0.05); however, there was no interaction (P > 0.05). Dominant follicles had greater diameters (P â¤Â 0.05) in the G-low than in the G-high at D4 (7.3 ± 2.2 vs. 6.2 ± 1.4 mm, respectively, P = 0.06), D8 (11.2 ± 1.8 vs. 9.5 ± 1.8 mm, respectively), D9 (12.3 ± 1.7 vs. 10.6 ± 1.7 mm, respectively), and D10 (13.4 ± 1.3 vs. 12.2 ± 1.8 mm, respectively), as well as greater estimated diameters of ovulatory follicles (14.4 ± 1.5 vs. 13.4 ± 2.1 mm, respectively, P = 0.08). In study II, the cows with fewer AFCs had greater (P â¤Â 0.05) conception rates (61.7%) than the cows with the intermediate (52.9%) and greater (49.5%) AFCs. Nelore cows with fewer AFCs subjected to synchronization of time of ovulation had a larger follicular diameter and a greater conception rate than the groups with intermediate and a greater AFCs.
Related Topics
Life Sciences
Agricultural and Biological Sciences
Animal Science and Zoology
Authors
Fábio Morotti, Rogério Moretti, Gustavo Martins Gomes dos Santos, Katia Cristina Silva-Santos, Pedro Henrique Ramos Cerqueira, Marcelo Marcondes Seneda,