Low versus high antral follicle count on the fertility of timed AI Nelore heifers
Keywords:Bos indicus, Cattle, Ovulation, Pregnancy
This study aimed to determine the effect of antral follicle count (AFC), and pubertal status on the fertility of beef heifers. In this study, 230 Nelore heifers, 20±2 months of age, were subjected to an estradiol progesterone-based timed artificial insemination (TAI) program. On Day 0 of the TAI protocol, the heifers were examined by transrectal ultrasound to record videos of the ovaries. Later, in the darkroom of the laboratory of images, the videos were analyzed for AFC (≥ 3 mm) of each ovary. Females who failed the first TAI were resynchronized with the same hormonal protocol. The pregnancy status was evaluated by ultrasonography 30 days after each FTAI. The general mean of the AFC was 22.0 follicles. Thus, the heifers were divided into 2 groups according to AFC: Low AFC (˂ 22 follicles, n = 114), and High AFC (≥ 22 follicles, n = 116). No differences (P > 0.05) in the pregnancy per AI (P/AI) were observed between the Low and High AFC groups, and between pubertal and prepubertal categories. The P/AI was not different between heifers that displayed or did not estrus (P = 0.2). However, considering the estrus response of each AFC group, High AFC heifers that displayed estrus had greater P/AI (P = 0.01) than High AFC heifers that did not display estrus. In summary, AFC and pubertal
status did not affect the fertility of Nelore heifers. In contrast, the P/AI of heifers that did not display estrus was lower than heifers observed in estrus only in the High AFC group.
Broekmans FJ, de Ziegler D, Howles CM, Gougeon A, Trew G, Olivennes F. The antral follicle count: practical recom-mendations for better standardization. Fertil Steril. 2010;94(3):1044-51. http://dx.doi.org/10.1016/j.fertnstert.2009.04.040. PMid:19589513.
Burns DS, Jimenez-Krassel F, Ireland JLH, Knight PG, Ireland JJ. Numbers of antral follicles during follicular waves in cattle: evidence for high variation among animals, very high repeatability in individuals, and an inverse association with serum follicle-stimulating hormone concentrations. Biol Reprod. 2005;73(1):54-62. http://dx.doi.org/10.1095/biolreprod.104.036277. PMid:15744026.
Cunha F, Cushman RA, Santa Cruz R, de Nava G, Viñoles C. Antral follicular count has limited impact in the selection of more fertile beef heifers. Livest Sci. 2020;241:104230. http://dx.doi.org/10.1016/j.livsci.2020.104230.
Evans ACO, Mossa F, Walsh SW, Scheetz D, Jimenez-Krassel F, Ireland JLH, Smith GW, Ireland JJ. Effects of ma-ternal environment during gestation on ovarian folliculogenesis and consequences for fertility in bovine offspring. Reprod Domest Anim. 2012;47(Suppl 4):31-7. http://dx.doi.org/10.1111/j.1439-0531.2012.02052.x. PMid:22827347.
Ireland JJ, Ward F, Jimenez-Krassel F, Ireland JLH, Smith GW, Lonergan P, Evans ACO. Follicle numbers are highly repeatable within individual animals but are inversely correlated with FSH concentrations and the proportion of good-quality embryos after ovarian stimulation in cattle. Hum Reprod. 2007;22(6):1687-95. http://dx.doi.org/10.1093/humrep/dem071. PMid:17468258.
Ireland JL, Scheetz D, Jimenez-Krassel F, Themmen AP, Ward F, Lonergan P, Smith GW, Perez GI, Evans AC, Ireland JJ. Antral follicle count reliably predicts number of morphologically healthy oocytes and follicles in ovaries of young adult cattle. Biol Reprod. 2008;79(6):1219-25. http://dx.doi.org/10.1095/biolreprod.108.071670. PMid:18768912.
Lima MA, Morotti F, Bayeux BM, Rezende RG, Botigelli RC, De Bem THC, Fontes PK, Nogueira MFG, Meirelles FV, Baruselli PS, Silveira JC, Perecin F, Seneda MM. Ovarian follicular dynamics, progesterone concentrations, pregnancy rates and transcriptional patterns in Bos indicus females with a high or low antral follicle count. Sci Rep. 2020;10(1):19557. http://dx.doi.org/10.1038/s41598-020-76601-5. PMid:33177637.
Melo Filho GA, Queiroz HP. Gado de corte: o produtor pergunta, a Embrapa responde. 2. ed. Brasília, DF: Embrapa Informação Tecnológica; 2011. 261 p.
Moraes FLZ, Morotti F, Costa CB, Lunardelli PA, Seneda MM. Relationships between antral follicle count, body condition, and pregnancy rates after timed-AI in Bos indicus cattle. Theriogenology. 2019;136(15):10-4. http://dx.doi.org/10.1016/j.theriogenology.2019.06.024. PMid:31234052.
Morotti F, Barreiros TRR, Machado FZ, Gonzalez SM, Marinho LSR, Seneda MM. Is the number of antral follicles an interesting selection criterium for fertility in cattle? Anim Reprod. 2015;12(3):479-86.
Morotti F, Moretti R, Santos GMG, Silva-Santos KC, Cerqueira PHR, Seneda MM. Ovarian follicular dynamics and conception rate in Bos indicus cows with different antral follicle counts subjected to timed artificial insemination. Anim Reprod Sci. 2018;188:170-7. http://dx.doi.org/10.1016/j.anireprosci.2017.12.001. PMid:29224967.
Mossa F, Walsh SW, Butler ST, Berry DP, Carter F, Lonergan P, Smith GW, Ireland JJ, Evans AC. Low numbers of ovarian follicles≥ 3 mm in diameter are associated with low fertility in dairy cows. J Dairy Sci. 2012;95(5):2355-61. http://dx.doi.org/10.3168/jds.2011-4325. PMid:22541464.
Nogueira GP. Puberty in South American Bos indicus (Zebu) cattle. Anim Reprod Sci. 2004;82–83:361-72. http://dx.doi.org/10.1016/j.anireprosci.2004.04.007. PMid:15271466.
Oliveira Junior JS, Moreira G, Rachele V, Nunes R, Andrade ER, Seneda MM, Pfeifer LFM. Anticipation of estrus and ovulation in Nelore heifers with low antral follicle count. Res Soc Dev. 2022;11(6):e1211628576. http://dx.doi.org/10.33448/rsd-v11i6.28576.
Seneda MM, Morotti F, Zangirolamo AF, Silva NC, Sanches TK, Blaschi W, Barreiros TRR. Antral follicle population in prepubertal and pubertal heifers. Reprod Fertil Dev. 2018;31(1):10- 6. http://dx.doi.org/10.1071/RD18344. PMid:32188538.
Silva-Santos KC, Santos GM, Koetz Júnior C, Morotti F, Siloto LS, Marcantonio TN, Urbano MR, Oliveira RL, Lima DC, Seneda MM. Antral follicle populations and embryo production - in vitro and in vivo - of Bos indicus-taurus donors from weaning to yearling ages. Reprod Domest Anim. 2014;49(2):228-32. http://dx.doi.org/10.1111/rda.12255. PMid:24456094.
Souza AL, Kozicki LE, Oliveira DAM, Weiss RR, Bertol MAF, Abreu ACM, Talini R. Reproductive performance of prepubertal and pubertal heifers submitted to timed artificial insemination protocols. J Dairy Vet Anim Res. 2017;5:208-10.
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