Animal Reproduction (AR)
Animal Reproduction (AR)

Evaluation of three classification methods of antral follicle count and fertility to the timed artificial insemination in cattle

Fabio Morotti; Suellen Miguez-Gonzalez; Marcela Bortoletto Cerezetti; Marcelo Marcondes Seneda

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Abstract: The controversial data about antral follicle count (AFC) may be partially explained by the different criteria used to determine what is high, intermediate and low AFC. This study evaluated different classification methods for AFC groups, relating them to the conception rate, dominant follicle size and body condition score (BCS) in cows submitted to timed artificial insemination (TAI). Nelore cows (Bos indicus; n = 935), received a reproductive program consisting of TAI and natural breeding. Conception rate, BCS and dominant follicle size during TAI were evaluated by three AFC methodologies: i) mean and standard deviation: low (≤ 15 follicles); intermediate (≥ 16 to ≤ 44 follicles) or high (≥ 45 follicles); ii) quartiles: low (≤ 15 follicles); intermediate (≥ 16 to ≤ 39 follicles), or high (≥ 40 follicles); and iii) AFC score: I (low; ≤ 15 follicles); II (intermediate; ≥ 16 to ≤ 30 follicles); III (high; ≥ 31 to ≤ 44 follicles) or IV (very high; ≥ 45 follicles). Data were analyzed by a GLIMMIX and Tukey test or binary logistic regression model (P ≤ 0.05). The conception rate to TAI was influenced (P < 0.05) by AFC in the three methods classification, being the highest conception rate observed in the low AFC group regardless of method utilized: Mean (low 61.73%a, intermediate 54.02%ab and high 49.48%b), Quartiles (low 61.73%a, intermediate 53.59%ab and 51.46%b) and Score (I 61.73%a, II 54.80%ab, III 53.23%ab and IV 49.48%b). There were variations (P < 0.05) in the conception rate within the 2.50 to 2.75 BCS range for all AFC classification methods, with the low AFC females presenting the best results, regardless of the method used. Also, females with low AFC showed larger (P < 0.05) diameters of dominant follicles at the TAI regardless of method. The different methodologies used (Mean, Quartile and Score) to AFC classification showed a consistency between the main findings, and we believe that this standardization will facilitate the interpretation of data involving AFC.


antral follicle, cattle, insemination, fertility


Andersen K, LeFever D, Brinks J, Odde K. The use of reproductive tract scoring in beef heifers. Agri Practice. 1991;12:19-26.

Ayres H, Ferreira RM, Torres-Júnior JRS, Demétrio CGB, Lima CG, Baruselli PS. Validation of body condition score as a predictor of subcutaneous fat in Nelore (Bos indicus) cows. Livest Sci. 2009;123(2):175-9.

Baruselli PS, Ferreira RM, Colli MHA, Elliff FM, Sá MF Fo, Vieira L, et al. Timed artificial insemination: current challenges and recent advances in reproductive efficiency in beef and dairy herds in Brazil. Anim Reprod. 2018;14(3):558-71.

Bonato DV, Ferreira EB, Gomes DN, Bonato FGC, Droher RG, Morotti F, Seneda MM. Follicular dynamics, luteal characteristics, and progesterone concentrations in synchronized lactating Holstein cows with high and low antral follicle counts. Theriogenology. 2022;179:223-9. PMid:34896744.

Burns DS, Jimenez-Krassel F, Ireland JL, 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. PMid:15744026.

Colégio Brasileiro de Reprodução Animal – CBRA. Manual para exame andrológico e avaliação de sêmen animal. Belo Horizonte: CBRA; 2013.

Cushman RA, Allan MF, Kuehn LA, Snelling WM, Cupp AS, Freetly HC. Evaluation of antral follicle count and ovarian morphology in crossbred beef cows: investigation of influence of stage of the estrous cycle, age, and birth weight. J Anim Sci. 2009;87(6):1971-80. PMid:19286826.

Droher RG, Morotti F, Sanches TK, Seneda MM. Efeitos da contagem de folículos antrais sobre a taxa de concepção de vacas Holandesas. Rev Acad Ciênc Anim. 2017;15(2):27-8.

Evans AC, Mossa F, Walsh SW, Scheetz D, Jimenez-Krassel F, Ireland JL, Smith GW, Ireland JJ. Effects of maternal environment during gestation on ovarian folliculogenesis and consequences for fertility in bovine offspring. Reprod Domest Anim. 2012;47(Suppl. 4):31-7. PMid:22827347.

Figueiredo RA, Barros CM, Pinheiro OL, Soler JM. Ovarian follicular dynamics in Nelore breed (Bos indicus) cattle. Theriogenology. 1997;47(8):1489-505. PMid:16728093.

Garcia SM, Morotti F, Cavalieri FLB, Lunardelli PA, Santos AO, Membrive CMB, Castilho C, Puelker RZ, Silva JOF, Zangirolamo AF, Seneda MM. Synchronization of stage of follicle development before OPU improves embryo production in cows with large antral follicle counts. Anim Reprod Sci. 2020;221:106601. PMid:32961391.

Ireland J, Zielak-Steciwko A, Jimenez-Krassel F, Folger J, Bettegowda A, Scheetz D, Walsh S, Mossa F, Knight PG, Smith GW, Lonergan P, Evans AC. Variation in the ovarian reserve is linked to alterations in intrafollicular estradiol production and ovarian biomarkers of follicular differentiation and oocyte quality in cattle. Biol Reprod. 2009;80(5):954-64. PMid:19164170.

Ireland JJ, Smith GW, Scheetz D, Jimenez-Krassel F, Folger JK, Ireland JL, Mossa F, Lonergan P, Evans AC. Does size matter in females? An overview of the impact of the high variation in the ovarian reserve on ovarian function and fertility, utility of anti-Mullerian hormone as a diagnostic marker for fertility and causes of variation in the ovarian reserve in cattle. Reprod Fertil Dev. 2011;23(1):1-14. PMid:21366975.

Ireland JJ, Ward F, Jimenez-Krassel F, Ireland JL, Smith GW, Lonergan P, Evans AC. 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. 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. PMid:18768912.

Jimenez-Krassel F, Folger JK, Ireland JL, Smith GW, Hou X, Davis JS, Lonergan P, Evans AC, Ireland JJ. Evidence that high variation in ovarian reserves of healthy young adults has a negative impact on the corpus luteum and endometrium during estrous cycles in cattle. Biol Reprod. 2009;80(6):1272-81. PMid:19211804.

Jimenez-Krassel F, Scheetz DM, Neuder LM, Ireland JL, Pursley JR, Smith GW, Tempelman RJ, Ferris T, Roudebush WE, Mossa F, Lonergan P, Evans AC, Ireland JJ. Concentration of anti-Mullerian hormone in dairy heifers is positively associated with productive herd life. J Dairy Sci. 2015;98(5):3036-45. PMid:25726106.

Jimenez-Krassel F, Scheetz DM, Neuder LM, Pursley JR, Ireland JJ. A single ultrasound determination of ≥25 follicles ≥3 mm in diameter in dairy heifers is predictive of a reduced productive herd life. J Dairy Sci. 2017;100(6):5019-27. PMid:28390729.

Lima MA, Morotti F, Bayeux BM, de 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. PMid:33177637.

Lowman B, Scott N, Somerville S. Condition scoring of cattle. Edinburgh: East of Scotland College of Agriculture; 1976. (Bulletin, No. 6).

Machado R, Corrêa R, Barbosa R, Bergamaschi M. Escore da condição corporal e sua aplicação no manejo reprodutivo de ruminantes. São Carlos: Embrapa Pecuária Sudeste; 2008. (Circular Técnica).

Marques MO, Morotti F, Silva CB, Ribeiro M Jr, Silva RC, Baruselli PS, Seneda MM. Influence of category-heifers, primiparous and multiparous lactating cows-in a large-scale resynchronization fixed-time artificial insemination program. J Vet Sci. 2015;16(3):367-71. PMid:25797292.

Martinez MF, Sanderson N, Quirke LD, Lawrence SB, Juengel JL. Association between antral follicle count and reproductive measures in New Zealand lactating dairy cows maintained in a pasture-based production system. Theriogenology. 2016;85(3):466-75. PMid:26489910.

Meneghetti M, Sá OG Fo, Peres RF, Lamb GC, Vasconcelos JL. Fixed-time artificial insemination with estradiol and progesterone for Bos indicus cows I: basis for development of protocols. Theriogenology. 2009;72(2):179-89. PMid:19344942.

Meteer WC, Shike DW, Cardoso FC. Prepartum and postpartum nutritional management to optimize fertility in beef cattle. Acta Sci Vet. 2015;43(1286):2932-43.

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;136:10-4. PMid:31234052.

Morotti F, Barreiros T, Machado F, González S, Marinho L, Seneda M. Is the number of antral follicles an interesting selection criterium for fertility in cattle. Anim Reprod. 2015;12:479-86.

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. PMid:29224967.

Morotti F, Zangirolamo AF, Silva NC, Silva CB, Rosa CO, Seneda MM. Antral follicle count in cattle: advantages, challenges, and controversy. Anim Reprod. 2017;14(3):514-20.

Mossa F, Walsh SW, Butler ST, Berry DP, Carter F, Lonergan P, Smith GW, Ireland JJ, Evans AC. Low numbers of ovarian follicles ≥ 3mm in diameter are associated with low fertility in dairy cows. J Dairy Sci. 2012;95(5):2355-61. PMid:22541464.

Pfeifer LF, Castro NA, Melo VT, Neves PM, Cestaro JP, Schneider A. Timed artificial insemination in blocks: a new alternative to improve fertility in lactating beef cows. Anim Reprod Sci. 2015;163:89-96. PMid:26481047.

Pfeifer LF, Castro NA, Neves PM, Cestaro JP, Siqueira LG. Development and validation of an objective method for the assessment of body condition scores and selection of beef cows for timed artificial insemination. Livest Sci. 2017;197:82-7.

Pfeifer LFM, Leal SCBS, Schneider A, Schmitt E, Corrêa MN. Leal SdCBdS, Schneider A, Schmitt E, Corrêa MN. Effect of the ovulatory follicle diameter and progesterone concentration on the pregnancy rate of fixed-time inseminated lactating beef cows. Rev Bras Zootec. 2012;41(4):1004-8.

Ribeiro ES, Bisinotto RS, Lima FS, Greco LF, Morrison A, Kumar A, Thatcher WW, Santos JE. Plasma anti-Müllerian hormone in adult dairy cows and associations with fertility. J Dairy Sci. 2014;97(11):6888-900. PMid:25173464.

Rosa CO, Bonato DV, Souza AK, Morotti F, Francisco RC, Basso AC, Martins MIM, Seneda MM. Improvement on the efficiency of doses per conception by using a semen extender in timed artificial insemination. Livest Sci. 2019;221:77-81.

Sá MF Fo, Crespilho AM, Santos JE, Perry GA, Baruselli PS. Ovarian follicle diameter at timed insemination and estrous response influence likelihood of ovulation and pregnancy after estrous synchronization with progesterone or progestin-based protocols in suckled Bos indicus cows. Anim Reprod Sci. 2010;120(1-4):23-30. PMid:20395079.

Santos GMG, Silva-Santos KC, Barreiros TRR, Morotti F, Sanches BV, de Moraes FLZ, Blaschi W, Seneda MM. High numbers of antral follicles are positively associated with in vitro embryo production but not the conception rate for FTAI in Nelore cattle. Anim Reprod Sci. 2016;165:17-21. PMid:26711683.

Silva-Santos KC, Santos GM, Koetz C Jr, 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. PMid:24456094.

Silveira E, Bortolloti L, Morotti F, Silva-Santos K, Santos G, Andrade E, Seneda MM. Insemination of four cows per dose of frozen semen with a fixed-time artificial insemination protocol. Anim Reprod. 2018;10(2):124-6.

Soca P, Carriquiry M, Claramunt M, Ruprechter G, Meikle A. Metabolic and endocrine profiles of primiparous beef cows grazing native grassland. 2. Effects of body condition score at calving, type of suckling restriction and flushing on plasmatic and productive parameters. Anim Prod Sci. 2014;54(7):862-8.

Vaz R, Lobato J, Restle J, Conceição V, Ferreira O, Costa J, Eloy LR. Performance of calves born in different periods of the calving season in intensive beef cattle farming. Arq Bras Med Vet Zootec. 2020;72(5):1874-80.

Zangirolamo AF, Morotti F, Silva NC, Sanches TK, Seneda MM. Ovarian antral follicle populations and embryo production in cattle. Anim Reprod. 2018;15(3):310-5. PMid:34178154.

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