scholarly journals Folliculogenesis, Fertility and Biotechnology in Dairy Cattle

2021 ◽  
Author(s):  
Marcelo M. Seneda ◽  
Sofia B. Delchiaro ◽  
Amanda F. Zangirolamo ◽  
Amauri A. Alfieri ◽  
Fabio Morotti
Keyword(s):  
Reproductive Performance ◽  
Growth Phase ◽  
Final Stage ◽  
Ovarian Follicle ◽  
Antral Follicle ◽  
Antral Follicle Count ◽  
Productive Efficiency ◽  
Dairy Herds ◽  
Fetal Life ◽  
Antral Follicles

The ovarian follicle population is formed by thousands of follicles, preantral and antral, where oocytes are included. During fetal life, the first follicles produced are preantral, and, as they undergo the development process, they reach the final stage of antral follicles, where a cavity/or antrum is developed. All this growth phase is called folliculogenesis, and this chapter will abord the most important aspects of this process. Moreover, not all follicles reach the preovulatory phase and can be fertilized, so we will discuss how reproductive biotechniques can positively influence the fertility of bovine females. We will also discuss the possibility of antral follicle count to influence reproductive performance and the correlation to biotechniques. Finally, we present alternatives on how to improve fertility and productive efficiency in dairy herds.

138 Relationships Between Antral Follicle Count, Ovarian Volume, Pre-Antral Follicle Number, and Oocyte Quality

2018 ◽  
Vol 30 (1) ◽  
pp. 209
Author(s):  
G. L. Vasconcelos ◽  
R. Maculan ◽  
N. Alves ◽  
A. L. A. P. L. Ribeiro ◽  
A. W. B. Silva ◽  
...  
Keyword(s):  
Ovarian Follicle ◽  
Primordial Follicle ◽  
Antral Follicle ◽  
Oocyte Quality ◽  
Antral Follicle Count ◽  
Primary Follicle ◽  
Ovarian Volume ◽  
Primordial Follicles ◽  
Antral Follicles ◽  
Grade 3

The objective was to evaluate the possible relationships between AFC, ovarian volume, ovarian follicle reserve and oocyte quality in abattoir-derived ovaries (experiment 1) and in cows (experiment 2) submitted to OPU. Antral follicle counts of ≥25, 16 to 24, and ≤ 16 were used to define AFC classes as high (HAFC), intermediate (IAFC), and low (LAFC) in both experiments. In experiment 1, after antral follicles were aspirated, abattoir ovaries (n = 10 per AFC class) were processed by conventional histology and pre-antral follicles were counted within primordial, primary, secondary, and tertiary classes and classified as either healthy or degenerate under regular microscopy (Cushman et al. 1999). In experiment 2, HAFC (n = 42), IAFC (n = 34), and LAFC (n = 29) cows were submitted to OPU and oocytes classified as grades 1, 2, and 3 or degenerate (IETS, 2010). Antral follicles (≥3 mm in diameter) were counted by ultrasonography. Data were analysed by GENMOD and GLM procedures of SAS (SAS Institute Inc., Cary, NC, USA) after transformations, when required. In experiment 1, mean normal primordial follicle number was higher (P < 0.001) in HAFC (137.0 ± 1.6)a compared with IAFC (52.6 ± 1.9)b and LAFC (20.2 ± 5.3)c ovaries. However, the mean number of degenerate primordial follicles was lower (P < 0.001) in low count ovaries (2.4 ± 0.6) compared with HAFC (19.0 ± 4.7) and IAFC (16.4 ± 1.5, P < 0.001). Normal primary follicle number was higher in the HAFC compared with IAFC and LAFC ovarian classes (86.2 ± 7.0a v. 34.6 ± 5.1b and 14.4 ± 3.3c, respectively; P < 0.01). Degenerate primary follicles were higher in the HAFC compared with LAFC ovarian class (16.8 ± 6.5 v. 5.2 ± 2.64; P < 0.05). Normal secondary follicle number was also higher in the HAFC compared to LAFC ovarian classes (25.2 ± 7.67 v. 2.4 ± 0.8; P < 0.05). The number of degenerate secondary follicles differed (P < 0.01) only between the IAFC and the LAFC ovarian classes (0.6 ± 0.4 and 7.2 ± 2.4, respectively), which were similar (P > 0.5) to the HAFC class (3.8 ± 1.0). In experiment 2, grade 1, 2, and 3 oocytes, viable oocytes, and ovarian volume (mm3) were higher (P < 0.001) in HAFC compared with IAFC and LAFC cows (grade 1: 7.9 ± 0.6a, 4.9 ± 0.7b and 3.3 ± 0.7c; grade 2: 4.0 ± 0.4a, 2.8 ± 0.4b and 1.2c; grade 3: 2.1 ± 0.4a, 2.5 ± 0.4a and 1.3 ± 0.5b, respectively; viable oocytes: 16.3 ± 1.1a, 13.1 ± 1.2b, and 8.1 ± 1.3c, respectively; (volumes: 12.6 ± 0.7a, 10.1 ± 0.8b, and 8.1 ± 0.9c, respectively). In conclusion, high AFC is linked to a higher follicular reserve, oocyte quality, and ovarian volume. It is safe to apply AFC in the selection of bovine females without compromising oocyte or pre-antral follicular population qualities.

Relationship between anti-Müllerian hormone and antral follicle count across the menstrual cycle using the Beckman Coulter Access assay in comparison with Gen II manual assay

2017 ◽  
Vol 55 (7) ◽  
Author(s):  
Julia Schiffner ◽  
Judith Roos ◽  
David Broomhead ◽  
Joseph van Helden ◽  
Erhard Godehardt ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Transvaginal Ultrasound ◽  
Ovarian Follicle ◽  
Antral Follicle ◽  
Antral Follicle Count ◽  
Cycle Number ◽  
Antral Follicles ◽  
Menstruating Women ◽  
Conversion Equation ◽  
Antral Follicle Counts

AbstractBackground:The study aim was to validate Beckman Coulter’s fully automated Access Immunoassay System (BC Access assay) for anti-Müllerian hormone (AMH) and compare it with Beckman Coulter’s Modified Manual Generation II assay (BC Mod Gen II), with regard to cycle AMH fluctuations and antral follicle counts.Methods:During one complete menstrual cycle, transvaginal ultrasound was performed on regularly menstruating women (n=39; 18–40years) every 2 days until the dominant ovarian follicle reached 16mm, then daily until observed ovulation; blood samples were collected throughout the cycle. Number and size of antral follicles was determined and AMH levels measured using both assays.Results:AMH levels measured by the BC Access assay vary over ovulatory menstrual cycles, with a statistically significant pre-ovulatory decrease from –5 to +2 days around objective ovulation. Mean luteal AMH levels were significantly lower (–7.99%) than mean follicular levels but increased again towards the end of the luteal phase. Antral follicle count can be estimated from AMH (ng/mL, BC Access assay) concentrations on any follicular phase day. BC Access assay-obtained AMH values are considerably lower compared with the BC Mod Gen II assay (–19% on average); conversion equation: AMH BC Access (ng/mL)=0.85 [AMH BC Mod Gen II (ng/mL)]Conclusions:AMH levels vary throughout the cycle, independently of assay utilised. A formula can be used to convert BC Access assay-obtained AMH levels to BC Mod Gen II values. The number of antral follicles can be consistently estimated from pre-ovulatory AMH levels using either assay.

Should fertile women quit drinking alcohol to produce better quality oocytes?

Zygote ◽  
2020 ◽  
pp. 1-3
Author(s):  
Burcu Ozbakir ◽  
Pinar Tulay
Keyword(s):  
Alcohol Consumption ◽  
Young Women ◽  
Antral Follicle ◽  
Antral Follicle Count ◽  
Control Group ◽  
Social Drinkers ◽  
Antral Follicles ◽  
Healthy Women ◽  
Significant Difference

Summary Alcohol consumption has long been shown to affect both fetal health and pregnancy. In this study, antral follicle count, maturation level of oocytes including morphological assessment and number of metaphase I (MI), metaphase II (MII) and germinal vesicle (GV) stage oocytes obtained from young women (age < 30 years old) with or without alcohol consumption were investigated. In total, 20 healthy women who were social drinkers and 36 healthy women who do not consume alcohol were involved in this study. Women in both study and control groups were undergoing controlled ovarian stimulation. The antral follicle count and the number and quality of the oocytes retrieved were evaluated and recorded. In total, 635 antral follicles, 1098 follicles and 1014 oocytes with 820 MII, 72 MI and 78 GV stage oocytes were collected from the social drinkers. In the control group, 628 antral follicles, 1136 follicles and 1085 oocytes with 838 MII, 93 MI and 102 GV stage oocytes were evaluated. The results of this study showed that the antral follicle count was very similar in both groups. The number of oocytes and MII stage oocytes was slightly higher in the control group, although it was not a significant difference. This study showed that although the consumption of alcohol may have adverse effects post-implantation, it may not have a solid effect during oogenesis in young women. The results of this study are especially important in clinical settings as some women who are social drinkers undergo in vitro fertilization treatments.

scholarly journals AMH: Could It Be Used as A Biomarker for Fertility and Superovulation in Domestic Animals?

Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1009 ◽  
Author(s):  
Saqib Umer ◽  
Shan Jiang Zhao ◽  
Abdul Sammad ◽  
Bahlibi Weldegebriall Sahlu ◽  
YunWei Pang ◽  
...  
Keyword(s):  
Single Dose ◽  
Animal Species ◽  
Assisted Reproductive Technologies ◽  
Antral Follicle ◽  
Reproductive Technologies ◽  
Domestic Animals ◽  
Antral Follicle Count ◽  
Fetal Life ◽  
Factors Affecting ◽  
Potential Predictor

Anti-Müllerian hormone (AMH) is a reliable and easily detectable reproductive marker for the fertility competence of many farm animal species. AMH is also a good predictor of superovulation in cattle, sheep, and mares. In this review, we have summarized the recent findings related to AMH and its predictive reliability related to fertility and superovulation in domestic animals, especially in cattle. We focused on: (1) the dynamics of AMH level from infancy to prepubescence as well as during puberty and adulthood; (2) AMH as a predictor of fertility; (3) the association between antral follicle count (AFC) and plasma AMH level; (4) AMH as a predictor of superovulation; and (5) factors affecting AMH levels in domestic animals, especially cattle. Many factors affect the circulatory levels of AMH when considering the plasma, like nutrition, activity of granulosa cells, disease state and endocrine disruptions during fetal life. Briefly, we concluded that AMH concentrations are static within individuals, and collection of a single dose of blood has become more popular in the field of assisted reproductive technologies (ART). It may act as a potential predictor of fertility, superovulation, and ovarian disorders in domestic animals. However, due to the limited research in domestic animals, this potential of AMH remains underutilized.

Antral follicle population in prepubertal and pubertal heifers

2019 ◽  
Vol 31 (1) ◽  
pp. 10 ◽  
Author(s):  
M. M. Seneda ◽  
F. Morotti ◽  
A. F. Zangirolamo ◽  
N. C. da Silva ◽  
T. K. Sanches ◽  
...  
Keyword(s):  
Antral Follicle ◽  
Antral Follicle Count ◽  
Young Female ◽  
Reproductive Efficiency ◽  
Young Females ◽  
Antral Follicles ◽  
Female Cattle ◽  
Selection Of

The antral follicle count (AFC) is an important tool in the selection of bovine females destined for biotechnology. However, little is known about AFC in prepubertal and pubertal heifers. Some challenges inherent to the physiology of young females must be considered to achieve efficient rates with different procedures, such as ovum pick-up and IVF. This paper covers some important topics about ovarian physiology related to the population of antral follicles and reproductive efficiency in young female cattle.

scholarly journals Evaluation of Anti-Mullerian Hormone Predictive Value and Antral Follicle Count in the Success Rate of Ovarian Drilling in Polycystic Ovary Syndrome

2020 ◽  
Vol 21 (6) ◽  
Author(s):  
Leili Hafizi ◽  
Akram Behrouznia ◽  
Maliheh Amirian ◽  
Mina Baradaran ◽  
Seyedeh Azam Pourhoseini
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Polycystic Ovary ◽  
Clomiphene Citrate ◽  
Antral Follicle ◽  
Serum Levels ◽  
Antral Follicle Count ◽  
Ovary Syndrome ◽  
Antral Follicles ◽  
Laparoscopic Ovarian Drilling ◽  
Ovarian Drilling

Background: Laparoscopic ovarian drilling (LOD) is recommended for the treatment of women with polycystic ovary syndrome (PCOS) resistant to clomiphene citrate. Objectives: This study aimed to evaluate the effect of ovarian drilling on the serum levels of anti-mullerian hormone (AMH), androgens, and the number of antral follicles. Methods: This was a pre- and post-clinical trial performed on 30 infertile women with PCOS resistant to clomiphene citrate. Patients underwent standard laparoscopic ovarian drilling. Serum levels of AMH and androgens and antral follicle count (AFC) were surveyed before LOD and three and six months after LOD. The ovarian ovulation rate in each month was also monitored for six months. Then, the association between changes in these parameters, especially the level of AMH, and postoperative ovulation was investigated. A P < 0.05 was considered statistically significant. Results: The number of antral follicles three (3.00 ± 8.00) and six months (7.73 ± 4.14) after ovarian drilling showed a significant decrease compared to preoperative values (12.40 ± 4.02) (repeated-measures ANOVA, P < 0.001). The mean AMH (6.78 ± 1.08 versus 12.25 ± 1.35; P = 0.005) and the antral follicle count (7.71 ± 0.54 versus 12.29 ± 0.67 and P < 0.001) were lower in ovulation than in non-ovulation patients. The significantly more AMH reductions were seen in pregnant women (3.63 ± 5.61) than in non-pregnant women (3.63 ± 1.24) (P = 0.01). Conclusions: It may be possible to use the changes in AMH and AFC to predict the success rate of LOD.

130 Increased antral follicle population at 60 days of gestation in Holstein cows with low antral follicle count

2020 ◽  
Vol 32 (2) ◽  
pp. 192
Author(s):  
R. G. Droher ◽  
F. Morotti ◽  
A. Guidugli Lindquist ◽  
A. Fonseca Zangirolamo ◽  
M. Marcondes Seneda
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Antral Follicle ◽  
Generalized Linear Mixed Model ◽  
Antral Follicle Count ◽  
Antral Follicles ◽  
Intermediate Group ◽  
The Mean ◽  
Main Factors ◽  
High Repeatability

The antral follicle count (AFC) has been pointed out as one of the main factors that influence the efficiency of reproductive biotechniques. Thus, AFC is considered a fertility marker, which has high repeatability in the same animal. The objective of this study was to evaluate AFC in cows at AI (nonpregnant) and at two moments of gestation (30 and 60 days). For this, 35 pregnant cows, aged 23 to 99 months, confined in a freestall system, kept in the same environmental conditions (24°46'28”S, 49°56'42”W) and under the same feeding conditions, were selected for this study. The same technician performed the AI of the females, after detection of natural or induced oestrus, with 25mg of Dinoprost (Lutalyse) intramuscularly (IM). We established AFC (antral follicles ≥3mm diameter) using a convex intravaginal transducer at the time of AI and at 30 and 60 days of pregnancy. Females were distributed in groups of low (≤18 follicles, n=11), intermediate (≥24 and ≤28 follicles, n=11), or high AFC (≥30 follicles, n=13). Data were analysed using a generalized linear mixed model (Minitab version 18.1), with significance declared at P ≤ 0.05. In the low AFC group, there was an increase in the mean number of antral follicles in relation to gestation, presenting 14.82±1.36 at the time of AI and 23.45±2.31 and 35.18±3.17 at 30 and 60 days of pregnancy, respectively (P&lt;0.0001). Similarly, the intermediate group presented an increase in mean AFC, from 24.64±0.76 at the time of AI and 29.27±3.32 at 30 days to 43.36±5.91 at 60 days of gestation (P=0.001). There was no difference in the high AFC group at different moments, as these presented 41.92±3.50 at the time of AI, 38.31±3.96 at 30 days, and 50.92±5.49 at 60 days of pregnancy. Although mean AFCs differed (P&lt;0.0001) between the low, intermediate, and high AFC groups at time of AI and at 30 days of gestation, there were no differences in AFC between the three groups at 60 days of gestation (P=0.329). In conclusion, low AFC females presented an increase in the number of antral follicles at gestation moments 30 and 60 days from AI. This finding reinforces the strategy of using this category more efficiently for ovum pickup at the beginning of gestation.

scholarly journals Relationship of Conception Rate with Antral Follicle Count, Nutritional Parameters and Animal Behavior in Brahman Cows Submitted to TAI

2021 ◽  
Vol 24 (5-esp.) ◽  
pp. 455-461
Author(s):  
Maria Eduarda Scheel Bomtempo ◽  
Marcela Bortoletto Cerezetti ◽  
Fábio Lucas Zito de Moraes ◽  
Renan Carlos Vicentin de Campos Silva ◽  
Elis Lorenzetti ◽  
...  
Keyword(s):  
Body Condition ◽  
Animal Behavior ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Management Practices ◽  
Live Weight ◽  
Antral Follicle ◽  
Antral Follicle Count ◽  
Conception Rate ◽  
Relationship Of

Melhorar o desempenho reprodutivo é importante para aumentar a lucratividade das propriedades. Assim, nós avaliamos a contagem de folículos antrais (CFA), o escore de condição corporal (ECC), o peso vivo e o comportamento animal sobre à taxa de concepção de vacas Brahman submetidas à inseminação artificial em tempo-fixo (IATF). Vacas (n=122) receberam um protocolo convencional de IATF de três manejos (D0, 8 e 10) a base de estrógeno e progesterona, além do monitoramento da expressão de estro antes da inseminação. O ECC e o comportamento animal foram avaliados em todos os dias do protocolo, o peso foi mensurado no D0 e no diagnóstico de gestação (D40) e a CFA no D0. Para análise, estabeleceu-se os grupos de CFA (baixa, intermediária e alta), do comportamento (calma, inquieta e agitada), do peso (ganhando, mantendo e perdendo) e do ECC (ganhando, mantendo e perdendo). A taxa de concepção geral foi de 50%, e não esteve associada (p>0,05) a classificação da CFA (baixa/52,6%, intermediária/50,9% e alta/45,4%), do peso (ganhando/43,0%, mantendo/54,7% e perdendo/47,1%), do ECC (ganhando/44,0%, mantendo/54,3% e perdendo/37,5%) e do comportamento (calma/43,0%, inquieta/54,7% e agitada/47,1%). No entanto, a baixa CFA apresentou maior (p=0,05) proporção de animais com alta intensidade de estro (94,7%) e foi observado maior escore de reatividade (p=0,001) no primeiro dia de manejo da IATF em relação aos outros dias. Vacas com baixa CFA resultaram em maior proporção de expressão de estro e o primeiro dia de manejo da IATF determinou uma maior reatividade animal em relação aos outros dias do protocolo.   Palavras-chave: Condição Corporal. Inseminação Artificial. Performance Reprodutiva. Peso Vivo.    Abstract Improving reproductive performance is important to increase farm profitability. The  relationship of antral follicle count (AFC), body condition score (BCS), weight, and animal behavior on the conception rate in cows submitted to timed artificial insemination (TAI). Cows (n=122) received a conventional TAI protocol of three managements (D0, 8, and 10) based on estrogen and progesterone, in addition to monitoring estrus expression before insemination. The BCS and behavior score were assessed every day of the TAI protocol. Weight was measured at D0 and in the pregnancy diagnosis (D40), and AFC was determined at D0. For analysis, the groups were established according to AFC (low, intermediate, and high), behavior animal (calm, restless, and agitated), weight variation (gaining, maintaining, and losing), and BCS variation (gaining, maintaining, and losing). The overall conception rate was 50%, and it was not associated with (P>0.05) the AFC classification (low/52.6%, intermediate/50.9%, and high/45.4%), weight variations (gaining/43.0%, maintaining/54.7%, and losing/47.1%), BCS variations (gaining/44.0%, maintaining/54.3%, and losing/37.5%) and animal behavior (calm/43.0%, restless/54.7%, and agitated/47.1%). However, the low AFC showed a higher (P=0.05) proportion of animals with high intensity of estrus expression (94.7%). In addition, a higher score for animal reactivity (P=0.001) was noted on the first day of the management of TAI protocol than to the other days of the hormonal protocol. The low AFC resulted in a higher proportion of cows with high estrus expression and the management practices for TAI determined a greater animals reactivity at the beginning of the breeding program.   Keywords: Body Condition. Artificial Insemination. Reproductive Performance. Live Weight.

250 ANTI-MÜLLERIAN HORMONE: IMPLICATIONS FOR FOLLICULAR RESERVE, FOLLICULAR FUNCTION, AND FERTILITY IN THE MARE

2016 ◽  
Vol 28 (2) ◽  
pp. 257 ◽  
Author(s):  
B. A. Ball ◽  
A. Claes ◽  
T. E. Curry ◽  
M. H. T. Troedsson ◽  
E. L. Squires ◽  
...  
Keyword(s):  
Follicular Fluid ◽  
Age Groups ◽  
Antral Follicle ◽  
Antral Follicle Count ◽  
Middle Aged ◽  
University Of Kentucky ◽  
Antral Follicles ◽  
Follicular Reserve ◽  
The University ◽  
The Relationship

Anti-Müllerian hormone (AMH) is a granulosa-cell derived glycoprotein which plays an important regulatory role during folliculogenesis. Antral follicle count (AFC) and AMH have been used in several species to assess ovarian reserve, but relatively little is known about these parameters in mares. The objectives of this study were to determine (i) plasma AMH concentrations and AFC in mares of different ages, as well as their repeatability within and across oestrous cycles; (ii) the relationship between plasma AMH concentrations and AFC with regard to age and follicle size; and (iii) endocrine and molecular changes in growing and preovulatory follicles in relation to AFC and peripheral AMH concentrations. In Exp. 1, young (3–8 years), middle-aged (9–18 years), and old (>18 years) mares were examined by transrectal ultrasonography over 2 to 3 oestrous cycles and changes in the number and size of all detectable antral follicles were recorded. Concentrations of AMH were determined by ELISA. In Exp. 2, molecular and endocrine differences in growing and dominant equine follicles were examined in relationship to variation in AFC, peripheral AMH concentrations and mare age. Follicular fluid oestradiol and AMH concentrations were determined by immunoassay, and expression of AMH, AMHR2, ESR1, ESR2, FSHR, IGF1, INHA, INHBA, and CYP19A1 was determined by quantitative RT-PCR. Antral follicle counts were significantly lower in old mares than in young and middle-aged mares, and AMH concentrations were significantly lower in old mares than in middle-aged mares. A positive relationship was detected between AFC and AMH, and this relationship varied by mare age with a strong correlation in older mares (ρ = 0.86; P < 0.0001), a moderate correlation in middle-aged mares (ρ = 0.60; P = 0.01), and no correlation (ρ = 0.40, P < 0.4) in young mares. Circulating AMH concentrations were significantly related to the number of antral follicles between 6 and 20 mm in diameter, and the repeatability of AFC and AMH concentrations was high within and between oestrous cycles. Within growing follicles, expression of AMH, AMHR2, ESR2, and INHA in granulosa cells was significantly associated with AFC and plasma AMH concentrations, whereas expression of ESR1 and FSHR were significantly correlated with AMH concentrations alone. In follicular fluid, AMH concentrations declined and oestradiol concentrations increased in dominant compared to growing follicles. Our findings indicate that the relationship between AMH and AFC varies across age groups, and that variations in AFC and plasma AMH concentrations are associated with molecular differences in the equine follicle, which, in turn, may have an impact on follicular function. Funded by the Albert G. Clay Endowment at the University of Kentucky.

scholarly journals Influence of age and ovarian antral follicle count on the reproductive characteristics of embryo donor mares

2020 ◽  
Vol 186 (17) ◽  
pp. 564-564
Author(s):  
Gustavo Romero Goncalves ◽  
Fábio Morotti ◽  
Antonio Hugo Bezerra Colombo ◽  
Denis Vinicius Bonato ◽  
Camila Bizarro-Silva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Antral Follicle ◽  
Antral Follicle Count ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Antral Follicles ◽  
Reproductive Characteristics ◽  
The Third ◽  
Follicle Diameter ◽  
Quarter Horse

BackgroundAge and antral follicle count (AFC) are related to fertility in cattle, but this information remains limited in mares.MethodsTo verify the influence of age and AFC on the reproductive characteristics of mares, 15 Quarter Horse donors, with 5–15 antral follicles, ranging from three to 17 years old, healthy and in good nutritional status, were divided into groups with low AFC (≤9 follicles) or high AFC (≥10 follicles) and mares considered young (≤9 years) or old (≥10 years). Mares were submitted to ultrasonography to determine the dominant follicle diameter, follicular growth rate, degree of uterine oedema and embryonic recovery for a minimum of three oestrous cycles.ResultsAFC was higher (P=0.001) in young mares compared with old mares. An interaction (P=0.001) between AFC and age was observed with regard to follicular growth rate, being that mares with low AFC and are old showed the lowest follicular growth compared with those of low AFC and young, high AFC and old, and high AFC and young. Younger mares and those with high AFC exhibited higher degree of uterine oedema (P<0.05) on the third day of oestrus compared with older mares and with low AFC (3 and 2, respectively). However, in both groups, the degree of oedema reduced by the time of ovulation.ConclusionFollicular growth rate, degree of uterine oedema and the number of antral follicles are higher in young mares with high AFC. However, the rate of embryonic recovery is not influenced by donors’ age or AFC.

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