“…5 ) are differently expressed in animals with a low compared with a high AFC. Finally, this study reports a relevant description that supports, on a molecular basis, greater TAI fertility in Nelore ( Bos indicus ) cows with a low AFC, corroborating recent publications on the relationship between fertility and AFC in cattle 4 , 7 , 8 . Figure 5 Genes differentially expressed in oocytes and cumulus cells from heifers with a low antral follicle count (L-AFC) or high AFC (H-AFC).…”
Section: Discussionsupporting
confidence: 89%
“…These positive aspects discussed certainly contributed to the greater pregnancy rate in the females with a very low count, which was approximately 12% greater than in the high AFC group. In Bos indicus (Nelore), Morotti et al 8 detected similar results, and Moraes et al 7 not only detected a better effect of a low AFC but also observed an interaction of AFC with the BCS: cows with a high AFC and a high BCS had the worst reproductive performance during the breeding season. In dairy cattle, Jimenez-Krassel et al 4 also showed productive and reproductive advantages for females with a low AFC, and a high count in females was associated with a shorter productive life within the herd and suboptimal fertility.…”
Section: Discussionmentioning
confidence: 73%
“…On the other hand, a high AFC has resulted in great efficiency in embryo production both in vivo and in vitro in indicus and indicus-taurus beef cattle 5 , 6 , 20 . However, studies on reproductive performance in Nelore cattle ( Bos indicus ) that received the TAI programme showed that the pregnancy rate for cows with a low AFC was up to 10% greater than that for cows with a high AFC 7 , 8 . In addition, Morotti et al 8 revealed that certain aspects of ovarian follicular dynamics, such as a large dominant and ovulatory follicle diameter when undergoing TAI programmes, are more favourable for the low AFC group.…”
We evaluated the effect of the antral follicle count (AFC) on ovarian follicular dynamics, pregnancy rates, progesterone concentrations, and transcriptional patterns of genes in Nelore cattle (Bos taurus indicus) after a timed artificial insemination (TAI) programme. Cows were separated based on the AFC, and those with a high AFC showed a larger (P < 0.0001) ovarian diameter and area than those with a very low AFC. Females with a very low AFC exhibited a larger (P < 0.01) diameter of the dominant follicle at TAI (13.6 ± 0.3 vs. 12.2 ± 0.4 mm) and a tendency (P = 0.06) to have different serum progesterone concentrations (2.9 ± 0.3 vs. 2.1 ± 0.3 ng/mL; on day 18, considering day 0 as the beginning of the synchronization protocol) than those with a high AFC. The pregnancy rate was higher (P ≤ 0.05) in animals with a very low (57.9%) and low (53.1%) AFC than in those with a high AFC (45.2%). The expression of genes related to intercellular communication, meiotic control, epigenetic modulation, cell division, follicular growth, cell maintenance, steroidogenesis and cellular stress response was assessed on day 5. In females with a low AFC, 8 and 21 genes in oocytes and cumulus cells, respectively, were upregulated (P < 0.05), while 3 and 6 genes in oocytes and cumulus cells, respectively, were downregulated. The results described here will help elucidate the differences in ovarian physiology and the reproductive success of Bos indicus females with a low or high AFC.
“…5 ) are differently expressed in animals with a low compared with a high AFC. Finally, this study reports a relevant description that supports, on a molecular basis, greater TAI fertility in Nelore ( Bos indicus ) cows with a low AFC, corroborating recent publications on the relationship between fertility and AFC in cattle 4 , 7 , 8 . Figure 5 Genes differentially expressed in oocytes and cumulus cells from heifers with a low antral follicle count (L-AFC) or high AFC (H-AFC).…”
Section: Discussionsupporting
confidence: 89%
“…These positive aspects discussed certainly contributed to the greater pregnancy rate in the females with a very low count, which was approximately 12% greater than in the high AFC group. In Bos indicus (Nelore), Morotti et al 8 detected similar results, and Moraes et al 7 not only detected a better effect of a low AFC but also observed an interaction of AFC with the BCS: cows with a high AFC and a high BCS had the worst reproductive performance during the breeding season. In dairy cattle, Jimenez-Krassel et al 4 also showed productive and reproductive advantages for females with a low AFC, and a high count in females was associated with a shorter productive life within the herd and suboptimal fertility.…”
Section: Discussionmentioning
confidence: 73%
“…On the other hand, a high AFC has resulted in great efficiency in embryo production both in vivo and in vitro in indicus and indicus-taurus beef cattle 5 , 6 , 20 . However, studies on reproductive performance in Nelore cattle ( Bos indicus ) that received the TAI programme showed that the pregnancy rate for cows with a low AFC was up to 10% greater than that for cows with a high AFC 7 , 8 . In addition, Morotti et al 8 revealed that certain aspects of ovarian follicular dynamics, such as a large dominant and ovulatory follicle diameter when undergoing TAI programmes, are more favourable for the low AFC group.…”
We evaluated the effect of the antral follicle count (AFC) on ovarian follicular dynamics, pregnancy rates, progesterone concentrations, and transcriptional patterns of genes in Nelore cattle (Bos taurus indicus) after a timed artificial insemination (TAI) programme. Cows were separated based on the AFC, and those with a high AFC showed a larger (P < 0.0001) ovarian diameter and area than those with a very low AFC. Females with a very low AFC exhibited a larger (P < 0.01) diameter of the dominant follicle at TAI (13.6 ± 0.3 vs. 12.2 ± 0.4 mm) and a tendency (P = 0.06) to have different serum progesterone concentrations (2.9 ± 0.3 vs. 2.1 ± 0.3 ng/mL; on day 18, considering day 0 as the beginning of the synchronization protocol) than those with a high AFC. The pregnancy rate was higher (P ≤ 0.05) in animals with a very low (57.9%) and low (53.1%) AFC than in those with a high AFC (45.2%). The expression of genes related to intercellular communication, meiotic control, epigenetic modulation, cell division, follicular growth, cell maintenance, steroidogenesis and cellular stress response was assessed on day 5. In females with a low AFC, 8 and 21 genes in oocytes and cumulus cells, respectively, were upregulated (P < 0.05), while 3 and 6 genes in oocytes and cumulus cells, respectively, were downregulated. The results described here will help elucidate the differences in ovarian physiology and the reproductive success of Bos indicus females with a low or high AFC.
“…Compared with other single factor pre-breeding variables including age and body weight, RTS was found to have the greatest predictive ability for positive reproductive outcomes including AI pregnancy rate and reduced days to calving (Holm et al, 2009). More recently, antral follicle count has been used in combination with RTS, as high antral follicle count is associated with fewer services per conception (Mossa et al, 2012), increased P4 and estradiol production (Ireland et al, 2009;Jimenez-Krassel et al, 2009), increased uterine protein secretion (McNeel et al, 2017) and greater embryo production (Majumder et al, 2010) contributing to overall improved fertility (Moraes et al, 2019). Within pubertal heifers, however, other physiological differences resulting in sub-and infertility are less apparent.…”
Section: Maternal Vs Paternal Contribution To Pregnancy Loss Female Cmentioning
Reproductive failure and pregnancy loss in cattle are some of the largest economic burdens to cattle producers and one of most perplexing factors influencing management decisions. Pregnancy loss may occur at any point during gestation with the largest percentage of loss occurring in the first 30 days and, subsequently, decreasing as the pregnancy progresses. Losses may be attributed to numerous factors, predisposed issues or environmental conditions such as nutritional stressors or disease. From a research perspective, determining the exact causes of pregnancy loss or embryonic mortality in cattle have been difficult, due to limitations of accurately determining early gestation pregnancy status. Until methods that precisely determine embryo success early in gestation are available, our understanding of in vivo pregnancy loss will lack clarity necessary to develop management strategies to decrease such loss. In this review, we will briefly discuss the pivotal periods of pregnancy loss affecting beef and dairy cattle, methods and technologies to determine pregnancy status and embryo viability and potential opportunities to decrease reproductive failure.
“…Initially, studies pointed to reproductive advantages and high fertility for cows with high AFC when subjected to reproductive techniques such as artificial insemination (AI), timed AI and embryo technologies 4 10–13 . However, reports have shown that females with low count exhibited better reproductive and productive performance than females with high AFC 7 9 14–16 . Although highly investigated in cattle, there remains no full consensus on this relationship.…”
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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