Repeatability of antral follicle counts and anti-Müllerian hormone and their associations determined at an unknown stage of follicular growth and an expected day of follicular wave emergence in dairy cows
“…These results confirm the strong relationship between AMH, and the AFC established in the Holstein breed by previous works under normal altitude, observed a correlation with a value of r = 0.59 ( P < 0.001) in cows in stabling (Rico et al ., 2009). The correlation was even stronger among bovines raised at sea level ( r = 0.79, P < 0.001; Gobikrushanth et al ., 2017). Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Levels of this hormone are directly related to AFC in Bos taurus cows (Souza et al ., 2015). However, the level of AMH taken at an unknown moment of the estrous cycle varies with animals, with high individual repeatability (Gobikrushanth et al ., 2017), preventing the standardized use of AMH concentration as an endocrine marker without previous evidence of the intensity of such relationship at a given moment of the estrous cycle. Moreover, whether this relationship also holds in grazing feeding systems in the high tropics is unclear.…”
We evaluated the relationship between plasma levels of anti-Müllerian hormone (AMH) and the number of antral follicles at the restart of the follicular wave in crossbred Holstein cows reared under extensive grazing systems over 2500 m above sea level. The study included 140 cows from 15 farms that were in average at the 75.3 ± 2.10 d post partum. Animals were synchronized according to the following regime: day 0 = intravaginal progesterone releasing device (IPD) + estradiol benzoate (EB); day 7: withdrawal of IPD + prostaglandin; and day 8: EB, for restart of the follicular wave on day 11. On this day 11, antral follicle counts (AFCs) were made by transrectal ultrasound, and a plasma sample was taken for the determination of AMH. The mean AMH plasma level was 0.06 ± 0.03 ng/ml and the mean AFC was 17.26 ± 0.38 follicles. A strong positive linear correlation was found between these two variables (r = 0.783, r = 0.613, P < 0.0001). Cows were categorized according to AMH concentration as high (>0.09 ng/ml), intermediate (0.09–0.05 ng/ml) or low (<0.05 ng/ml). Cows with high AMH presented a higher AFC (25.0 ± 2.21 follicles) than those with low AMH (14.08 ± 2.68 follicles; P < 0.001. Our results suggest that the cut-off value of AMH = 0.09 ng/ml may be useful for selecting donors in multiple ovulation embryo transfer programs involving cows with these characteristics. Our data further suggest that AMH plasma concentration correlates with AFC and can be used as an endocrine biomarker of the number of antral follicles present at a given moment of the estrous cycle in crossbred Holstein cows raised at altitudes above 2500 m.
“…These results confirm the strong relationship between AMH, and the AFC established in the Holstein breed by previous works under normal altitude, observed a correlation with a value of r = 0.59 ( P < 0.001) in cows in stabling (Rico et al ., 2009). The correlation was even stronger among bovines raised at sea level ( r = 0.79, P < 0.001; Gobikrushanth et al ., 2017). Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Levels of this hormone are directly related to AFC in Bos taurus cows (Souza et al ., 2015). However, the level of AMH taken at an unknown moment of the estrous cycle varies with animals, with high individual repeatability (Gobikrushanth et al ., 2017), preventing the standardized use of AMH concentration as an endocrine marker without previous evidence of the intensity of such relationship at a given moment of the estrous cycle. Moreover, whether this relationship also holds in grazing feeding systems in the high tropics is unclear.…”
We evaluated the relationship between plasma levels of anti-Müllerian hormone (AMH) and the number of antral follicles at the restart of the follicular wave in crossbred Holstein cows reared under extensive grazing systems over 2500 m above sea level. The study included 140 cows from 15 farms that were in average at the 75.3 ± 2.10 d post partum. Animals were synchronized according to the following regime: day 0 = intravaginal progesterone releasing device (IPD) + estradiol benzoate (EB); day 7: withdrawal of IPD + prostaglandin; and day 8: EB, for restart of the follicular wave on day 11. On this day 11, antral follicle counts (AFCs) were made by transrectal ultrasound, and a plasma sample was taken for the determination of AMH. The mean AMH plasma level was 0.06 ± 0.03 ng/ml and the mean AFC was 17.26 ± 0.38 follicles. A strong positive linear correlation was found between these two variables (r = 0.783, r = 0.613, P < 0.0001). Cows were categorized according to AMH concentration as high (>0.09 ng/ml), intermediate (0.09–0.05 ng/ml) or low (<0.05 ng/ml). Cows with high AMH presented a higher AFC (25.0 ± 2.21 follicles) than those with low AMH (14.08 ± 2.68 follicles; P < 0.001. Our results suggest that the cut-off value of AMH = 0.09 ng/ml may be useful for selecting donors in multiple ovulation embryo transfer programs involving cows with these characteristics. Our data further suggest that AMH plasma concentration correlates with AFC and can be used as an endocrine biomarker of the number of antral follicles present at a given moment of the estrous cycle in crossbred Holstein cows raised at altitudes above 2500 m.
“…Nevertheless, the relationship between AFP and fertility has not been observed in B. indicus (Nellore) and crossbred beef cows (Baruselli et al, 2015;Morotti et al, 2015;SilvaSantos et al, 2014a). The number of recruited follicles in each follicular wave is highly variable between individuals; however, a high level of individual repeatability is observed (Evans et al, 2010;Oliveira Junior et al, 2015;Batista et al, 2014;Gobikrushanth et al, 2017). High correlation of AFP with in vivo and in vitro embryo production may be used as an auxiliary tool to select donor cows for embryos and oocytes (Silva-Santos et al, 2014a;Baruselli et al, 2015;Ghanem et al, 2016).…”
Antral follicular population (AFP) and antiMüllerian hormone (AMH) concentration are strongly associated. Thus, analyzing AMH concentration is a reliable method to predict animals with high AFP, an important feature to select donor cows for embryos and oocytes. However, not much is known about this parameter in heifers, particularly in crossbred animals. The aim of this study was to assess AFP in heifers and cows and its relation to serum AMH levels. Bos taurus indicus cows (36-60-months-old; n = 30) and heifers (12-14-months-old; n = 17) of the same breed were evaluated. A single procedure of follicular counting was performed by ultrasound for each animal. Random sampling was performed to analyze serum AMH concentration. Cows showed higher AFP than heifers; nonetheless, plasma AMH concentration did not differ between the categories. A high correlation of AFP with plasma AMH concentration was observed in Girolando heifers. Thus, it is suggested that AMH concentration could be a reliable and less invasive method for selecting heifers with high AFP.
“…A phenotype that has high variability, repeatability, and heritability would be an ideal candidate for genetic selection. The variability and repeatability of other novel fertility traits such as anti-Müllerian hormone and antral follicle count (Burns et al, 2005;Ireland et al, 2008;Gobikrushanth et al, 2017) and their association with fertility outcomes have been of recent interest to many researchers (Mossa et al, 2012;Ribeiro et al, 2014). However, the variability, repeatability, and association with fertility under minimal influence of P4 have not been examined for GnRH-induced LH responses in dairy cows.…”
The primary objective was to determine the variability and repeatability of GnRH-induced LH responses. The secondary objective was to evaluate the associations among plasma LH, FSH, estradiol (E2), and progesterone (P4) concentrations. One hundred lactating Holstein cows (35 primiparous, 65 multiparous) were initially subjected to a presynchronization protocol (d 0, PGF; d 3, GnRH) followed 7 d later by Ovsynch (d 10, GnRH; d 17, PGF; 56 h later, GnRH) and timed artificial insemination 16 h after the last GnRH. Blood samples were collected immediately before the GnRH injection of presynchronization and the second GnRH of Ovsynch to determine plasma concentrations of LH, FSH, and P4. A second blood sample was collected 2 h after each of the above GnRH injections to determine GnRH-induced LH and FSH concentrations. Plasma concentrations of E2 were also determined in samples collected immediately before the second GnRH of Ovsynch. Cows that (1) had higher LH concentrations at 0 h than at 2 h after GnRH, (2) showed an ongoing spontaneous LH surge, (3) did not respond to GnRH, and (4) had P4 ≥ 0.5 ng/mL at GnRH of presynchronization and the second GnRH of Ovsynch were excluded from the analysis. The variability (coefficient of variation) and repeatability [between animal variance/(within animal variance + between animal variance)] of GnRH-induced LH response were determined from samples collected 2 h after the GnRH of presynchronization and the second GnRH of Ovsynch. The associations among plasma LH, FSH, E2, and P4 were determined at the second GnRH of Ovsynch. Mean (±SEM) LH concentrations before GnRH were 0.5 ± 0.04 and 0.6 ± 0.03 ng/mL, whereas mean LH concentrations 2 h after GnRH were 9.8 ± 1.0 and 12.1 ± 0.8 ng/mL at GnRH of presynchronization and the second GnRH of Ovsynch, respectively. The variability of GnRH-induced LH was 76.1 and 52.1% at GnRH of presynchronization and the second GnRH of Ovsynch, respectively. The repeatability estimate for GnRH-induced LH concentration between GnRH of presynchronization and Ovsynch assessments was 0.10. Plasma concentrations of LH were positively associated with FSH and E2 (r = 0.61 and 0.30, respectively) and negatively associated with P4 (r = -0.46) at the second GnRH of Ovsynch. In summary, GnRH-induced LH responses were highly variable and unrepeatable, and LH concentrations were positively associated with FSH and E2 and negatively associated with P4.
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