The associations of semen abnormalities with circulating hormones (estrogens, glucocorticoid, insulin) and common biochemical parameters are unclear in beef bulls. We compared plasma concentrations of estradiol-17β, cortisol, and insulin and serum biochemical parameters surrounding puberty in Japanese Black beef bulls (n = 96) with normal post-thaw or abnormal semen (fresh and frozen). Blood samples were collected monthly from 4 to 24 months of age (n = 50) for the assays of plasma estradiol, cortisol, and insulin and every 3 months from 6 to 21 months of age (n = 92) for the serum biochemical analyses. Semen was collected weekly from 12 months until at least 18 months of age. Fresh semen was evaluated for semen volume, sperm progressive motility, concentrations, and morphological defects. The normal fresh semen was frozen by a standard method and examined for post-thaw sperm motility and fertility, which were evaluated for rates of transferable embryos. Bulls were classified as having either normal fresh semen or abnormal fresh semen (when at least one of the above test items was abnormal for 6 months). The normal fresh semen was categorized as having either normal post-thaw semen or low fertility post-thaw semen. The abnormal fresh semen was categorized as having sperm morphological defects, low motility, or morphological defects plus low motility. Plasma cortisol concentrations in the abnormal fresh semen group were higher than those of the normal fresh semen group (p < 0.0001). Plasma estradiol-17β and insulin concentrations in the low-fertility post-thaw semen group were lower than those of the normal post-thaw semen group (p < 0.0001). Serum aspartate aminotransferase and magnesium concentrations were greater for the abnormal fresh semen group vs. the normal fresh semen group (p < 0.005). These results suggest that fresh semen abnormality in pubertal beef bulls might be associated with increased circulating aspartate aminotransferase, magnesium and cortisol. Low-fertility post-thaw semen could have been involved with the lower peripheral estradiol and insulin levels in beef bulls.

中文翻译：

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精液正常和异常的日本黑公牛青春期周围的血浆雌二醇-17β、皮质醇和胰岛素浓度和血清生化参数

在牛中，精液异常与循环激素（雌激素、糖皮质激素、胰岛素）和常见生化参数之间的关联尚不清楚。我们比较了日本黑牛（n = 96）与正常解冻后精液或异常精液（新鲜和冷冻）的青春期前后雌二醇-17β、皮质醇和胰岛素的血浆浓度和血清生化参数。从 4 到 24 个月大（n = 50）每月收集一次血样用于血浆雌二醇、皮质醇和胰岛素的测定，从 6 到 21 个月大（n = 92）每 3 个月收集一次用于血清生化分析。从 12 个月到至少 18 个月，每周收集一次精液。评估新鲜精液的精液量、精子进行性运动、浓度和形态缺陷。正常的新鲜精液通过标准方法冷冻，并检查解冻后的精子活力和生育力，并评估可移植胚胎的比率。公牛分为新鲜精液正常或异常新鲜精液（当上述测试项目中至少一项异常持续6个月时）。正常的新鲜精液被分类为具有正常解冻后精液或具有低生育力解冻后精液。异常新鲜精液分为精子形态缺陷、低运动性或形态缺陷加低运动性。异常新鲜精液组的血浆皮质醇浓度高于正常新鲜精液组（p < 0.0001）。低生育力解冻后精液组的血浆雌二醇-17β 和胰岛素浓度低于正常解冻后精液组（p < 0.0001）。与正常新鲜精液组相比，异常新鲜精液组的血清天冬氨酸转氨酶和镁浓度更高（p < 0.005）。这些结果表明，青春期公牛的新鲜精液异常可能与循环天冬氨酸转氨酶、镁和皮质醇增加有关。低生育力解冻后精液可能与牛的外周雌二醇和胰岛素水平较低有关。这些结果表明，青春期公牛的新鲜精液异常可能与循环天冬氨酸转氨酶、镁和皮质醇增加有关。低生育力解冻后精液可能与牛的外周雌二醇和胰岛素水平较低有关。这些结果表明，青春期公牛的新鲜精液异常可能与循环天冬氨酸转氨酶、镁和皮质醇增加有关。低生育力解冻后精液可能与牛的外周雌二醇和胰岛素水平较低有关。