SEASONAL INFLUENCE ON SEMINAL PATTERN AND FREEZABILITY OF PANTANEIRO BULL SEMEN

Abstract The purpose of this paper was to investigate the effect of the season of the year on testicular morphology, fresh and frozen/thawed semen quality from Pantaneiro bulls bred in Brasilia, DF. Six bulls were submitted, once a month for one year, to evaluation of testicular measurements, semen collection using an artificial vagina and cryopreserved with medium containing Tris-based, egg yolk and glycerol. The testicular length and volume were greater (P 0.05). In conclusion, Pantaneiro bulls, bred in the Midwest region of Brazil, can be used in natural mating programs in all seasons. Aiming to improve the Brazilian Animal Germplasm Bank with a higher number of samples collected, we suggest that the freezing of the semen is done between June and August, although there will be no losses of semen quality at any time.摘要 本研究旨在探究巴西联邦区巴西利亚地区饲养的潘塔内罗公牛（Pantaneiro bulls）的全年季节对其睾丸形态、新鲜及冻融精液品质的影响。试验选取6头公牛，每月开展1次检测，持续时长1年，依次进行睾丸尺寸测定、采用假阴道（artificial vagina）采集精液，并使用以Tris（三羟甲基氨基甲烷）为基础、添加蛋黄与甘油的稀释液对精液完成冷冻保存。结果显示，睾丸长度与体积在不同季节间存在差异（P 0.05）。综上，在巴西中西部地区饲养的潘塔内罗公牛，可于全年所有季节应用于自然配种计划。为进一步扩充巴西动物种质资源库（Brazilian Animal Germplasm Bank）的样本储量，我们建议精液冷冻操作可安排在6月至8月期间，尽管全年任一时段开展该操作均不会造成精液品质损失。