Pearson Jennifer M
University of Calgary Faculty of Veterinary Medicine, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
Anim Reprod Sci. 2025 Feb;273:107669. doi: 10.1016/j.anireprosci.2024.107669. Epub 2024 Dec 12.
This review focuses on bull breeding behaviors and management strategies to improve reproductive efficiency. Breeding soundness evaluations are utilized to classify a bull's physical ability and sperm quality, yet roughly 20 % of bulls fail to meet the minimum criteria. Furthermore, despite achieving the minimum criteria, few bulls in multi-sire breeding groups sire the majority of calves, indicating a need for better understanding of bull behavior that impact siring capacity, and thus, a bull's reproductive efficiency. Several factors influence bull libido such as age, breed, and environmental conditions. Although service capacity tests have been used to measure libido, standardization and repeatability, along with variability in age and breed, can be problematic. Management in collection facilities largely focuses on the pre-stimulation of bulls through behavioral cues for better sperm quality and quantity during collection, thus improving a bull's reproductive efficiency through fewer collections with increased breeding doses harvested. In management of multi-sire breeding groups, understanding social interactions, bull-to-female ratios, synchronization of females, and DNA testing to determine parentage, are techniques that can be utilized to improve reproductive efficiency. New research utilizing remote monitoring technology is being developed to better understand bull behavior without the constraints of direct observation. This technology may be used to predict siring capacity, better manage bulls based on social dynamics, and potentially detect lameness or injury in bulls that may impact siring capacity. A better understanding of developing management strategies of breeding behaviors should be further investigated to improve reproductive success of bulls.
本综述聚焦于公牛的繁殖行为及提高繁殖效率的管理策略。繁殖健全性评估用于对公牛的身体能力和精子质量进行分类，但约20%的公牛未能达到最低标准。此外，尽管达到了最低标准，但在多头公牛繁殖组中，很少有公牛能使大多数母牛受孕，这表明需要更好地了解影响授精能力进而影响公牛繁殖效率的行为。有几个因素会影响公牛的性欲，如年龄、品种和环境条件。虽然已使用配种能力测试来衡量性欲，但标准化和重复性以及年龄和品种的差异可能存在问题。采精设施的管理主要侧重于通过行为线索对公牛进行预刺激，以便在采精时获得更好的精子质量和数量，从而通过减少采精次数、增加每次采集的输精剂量来提高公牛的繁殖效率。在多头公牛繁殖组的管理中，了解社会互动、公母比例、母牛同期发情以及用于确定亲子关系的DNA检测等技术，都可用于提高繁殖效率。目前正在开发利用远程监测技术的新研究，以便在不受直接观察限制的情况下更好地了解公牛行为。该技术可用于预测授精能力，并根据社会动态更好地管理公牛，还可能检测出可能影响授精能力的公牛跛足或受伤情况。应进一步深入研究如何更好地制定繁殖行为管理策略，以提高公牛的繁殖成功率。
