The presence of keel bone fractures (KBF) in laying hens has been documented and discussed by several authors, nevertheless the causative factors behind KBF remain uncertain. High prevalence of KBF have been reported in all commercial egg production systems, in different genetic lines and at different ages. Several of the proposed causal mechanisms behind KBF are linked to selection for efficient production. It is, therefore, of interest to explore whether less selected breeds have a lower occurrence of keel bone fractures compared to reports from highly selected, modern laying hen breeds. Thus, the aim of the current study was to investigate keel bones of hens from four non-commercial layer breeds. Birds were housed in furnished cages and keel bones examined at 30 and 63 weeks of age, using a portable x-ray equipment. The results from this descriptive study indicate a low prevalence of KBF at both ages in all four breeds, with only five KBF detected in 213 x-ray pictures taken from 126 birds. Of these, four of the KBF were observed in the most genetically selected breed, with an early onset of lay. None of the roosters examined exhibited KBF. The overall low numbers of KBF found indicate that genetic factors may be involved in KBF and, thus that selective breeding may help to reduce the susceptibility to KBF. Finally, this study highlights the importance of poultry conservation to secure genetic diversity, which may be an important resource in future selection schemes.

中文翻译：

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描述性研究来自装备在笼子里的四个非商业产蛋鸡和母鸡的龙骨骨折

几位作者已经对蛋鸡中的龙骨骨折（KBF）进行了记录和讨论，尽管如此，KBF背后的致病因素仍然不确定。据报道，KBF在所有商业化鸡蛋生产系统中，在不同的遗传系和不同的年龄中都很高。KBF背后提出的几种因果机制与有效生产的选择有关。因此，探索与精选的现代蛋鸡品种相比，选择较少的品种是否具有较低的龙骨骨折发生率很有意义。因此，本研究的目的是研究来自四个非商业性蛋鸡品种的母鸡的龙骨。使用便携式X射线设备将鸟类圈养在带家具的笼子中，并在30和63周龄时检查龙骨。这项描述性研究的结果表明，在所有四个品种的两个年龄段，KBF的患病率均较低，在从126只鸟拍摄的213张X射线照片中仅检测到5个KBF。其中，在最基因选择的品种中观察到四个KBF，且早产。检查的所有公鸡均未表现出KBF。发现的KBF总体较低，表明遗传因素可能与KBF有关，因此选择性育种可能有助于降低对KBF的易感性。最后，本研究强调了家禽保护对于确保遗传多样性的重要性，这可能是未来选择计划的重要资源。在基因选择最充分的品种中，有四只KBF发生，而且早产。检查的所有公鸡均未表现出KBF。发现的KBF总体较低，表明KBF可能涉及遗传因素，因此选择性育种可能有助于降低对KBF的易感性。最后，本研究强调了家禽保护对于确保遗传多样性的重要性，这可能是未来选择计划的重要资源。在基因选择最广泛的品种中，有四只KBF发生，且早产。检查的所有公鸡均未表现出KBF。发现的KBF总体较低，表明KBF可能涉及遗传因素，因此选择性育种可能有助于降低对KBF的易感性。最后，本研究强调了家禽保护对于确保遗传多样性的重要性，这可能是未来选择计划的重要资源。