The aim of this study was to determine if body weight or range use has a significant impact on bone health in commercial free-range laying hens, and to correlate tibia bone quality parameters with individual range usage and body weight. A total of 30 Lohmann Brown hens at 74 wk of age were selected from a commercial free-range farm and were either classified as heavy (mean ± SEM body weight 2.11 ± 0.034 kg, n = 14) or light (1.68 ± 0.022 kg, n = 16) body weight, and also classified as rangers (accessed the range for 86.7% of available days, n = 16) or stayers (accessed the range for 5.00% of available days, n = 14). The left tibiae of all individuals were analyzed for morphological parameters using computed tomography, evaluated for bone breaking strength, and ashed to determine mineral composition. Keel bone scoring was performed based on observation. Data were analyzed using a 2 × 2 factorial ANOVA, and regression analysis was performed. There was no measurable effect of range usage on any of the tibia parameters investigated. The body weight was significantly correlated with tibia breaking strength (r = 0.59), tibia weight (r = 0.56), tibia length (r = 0.64), diaphyseal diameter (r = 0.61), and total tibia volume (r = 0.67). In conclusion, range access had no beneficial effect on bone health. The impact of internal hen house furnishing and movement on bone health needs further investigation.

中文翻译：

---

各种骨骼参数与母鸡体重呈正相关，而范围访问对散养层的胫骨健康没有有益影响。

本研究的目的是确定体重或范围使用是否对商业散养蛋鸡的骨骼健康产生重大影响，并将胫骨质量参数与个体范围使用和体重相关联。从商业散养农场中选择了总共 30 只 74 周龄的 Lohmann Brown 母鸡，它们被归类为重（平均 ± SEM 体重 2.11 ± 0.034 kg，n = 14）或轻（1.68 ± 0.022 kg， n = 16) 体重，也分为护林员（86.7% 的可用天数进入该范围，n = 16）或留守者（5.00% 的可用天数进入该范围，n = 14）。使用计算机断层扫描分析所有个体的左胫骨的形态参数，评估骨折强度，并灰化以确定矿物质成分。基于观察进行龙骨骨评分。使用 2 × 2 因子 ANOVA 分析数据，并进行回归分析。范围使用对所研究的任何胫骨参数都没有可测量的影响。体重与胫骨断裂强度（r = 0.59）、胫骨重量（r = 0.56）、胫骨长度（r = 0.64）、骨干直径（r = 0.61）和胫骨总体积（r = 0.67）显着相关。总之，范围访问对骨骼健康没有有益影响。鸡舍内部陈设和运动对骨骼健康的影响需要进一步研究。体重与胫骨断裂强度（r = 0.59）、胫骨重量（r = 0.56）、胫骨长度（r = 0.64）、骨干直径（r = 0.61）和胫骨总体积（r = 0.67）显着相关。总之，范围访问对骨骼健康没有有益影响。鸡舍内部陈设和运动对骨骼健康的影响需要进一步研究。体重与胫骨断裂强度（r = 0.59）、胫骨重量（r = 0.56）、胫骨长度（r = 0.64）、骨干直径（r = 0.61）和胫骨总体积（r = 0.67）显着相关。总之，范围访问对骨骼健康没有有益影响。鸡舍内部陈设和运动对骨骼健康的影响需要进一步研究。