The development of alternative housing systems has increased the opportunity for falls and collisions, which are associated with kneel injuries and bone damage. It has been suspected that genetic factors underlie susceptibility of hen’s bone quality issues; however, assessment of bone quality parameters is made post-mortem which makes it hard to implement genetic selection to improve bone quality. Previous technologies for live bird evaluation are too time consuming to be practical. Researchers used 50 end of lay (~65 wks) Lohmann brown hens to optimize the assessment of images obtained through X-ray exposure of the dead hens. Hen bones were then measured through the traditional post-modem bone quality measuring system. Next, diet manipulation of Hy-line Brown Layers was used to produce a large range of bone breaking strength and density values. Live radiographs were taken three times throughout the various feeding trials and the hens were culled for post-mortem assessment. The methodology developed for measuring bone qualities with x-ray imagery correlated strongly with accepted post-mortem bone quality measurements for bone density. Reproducibility and repeatability of this technology; in addition to its portability, rapid image-taking ability (45 sec), and lack of need for sedation makes this a practical method to measure laying hen leg bones for reduced damage and fracture. In addition, human radiation exposure allowed for over 60,000 radiographs to be taken per year before reaching regulated maximum annual dosage limits.
Producer Takeaway: New technology makes it possible for genetics companies to evaluate bone quality measurements in live birds. This may speed up the genetic selection process for laying hen leg bone strength traits.