Model output assessing inter-bone correlations within animals for biomechanics.

<p>Model components detailing the correlation between biomechanical properties at the base of the manubrial spine with age, and the associated biomechanical property in the tibia and humerus where the model components under ‘Bone Effect’ detail the correlation between the keel property and corresponding measure in the tibia or humerus, e.g., changes in the keel load corresponded with a similar change of 0.85 in the tibia.</p

Outcome of collision events in terms of fracture and severity at tested impact kinetic energies.

<p>Outcomes are listed under the column ‘Keel fracture score’ where ‘0’ would be the absence of fracture and ‘1’, ‘2’, and ‘3’ are fractures of increasing severity. For each kinetic energy, the actual number as well as percentage of collision events for each fracture score is provided.</p

Model output assessing inter-bone correlations within animals for bone mineral density.

¥<p>Data was transformed using (response+1)∧.5</p><p>Model components detail the correlation between keel bone mineral density (g/cm³) with age and the associated measure in the tibia and humerus. The model components under ‘Bone Effect’ specify the correlation between the keel surface or base and corresponding measure in the tibia or humerus, e.g., changes in the keel base corresponded with a similar change of 0.12 in the tibia.</p

Areas of the keel for structural and biomechanical testing.

<p>Manubrial spine (A) for biomechanical testing where the arrow indicates the direction of applied force during biomechanical testing; lateral surface (B) and base (C) for bone mineral density quantification.</p

Model output for the associated likelihood of fractures occurring with varying severity.

†<p>For analysis of fracture severity, only data from 31 and 45 weeks was used, thus this term indicates the likelihood of fractures relative to 31 weeks.</p><p>The model used a cumulative distribution model that compared the likelihood of a ‘1 and 2’ or a ‘2’ occurring against a ‘3’. Calculated odds ratios are provided for the relevant outcome.</p

Schematic diagram of the impact device used to deliver loads during impacts.

<p>The device consisted of columns placed vertically between which an aluminium block (5×5×2 cm) of a specified mass (3.8 kg) could be dropped from specific heights onto a bird positioned at the base of the device. Runners affixed to the drop mass ensured the load could be delivered with high accuracy and precision to a target with minimum friction during travel. By altering the height from which the drop mass was released, the energy of impact could be changed accordingly. A rod extending from the base of the drop mass contained a force transducer which provided the peak force during impact. Actual contact with the bird was made with a crescent shaped metal flashing attached to the end of the rod.</p

Severity score assessing the extent of damage.

<p>Hash marks indicate 1 mm.<u>Panel A</u>: Severity score = 0: No fracture. <u>Panel B</u>: Severity Score = 1: Small transverse fracture on the ventrolateral or dorsolateral aspect of the keel plate without extending to the ventral borders. <u>Panel C:</u> Severity Score = 2: Large transverse fracture extending from the ventral to the dorsal borders. The impact fracture can also be seen on the dorsoventral aspect of the base of the keel (inset). <u>Panel D:</u> Large transverse impact fracture extending from the ventral to the dorsal borders of the keel bone resulting in displacement of the tip of the keel bone.</p

Model output and resulting odds ratios for the likelihood of a fracture occurring.

<p>Model output and resulting odds ratios for the likelihood of a fracture occurring.</p

Non-damaged keel bones.

<p>Absolute numbers and modelled % of birds with a non-damaged keel bone over the course of the experiment for each of the four perch type by genetic line combinations.</p

Model output for the likelihood of non-damaged keel bones occurring.

<p>^†For this analysis, the category in the `Ref`column serves as the reference from which the other category is compared against (Hybird ISA vs. DW; Perch type soft vs. hard).</p><p>Model output for the likelihood of non-damaged keel bones occurring.</p