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Biomedical subjects

J P Harner

Publications and source records attributed to J P Harner.

2 recordsLinked to original sources

Effect of body size and cage profile on the shear strength of bones of caged layers.

The effects of body size and cage profile on the shear strength of bones from caged layers aged 72 weeks were studied. Bones tested included the radius, ulna, humerus, femur, and tibiotarsus. The ultimate shear force of the femur, tibia, and humerus all increased as body size increased (P less than 0.01). The wing bones of birds housed in high profile cages had higher shear breaking loads than birds housed in low profile cages. The ultimate shear stresses of the bones were not affected by body size or cage profile. The radius had the highest shear stress (29.2 MPa), followed in descending order by the ulna (19.1 MPa), tibiotarsus, humerus (11.4 MPa) and femur (11.3 MPa).

Animals

Bone strength statistical distribution functions for broilers.

Shear and three-point bending tests were conducted on the femur and tibia bones from Hubbard broilers to establish the type of statistical distribution function that best fits bone strength data. In the past it was assumed that these types of data followed a normal distribution. The results of this investigation indicate that a log-normal function best describes the mechanical properties of the tibia and a normal function describes the properties of the femur. Overall the results of the distribution analysis indicate that the mechanical properties of bone tend to follow a log-normal distribution.

Animals