Abstract

Peak bone mass in cattle is influenced by factors prior to puberty and insufficient peak bone mass prior to the first lactation predisposes heifers to the risk of spontaneous humeral fractures. At post-mortem examination, affected heifers present with osteoporosis (reduced periosteal circumference and reduced cortical wall thickness). Due to its location, there is no cost-effective way to scan the humerus in the live animal. However, the metacarpal bones (MC3/MC4) are straightforward to scan in a live anaesthetised animal. The aim of this experiment was to determine if the metacarpal could be used to predict bone mass and material properties of the humerus. The left humerus and metacarpal bones were obtained from 57 cattle aged six weeks to eight years. Bones were scanned at the mid-diaphysis using peripheral quantitative computed tomography (pQCT), to obtain measures of bone mass and material properties (strength). Strong positive relationships were observed (R2=0.89 - 0.98, P<0.0001) for pQCT measurements of bone mass and strength. Thus, the metacarpus is a good predictor of bone content and material properties of the humerus across cattle of differing age and maturity.

MJ, Gibson, CW Rogers, K Dittmer, RE Hickson, EJ Pettigrew, and PJ Back

New Zealand Journal of Animal Science and Production, Volume 79, Palmerston North, 8-12, 2019