Trabecular bone only makes up 20% of the human skeleton, yet it is the main t. While bone mineral density (BMD) is commonly used to measure bone strength, it has been identified that combining it with 3D trabecular microstructural indices improves the accuracy of assessing mechanical properties (Ulrich et al. Bone 1999). Investigating trabecular osteogenesis, specifically trabecular microarchitecture, is therefore crucial for understanding bone development and improving diagnosis of bone-related diseases. In this study, goats were used as an animal model to study long bone development because they experience similar levels of loading to humans. Unlike humans, goats only have 2 phalanges, and their metacarpus is fused for both phalanges, thus one phalanx can be purposefully overloaded and the other under-loaded. Ruminants have previously been used as large animal models in bone development research, including studies on osteoporosis (Dias et al., Curr Osteoporos Rep, 2018).

In this experiment, high-resolution micro-computed tomography (µCT) was used to quantify trabecular bone microarchitecture by calculating morphometric indices and bone volume in goat distal phalanges 1 (P1) and metacarpus from birth to adulthood. The fusion of the epiphyseal metacarpus in goats occurs during postnatal development and was quantified by measuring the fusion length at the different maturation stages. The aim of this study is to establish a baseline of trabecular bone growth to encourage future research on the underlying mechanobiology and effects of mechanical cues on bone development. 

The findings revealed dynamic growth in P1 and stable growth in metacarpi, making these bones useful models for studies on bone development under experimentally altered loading conditions. Additionally, the epiphyseal fusion makes the metacarpal bone also a potential model for bone fusion disorders.

Future studies will employ histology to explore changes in cellular architecture during postnatal development. Furthermore, we plan to use goats as a model system to alter the mechanical environment to examine how mechanical loading affects trabecular osteogenesis and metacarpal fusion.