Changes in subchondral bone mineral density and collagen matrix organization in growing horses☆☆Sources of funding: Financial support was received from the Ministry of Education in Finland (projects 25/627/2006 and 61/627/2005), Academy of Finland (projects 113112, 213548, and 216231), the National Graduate School of Musculo-Skeletal Diseases in Finland and the North-Savo Fund of the Finnish Cultural Foundation. The GEXA study is a project by the Global Equine Research Alliance for which the financial support was granted by the Marilyn Simpson Trust (USA), Horserace Betting Levy Board (UK), Utrecht University (The Netherlands) and the New Zealand Racing Board.