COMP and osteoarthritis: Thus, biomarkers of bone anabolism (N-MID; Figure 6A) and catabolism (CTX-I; Figure 6B), cartilage anabolism (CPII; Figure 7A) and catabolism (CTX-II; Figure 7B), and osteoarthritis (COMP and HA; Figure 7C,D) were quantified from birth to 33 months using blood samples collected from both groups of castrated horses.