Purpose:To determine the efficacy of an equine joint supplement STEADFAST ® and/or its active components (Natural Eggshell Membrane [NEM ® ] and chelated trace minerals [CTM]) in horses with naturally occurring osteoarthritis or in a chemically induced osteoarthritis rat model. In addition, the efficacy of CTM vs inorganic trace minerals (ITM) (Zn, Mn, and Cu) in reducing culling rates in swine was evaluated. Methods: Horse trial: 16 mature horses with existing lameness were fed test joint supplement or placebo for 42 d. Lameness (American Association Equine Practitioner scoring system), serum biomarkers (C-terminal cross-linked telopeptide type II collagen [CTXII] and N-propeptide type IIA collagen [PIIANP]), and synovial fluid WBC were assessed biweekly. Rat trial: A chemically induced (monoiodoacetate [MIA]) osteoarthritis rat model was utilized. Rats were fed either negative control or joint supplement at 1% or 2% inclusion in Exp 1 (n=54) for 56 d. In Exp 2 (n=48), rats were fed control, NEM, CTM, or NEM + CTM for 42 d (28 d prefeed + Exp period). Rats were injected with MIA d29. Pain, knee swelling, and CTXII were measured post-MIA injection. Sow trial: Two farms with 6,400 sows each were fed ITM or 50:50 blend of ITM:CTM at equal TM levels for ∼3 yr. Treatments were initiated at weaning through entry into the breeding herd. Sows remained on treatment until culled. Sow retention rate and reasons for removal were measured. Results: In horse and rat trials, chondromodulating effects of the joint supplement were observed: increased cartilage synthesis (PIIANP) or decreased cartilage degradation (CTXII). CTM + NEM decreased pain, swelling, and CTXII, compared to control and/or CTM or NEM alone (P,0.05). Gilt and sow culling rates were reduced .30% with CTM supplementation (P,0.001). Conclusion: CTM, NEM, and the joint supplement improved skeletal and joint health. Our studies demonstrate the importance of CTM for the prevention and treatment of lameness.