Effect of dietary calcium and vitamin D supplements on plasma bone turnover biomarkers, bone mineralization, bone strength, and lameness score in gilts

Lameness is a significant concern in today's pig industry, posing a threat to production sustainability by hampering the performance and longevity of the sows. The structural robustness of legs during the growth phase can affect bone development and the prevalence of lameness in the subsequent reproductive phases. Mineral nutrition such as calcium (Ca) and phosphorus, in combination with vitamin D, plays a pivotal role in regulating bone mineralization. This study investigated the effects of high Ca and different vitamin D3 levels and sources on bone mineralization and lameness scores in gilts fed the dietary treatments in 2 phases from 32-180 kg body weight. Findings indicated that high Ca supplementation did not alter the plasma Ca concentration but led to increased urinary concentration of Ca. While the dietary regimens did not significantly impact the overall plasma concentrations of bone metabolism biomarkers, gilts fed high levels of Ca and vitamin D3 had greater bone-specific alkaline phosphatase in the later growth stage. Furthermore, gilts fed diets containing high levels of Ca, in combination with either adequate (856 IU/kg) based on Danish feeding standards or high (2,000 IU/kg) level of vitamin D3 had greater bone strength compared with those given adequate level of Ca and vitamin D3, or those fed diet supplemented with 50 mu g/kg 25-hydroxyvitamin D3 with varying levels of Ca. However, the dietary interventions did not demonstrate any notable improvements or deteriorations in either the lameness score or the selection rate of the gilts.