[Changes in blood concentrations of bone-specific biomarkers, osteocalcin and C-telopeptide, in third or higher parity sows after administration of calcium and vitamin D].

Changes in blood concentrations of bone-specific biomarkers, osteocalcin and C-telopeptide, in third or higher parity sows after administration of calcium and vitamin D The study had two objectives: 1, to measure levels of two bone-specific biomarkers, with a view to identifying sows with leg problems; 2, to evaluate the effect of additional vitamin D/ monocalcium phosphate on the two bone-specific biomarkers and the number of stillborn piglets. Of 272 third or higher parity sows, 136 were randomly selected to receive a high dose (33 times the normal dose) of vitamin D (as depot) 1 to 5 days before parturition plus 20 g monocalcium phosphate 3 days before and 3 days after parturition. The sows in the control group received no treatment. The housing and feeding conditions of the two groups of sows were identical. Blood samples were taken from five sows per group just before parturition, 2-3 days after parturition, 3 weeks after parturition, and 1 week after weaning for the measurement of osteocalcin (bone formation, osteoblastic activity) and C-telopeptide (CTX, bone degradation, osteoclast activity), calcium, and phosphorus. The total number of piglets born, stillborn piglets, and weaned piglets were registered per group. The bone metabolism of sows is comparable with that of mice, sheep, and goats. CTX levels increased and osteocalcin levels decreased after parturition, and the reverse pattern was seen after weaning, with a decrease in CRX levels and an increase in osteocalcin levels. Thus these two bone-specific biomarkers can be used to monitor bone metabolism in sows. Serum calcium and CTX levels were clearly correlated. Blood calcium levels increased significantly after treatment with vitamin D/monocalcium phosphate in sows with low calcium levels at the start of the study but not in sows with normal calcium levels at the start of the study. Treatment with vitamin D/monocalcium phosphate did not influence the number of stillborn piglets or the number of weaned piglets.