Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: March 12, 2001
Publication Date: N/A
Technical Abstract: In the last few days of pregnancy, calcium transport into the fetus and the filling mammary calcium storage pools often overpower the calcium homeostatic systems of the dairy cow when lactation is initiated. The adaptation of the maternal calcium homeostatic systems to the needs of lactation are the result of a complex interplay between calciotropic hormones and the tissues (intestine, bone and kidney) responsible for providing the large amounts of calcium needed for late fetal development, mammary calcium requirements and milk secretion. This overview will discuss general vitamin D and calcium homeostatic mechanisms followed by a review of specific adaptations required by the human rat and cow to meet lactational demands for lactation. This comparative approach will highlight the unique aspects of dairy cow management and physiology, other than high milk production, that makes her so susceptible to hypocalcemia. The final section will deal with the role that the mammary gland plays in the calcium stress of the periparturient cow and how the mechanisms that regulate calcium storage and transport through the gland may be the key to a better understanding of hypocalcemia in dairy cows.