Submitted to: Journal of Mammary Gland Biology and Neoplasia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 20, 2005
Publication Date: April 10, 2005
Citation: Horst, R.L., Goff, J.P., Reinhardt, T.A. 2005. Adapting to the transition between gestation and lactation: differences between rat, human and dairy cow. Journal of Mammary Gland Biology and Neoplasia. 10(2):141-156. Interpretive Summary: A number of adaptive changes must take place in mammals in order to meet the increased demand for Ca during lactation. Unlike most mammalian species, the dairy cow faces the biggest challenges at the initiation of lactation, not late gestation. The dairy cow is therefore at great risk of developing severe hypocalcemia at the onset of lactation. During the past several years, significant advances have been made in our understanding of the pathogenesis of milk fever in dairy cattle. Most notably are the recent observations outlining the importance of acid base balance on PTH function and Ca homeostasis in dairy cattle. These concepts have provided the background for implementing new practical approaches for prevention of milk fever by dairy producers and have also provided new focus for basic and applied research. Future research will focus on identifying regulatory events responsible for transport of Ca into the mammary gland as well as characterizing further the physiological and cellular events responsible for modifying hormonal regulation of Ca metabolism.
Technical Abstract: Adequate blood calcium concentrations are vital to normal function of mammals. Mechanisms for maintaining normal blood calcium function adequately most of the time; however, occasionally they fail and calcium homeostasis is compromised. Milk fever or periparturient hypocalcemia in dairy cattle is a well-documented example of a breakdown in calcium homeostatic mechanisms. This disease occurs at the time of parturition and is unique to adult dairy animals. The disease results from the inability of animals to cope with the sudden demand for calcium in support of colostrum formation. Animals developing the disease become hypocalcemic and require intravenous calcium to survive. The precise metabolic lesions responsible for the onset of milk fever are still being debated. This report will highlight some of the current concepts related to the causes and prevention of milk fever in dairy cattle, as well as contrasting differences in calcium demands that exist between dairy cattle, humans, and rats at the onset of lactation.