MULTIELEMENT ASSAY OF MAMMARY SECRETIONS AND SERA FROM PERIPARTURIENTMARES BY INDUCTIVELY-COUPLED ARGON PLASMA EMISSION-SPECTROSCOPY

Objective-To document and determine changes in the mineral profiles of sera and mammary secretions from a population of periparturient mares . Animals-18 clinically normal periparturient Arabian broodmares. Proc edure-inductively coupled argon emission spectroscopy was used to meas ure Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn concentrations in sera and ma mmary secretions of periparturient mares. In addition, S was measured in mammary secretions. Results-Serum concentrations of Ca, Cu, Fe, K, Mg, Na, P, and Zn remained constant throughout late pregnancy and the first 7 days of lactation. Compared with values on day 11 before foali ng, mammary fluid concentrations of Ca, Cu, K, Mg, P, S, and Zn increa sed prior to parturition and all element concentrations, except Ca, de creased with the onset of lactation. in contrast, Na concentrations in mammary secretions decreased precipitously as parturition approached. Iron concentrations in mammary secretions remained relatively constan t up to the time of parturition, decreased at parturition, and remaine d constant during lactation. Conclusions and Clinical Relevance-Prior to foaling, increasing concentrations of Ca, Cu, K, Mg, P, S, or Zn in mammary secretions in concert with precipitous decreases in Na concen trations may provide a predictive index of impending parturition in th e mare and a means of assessing fetal readiness for birth.