THE RELATIONSHIP BETWEEN THE CONCENTRATION OF IONIZED CALCIUM AND PARATHYROID HORMONE-RELATED PROTEIN (PTHRP[1-34]) IN THE MILK OF MARES

Once lactation is established in mares, there is little change in the ionised calcium concentration in their milk. In contrast, the concentr ation of PTHrP(1-34) in the milk increases to a maximum level by the e nd of the second week of lactation, near which it remains for the rest of the lactation. As found in other species, the concentration of PTH rP(1-34) in mare's milk is considerably higher than that in plasma, sa mpled at the same time. No significant correlation could be demonstrat ed between the concentrations of PTHrP(1-34) and ionised calcium in th e milk except during the last 10 weeks of lactation.