Macro-mineral concentrations in milk of two goat breeds at different stages of lactation

Abstract

First-year freshened French-Alpine and Anglo-Nubian does, ten each, were randomly selected from the University milking herd to study concentration profiles of calcium, phosphorus, sodium, potassium, magnesium and sulphur for 0 h, 6 h, 12 h, 24 h, and 2, 3, 10, 30, 60, 90, 120 and 150 days postpartum and to evaluate differences in levels of teh six major minerals between breeds, stages of lactation and their interactions. Overall mean contents (mg/100ml) for Alpines and Nubians were: calcium: 138.6, 139.3; phosphorus: 129.2, 142.8; sodium: 55.4, 66.1; potassium: 110.8, 87.0; magnesium: 17.6, 19.2; sulphur: 2.97, 2.81, respectively. For pooled breed data, there were no differences in mean contents of calcium, phosphorus and sodium among lactation periods, but a few variations occurred in separate breed cases. The magnesium and sulphur levels revealed typical lactation trends, where colostrum contained significantly ( P<0.05) greater levels than normal milk. The potassium levels fluctuated greatly by periods, and potassium and sodium levels were significantly ( P<0.01) different between breeds. Interactions between breeds and lactation periods had no influence on the levels of any minerals. There were significant ( P<0.01), positive correlations between calcium and phosphorus and negative correlations between sodium and potassium or calcium in the milk.