Factors Affecting Chloride Content and Relationship of Chloride, Protein, and Solids-Not-Fat in Guernsey Milk

Abstract

A total of 725 milk samples from 133 Guernsey cows was analyzed for their content of chloride, total protein, milk fat, and solids-not-fat. The chloride content increased as lactation and age advanced. Weighted means for chloride content were 0.079 {+/-} 0.0004 for first and second lactations combined, 0.102 {+/-} 0.0016 for third and fourth lactations, and 0.116 {+/-} 0.0020 for fifth to eleventh lactations. The changes, with a trend upward in chloride content, from the first to the tenth month of lactation in each group, respectively, were 0.074 to 0.085, 0.080 to 0.128, and 0.096 to 0.136%. The protein and solids-not-fat content also increased as the lactation period progressed. Seasonal trends were more evident in total protein and solids-not-fat percentage than in chloride content. Total protein was relatively more important than chloride content as a possibility to use for improving the accuracy of lactometric determination for solids-not-fat.