Effect of mastitis on raw milk compositional quality.

Abstract

In this study, we investigated the impact of mastitis infection on the quality of milk composition in small-scale dairy bovine herds. The purpose of this study was to find a milk quality somatic cell count (SCC) standard that could be used as an integral component of a control program. In all, 396 quarter milk samples from lactating cross-bred cows (Holstein & Zebu) were analyzed; 56% of these quarters were experiencing intramammary infection, with an overall mean SCC of 5.46 x 10(5) +/- 2.30 x 10(4)cells/ml. Infected quarters had significantly (p < 0.05) higher mean SCC levels (6.19 x 10(5) +/- 4.40 x 10(4)cells/ml) compared to healthy quarters (2.65 x 10(5) +/- 2.40 x 10(4)cells/ml). In high SCC milk and infected quarters, the concentrations of non-casein fractions, sodium, chloride, and free fatty acid were higher (p < 0.05), while the casein content, lactose, casein-to-total protein, potassium, and calcium were lower (p < 0.05) compared to normal quarters. These findings suggest a mean SCC threshold limit of 5.46 x 10(5)cells/ml for the region. It was concluded that the results could be used to propose a milk quality SCC standard that can be used as an integral component of a control program.