Somatic Cell Content Variation in Fraction-Collected Milk

Abstract

The total milk somatic cell content of various fractions of milk collected during milking was estimated by reflectance Feulgen-deoxyribonucleic acid (DNA) to determine which portion provided the best estimate of the number of somatic cells in primary milk and to understand the cellular variation in various fractions of milk. The first 5 fractions did not differ significantly (P;> 0.05) from primary milk, but strippings and complementary milk each contained significantly (P< 0.01) more somatic cells than primary milk. Correlations between the cell content in each fraction with the cell content in primary milk ranged from 0.91-0.97. Granulocytes constituted 66.4, 68.5, 66.8 and 69.2% (P>0.05) and mammary epithelial cells 27.6, 24.9, 24.3 and 21.1% (Pi. <0.01) of the total somatic cells in the 1st 20-ml, 9th 20-ml, strippings and complementary milk, respectively.