Effect of Parity, Stage of Lactation, and Intramammary Infection on Concentration of Somatic Cells and Cytoplasmic Particles in Goat Milk

Abstract

Aseptic foremilk samples (.apprx. 15 ml) were collected biweekly for 4 samplings and then monthly throughout lactation from 35 does in 3 herds on Dairy Herd Improvement test. Bacteriology, direct microscopic somatic cell counts and cytospin differential cell counts were performed on all samples. Milk yield was obtained from monthly Dairy Herd Improvement records. Of udder halves, 39% were infected, and coagulase-negative staphylococci were the most frequent isolates (201 of 205). Somatic cell counts were influenced by lactation number, stage of lactation and intramammary infection. Infection of 1 udder half increased somatic cells in the corresponding uninfected mammary half of the same animal. Cytoplasmic particles were not affected by stage of lactation or by intramammary infection but were greater for goats in 1st lactation. Milk yield was influenced by lactation number, stage of lactation and intramammary infection.