Total and differential cell count in milk of primiparous Comisana ewes without clinical signs of mastitis

Abstract

Total and differential cell counts were carried out on foremilk and bulk milk taken from single half-udders from ten primiparous Comisana ewes. The aim of this study was to characterise the cellular composition of milk in relation to the different stages of lactation, milk fractions and bacteriology. Total somatic cell count (SCC) and differential cell count (DCC) of neutrophil (PMNL) and eosinophil (EO) leukocytes, lymphocytes (LY), macrophages (MA) and epithelial cells (EC) were determined on all milk samples during the entire lactation period. The arithmetic mean of SCC in milk during the milking stages considered (including foremilk and bulk milk samples from single half-udders) was 56.7 ± 45.2 × 10 3 ml −1 consisting of 30.6% PMNL, 57.3% MA, 8.2% LY, 2.2% EC, and 0.1% EO. The results showed an influence of bacterial infection, different lactation stages and the two different milk fractions on the number of different cell classes. Lactation stage seemed to have an effect on total somatic cell number and all cell classes, while the positive bacteriology of milk samples seemed to influence especially the number of PMNL, and the milk fractions influenced mainly the number of mononucleate cells (MA, LY and EC). In spite of these variations, primiparous Comisana ewe milk, from clinically healthy and non-infected udders, seemed to have a low content of somatic cells (< 100 000 ml −1) with PMNL less than 50 000 ml −1.