Variation in Milk Somatic Cells of Heifers at First Calving

Abstract

To evaluate variation in milk somatic cells, 24 primiparous cows (paired by calving date) were sampled during the first 75 d of lactation. Milk somatic cell counts were lowest at 9 to 10 wk. For differential cell counts in milk, only percentage of macrophages changed significantly during first 75 d (33% at 1 wk, 25% at 6 wk, and 34% at 11 wk). Epithelial cells were identified and ranged from 11 to 20% of total. For milk somatic cell count, variation between cows within pairs sampled contemporaneously was small (3 to 24%). However, variation between cows was much greater for the differential cell counts (46% of total for lymphocytes and 34% for epithelial cells). Of 1021 quarter foremilk samples, 26 were positive for major pathogens, but 326 were positive for various species. Prevalence of bacteria was significantly higher during first 10 d after calving. Rear quarters had significantly higher bacterial presence: 47% for left rear versus 21% for left front and 37% for right rear versus 24% for right front. Total milk somatic cell count after first calving appears to depend primarily on differences in temporary factors and is not a stable characteristic of individual cows. Proportions of the different somatic cell types in milk may vary consistently by cow in early first lactation.

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

“…Boutinaud et al (2008) isolated approximately 162 days pp comparable 2.7 × 10 6 pBMEC from 1750 ml of milk of Holstein-Friesian cows which comprised 2% of total milk cells. Despite the constant discharge of pBMEC, it is well established that fraction of pBMEC of total milk cells is low (Miller et al, 1991;Boutinaud and Jammes 2002). In our study, pBMEC represented about 2−6.7% of total milk cells and that proportion was the highest during peak lactation.…”

Role of the neutrophil leucocyte in the local and systemic reactions during experimentally induced e.coli mastitis in cows immediately after calving

“…Milk somatic cell counts from non-infected glands are low, averaging 150.000 cells/ml (42,44,48). Counts are slightly higher during early and late lactation (25,37,38,48). During early and late lactation the percentage of neutrophils tends to increase while the percentage of lymphocytes decreases (35)(36)(37)(38).…”

“…Counts are slightly higher during early and late lactation (25,37,38,48). During early and late lactation the percentage of neutrophils tends to increase while the percentage of lymphocytes decreases (35)(36)(37)(38). Neutrophils are the predominant cell type during the first 4 weeks after cessation of milking, followed by macrophages and lymphocytes (25,35,37,38).…”

“…During early and late lactation the percentage of neutrophils tends to increase while the percentage of lymphocytes decreases (35)(36)(37)(38). Neutrophils are the predominant cell type during the first 4 weeks after cessation of milking, followed by macrophages and lymphocytes (25,35,37,38). During the first two weeks before parturition lymphocytes predominate, followed by macrophages and neutrophils (36).…”

“…The incidence of udder infection and clinical mastitis is usually highest at calving and during early lac- (37)(38)(39)43). Because of the presence of epithelial cells in milk, Paape (41) coined the phrase 'milk somatic cells', which is now used internationally as the accepted terminology.…”