EFFECTS OF PARTURITION AND LACTATION ON BLOOD AND MILK CELL CONCENTRATIONS, CORTICOSTEROIDS, AND NEUTROPHIL PHAGOCYTOSIS IN COW

  • 1 January 1976
    • journal article
    • research article
    • Vol. 37  (10) , 1195-1200
Abstract
Blood differential leukocytes, erythrocytes, milk somatic cells and neutrophil phagocytosis in 14 Holstein-Friesian cows were measured at 2-day intervals for 2 wk before parturition, on the day of parturition, on postpartum days 1, 2, 5, 10, 15 and 30, and at monthly intervals throughout lactation. Circulating corticosteroids were measured in 6 cows on days -6, -4, -2, on the day of parturition, and on days +1, +2, +5, +10, +15, +30 and +60. Circulating neutrophils on day -2, on the day of parturition, on days 2, 10 and 15 averaged 3363, 5889, 3085, 4116 and 3558/mm3, respectively. The increase in neutrophils at parturition was accompanied by an increase in corticosteroids (2.7, 9.0, 11.1, 6.1 and 5.4 ng/ml of blood plasma on days -4 and -2, on the day of parturition, and on days +1 and +2, respectively). The phagocytic ability of circulating neutrophils was determined by incubating yeast cells with whole blood (30 min, 37.degree. C) and microscopically counting yeast cells per neutrophil. Mean yeast cells per neutrophil decreased (P < 0.01) during the 2nd wk after parturition (7.4, 6.5, 6.6 and 7.2 on days +2, +10, +15 and +30, respectively). This decrease was compensated for by an increase in circulating neutrophils during the same period.