Variations in milk somatic cell count and haematologic values of dairy cows during lactation

Variations in milk somatic cell count (SCC) and haematologic values were studied in a dairy cow colony of the Holstein-Friesian and Hungarian Red-Spotted breeds (n = 23) from May 1992 to July 1993. Milk and blood samples were taken approximately at monthly intervals and data were assigned into ten lunar months of lactation. After a maximum in month I, SCC dropped abruptly in month II and continued to decline through the subsequent four months, then it again tended to increase through months VII-X. The SCCs varied within the physiological range throughout the lactation period parallel with red blood cells and white blood cells constituting a major segment of the somatic cell population. Positive correlations were recorded between SCC and the blood variables (packed cell volume, red blood cell count, white blood cell count). The lactation pattern of SCC was comparable to previous observations.