SOMATIC CELL COUNT IN MILK AND ITS RELATION WITH CLINICAL MASTITIS AND LINEAR TYPE TRAITS IN BLACK-AND-WHITE COWS

IVAYLO MARINOV

Abstract: The aim of the study was to establish the relationship between some environmental and parathypical factors and udder type traits and the somatic cells count and the cases of clinical mastitis in Black-and-white cows. In the study 317 Black-and-white cows from 9 dairy farms were included. Farms were from different regions of the country and with different housing system, respectively 3 with tied housing, 1 with a loose housing and 5 with free stall housing system. Cows included in the study were from first to third lactation, respectively 129 on first, 121 on second and 67 on third lactation. The average milk yield for 305-day lactation of the cows included in the study was 7438.6 kg. The average somatic cell count was 237 880 cells/ml, and the average percentage of clinical mastitis incidence was 14.03% with variation for the different farms from 6.0% to 26.3%. A statistically significant effect of the farm (p<0.001) and parity (p<0.01) on SCC in milk was found, and on clinical mastitis significant effect only of the farm (p<0.01) was reported. The level of milk yield had no significant effect on both traits. A significant phenotypic correlation between somatic cell count and rear udder height (-0.25), central ligament (-0.23), udder depth (-0.11), rear teat position (0.11), and teat length (0.13) was found. The phenotypic correlation between somatic cell count and clinical mastitis was 0.14. A significant correlation between clinical mastitis and udder conformation traits was not reported.

Keywords: clinical mastitis; dairy cows; milk yield; somatic cells count; udder conformation traits

Date published: 2018-04-20