Effect of the Degree of Udder Contamination in Dairy Cows on the Somatic Cell Count in Milk

The study includes a total of 310 Black-and-white cows from 9 herds throughout the period from November 2010 till January 2011. The farms used two rearing technologies (free and tied) and were of different capacity. To assess the degree of udder contamination a 4-grade system has been used. The rearing technology and the farm capacity had a reliable effect on somatic cells count (SCC) in milk. In tied rearing higher SCC have been recorded than in free rearing, a lesser relative share of cows with clean udders (hygiene score -1) and a greater one of cows with contaminated udders (hygiene score 3 and 4). The greatest was the relative share of cows with contaminated udders (hygiene score 3 and 4) and the least clean were the cows in farms with tied rearing and capacity from 50 to 100 cows. Cows with score 1 (clean udder) had the smallest somatic cell count – 172.4x10^3/ml, which was related to low risk of mastitis diseases. The ones with score 3 and 4 had somatic cell count over 400x10^3 /ml. The availability of more than 20% of cows with udder hygiene score 3 and 4 was an indicator for increased risk of mastitis in the herd and obtaining low quality milk. Somatic cell count in milk depended largely on the maintenance of bedding and the farm hygiene rather than the farm capacity and the rearing technology.