The use of the DHI-SCC program to select cows for bacteriological milk culture and subsequent treatment, early dry-off or culling

A 6-month trial was carried out on the comparative effects of lactation therapy (systemic and intramammary), early drying off followed by dry-cow therapy, and culling based on milk somatic cell count (SCC), on mastitis incidence in a 124-cow herd. In the 6 months prior to the trial, between 14.6 and 18.5% of cows had milk SCC of >250 000/ml, and incidence of clinical mastitis in any month ranged from 0 to 7.52%. During the trial, 15 of 20 cows on lactation therapy and 10 of 12 cows on early drying off and dry-cow therapy had decreased SCC, and there were 3 and 1 new infections, resp., on the 2 treatment systems. The most common isolates from cows with milk SCC >250 000/ml were coagulase-negative staphylococci (5.3%). The most cost-effective mastitis control method is a combined teat-dipping and dry-cow therapy programme..