BOVINE MASTITIS IN FINLAND IN 1988 AND 1995 - CHANGES IN PREVALENCE AND ANTIMICROBIAL RESISTANCE

Two surveys were carried out (during 1988 and 1995) to estimate the pr evalence of bovine mastitis in Finland. In 1988, 17 111 quarter milk s amples were obtained from 4495 cows, and in 1995 the corresponding fig ures were 10410 and 2648. Antimicrobial susceptibility of mastitis pat hogens was studied. Prevalence of mastitis on cow basis decreased from 47.8% in 1988 to 37.8% in 1995. Staphylococci was the largest group o f pathogens isolated. The proportion of Staphylococcus aureus decrease d and that of coagulase-negative staphylococci (CNS) increased. The pr oportion of strains resistant to at least one antibacterial drug incre ased with regard to S. aureus from 36.9% in 1988, to 63.6% in 1995 and with CNS from 26.6% to 49.7%. Most of the increase in antibacterial r esistance was due to a higher number of beta-lactamase producing strai ns. Multiresistance also increased, but it was proportional to the ove rall increase in resistance. All the predominant mastitis streptococci were susceptible to beta-lactams tested.