Efficiency of Polyvalant Mastitis Vaccine in Lactating Dairy Cows

The aim of the study was to investigate the efficacy of a polyvalent mastitis vaccine under field conditions. Dairy cows (n=218) that had not been previously received a mastitis vaccine were separated into two treatment groups; vaccine (n=111) and control (n=107) in four different dairy farms. Initially, individual Somatic Cell Count (SCC), California Mastitis Tests (CMT) scores and clinical mastitis (CM) cases were detected. Two doses of the vaccine, 4 weeks apart, were administered in vaccine group by intramuscular injection. Cows in control group were received physiological saline. After the treatments, animals were examined monthly for SCC, CMT and CM during six months. In addition, milk samples were also taken from udder quarters of the cows with CMT +3 scores and CM for bacteriological examination. SCC of vaccine group was lower (P<0.056) than the control at the end of the study. CM rates were not significant in the vaccine (26.1%) and control (18.7%) groups. Staphylococcus aureus (S. aureus) isolations from milk samples of udder quarters with CMT (+3) scores were not different in the vaccine (25.8%) and control (34.8%) groups. Streptecoccus uberis (S. uberis), Coagulase Negative Staphylococcus (CNS) and Streptecoccus spp. intamammary infection (IMI) isolation rates was not different between groups. Thus, polyvalent mastitis vaccine did not have enough protective effect against mastitis, nevertheless CM that occured in vaccine group seemed to have fewer inflamation degrees