Prevalence and major pathogen causes of dairy cows subclinical mastitis in Northeast China

Abstract

The prevalence of subclinical mastitis in dairy cows was surveyed in Northeast China between June, 2011 and September, 2011. A total of 1860 apparently healthy dairy cows were detected from three provinces (Heilongjiang, Jilin and Liaomng) that locate in Northeast China. All milk samples were examined by California Mastitis Test (CMT). All positive milk samples were analyzed by microbiologically. The results showed that the overall prevalence of subclinical mastitis in dairy cows was 34.0% and the prevalence is similar in 3 different province whichHeilongjiang(32.0%, 236/738), Jilin(36.9%,173/469) and Liaoning (34.3%, 224/653), respectively. The prevalence in intensively reared dairy cows (15.3%, 155/1016) was lower than that in semi-intensively reared dairy cows (56.6%, 478/844), (p<0.05). The dominant bacterial isolates in the study were Staphylococcus species (32.0+26.9 = 62.9%), Streptococcus species (6.2+7.3+2.0 = 15.5%) and Escherichia coli species (12.4%). The results of this survey indicated the presence of subclinical mastitis in dairy cows in Northeast China and rearing system is an important factor to affect the subclinical mastitis in dairy cows in Northeast China and Staphylococcus specie was major pathogen. © Medwell Journals, 2012.