Investigation Of Epidemiology Of Bovine Mastitis In Private Dairy Farms In Some Regions In China

The present study was conducted to investigate the prevalence of clinical and sub-clinical mastitis and the risk factors in 8540-quarters milk samples from 2173 cows in 105 dairy farms around six cities (Lanzhou,Chengdu,Haerbin,Zhengzhou,Jinan and Nanchang).The results showed that the cows prevalence rates of clinical and sub-clinical mastitis was 5.3%and 59.3%,respectively.And the quarters prevalence rates was 1.7%and 31.8%,respectively.The average number of somatic cells in bulk tank milk samples was 73.6×10~4/ml.At one time 340 quarters milk samples from 280 cows in 105 dairy farms around six cities were taken to isolate and identify bacteria,as part of an epidemiological investigation.A total of 316 cultures of 12 species of bacteria were grown.The cows bacteria positive rates and the quarters bacteria positive rates were 84%and 80%,respectively.A total of 180 of 7 bacterial species were closely related to mastitis,The main bacteria were Streptococcus dysgalactiae(37.78%),E.coli(24.44%),Streptococcus agalactiae(15.56%), Staphylococcus aureus(13.33%),Pseudomonas aeruginosa(4.44%),Klebsiella(2.22%)and Proteus (2.22%).The distribution of bacteria differed between cities.Out of 152 bulk tank milk samples 119 were bacteria positive(78%)and 140 cultures of 7 bacteria species were found,A total of 35 of 4 bacterial species were closely related to mastitis,The main bacteria were Streptococcus dysgalactiae (68.57%),E.coli(17.14%),Streptococcus uberis(11.43%)and Streptococcus agalactiae(2.86%).A comprehensive system was used to control mastitis in 259 adult dairy cows in 4 private dairy farms around Lanzhou.The average cow prevalence of clinical mastitis in lactation reduced from 7.34%to 3.13%and that Of sub-clinical mastitis from 58.3%to 28.52%.The average quarter prevalence of clinical mastitis in lactation reduced from 2.82%to 1.28%and that of sub-clinical mastitis from 29.61%to 15.72%.The average of milk yield increased from 4960kg to 5450kg,increase 490 kg. These bacteriological investigations indicate the bacterial distribution in private dairy farms in China and the results will aid combinative prevention and treatment bovine mastitis in private dairy COWS.