Prevalent Mastitis-Causing Bacteria In Dairy Cows And Therapy Of Mastitis With Nisin

Mastitis, one of widespread disease for dairy cows, made a great loss to dairy production with high incidence. Subclinical mastitis can result in an elevated milk SCC and decrease milk yield, change the composition of milk to influnce milk quality. If the disease was not treated in time, subclinical mastitis may lead to clinical mastitis, even teat blind or culling. At present, intramammary infusion of antibiotics is the main approach to mastitis, however, this can increase the resistance of mastitis pathogens, residues in milk and accumulation in vivo, which does harm to human.To investigate the pathogen of bovine mastitis, there were Staphylococcus aureus, CNS and Streptococcus agalactiae.The result of susceptivity showed that Staphylococcus aureus was resistant to Penicillin, Oxacillin and Ampicillin, but sensitive to Cefitiofur Amikacin and Vancomycin. To study the Staphylococcus aureus by PFGE, the result indicated the comparability of S.aureus separated from two dairy farms was type A, belong to the same epidemic pathogen. The residue of antibiotic in milk was detected by ECLIPSE50 after treating mastitis with GentamycinIn this study, bovine subclinical mastitis was detecded by HMT every month.Then the subclinical cases were treated with Nisin at a dose of 2.5×106 IU once daily.The SCC and bacterial scores of bulk milk were decreased after treatment.The proportion of lactose and Total Solid in milk was increased compared with the control group. During the treatment with Nisin, the residues of Nisin can not be detected by ECLIPSE50. The subclinical mastitis was treated with Nisin, the bulk SCC and total bacteria count were lower than the control group, while the percentages of protein, lactose and NSF were higher than the control group.The result indicated subclinical mastitis can be treated effectively with Nisin.