The Incidence of Clinical Mastitis and Distribution of Microorganisms in Yangtze Dairy Farm

Aims: Mastitis is a frequently occurring and economically important disease for dairy industries worldwide. This study was conducted to research the incidence of clinical mastitis and the distribution of organisms isolated from clinical cases in dairy cows of Yangtze Dairy Farm.

Study Design: 782 dairy cows were examined clinically from March to May 2017. The clinical mastitis milk samples were collected and the microorganisms were isolated and identified.

Place and Duration of Study: The study was conducted in the Yangtze Dairy Farm and the sample analysis was done at the Laboratory of Clinical Veterinary of Yangtze University.

Methodology: The animals were physically examined and the clinical mastitis milk samples were collected aseptically before antibiotic treatment. Milk samples were plated onto a blood agar and a MacConkey agar plate. The plates were examined for growth, morphology, pigmentation, hemolytic features, and the numbers of each colony type at 24, 48, and 72 h after inoculation. Identification of bacteria was done by Gram staining, inspection of the colony morphology, haemolytic reaction, and biochemical testing.

Results: The average incidence of clinical mastitis at cow and quarter levels in the study period were found to be 4.86% (38/782) and 1.63% (51/3128), respectively. The commonly recovered organisms were Escherichia coli, Staphylococcus aureus, Yeast, coagulase-negative staphylococci, coagulase-positive staphylococci (other than S. aureus), Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Proteus spp., and Corynebacterium spp. Among the isolated pathogens, E. coli, S. aureus and Yeast were the most prevalent that accounted 31.25%, 18.75% and 10.42%, respectively.

Conclusion: The incidence of clinical mastitis in Yangtze Dairy Farm was 4.86% in cow and 1.63% in quarter level, respectively. The major isolated pathogens were E. coli, S. aureus, and Yeast.