Assessment of Milk Yield and Composition During Bovine Mastitis Caused by a Variety of Pathogens
A better understanding of milk alteration during mastitis at genus-species level of causative pathogen is essential to guide prospective control strategies. The current study aimed to identify the correlation between individual genus or species of pathogens causing bovine mastitis and alteration of milk volume and composition. The study was conducted at individual cow level (n=2,676) from a commercial dairy farm near Mount Gambier, SA, Australia. Milk samples were subjected to conventional microbial culture. A database of individual cow yield production parameters (yield, total milk solids, fat and protein percentage) and somatic cell count (SCC) was obtained from herd testing information. Results showed five individual pathogens at genus or species level isolated from milk. Mixed growth was the most common (30.3%) followed by Coagulase negative Staphylococci CoNS (15.6%), Staphylococcus aureus 231 (8.6%), Streptococcus spp. 152 (5.7%), Escherichia coli 134 (5.1%), Enterococcus spp. 122 (4.6%), and there was “No growth” in 807 (30.2%) samples. Milk quality and quantity were affected by all individual pathogens. S. aureus showed the highest effect on milk yield. Similarly, Enterococcus spp. has the most significant effect on SCC. However, Escherichia coli revealed mild to non-significant effect on milk volume and components. Mastitis pathogens varies across regions and times, and the implications of the current study will contribute to the control of bovine mastitis.