Clinical mastitis remains an important animal health issue, affecting from 20% to 30% of dairy cows at least once during lactation. Lack of Mastitis infection control in cattle causes heavy economic losses to milk producers and to the dairy industry as it causes a reduction in the quality of milk and output, and increases veterinary expenses due to excessive use of medications, and risk of residues in the milk/ meat. Consequently, this becomes a public health issue.

Estimated costs per infection of clinical mastitis range from $178 to $489 depending on stage of lactation, milk prices and production level in affected cows.

The most common causes of antibiotic use in dairy cows are the treatment and prevention of mastitis. In order to avoid its indiscriminate antibiotic use and to reduce the economic burden of clinical mastitis, it is critical to implement an on-farm rapid identification of the pathogens.

CHROMagar^TM Mastitis is a new commercially available tool for the rapid and simple differentiation of the key bacteria involved in Mastitis infections. This new product is supplied as a kit with two separate media, one for gram-positive bacteria (GP), and the other for gram-negative bacteria (GN).

Colony Appearance on CHROMagar Mastitis GP

• Strep agalactiae → blue-green
• Strep uberis → metallic blue
• Staph aureus → mauve with mauve halo
• Gram negative bacteria → inhibited

Colony Appearance on CHROMagar Mastitis GN

• E.coli → red
• Klebsiella, Enterobacter, Citrobacter → metallic blue
• Proteus → brown halo
• Pseudomonas → cream, translucent
• C.albicans → white, opaque, small
• Gram positive bacteria → inhibited