Currently robbing the U.S. dairy industry of $1.7 billion a year, mastitis can be debilitating to a dairy operation because of decreased milk production and increased chronic health problems.

“With demand for higher milk quality standards increasing, dairy producers need to implement measures to prevent, control and treat mastitis,” said Jerry Olson, DVM, MS, Pfizer Animal Health. “Such measures should include identifying both clinical and subclinical mastitis and instituting efficient protocols for effective treatment.”

Effects of clinical and subclinical mastitis
Three studies have shown 8 to 15 percent higher conception rates for animals not affected by mastitis in comparison to those experiencing clinical cases. Uninfected animals became pregnant faster with approximately 19 to 25 fewer days open.

“Reduced milk quality, decreased reproductive performance, extra labor, increased replacement cow costs, veterinary fees and treatment costs all reinforce the importance of implementing a control plan, regardless of a cooperative bonus plan,” Olson said. “Not only can mastitis impact a cow’s milk production, but also her reproductive performance.”

A good control practice for avoiding devastating effects on any dairy is to categorize clinical mastitis events by their level of visual severity – mild, medium or severe.


Mild mastitis is visually recognizable by the appearance of a few flakes and clots, which may not be caught in herds that do not fore-strip.

Medium mastitis displays flakes and clots in the milk, which are indications of inflammation of the udder, an infected swollen quarter or possible redness and disparity in comparison to the matching quarter.

Severe mastitis is recognized through abnormalities in the milk, indications of inflamed glands and systemic signs of the cow being ill. These cows may be off-feed, lethargic or appear to be lame because of the swollen quarter.

Unlike clinical mastitis, subclinical mastitis must be determined through testing and culture sampling. Depending on the situation, the producer may be testing cows individually through the National Dairy Herd Information Association (DHIA) or monitoring bulk tank somatic cell counts (SCC) to identify overall herd SCC changes. With individual SCC scores, a strong correlation exists between the linear score and the amount of milk lost due to mastitis.

Tips to avoid mastitis in the herd
Along with the ability to identify clinical and subclinical mastitis, producers should practice tips for preventing mastitis in herds. The National Mastitis Council has developed a five-point program for producers to implement as standard protocol on all dairies. This includes post-milking teat disinfection, total dry cow therapy, therapy of clinical cases during lactation, proper maintenance of the milking machines and culling chronic problem cows.

“Maintaining a clean environment is important in limiting mastitis infections,” said Francisco Rivas, quality milk manager, Pfizer Animal Health. “Producers can treat all they want, but the infection rate will remain high unless the cow environment is less hospitable to mastitis pathogens.” Things such as composting manure and utilizing a proper milking routine can go a long way in lowering incidence rates.

In addition, record keeping and a solid protocol are two tools a producer should utilize in the fight against mastitis. Computer programs designed to help track events such as mastitis will help producers track infected cows and the frequency of infection. “Producers can benchmark their subclinical infection rate and set a goal through proper protocols to bring that number down,” Rivas said. “Even dropping the incidence rate a few percentage points can pay dividends.”

Although these initial points are very effective, additional tools are available to producers. First, producers should add routine vaccination of cows with E. coli J-5 Bacterin to the system. This helps control clinical signs associated with coliform mastitis. Second, producers should establish a prevention plan that includes an internal teat sealant, such as ORBESEAL®. Fifty percent of the clinical mastitis cases that occur within the first 30 days post-calving are the result of new infections that have occurred in the dry period. Tools such as ORBESEAL can reduce these infections and thus help avoid mastitis being introduced.

“Instituting an on-farm protocol will help with the treatment of mastitis also,” says Olson. “Protocols should be developed by both the producer and veterinarian to help define how to reach a diagnosis, as well as provide a treatment protocol that automatically kicks in after diagnosis.”

Disease prevention programs are an important part of keeping cows healthy. A sound mastitis prevention program, including the identification of mastitis, helps keep cows healthy and may increase the milk quality premiums producers receive. PD

References omitted due to space but are available upon request by emailing .

Excerpts from Pfizer Animal Health news release