“Mastitis is a disease of details,” said Luciana da Costa during an Ohio State University Extension webinar. Any dairy farmer who has worked with identifying mastitis cases, tracking down the causative organism, finding the right treatment, and preventing similar infections from happening again can surely relate.
Pathogens that cause mastitis can be transferred via the environment or the milking process. There are also internal factors that can predispose a cow to an intramammary infection, da Costa said. And of course, there are a range of impacts on cow well-being and profitability, from milk yield and treatment costs to premature culling and reduced health. So, the associate professor walked through four steps she takes when addressing a mastitis challenge.
First is to define the problem. Identify the cows that are causing a high herd somatic cell count (SCC) or that have dealt with chronic mastitis cases. Dairy Herd Information (DHI) tests, records of clinical mastitis cases, bulk tank samples, California Mastitis Test (CMT) information, and physical exams are all methods for uncovering where an udder health problem is occurring. Look for patterns — are there certain ages of animals or groups that have more issues? “Confirming that a problem exists is half of the solution,” da Costa believes.
Next, define the organisms. “Our success is dependent on understanding what type of bacteria we have,” da Costa reminded. At the least, identifying if you are dealing with a contagious or environmental pathogen will help you determine if you need to focus on making adjustments to the milking process or the cow’s environment.
Being able to identify the causative organism also helps you make better treatment decisions. For example, da Costa said that Staphylococcus chromogenes is often the most common non-aureus Staphylococci pathogen found on farms. Although it differs from Staph. aureus, both can result in chronic infections that typically don’t respond to treatment. Knowing this will aid in culling decisions and save on costs for treatments that won’t work.
After you have determined the responsible organism, identify where it came from and how it came in contact with the cow’s udder. Many problems are often related, da Costa pointed out. Is postdipping not occurring because of insufficient training? Are stalls not bedded or cleaned well enough because of a lack of time or labor? Connecting problems to each other can help you get to the true root of the issue, she encouraged.
Finally, come up with a game plan by engaging the entire farm team — not just those involved in milking. Because mastitis develops in so many detailed ways, you never know where a pathogen may come from. Da Costa emphasized that it takes everyone to cut down on this problem. That means covering everything from making sure cow pushers know the value of cleaning stalls to feeders and herd managers recognizing that reduced eating time and cud chewing can lead to less bacterial diversity in the rumen and potentially more harmful bacteria.
Don’t forget the basics, either. Pre- and postdipping are one of the most accepted methods for reducing intramammary infections. Da Costa reminded farms that following the manufacturer’s directions for dilution and effectively covering the entire teat are more important than the specific product as long as you are using an approved dip.
Forestripping is also a critical way to find and cut down on the spread of mastitis-causing pathogens. In a study her group conducted, da Costa said only 59% of farms were stripping cows before milking. This makes it much more likely contagious pathogens will go undetected and infect other quarters. Da Costa explained that for a contagious pathogen like Staph. aureus, having one infected quarter makes the others 4.5 times more likely to become infected. If two are infected, the others are 6.8 times more likely to also become infected. And if three quarters are infected, the chances of the last quarter also becoming infected are 15.4 times more likely.
