Mastitis is a costly and persistent issue for dairy producers, with clinical cases in early lactation leading to significant financial losses. While preventing mastitis remains a primary focus, there’s often less discussion about the specific pathogens behind the disease. Do you fully understand the impact these pathogens have on cow health and milk quality? Are the common strategies used to combat mastitis truly addressing the root of the problem?
The true cost
To understand how mastitis can be managed more effectively, it’s essential to examine the specific pathogens behind the disease. One of the most significant culprits is Streptococcus agalactiae (Strep ag.) a highly contagious bacteria that can degrade milk quality. Most infected cows show no clinical signs (such as abnormal milk) of the disease, however, they will have high somatic cell counts (SCC) and decreased milk production. Strep ag. can survive for short periods of time on things like milking equipment and teat ends, however it can only grow and multiply in the udder. This is the main reason it is considered a truly contagious pathogen as opposed to environmental.
Economic loss from Strep ag. infections come primarily from drops in milk quality and production. While management strategies and modern milking technology have greatly reduced the presence of Strep ag. infections, the consolidation of herds contribute to this pathogen’s continued threat. Additionally, during an outbreak, the cost to test, identify, and treat all infected cows can add up quickly. Proactively screening incoming purchased cows and newly fresh cows provides the ability to identify the problem before it becomes widespread.
Effective control measures
Similarly to the management of Staphylococcus aureus (Staph. aureus) and Mycoplasma bovis (M. bovis), controlling Strep ag. relies heavily on early identification of infected animals. The good news about Strep ag. is that infected cows do tend to respond well to antimicrobial interventions when proper treatment protocols are put into place. Blanket dry cow therapy has historically proven effective in reducing incidences of Strep ag. mastitis infection. The usual course of action for eradication typically includes testing the entire herd and treating all infected cows. Even with this method, ongoing testing is still required to ensure all infected animals clear the pathogen and that any new cases are identified immediately to avoid a resurgence. Additionally, efforts to sanitize the milking environment play a crucial role in managing Strep ag. infections.
Key to prevention and spread
Monthly testing of bulk tank samples for Strep ag. can be a great way to monitor the herd overall. The increased sensitivity of PCR reduces the risk of missing low-level infections, even in larger herds. When Strep ag. is detected, individual cow testing will be necessary to address the problem, typically for multiple consecutive months. Identification and treatment of infected animals is the best way to control widespread outbreaks. Proactive monitoring, even when everything seems to be going well, is the key to success.
Author: Michelle Kaufmann, CentralStar Customer Solutions Advisor
Sources:
https://www.vet.cornell.edu/animal-health-diagnostic-center/testing/testing-protocols-interpretations/streptococcus-agalactiae-strep-ag#:~:text=Streptococcus%20agalactiae%20(Strep%20ag)%20is%20an%20important,somatic%20cell%20counts%20and%20decreased%20milk%20production
https://qualitycounts.umn.edu/sites/qualitycounts.umn.edu/files/2022-01/f-mc-2.pdf