What Are the 3 T’s of Mastitis Protection?
As we've discussed previously, mastitis is a costly disease not just in terms of production loss but also in treatment expense.
Control programs aim to prevent the incidence of the disease and minimize production loss while treating the infection as effectively and economically as possible. Effective control programs are generally two-pronged:
- Targeting the causative pathogen for individual infections (rather than following a blanket treatment approach) aims to speed recovery and decrease the risk of reinfection.
- Targeting the infected cow’s lactation point to determine treatment is generally intended to decrease production loss.
Somatic Cell Count (SCC) testing is an important element in any control program. Counts are essential during and after the treatment period to ensure that the treatment was successful and the infection has cleared. This will also aid in refining targeted treatment protocols.
What are the 3 T's of mastitis protection?
There are many different organisms that can cause mastitis, the two most common being Staphylococcus aureus and Streptococcus spp. Pathogenic species have different modes of transmission and host immune responses, therefore each pathogen responds differently to control measures and treatments.
Staphylococcus aureus is a contagious pathogen that is mostly transmitted at milking time on equipment or hands from infected cows to uninfected cows, spreading throughout the herd. Streptococcus spp. are mostly environmental pathogens, originating in soiled bedding, then multiplying on the udder skin and penetrating the teat canal.
Lactation point also plays a role in targeting treatment effectively. The risk of the disease is higher at the start of the dry period as pressure in the udder increases, dilating the teat canal and giving easier access to bacteria. The periods of colostrogenesis (3-4 weeks pre-calving), calving and early lactation are also high-risk due to the natural state of immune suppression. Mastitis occurring early in lactation has the potential to incur severe production losses if not treated appropriately, as well as increase the risk of reinfection late in the lactation period.
After targeting the causative pathogen and lactation point, an effective treatment plan can be developed. Some contagious pathogens, especially Staphylococcus aureus, have a poor response to antibiotics and infected cows may need to be segregated or even culled to avoid transmitting the disease to the rest of the herd. Most environmental pathogens respond well to antibiotics and are easier to control through proper barn and cow hygiene. Veterinary professionals should always be consulted for treatment products and dosages.
Mastitis occurring in late lactation is effectively and economically treated by drying off early. Less yield is lost and antibiotics are generally more effective during the dry period due to the absence of a growth medium (milk) in which bacteria multiply. Dry therapy also eliminates the need to withhold milk after the infection is cleared to avoid antibiotic residues in the bulk tank.
The incidence of subclinical mastitis in early lactation with a decrease in SCC during late lactation likely indicates a dry cow management problem or environmental risk issues in maternity pens. The incidence of mastitis increasing throughout lactation points to contagious pathogens and improving milking hygiene, practices and equipment cleaning protocols may be required.
Effectively clearing a mastitis infection doesn’t stop at administering treatment. Cows undergoing treatment should be tested for SCC throughout the treatment and recovery period for several reasons. As in the case of Staphylococcus aureus infections discussed above, there is a high risk that the infection will be non-responsive to antibiotic treatment.
Testing such cows after attempting treatment ensures that a decision can be made to segregate or cull rather than potentially reintroduce an infection reservoir into the herd. Depending on the SCC level after treatment, milk sample culturing may be necessary to determine if the infection is a relapse from unsuccessful treatment or a new infection by a different pathogen species.
Testing after dry cow therapy ensures that management and therapy during this high-risk period is effective and can predict whether a certain cow may be likely to experience an infection later in lactation. SCC testing throughout the treatment period can help establish general timelines for recovery from infection by specific pathogens. Monitoring SCC also helps create more effective treatment protocols based on causative pathogen and lactation point.
Mastitis incurs costs to farmers through production loss as well as treatment and control costs. Targeting a treatment plan to a causative pathogen and lactation point, as well as SCC testing of treated cows ensures efficient, effective treatment and establishes specific treatment protocols for future cases.
Having these protocols in place allows treatment to be started as quickly as possible, minimizing losses and increasing the probability of clearing the infection.
About the Author
Anna Schwanke is an undergraduate student at the University of Guelph, Ontario. She is responsible for researching and writing about a wide variety of topics related to dairy cow welfare and management for Dairy Quality Inc. The 10 years she spent living in Australia, as well as her love of travelling, give her a firsthand viewpoint of issues facing the international dairy community. She plans to graduate from the University’s College of Physical & Engineering Science in 2019 and pursue a career in the Life Sciences or Agriculture industry.
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