EK

MASTITIS & METABOLIC & MISC

Mastitis Overview

Definition

Mastitis is defined as the inflammation of the mammary gland, which is typically caused by bacterial infections. The condition can affect one or more quarters of the udder, leading to significant health concerns for dairy cows and economic consequences for dairy producers.

Importance to Dairy Producers

  • Production Losses: Mastitis results in reduced yield and quality of milk. Milk produced during an active infection may be discarded or subject to penalties due to contamination risks.

  • Financial Implications: There are substantial costs associated with the treatment of mastitis, alongside withdrawal times for affected cows from milk production, which is crucial for maintaining economic viability.

  • Animal Welfare: Mastitis is associated with pain and discomfort in cows, raising serious welfare considerations for dairy farmers to address.

  • Risks: There is a risk of vat contamination with antibiotics post-treatment, which can lead to economic losses. Severe cases may result in mortality risks or potential culling of affected cows due to chronic issues.

Causes of Mastitis

  • Entry of Bacteria: Mastitis-causing bacteria generally enter the udder through the teat canal. Some pathogens like Mycoplasma may also enter through respiratory or joint routes. Bacteria can be categorized as either environmental or contagious.

  • Factors Leading to Infection: An increased bacterial presence at the teat end often indicates compromised defenses, making the udder more susceptible to infection.

Natural Defense Mechanisms of the Udder

  • Teat Skin: The skin on the teat is thick and keratinized, but can be compromised by cuts or chafing, increasing the risk of infection.

  • Teat Canal: It plays a pivotal role in protecting against contamination. The keratinized epithelium and waxy layer help form a protective plug that prevents pathogens from entering. The canal stretches during milking and takes approximately 30 minutes to contract after milking, during which the risk of infection may increase.

  • Antibacterial Agents in Milk: Milk contains various antibacterial components, such as lactoferrin, which inhibits bacterial growth, and the lactoperoxidase enzyme system that enhances milk’s natural defense. Additionally, complement proteins work to identify and neutralize pathogens.

  • Cellular Immune Response: Neutrophils are mobilized to the mammary gland as part of the immune response to combat infection, forming a crucial part of the udder’s defense mechanism.

  • Flushing Effect: The milking process effectively helps remove bacteria from the udder, serving as a natural defense mechanism against infection.

Prevention Strategies for Mastitis

Key Aspects of Prevention

  • Milking Management: Proper milking techniques and regular maintenance of milking equipment can reduce the risk of introducing bacteria.

  • Calving Management: Ensuring sanitary conditions around calving can prevent contamination during this vulnerable period.

  • Milking Machine Maintenance: Regular inspection and cleaning of milking machines are crucial to maintain hygiene and equipment efficiency.

  • Protection Against Environmental Contamination: Keeping bedding clean, dry, and well-managed reduces exposure to environmental pathogens.

  • Optimizing Teat Defenses: Regularly monitoring and maintaining the health of udder and teat integrity is essential for preventing mastitis.

  • Enhancing Immune Response: Providing adequate nutrition, including trace minerals and vitamins, is key to strengthening a cow's immune response against infections.

Severity Forms of Mastitis

  • Severe Mastitis: Symptoms may include profound depression in the cow, drastic reductions in milk yield, elevated body temperature (41-42°C), increased heart and respiratory rates, visible pain, swelling, and abnormal secretions, indicating a severe systemic infection.

  • Clinical Mastitis: Marked by noticeable changes in the appearance and condition of milk, particularly swelling or heat in the affected quarter.

  • Subclinical Mastitis: This is the most common form, which shows minimal visible changes in the udder or milk; however, there is an increased somatic cell count (SCC) indicating infection.

Types and Pathogens of Mastitis

Pathogens

  • Contagious Pathogens: Key pathogens include Streptococcus agalactiae, Staphylococcus aureus, and Mycoplasma, with the udders primarily serving as their reservoir.

  • Environmental Pathogens: Common contaminants often originating from fecal matter include Streptococcus uberis, E. coli, and Klebsiella, which thrive in unsanitary environments.

Mastitis Diagnosis and Monitoring

Diagnostic Tests

  • Regularly observing udder condition and fore milk changes, along with somatic cell counts, can provide insights into mastitis prevalence.

  • Rapid mastitis tests and milk culture assays help determine the presence of specific pathogens.

  • Monitoring bulk milk somatic cell count is essential for assessing herd health, with a target threshold set at <200,000 cells/mL; exceeding this may indicate significant problems within the herd.

Risk Factors for Mastitis

  • Host Resistance: The general health of the cow, including any existing health issues, impacts susceptibility to infection.

  • Teat Condition: Teats that are chapped or cracked can increase the likelihood of bacteria entering the udder.

  • Milking Technique: Inadequate milking procedures can lead to physical teat damage and result in higher infection rates.

  • Nutritional Status: Adequate nutrition, especially in trace minerals such as zinc and selenium, plays a significant role in enhancing the cow's natural defenses against mastitis.

Treatment Options for Mastitis

  • Intramammary Treatment: Broad-spectrum antibiotics (e.g., cloxacillin and tetracyclines) are commonly used for treating mild to moderate cases of mastitis.

  • Systematic Treatments: For severe cases, administering intravenous antibiotics and anti-inflammatory medications should be considered for effective management.

  • Dry Cow Therapy: This approach is critical for treating existing infections and preventing new infections from developing during the dry period before calving.

Conclusion

Mastitis poses a significant threat to the dairy industry, affecting both production and the welfare of dairy cows. A thorough understanding of its causes, effects, prevention strategies, and treatment options is crucial for effective mastitis management in dairy herds, leading to better health outcomes for the animals and improved economic performance for producers.