Mastitis in Dairy Cows: Economic Implications and Breakthrough Treatments

Mastitis: Causes and Contributing Factors

Mastitis, primarily caused by bacterial infections (e.g., S. aureus, S. agalactiae, E. coli, and Pseudomonas aeruginosa), can also be triggered by various other microorganisms like fungi, algae, mycoplasmas, and viruses. The disease's complexity stems from interactions among microorganisms, udder anatomy and physiology, dairy practices, milking equipment, procedures, and environmental factors. Studies by Klastrup et al. suggest that 25% of susceptibility to infection is linked to environmental factors, 20% to genetic factors, and 50% to herd management. The udder's anatomical vulnerability makes it prone to both inflammatory and non-inflammatory conditions due to external influences.

Mastitis can be present in clinical or subclinical form as the inflammation of the mammary gland, accompanied by changes in milk composition and pathological alterations in udder tissue. Subclinical mastitis, more prevalent and often unnoticed, poses long-term economic losses and serves as a persistent infection source within herds. This form lacks visible macroscopic changes and requires laboratory tests for detection, typically through bacteriological examination and somatic cell count (SCC) analysis at the individual cow level and bulk milk testing at a larger scale.

Subclinical Mastitis: The Silent Threat

Subclinical mastitis, often undetectable in its early stages, poses a significant risk of progressing to clinical mastitis post-calving. Detecting subclinical cases is challenging due to the absence of obvious signs, complicating diagnosis in dairy management and veterinary practice. Subclinical mastitis is 15 to 40 times more prevalent than clinical mastitis, preceding it and persisting for extended periods, making affected animals continuous sources of infection within herds. Subclinical and clinical forms both lead to substantial economic losses, primarily through reduced milk production and quality. These losses, which account for 70–80% of the total economic impact, include milk discard, veterinary expenses, and the high costs associated with conventional antibiotic treatments. Despite their efficacy, antibiotics carry risks such as drug resistance, milk contamination with residues, and disruption of the host's gut flora when administered systemically.

The Economic Impact of Mastitis

Mastitis has profound economic implications for the dairy industry both globally and within the European Union. It is one of the costliest diseases in terms of production losses, stemming from reduced milk yield, increased veterinary costs, milk discard after treatment, and premature culling of affected cows.

On a global scale, the total annual economic losses due to mastitis are estimated at around $35 billion. A significant portion of these losses, approximately 70-80%, is attributed to reduced milk yield. Additionally, milk discard after treatment accounts for about 5-10% of the total losses, veterinary costs approximately 7-10%, and premature culling contributes to around 10-15% of the economic burden.

In the EU, one of the largest dairy-producing regions globally, the annual economic losses due to mastitis are estimated at around €2 billion. Within this region, reduced milk yield accounts for about 50-70% of the total economic losses, milk discard after treatment is responsible for 8-12%, veterinary costs range from 6-10%, and premature culling contributes around 12-15%. This breakdown highlights the significant financial impact of mastitis, emphasizing the need for effective management and treatment strategies to mitigate these losses.

Beyond financial losses, it is worth to mention, that mastitis also poses risks for transmitting zoonotic diseases such as tuberculosis, brucellosis, leptospirosis, and streptococcal sore throat to humans.

The Shift in Mastitis Therapy: Addressing Antibiotic Resistance and Costs

Traditionally, antimicrobial intramammary infusions have been the primary agents used to treat and control mastitis. However, the widespread use of antibiotics has led to several issues, including milk contamination, persistence of antibiotic residues in milk, and the development of antibiotic-resistant bacteria.

In the European Union, various antibiotics are employed in intramammary infusions to treat and control mastitis in dairy cows, including penicillins (e.g., penicillin G and cloxacillin), cephalosporins (e.g., cephapirin and cefquinome), aminoglycosides (e.g., neomycin and gentamicin), macrolides (e.g., tylosin and erythromycin), tetracyclines (e.g., oxytetracycline), and lincosamides (e.g., lincomycin). However, the effectiveness of these treatments is increasingly compromised by the development of antibiotic resistance.

For instance, resistance to penicillin G and cloxacillin is commonly reported among Staphylococcus aureus strains due to β-lactamase production. Similarly, resistance to cephalosporins like cephapirin and cefquinome is rising among Gram-negative bacteria such as E. coli. Aminoglycoside resistance, particularly to neomycin and gentamicin, is seen in bacteria like Pseudomonas aeruginosa, while macrolide resistance, involving tylosin and erythromycin, is observed in Staphylococcus aureus and Streptococcus species. Additionally, widespread resistance to oxytetracycline, driven by efflux pumps and ribosomal protection proteins, affects Gram-negative bacteria, and lincomycin resistance is noted among some Gram-positive bacteria.

Due to these concerns, there is a growing interest in alternative methods for treating and controlling mastitis. Herbal medicine is one promising alternative that has gained attention for its safety, efficacy, and cost-efficiency.

Regulatory Framework of Antibiotic Dry Cow Therapy in the European Union

Prophylactic antibiotic dry cow therapy is allowed in the European Union under specific conditions and regulations. It is a common practice aimed at preventing new intra-mammary infections in dairy cows during the dry period (the period between lactation cycles). However, its use is strictly regulated to minimize the risk of antibiotic residues in milk and to mitigate the development of antibiotic resistance in pathogens. The EU sets guidelines and restrictions regarding the types of antibiotics that can be used, the timing of administration, and withdrawal periods to ensure food safety and animal health standards are met. Organic dairy farms in the EU are prohibited from using antibiotics, including for dry cow therapy, and must rely on alternative management practices to prevent mastitis.

Herbal Formulations: Promising Alternatives for Mastitis Treatment

Herbal formulations such as MASTILEP GEL (Ayurvet Ltd.) have shown promise as alternative treatments for mastitis. This herbal preparation contains active ingredients like Cedrus deodara, Curcuma longa, Glycyrrhiza glabra, and Eucalyptus globulus, known for their antibacterial, anti-inflammatory, analgesic, antihistaminic, and immunomodulatory properties. numerous clinical studies have demonstrated the effectiveness of these herbal treatments in reducing somatic cell counts, increasing milk yield, and improving overall udder health. It functions as a non-irritant protective emollient, checks growth of microorganisms, and maintains hygiene, health, and productivity of the mammary gland when applied during different stages of lactation. These herbal treatments provide a safe, effective, and economical option for managing mastitis without the adverse effects associated with antibiotic use. Numerous clinical studies on MASTILEP have reported its usefulness in reducing SCC (somatic cell count) to normal, increasing milk yield and milk fat percentage in subclinical mastitis in cows. 

Cytokine Modulation: Understanding the Mechanisms of MASTILEP

Cytokines play a crucial role in the immune response during mastitis, an inflammation of the mammary gland usually caused by bacterial infection. When mastitis occurs, cytokines such as interleukins (IL-1, IL-6), tumor necrosis factor-alpha (TNF-α), and chemokines are released by immune cells in the mammary tissue. These signaling molecules help coordinate the body's defense mechanisms by promoting inflammation, recruiting white blood cells to the site of infection, and enhancing the bactericidal activities of immune cells. This inflammatory response, while essential for fighting off the infection, can also lead to tissue damage and the symptoms associated with mastitis. Modulating cytokine levels is a potential therapeutic strategy to manage inflammation and improve outcomes in mastitis cases.

Herbal molecules can influence cytokine production and activity, thereby modulating the immune response:

1. Inhibition of Pro-inflammatory Cytokines: Certain herbal compounds (such as the ones present in Curcuma longa and Glycyrrhiza glabra) can inhibit the production of pro-inflammatory cytokines like TNF-α, IL-1, and IL-6. This helps reduce inflammation and alleviate symptoms of conditions like mastitis.
2. Enhancement of Anti-inflammatory Cytokines: Some herbs (as Paedaria foetida and Cedrus deodara) can increase the production of anti-inflammatory cytokines, promoting a more balanced immune response.
3. Modulation of Immune Cell Signalling: Herbal molecules (as the ones found in Eucalyptus globulus) can affect the signalling pathways within immune cells that lead to the production of the production of pro-inflammatory cytokines.
4. Antioxidant Activity: Many herbs have antioxidant properties, which can reduce oxidative stress and subsequently decrease the production of pro-inflammatory cytokines, thereby reducing inflammation.

By influencing cytokine activity, herbal molecules can help manage inflammation and improve immune function, making them valuable in the treatment of inflammatory diseases like mastitis.

MASTILEP topical udder gel has demonstrated significant efficacy in both subclinical and clinical mastitis (Joshi et al., 1996). To elucidate MASTILEP's mechanism, a study has been done in order to identified its phytoactive constituents and targets. It has been concluded that the ingredients of MASTILEP gel influence cytokines by acting as an immunomodulator that dynamically regulates inflammatory molecules and enhances host cytokine responses. These mechanisms help manage inflammation and support immune responses crucial for addressing bovine mastitis effectively (Bhatt et al., 2014).

Optimizing Dairy Herd Health: Advanced Mastitis Management Techniques

Effective management practices are crucial for controlling mastitis. Maintaining a hygienic environment, ensuring proper udder health, and enhancing udder immunity are essential strategies. Both pre and post milking teat disinfection are the most effective management strategy for preventing new intra mammary infections in dairy cows. The use of herbal medicine, along with adequate nutritional supplementation, can help manage and prevent mastitis. Antioxidants like Vitamin E and selenium also play a significant role in boosting the immune response and maintaining udder health. Macro and micro minerals such as calcium, phosphorus, copper, cobalt, and manganese are also important for regulating the inflammatory process and overall homeostasis.

Conclusion

Mastitis remains one of the most prevalent and costly diseases affecting the dairy industry. Its economic impact is significant, encompassing decreased milk production, poor milk quality, increased veterinary costs, and higher culling rates. Traditional antibiotic treatments, while effective, pose risks of milk contamination, antibiotic residues, and resistance. Herbal medicine emerges as a viable alternative, offering safe and effective treatment options for mastitis. By integrating herbal formulations (such as MASTILEP) and adopting holistic management practices, dairy farmers can better control mastitis, improve animal health, and enhance overall productivity.