Ketoprofen as an alternative to antibiotics in the treatment of non-severe mastitis in dairy cows

Mastitis in dairy cows, which is literally the inflammation of the udder, is a common condition and, therefore, has a significant economic impact on farms. Most of the time, mastitis is due to an infection by a Gram-positive or Gram-negative bacterium. Therefore, antibiotics have been the go-to treatment for this disease. The condition not only affects the health and well-being of the cows but also impacts milk production and quality. Furthermore, when infection is treated with anti-infective, milk must be discarded from human consumption because of the withdrawal period of antibiotics drugs.

However, with growing concerns about antibiotic resistance and the push for more sustainable farming practices, researchers are exploring alternative treatments. A recent study published in 2025 by Krömker et al. investigates the efficacy of using ketoprofen, a non-steroidal anti-inflammatory drug (NSAID), as the sole initial treatment for non-severe cases of bovine mastitis. The findings suggest that this approach could significantly reduce antibiotic usage while maintaining effective treatment outcomes.

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Summary of the study (Kromker et al., 2025)

The study aimed to compare the effectiveness of ketoprofen against traditional antibiotic treatments for non-severe mastitis in dairy cows. The research involved 222 cases of non-severe clinical mastitis across three conventional dairy farms in Northern Germany. The cows were divided into two groups: one treated with ketoprofen and the other with intramammary antibiotics.

Farms and Cows

The research was carried out from August 2022 to November 2023. The farms were selected based on their participation in the dairy herd improvement (DHI) system and their willingness to engage in the study. The farms varied in size, with herd sizes ranging from approximately 384 to 1200 lactating German Holstein Friesian dairy cows. The annual milk production per cow ranged from 9,700 to 11,800 kg, and the bulk milk somatic cell counts (SCC) varied between 170 and 320 kcells/mL.

Inclusion criteria for the cows were stringent: only those with spontaneous, non-severe (mild or moderate) clinical mastitis (CM) and no antibiotic treatment in the preceding four weeks were included. Each cow had to be identifiable with a unique ear tag and free from significant udder, teat, or other concurrent diseases. The severity of mastitis was classified according to the International Dairy Federation (IDF, 2011) guidelines, with mild cases showing only changes in milk appearance and moderate cases exhibiting local clinical signs of udder inflammation but no global clinical signs such as hyperthermia for example.

Protocol

The 222 cows included in the study were randomly assigned to one of two treatment groups:

• Antibiotic Group (AB): Cows received local antimicrobial treatment with two applications of 200 mg cefalexin and 100,000 I.E. kanamycin at 24-hour intervals.
• Ketoprofen Group (KE): Cows received systemic treatment with ketoprofen intramuscularly at a dose of 3 mg per kg body weight, administered three times at 24-hour intervals. If there was no clinical improvement by day 3, cows in this group received additional intramammary antibiotic treatment as in the AB group.

Study Procedure

During daily milking routines, CM was detected and classified by trained milking personnel. If a cow met the inclusion criteria, a foremilk sample was aseptically collected for microbiological analysis. The cows were then treated according to their assigned group. Clinical examinations were performed every 8-12 hours for at least six days, with any abnormalities reported by farm staff.

Milk samples collected were frozen until bacteriological culture. Pathogens were identified using Gram staining and further analysed with MALDI TOF mass spectrometry.

The primary outcome measured was clinical cure at day 5. Secondary outcomes included bacteriological cure, recurrence of clinical mastitis within 60 days, and new infection risk. Clinical cure was defined as the absence of clinical symptoms in milk and udder quarter, while bacteriological cure was defined as the absence of the pre-treatment pathogen in post-treatment samples.

Results of using ketoprofen to treat non-severe mastitis in dairy cows

Among the 222 dairy cows with clinical mastitis included in the study, 118 cases were assigned to the antibiotic group (AB) and 104 cases to the ketoprofen group (KE). The severity of mastitis was classified as mild in 148 cases and moderate in 74 cases. Pathogens were detected in 75.2% of the quarters, with the most commonly isolated pathogens being Streptococcus uberis (23.4%), Non-aureus staphylococci (NAS) (10.1%), Escherichia coli (9.6%), and Streptococcus dysgalactiae (7.3%). No pathogens were detected in 24.8% of the cases.

Clinical Cure at Day 5 and bacteriological cure

• After adjusting for covariates, the clinical cure rate in the KE group was 67.8%, compared to 91.2% in the AB group. However, the difference in the clinical cure rate is mostly linked to streptococci infection, which were the most isolated pathogens. Conversely, the difference between the two treatment groups is not significant when we consider Gram-negative or staphylococci mastitis.
• In the same way, the probability of bacteriological cure was significantly higher in the AB group (79.3%) compared to the KE group (61.2%). However, the treatment groups did not differ significantly from each other in terms of bacteriological cure at pathogen group level.

Recurrence of Clinical Mastitis within 60 Days and New Infection Risk

• The recurrence rate of clinical mastitis within 60 days after the end of treatment was significantly lower in the AB group (7.3%) compared to the KE group (15.7%).
• The new infection risk did not differ significantly between the treatment groups, with an overall rate of 6.8%.

Antibiotic Reduction and Milk Losses

• The use of ketoprofen as the initial treatment led to an 86% reduction in antibiotic doses compared to the AB group.
• The amount of waste milk per mean case was significantly lower in the KE group (152 kg) compared to the AB group (243 kg), resulting in 91 kg (37.4%) less waste milk per case in the KE group.
• The multivariable analysis showed that the milk loss in the AB group up to clinical cure was 231 kg, compared to 144 kg in the KE group, with a difference of 87 kg.

Conclusion

While antibiotics remain essential for severe cases, ketoprofen presents a sustainable and economically advantageous alternative for mild and moderate cases. Although, the results of this study indicate that while ketoprofen is inferior to antibiotics in terms of clinical and bacteriological cure rates, it offers significant advantages in reducing antibiotic usage and milk losses. Indeed, the reduction in antibiotic doses and waste milk associated with ketoprofen treatment makes it an attractive alternative for the initial treatment of non-severe bovine mastitis, particularly in cases where the causative pathogen is not Gram-positive.

Further research is still needed to optimize treatment protocols and minimize recurrence rates. Nevertheless, the results of this study suggest that ketoprofen could play a significant role in reducing antibiotic usage in dairy farming.

Key messages

• Mild and moderate cases of mastitis may not always require antibiotic treatment. They can be effectively managed with ketoprofen alone, reducing the need for antibiotics.
• Using ketoprofen instead of antibiotics in non-severe mastitis in dairy cows, farmers can decrease the amount of milk that must be discarded due to antibiotic withdrawal periods.
• Reducing antibiotics consumption contributes to the global effort to combat antibiotic resistance.

References

IDF (International Dairy Federation). Suggested interpretation of mastitis terminology. Bulletin of the IDF, 2011; 448, Brussels, Belgium.

Krömker, V., Falkenberg, U., Wente, N., Zhang, Y., Leimbach, S., Nitz, J., ... & Nankemann, F. (2025). Ketoprofen as the sole initial treatment for non-severe bovine mastitis: efficacy and antibiotic reduction. Journal of Dairy Science.