Antibiotic dry buffalo therapy: effect of intramammary administration of benzathine cloxacillin against Staphylococcus aureus mastitis in dairy water buffalo.

Background: Mastitis is one of the most costly diseases in Mediterranean buffalo (MB). At present, just a few specific antibiotics registered for this dairy specie have been synthetized. Efficacy of an antibiotic dry buffalo therapy (aDBT) against Staphylococcus aureus (S. aureus) mastitis, based on intra-quarter administration of 600 mg of benzathine cloxacillin, have been evaluated for the first time. Eighty MB's quarters received a drying-off therapy (aDBT-group) and 80 were left untreated (no-aDBT-group). They were sampled at drying-off (pre-treatment) and at the resumption of milking [< 10 days in milk (DIM)]. Fresh calver mastitis rate, dry period new mastitis rate, dry period cure rate, and persistent mastitis rate were calculated for clinical monitoring. Overall proportion of positive quarters/animals, quarters affected by mastitis or intramammary infections (IMI), effects on somatic cell count (SCC) and milk yield were also assessed.
Results: An inter-group difference (aDBT vs. no-aDBT) was recorded for all the indexes considered. An intra-group (drying-off vs. < 10 DIM) difference was detected in aDBT-group regarding the proportion of positive-cultured quarters and animals. Concerning the latter, an inter-groups difference was also recorded at second sampling. No clinical mastitis due to the S. aureus was observed. Regarding the subclinical ones, a higher intra-group difference was observed in aDBT than no-aDBT group, while an inter-group difference was recorded at second sampling. No protective effect was observed against IMI. SCC showed an inter-group difference at second sampling, while none difference was instead detected for milk yield.
Conclusions: The effects against S. aureus mastitis of benzathine cloxacillin administration at drying-off were assessed for the first time in MB. Its use shows encouraging results in reducing the proportion of mastitis and positive animals at the resumption of the lactation.