Efficacy of targeted therapy of environmental mastitis using on-farm culturing in small dairy herds

Abstract

The aim of the study was to evaluate treatment protocols for improvement of clinical and bacteriological cure rate of non-severe clinical mastitis (CM) and selective dry cow therapy (SDCT). Mastitis management based on on-farm commercial culture system MicroMastTM and data analysis were implemented into two dairy herds. Quarters with evidence of Gram-positive agents were treated using benzyl penicillin or amoxicillin and/or by amoxicillin with clavulanic acid. In herd A, 31 quarters of non-severe CM were recorded. Of them, Streptococcus uberis was isolated in 16 (51.6%), non-aureus staphylococci (NAS) in 8 (25.8%), E. coli in 5 (16.1%) and no growth in 2 (6.5%) cases. Bacteriological cure was observed in 24/29 (82.8%) quarters. Antimicrobial consumption was reduced from 3.56 to 2.33 doses per case. Under the SDCT protocol, 28 quarters (13.2%) of 53 cows dried-off were included, achieving a reduction by 86.8% on the quarter level. In herd B, 23 quarters of non-severe CM were recorded. Of them, S. uberis and Escherichia coli were identified equally in 8 (34.8%) samples and NAS in 2 (8.7%) samples and with no growth in 5 (21.7%) cases. Bacteriological cure was achieved in 17/18 quarters (94.4%). Antimicrobial consumption was reduced from 4.45 to 1.83 doses per case. Only 5 (1.7%) quarters of 72 cows were included for SDCT with reduction in consumption of antimicrobials by 98.3% on the quarter level. In summary, innovated treatment protocols based on results of on-farm culture enabled a significant reduction of antimicrobial consumption and improvement of bacteriological cure rate in conditions of practise.