Evidence-Based Use of Antibiotics in Meat Calves

Abstract

Abuse of antibiotics is an increasing commonly feature in the media. Widespread preventive use of antibiotics without diagnostics in meat calf husbandry is a major public health concern. In this study, we compare a " trial and error " method, comprising of a first choice antibiotic, followed by a second and third choice (as recommended by the WHO), with a method which utilizes an antibiotic resistance test to first identify the best antibiotic out of first, second or third choice alternatives using decision tree analysis. Data were collected from farms with a known calf herd problem along with antibiograms from those herds. Samples were analysed for resistance to antibiotics against calf pneumonia on a herd level, rather than for resistance against specific antibiotics. Resistance tests were performed on batch samples composed of at least three diseased animals. A deep nasal swap was taken. In nasal swaps only ++ or +++ growth in all 3 samples were used for diagnosis. Other growth of bacteria was considered as contamination. A comparison of resistance rates across a range of antibiotics between farms with known calf pneumonia and calf diarrhoea issues was performed. The decision tree analysis presented provides strong support in favour of an evi-dence-based approach to antimicrobial treatment by using an antimicrobial resistance test, pro-viding an advantage of 58% per meat calf against the " trial and error " method, giving a financial gain of some CHF 320.09 under Swiss economic circumstances.