Impact of adopting non‐antibiotic dry‐cow therapy on the performance and udder health of dairy cows

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Background On dairy farms, the prophylactic use of antibiotics at drying‐off is being increasingly challenged. The objective of this study was to examine the effect of antibiotic dry‐cow therapy (DCT) or non‐antibiotic DCT on dairy cow performance and udder health. Methods Holstein cows ( n = 285) with low risk of intramammary infection (<200,000 cells/ml) were assigned to one of two treatments, either antibiotic DCT (A + TS; antibiotic treatment in combination with internal and external teat sealants) or non‐antibiotic DCT (TS; internal and external teat sealant only). Results There was no statistically significant ( p > 0.05) difference between treatments for mean cow milk yield, composition or energy corrected milk yield. Mean somatic cell count was 0.16 log e higher in the TS treatment (95% confidence interval [CI]: −0.00 log e to −0.33 log e ) compared to A + TS treatment ( p = 0.047). A 50% increase in the number of mastitis cases was observed in the A + TS treatment compared to TS treatment (odds ratio = 1.5, 95% CI: 0.80%–3.01%), although this was not significant. There was no statistical evidence ( p > 0.05) that treatment had any effect on colostrum quality and composition. Conclusion Results indicate that non‐antibiotic DCT can be adopted in ‘low‐risk’ cows who were offered grass silage‐based diets in cubicle accommodation, with low risk of adverse effects on performance or udder health.