Randomised controlled trial to evaluate the effect of foot trimming before and after first calving on subsequent lameness episodes and productivity in dairy heifers

•Lameness period and point prevalence were not significantly different between treatment groups.•The time to first lameness event was not significantly different between treatment groups.•The odds of heifer lameness were highest between 0 and 6 weeks post-partum.•Using repeated scoring at 2 week intervals allows standardised lameness detection for calculation of robust incidence rates.•44.2% of lameness events were single locomotion scores, supporting the concept of fluctuating scores and apparent self-cure.