Milk recording data highlight improvements in fertility and somatic cell counts but worsening longevity for the UK national dairy herd

• Herd size has increased but the proportion of cows in lactation 1 remained stable • Exit rates have increased in line with cows exiting the herd at a younger age • All fertility parameters have significantly improved, including conception rates • Milk yield per cow per year peaked at 8,797 kg in 2021 but decreased in 2021/2022 • The percent of cows dried-off with no SCC recordings ≥ 200,000 cells/ml increased Benchmarking of key performance indicators (KPIs) can be used by farmers and technical advisors to indicate areas for improvement and enable them to make more informed management decisions. Data for selected KPIs are readily available from a variety of sources. However, longitudinal data covering a mixture of KPIs in the same dataset are limited. Herein, milk recording data are used from a cross-section of 195 UK Friesian/Holstein herds which have milk recorded for a minimum of 10 years to examine trends in the median herds’ KPIs from 2014 to 2023. Herd size has increased by 15.8% but cows are being culled at a younger age. Fertility parameters have improved, most notably conception rates increased from 32.9% to 40.0% and the percent of cows conceived 100 days post-partum (DPP) increased from 30.4% to 39.0%. From 2014 to 2021, milk yield per cow per year increased from 8,394 kg to 8,797 kg and lifetime milk yield per cow per day increased from 11.7 kg to 12.8 kg, but both decreased slightly in 2022 and 2023. Many somatic cell count (SCC) related parameters improved between 2014 and 2023. Notably, the percent of cows dried-off with no SCC recordings ≥ 200,000 during a completed lactation increased from 39.7% in 2014 to 51.0% in 2023. Therefore, fertility and SCC related KPIs have demonstrated improvements but milk production appears to have peaked and recently plateaued, and the longevity of cows appears to have shortened. Decreased longevity appears at odds with pressure on farmers to attain environmental targets which would favour cows with longer, more productive lives.