In Great Britain three years ago the healthy cow index was introduced to help dairy farmers to choose sires. This provided dairy farmers a single genetic figure of which bulls were predicted to transmit the best overall health to their daughters. It has resulted in reductions in mastitis and lameness, better fertility and longer lifespans. For mastitis third calvers by the best 25 percent (Q1) sires had a 12.2 percent incidence, compared with 24.9 percent in daughters of Q4 bulls. A similar relationship is shown through all age groups. For lameness fifth calver daughters of Q1 bulls showed 13.3 percent compared with 19.2 percent for the same age group sired by the lowest quartile sires. For fertility the calving interval in every age group, the difference between Q1 and Q4 daughters was 11 or 12 days. For lifespans daughters of Q1 bulls were found to live, on average, an extra half lactation longer than those by Q4 HC bulls. Source: AHDB