The economic pressures on the dairy industry may force more farmers to consider reducing the amount of concentrates fed to cows in order to keep costs down. We have been testing whether the long-term performance of daughters of sires progeny tested in high concentrate systems maintain their advantage over cows of average genetic merit when managed in a lower input feeding system. This paper extends the scope of our initial report (Chalmers et al., 1997) and includes data on reproductive performance.

Data were from Holstein-Friesian cows managed at the Langhill Dairy Cattle Research Centre. Sires of the Selection (S) line are among the highest available in the UK for predicted transmitting abilities of weight of fat plus protein (PTA F+P). Sires of Control (C) line cows are about UK average for PTA F+P.