Length of productive life and lifetime production of cows-daughters of high yielding dams in Poland

Records of 19 017 Black-and-White and 10 135 Red-and-White cows and their d aughters used in 1978-1993 in the South-West region of Poland were analysed . Cows-dams were classified to a group of cows with high performance if the y exceeded the assumed production level ((x) over bar +1.96s or 1.28s, resp ectively). The following traits of cows-daughters were examined: number of lactations, number of calves, lifetime production of milk and fat, lifetime , length of productive life and milk and fat yield per life day and per pro duction day. Daughters of cows with high performance produced higher milk a nd fat yields per production day than daughters of other dams. Lifetime and length of productive life of those cows were shorter.