EN
The trial was performed on 208 heifers of Lowland Red-White breed raised in south-western part of Poland /Breeding State Farm in Głogówek, Opole voivodeship/. Their body weight was checked at birth, 18 months of age, 10 days before parturition and 100, 200 and 300 days after calving. The influence of growth rate /daily gains/ of heifers during rearing on body weight before calving, on milk yield during 1-st lactation and on fertility were investigated. There were 3 groups of heifers based on daily gains: to 650 g, from 651 to 750 g and over 750 g. It was found that growth rate and body weight of actually reared heifers of Lowland Red-White breed had no deterimental effect on milk and fat yield during 1-st lactation. Heifers after parturition were losing in average 67,8 kg /11,5%/ of their body weight and were gaining during lactation inaverage 69,3 kg /13,3%/. High milk yield was followed by more severe decrease in body weight after calving and smaller body gain during lactation what was the cause of lengthening of service period and decrease in fertility.