EN
Studies were conducted on the population of 936 heifers and 342 young bulls /Lowland-Black-White Breed/, reared on the free-stand farm /herd I/ and on farm pursuing the traditional technology of housing /herd II/. For both of herds, the data concerning the descent of animals, diseases diagnosed during the rearing period, size of body and growth rate in following months of life, were collected. It was documented, that 81.5 % calves from herd I and 54.7 % calves from herd II underwent the infections during the rearing period. Among of diseases occurred within the first 10 days of life, 80.0 % units were the disorders of digestion system. The most frequent diseases were noted in calves born from primiparae cows and those with the complicated parturitions. Marked differences related the number of cases and intensity of diseases were stated depending on descent from particular bulls. Within the herd, in which the heifers were subjected to the intensive medical care and therefore the growth rate in the beginning of life was not inhibited, any significant consequences of passing diseases on subsequent growth parameters were observed. Reversely, in the II herd where diseases lasted longer and the symptoms were more intensive, significant decreasing of growth rate affected also later periods of animals life.