In growth experiments, fattening performance and carcass value were determined in Black-Pied dairy and fattening hybrid bulls having a live weight of 500 kg. Specific studies were made to investigate the weight of the usable innards, the digestive tract, and the kidney and intestine fats in these genotypes and progeny groups of Black-Pied dairy cattle. Correlations show the effect of daily net weight gain on the traits under study. This effect is discussed from the viewpoints of breeding and production. In fattening hybrids bulls, the percentage of physiolgically important organs was lower (92.1%) and stomach and intestine weights were smaller (89.5%) as compared with Black-Pied dairy bulls. Intensified selection for daily net weight gain may reduce feed intake capacity and change the physiological conditions of the Black-Pied dairy cattle.