The aim of the research is to determine the growth characteristics of heifers and steers raised in the suckling period under the cow-calf system with the use of grazing and in its absence with feeding with concentrates and hay. We formed four groups of newborn calves of the Aberdeen Angus breed from cows of spring calving, 25 heads in each group. The control groups included steers and heifers kept in the suckling period on pasture, while the experimental groups included peers of animals from the control groups without grazing and fed with concentrates and roughage. All calves were under nursing mothers. In young animals of all groups, the most intensive growth rate was observed in the first months of ontogenesis, falling on the suckling period of rearing. During this period, heifers and steers of the experimental groups had average daily live weight gains of 975 and 1075 g, respectively, which was 134 g (P > 0.999) and 181 g (P > 0.999) higher than the values obtained from the control groups. The leading positions in this indicator for the whole period of ontogenesis were occupied by steers and heifers without grazing, which outperformed their peers raised under the system of distant-mountain housing in the summer period on pastures by 100 g (P > 0.999) and 60 g (P > 0.999), respectively. By the end of the study, the greatest increase in live weight compared to the values at birth was registered in the group of steers of the experimental group – 24.13 times against 21.31 times in the peers of the control group. Differences between heifers of the control and experimental groups are less significant, but, nevertheless, in favor of the individuals, which during the milk period were kept without grazing with feeding with hay and concentrates
Keywords
Steers, heifers, Aberdeen Angus breed, method of rearing, live weight, growth rate