THE DYNAMICS OF EXTERIOR – CONSTITUTIONAL PARAMETERS OF SIMMENTAL HEIFERS
The research was aimed to study the linear growth of Simmental heifers of different combinations and Herefords by the periods of their growth based on the analysis of the basic measurements data obtained in different age periods and calculated body structure indices. One group of Hereford heifers and 3 groups of sires of German and Canadian selection mated with native females were selected as objects of the study. The trials were conducted with newborn animals as well as when they achieved the age of 8, 15 and 18 months age. The basic exterior measurements of the animals were performed by means of standard methods and their live weights were determined. The animals were kept under similar feeding and maintenance conditions. However, due to the heredity factor the difference in live weights has been observed already in new – born calves and by the age of 18 months they were as follows: native Simmentals – 379.5 kg (group 1), Herefords – 381.7 kg (group II), heifers of the same age with 25% share of German Simmentals blood – 411.6 kg (group III) and heifers with 25% share of Canadian Simmentals blood – 396.5 kg. There were recorded differences in the basic measurements as well. The indices obtained were used to establish the format of body-build of the heifers under study and to reveal certain growth regularities of the animals. Hence, the Simmental heifers with the blood of animals of German and Canadian selection with age had higher indices of body wideness, meatiness, they were more compact and distinguished by harmonious body structure with well-expressed beef qualities.