Methods for regulating the cows’ reproductive function have been introduced into agricultural practice long ago. In most cases, the schemes existing in the Republic of Belarus are used in dairy farming. The present study is aimed at studying the effectiveness of using the “CO-Synch” scheme with subsequent resynchronization on Limousine beef cows and heifers using pharmacological agents, taking into account the animals age and the calving season. It has been found that the use of the sexual cyclicity synchronization-stimulation “CO-Synch” scheme contributed to the achievement of cows’ breeding efficiency in 43.9–55.5% of cases. The initial injection of hormonal preparations to heifers has contributed to fertile conception in 9.0–12.5–47.6% of cases. Resynchronization has increased their breeding efficiency to 50.0–63.6%. The best breeding efficiency of 60.0–61.5% has been observed in cows aged 5–9 years. Pregnancy has been found in 75.0% of animals calved in winter, 71.9% in spring, and 66.7% in summer.
Modern selection of beef cattle is impossible without a comprehensive assessment of the breeding value of an animal, which allows to analyze the transfer of a selection trait to offspring, to separate factors of production environment, to move from historically established phenotypic to genetic selection, in which selection of animals is formed only by their genotype. The article contains the results of research, the purpose of which was to study the genealogical structure and exterior-constitutional features of the Limousin breeding stock, bred in JSC “Turovschina” of Zhitkovichi district of Gomel region. It has been established that the greatest number of cows of the selection group belongs to the genealogical lines of bulls: KERN 767553941 (51 heads), NEBULEX 1096 (14 heads) and No. 4902116 (13 heads). Higher constitution indices (blockiness and breast) are typical for first-calf heifers, while boneiness and massiveness - for full-grown cows.
A high level of herd reproduction is achieved with the introduction of beef cattle breeding technology according to the “cow-calf” system, which provides for the maximum use of pastures and tour seasonal calving’s, the proper organization of which allows to get calves at a more favorable time of year and further to form uniform herds of young animals. In this regard, the goal of research was to study the efficiency of young stock rearing at calving of beef cows in different seasons of the year. It was found that the animals of Aberdeen-Angus breed of the UE “Molodovo-Agro” of the spring and summer periods of birth were superior to their counterparts in terms of live weight dynamics, intensity of growth, relative growth rate and the level of multiplicity
of live weight gain, which indicates the preferred comfort for starting capabilities of
newborn calves and therefore requires calving at this time of year.
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