SELECTION INTENSITY¢S INFLUENCE ON DAIRY PRODUCTIVITY AND ON UDDER¢S FUNCTIONAL CHARACTERISTICS OF COWS
Index selection increases the effectiveness of selection on a set of basic selection traits. The aim of our research was to study the rate of improvement in the productive qualities of morphological and functional properties of the udder fresh cows of black-motley breed farms "Voronovo" Podolsk district, Moscow region, originating from four sires: Master, Falls 2568, Virgil 1721111, Lily of the valley 423. The evaluation and selection of cows was performed at 2-3 months of lactation on daily milk yield, conformation evaluation of the udder, speed of milking, udder index, using our proposed selection index. For the application of selection index within each dairy herd determines the maximum (max) and minimum (min) values are indications of selection and then individually for each animal to calculate the value of selection index, whose value can range from 0 to 100. The higher the value of SI, the better developed from this animal key selection attributes and Vice versa. We analyzed milk production and udder morphological and functional properties, depending on the intensity of selection. The selection was performed on the basis of a selection index that takes into account the daily milk yield, conformation evaluation of the udder, milking speed, udder index. It is established that at different intensities of selection, the rate of change of size of each breeding trait are not the same. The rate of increase of the magnitude of the milk yield of cows can be influenced by applying a selection on conformation evaluation of the udder. The efficiency of selection in groups of daughters ranked sires varies that need to be considered when conducting breeding work with each herd of dairy cattle. Studying the relationship between the rate of increase in milk production and morphofunctional properties of the udder, established the existence of a very high positive correlation of the daily milk yield and conformation evaluation of the udder. In groups of daughters ranked sires, with different intensities of selection, the rate of change of size of each breeding trait are not the same. Taking into account set in course of research is very high positive correlation (r = + 0,95, P>0,95), the pace of increase the value of milk yield of cows can be affected, leading pro-choice on the exterior assessment of the udder.