Shkurko T. Substantiation of trends of increasing of milk cattle productive use duration.

Object - animals of Holstein, Black-and-White milk, Ukrainian Red milk, Angler breeds and their crosses. Purpose - to ground scientifically the technological parameters and selection methods of increasing of milk cattle productive use duration on the base of studding of adaptation, productive and technological traits. Methods - zootechnical, physical-chemical, physical, biochemical, ethological, bioenergetic and biometric. Novelty - firstly the new effective methods of increasing of milk cattle productive use duration owing to periodic complex estimation of productive, adaptation, exterior-constitutional, ethological and technological animal features at different technologies of milk production are scientifically grounded. The most optimal conditions of cattle delivery depending on a season, origin and technology of use are defined. Possibility of early prognostication and selection of replacement heifers inclined to long-term economic use as to the intensity of growth recession in early ontogenesis and the first calving cows with taking into consideration the modal (middle) classes of norm distribution as to the type of their constitution are theoretically grounded and experimentally proved. On the base of ethological experiments conducted at different modes of cow's maintenance the expediency of improvement of a number of technological methods concerning their operation was pointed out and stalls parameters were specified. Bioenergetic estimation of expenses for cows maintenance, depending on their life length was carried out and the effective term of their productive use was determined and economically substantiated. Results of researches - are being used in theory, practice and for the study purposes. Branch - animal production