РУАЭСТ (RUAEST)
PROBLEM OF EGG PRODUCTIVITY IN HENS AND ITS EARLY PREDICTION
The generalized processes of natural maturation of oocyte with egg yolk in the ovary, production of egg white and eggshell in the oviduct, as well as ovulation and laying cycle are under the genotype control. Besides, they are affected by the environment and regulated by neurohumoral (neurohormonal) system. All these factors determine ultimately the egg productivity in poultry. Thus, it is limited by time, required for the oocyte maturation and yolk synthesis, and also by the decreasing reproductive potency of hens and egg quality because of aging and/or influence of technological factors. Whatever it was, the observed phenotypic variability due to selection pressure and the applied intensive technologies in poultry indicates the physiological limits of productivity (i.e. egg-laying rate, egg weight and quality) to become wider in hens with intensive metabolism. In the modern egg hybrid crosses a daily ovulation occurs synchronously with a mature egg formation and laying during long productive usage. The egg laying chickens can be forecasted in the postembryonic ontogenesis by the number of large follicles which are maturing in the ovary, if 85-90 % egg productivity is reached within 5-6 weeks after the laying begins. The steady cycle of egg laying with small interval (1-2 days) is also of importance. Thus, the rapid formation of 5-6 follicles in the ovary coinciding with weekly maturation of the yolk in ovogenesis determines the biological potency of reproductive function in high-yield laying hens. The use of these parameters for assessing egg chicks and their offspring gives an opportunity to predict the high-producers in the early ontogenesis. It will speed up breeding to improve modern egg crosses, create new ones, and also to optimize the intensive technologies in poultry.