Adaptation of three layer breeds in the tropics.

      Аннотация: Dr Gwaza Deeve Sebastian, Senior Lecturer, University of Agriculture, Makurdi. He holds a B.Sc. Zool. in 1994 from Ahmadu Bello University Zaria. M.Sc and Ph.D 2002 and 2013 respectively from the University of Agriculture Makurdi. He is an Animal Geneticist. The book discusses the effect of pen conditions, the physiological responses they elicit that affected tolerance, susceptibility and performance of the chickens. The effect of breeds, cage position, pen and year effect on hen-day lay, the effect of interaction of breed by pen and cage position on hen-day lay, highlighting the physiological responses elicited by these conditions, their effect on hen-day lay, susceptibility, tolerance and adaptation. The text highlighted the interaction between the breeds, climatic and pen conditions and age of bird indicating breed superiority base on physiological responses Enhancing susceptibility, tolerance and adaptation as affected by age on hen-day lay, length of productive life and order of breed fitness. The book is design for commercial layer industries, potential farmers, livestock extension workers, undergraduate and postgraduate students in Animal Breeding and Genetics.

Ключевые слова: additive-effects, cage-position, genetic-superiority, heat-dissipation, hen-day-lay, peak-of-lay point-of-lay