Published online by Cambridge University Press: 06 May 2016
To those engaged in the improvement of livestock the problem of the generation interval needs virtually no introduction. In mammals, the generation interval consists of two well-defined phases :
(a) the interval between birth and sexual maturity and
(b) the gestation period.
Whereas the length of gestation within a species is a relatively fixed period subject only to minor variations, the ages at which puberty and sexual maturity are attained are very variable, being influenced both by genetic and environmental factors. Thus, breed, strain, season of birth, plane of nutrition and system of management all contribute to determining the onset of puberty and eventual attainment of sexual maturity.