An examination of the influence of nutrition on the series of chronological events in the breeding lifetime has suggested that satisfactory breeding animals can be produced on a range of regimens in early life. For example, nutrition during the rearing phase has to be fairly severe (50% of ad libitum or less) to significantly delay puberty.

Nutrition needs to serve the immediate reproductive needs of the animal and to ensure that the animal is in satisfactory body condition to reproduce throughout its breeding lifetime. Consequently, at certain stages there will be competition for energy and nutrients between the products of conception or lactation on the one hand and the maternal body tissues on the other.