A study of some aspects of the genetic variation and covariation of fertility in a flock of New Zealand Romney ewes : being a thesis presented in partial fulfilment of the requirements for the degree of M.Agr.Sc, Massey Agricultural College, University of New Zealand, May 1955

Abstract

"Fertility" is a term generally used to denote the expression of reproductive performance. Any precise definition of "Fertility", however, must depend ultimately on the purpose for which it is intended and the criterion by which it is measured. For the present purpose "Fertility" may be regarded as the rate of reproduction which is measured by some form of a lambing percentage. The economic importance of fertility in sheep production has not been, until recently, fully appreciated, but still less has its significance in the genetic improvement of sheep been realised. [FROM INTRODUCTION]