Pre-natal growth in Romney x Southdown cross and Australian Merino sheep. I. Introduction and external growth patterns in the two breeds

Abstract

An investigation has been made of vveight and length changes with age in Merino, and Romney X Southdown cross, foetuses. This breed difference had no effect on growth in length, but at the same age and body length the Romney X Southdown cross produced the heavier foetus. It appears probable, therefore, that the genetic effects (whether primary or through maternal influences) controlling this difference alter the muscle size and weight, the bone thickness, and also possibly the weight of the viscera, but do not affect the increase in length of the skeleton.