Effect of age, maternal handicap, birth and survival type on five fleece and body characters of Corriedale rams

Abstract

The effects of age, dam age, type of birth and rearing on weaning weight, clean fleece weight, hogget weight, fibre diameter and yield were estimated for 751 Corriedale rams aged 16-19 months, over three years. Twin born and reared rams were 20% lighter at weaning and 4% at hogget weighing than singles and cut 4% less wool. All characters except yield increased with the age of the ram, the effect being greatest for weaning weight with a regression coefficient of 0.17 kilogram per day of age. Of particular interest was fibre diameter, which increased with age; the regression coefficient was 0.026 pm per day of age. Clean fleece weight also increased with age; the regression coefficient was 0.0061 kilogram per day of age. The phenotypic correlation between clean fleece weight and fibre diameter was very high (0.45), other correlations were within previously published estimates. The relation between eight qualitative characters (head type, face cover, back cover, belly cover, wool quality, standard of feet, body size and classer grade) and three productive characters (clean fleece weight, weaning weight and hogget weight) was studied. Clean fleece weight was not correlated with face cover but was negatively correlated with belly cover (-0.30) and positively correlated with classer grade (0.41).