High Fleece Weight Research Articles

Efficiency of wool production of grazing sheep. 1. Differences between merino sheep selected for high and low fleece weight

The intake, wool production, and efficiency of wool production (wool production per unit intake) of rams drawn from two flocks selected for 13 years for high (Fleece Plus) and low (Fleece Minus) fleece weights were estimated while the rams grazed three pastures differing in the amount of herbage available. In a second experiment the rams were fistulated at the oesophagus and determinations were made of the digestibility and nitrogen content of the samples collected while the sheep grazed two pastures. The wool production, intake, and efficiency of the Fleece Plus rams were greater than those of the Fleece Minus on all pastures. Variability in wool production was primarily attributable to variability in efficiency. Differences between flocks in wool production and efficiency increased when herbage availability and wool production were high.

The relationship between fleece weight and efficiency in Romney and Corriedale sheep

Abstract In two experiments with Romney ewes and one with Corriedale ewes the efficiency with which individual sheep converted feed to wool was estimated by feeding the ewes in pens and relating wool grown to feed intake. In the Romney experiments the ewes employed were selected on the basis of either high or low fleece weight whilst under grazing conditions. Considerable differences in efficiency between sheep were observed. The efficiency of individual ewes was then correlated with their grazing fleece weights. Estimates of this correlation coefficient varied from 0.7 to 0.9. The significance of this high correlation is discussed.

Selection for economic characters in Australian Merino sheep. VI. Inheritance and interrelationships of some subjectively graded characteristics

Genetic and phenotypic relationships among subjectively graded characteristics were examined in a flock of Merino sheep a t Trangie Agricultural Experiment Station. Estimates of heritability were: wool handle, 0.30; wool colour, 0.63; wool character, 0.38; back wool, 0.00; hocks, 0.14; face cover, 0.38. The genetic correlation between face cover and fleece weights suggested that selection for fleece weight would increase "wool-blindness", with possible diminution of reproductive efficiency. Selection for wools of good character (well-defined crimp) would improve softness and would not decrease fleece weight. The conclusion emerging from this and previous studies is that intense selection for high fleece weight will be rewarded by substantial increases, and will be offset only partly by adverse changes in a few of the several characters investigated.