Last update: August 15, 2011 07:48:41 AM E-mail Print


Changes in production traits of a genetic strong wool Merino flock mated to genetic fine wool Merino rams

A G Bezuidenhout1*, J J Olivier, A C Greyling1, & J M Jansen van Rensburg1

Grootfontein ADI, Middelburg Cape, 5900, South Africa

1Cradock Experimental Station, Cradock, 5880, South Africa



When substantial price differences occur between fine and strong wool, the practice to mate strong wool ewes to fine wool rams usually increases considerably. The effect of this practice on several production traits of a strong wool ewe flock (29,7 micron), mated to fine wool rams (20 micron), was therefore investigated. Replacement ewes were selected annually from the progeny of the fine wool rams. Ewes and their progeny were kept on irrigated pastures. Production traits of both adult ewes and their progeny (at approximately 16 months of age) were compared to that of a strong wool control flock (26 micron) kept under similar conditions. Data recorded over five consecutive years were analysed by least square methods. The following trends in production traits (regression of deviation from control against year) were obtained:


Over the experimental period of five years, a significant (P  ≤ 0.05) decrease in fibre diameter of 5.75 micron (22.7%) in the ewe flock was accompanied by a reduction of 8.8% in body mass, 1.3% lower clean fleece mass and an increase of 3.4% in staple length. In the progeny however, no significant trends occurred. Since the reduction in fibre diameter was not associated with major negative changes in other production traits, this practice aimed at decreasing fibre diameter appears to be justified.



Proceedings SASAS Congress 1994