Last update: August 15, 2011 02:46:37 PM E-mail Print




J.J. Olivier, S.W.P. Cloete1 and A.G. Bezuidenhout2

Grootfontein Agricultural Development Institute, Middelburg 5900

1Elsenburg Agricultural Centre, Private Bag, Elsenburg 7607

2Cradock Experimental Station, Cradock 5880



Experts in the Merino stud industry have warned against the mating of strains with extreme mean fibre diameters, since it was alleged to increase variation in fibre diameter in offspring. Fibre diameter (FD) variance was determined on wool samples obtained from 5 locations on the body in progeny of fine wool, strong wool and fine x strong wool Merino sheep. The respective genetic groups numbered 48, 23 and 37 and were run as one flock on irrigated lucerne pastures. Fibre diameter variation was determined with an Optical Fibre Diameter Analyser by measuring the diameter of 4000 fibres in each sample. The variance in FD was lower (P ≤ 0,05) in fine wool progeny (13,74 ±: 0,54) than -in fine x strong wool I contemporaries (19,47 ± 0,64), which in turn had a lower variance (P ≤ 0,05) than strong wool progeny (23,87 ± 0,80). FD variance of fine x strong wool progeny was roughly equal to midparent values within and across body locations. Both traits tended to increase from the anterior to the posterior position of the fleece within and across genetic strains, with the means for samples obtained from the shoulder being lower (P ≤ 0,05) than that of britch samples. FD variance decreased (P ≤ 0,05) dorsoventrally in strong progeny, with a similar tendency in fine x strong wool contemporaries. In the fine wool progeny a similar but smaller trend was apparent. It is concluded that concern for excessive FD variation in progeny of fine wool rams mated to strong wool ewes is unwarranted and that adverse effects on the processing performance of this type of wool, is unlikely.



Proceedings 32nd SASAS congress