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Seasonal fleece changes in two selection lines of Scottish Blackface sheep during their lifetime on the hill

Published online by Cambridge University Press:  27 March 2009

M. L. Ryder
M. L. Ryder
Affiliation:
Agricultural Research Council, Animal Breeding Research Organisation, Edinburgh, EHQ 3JQ
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Summary

Ten Scottish Blackface ewes from each of three lines, a line selected for hairiness, a line selected for a fine fleece, and an unselected control, were fleece and skin sampled in April, June, September and December, during their 6J year life-span on the hill.

Fleece weight differed between individuals and between lines, and declined by 4% per year from 1·5 kg at 1 year, to 1·3 kg at 6 years. Fleece grade was inadequate as a method of denning fleece differences between the lines.

The height of the spring ‘rise’ in growth in April differed between years, and between lines, declining 2 mm a year from 26 mm at 1 year. Staple length was greatest in the Hairy group and least in the Fine group (P < 0·05). Growth in length was faster between September and December (autumn) than between April and June (spring). Staple length decreased by 14 mm a year.

The lines differed significantly (P < 0·05) in mean fibre diameter but not in modal fibre diameter. There was a highly significant decrease in diameter from summer to winter, ranging from 20% in the Fine line to 31% in the Hairy line, the greater decrease in the Hairy line being attributed to loss of medulla.

The selection had between 1954 and 1972 changed the S/P follicle ratio of 3·0 in the control to 2·8 in the Hairy line and 3·2 in the Fine line. Most seasonal follicle inactivity occurred in April, December came second, and June invariably had more follicle inactivity than September. The control line had the greatest values of primary follicle inactivity and the Fine least. Among the secondary follicles the Hairy line had most inactivity, and the control line least. Maximum primary fibre medullation occurred in either June or September, and medullation was at a minimum in December or April.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 98 , Issue 3 , June 1982 , pp. 553 - 562
Copyright
Copyright © Cambridge University Press 1982

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References

REFERENCES

Pilkington, J. M. & Purser, A. F. (1958). Fibre medullation in Blackface lambs and hoggs. Journal of Agricultural Science, Cambridge 51, 257–264.CrossRefGoogle Scholar
Purser, A. F. (1967). Selection experiments with hill sheep. In Proceedings 9th International Congress Animal Production Edinburgh 1966, pp. 32–38. European Association of Animal Production, Edinburgh.Google Scholar
Purser, A. F. (1980). Comparison of expected and realised responses in three sheep selection experiments. In Selection Experiments in Laboratory and Domestic Animals (ed. Robertson, A.), pp. 21–30. Farnham Royal: Commonwealth Agricultural Bureaux.Google Scholar
Ryder, M. L. (1974). Seasonal fleece changes in some Cheviot sheep. Journal of Agricultural Science, Cambridge 83, 93–99.CrossRefGoogle Scholar
Ryder, M. L. (1978). Growth cycles in the coat of ruminants. International Journal of Chronobiology 5, 369–394.Google Scholar
Ryder, M. L. & Stephenson, S. K. (1968). Wool Growth. London: Academic Press.Google Scholar
Slee, J. (1959). Fleece shedding, staple length and fleece weight in experimental Wiltshire Horn- Scottish Blackface sheep crosses. Journal of Agricultural Science, Cambridge 53, 209–223.CrossRefGoogle Scholar