Effect of season on fibre diameter
By Malcolm Hobson

Friday, 25th January 2019

Extracted from research by M.A. Snyman & N.M. Kritzinger , Grootfontein Agricultural Development Institute, and Mohair South Africa

Fibre diameter

Fibre diameter is the single most important price-determining variable of mohair and is of critical importance in determining the textile qualities and final manufacturing applications of mohair.

  • Age of the Angora goat largely determines the quality and quantity of mohair produced, and the fineness of the fleece is to a large extent determined by the age of the goat at the time of shearing.
  • There is substantial variation in fibre diameter over the fleece of individual Angora goats, with mohair from the neck usually stronger than that from the rest of the fleece. Fibre diameter also varies considerably within a staple, as well as along the length of individual fibres.

The aim of this study was to determine the variation in mean fibre diameter and its associated traits of various age groups within South African Angora goat flocks and to investigate the effect of season on the fibre diameter profile.

Data recorded

Data were recorded on mohair from adult ewes (21590 records), young goats (10923 records) and kids (11019 records) from 10 Angora goat producers from the summer 2000 until the winter 2004 shearing seasons.

Conclusions

From the above results and discussions the following can be concluded:

  • There are large differences in MFD as well as the other fibre diameter traits measured among the various producers. Differences between producers accounted for more variation in the traits than season.
  • Generally, winter adult mohair had a 0.8 µm higher MFD, a 0.5 % lower CV_MFD, the same SD_MFD and the same SD_ALONG compared to summer adult mohair. Theoretically it can be expected that the processing performance of winter and summer adult mohair will be similar.
  • Winter young goat mohair had a higher MFD, higher SD_MFD, higher CV_MFD and higher SD_ALONG compared to summer young goat mohair. Over and above the seasonal effect, age also contributed to differences in fibre diameter profile.
  • Summer kid mohair had a lower MFD, lower SD_MFD, higher CV_MFD and higher SD_ALONG than winter kid mohair. This could mainly be ascribed to an age effect.
  • The frequency distribution of CV_MFD for summer and winter adult as well as young goat mohair differed very little, while there was a considerable difference between summer and winter kid mohair.
  • Although there are some indications of seasonal effects on mohair production, the more pronounced effects of age, nutrition and reproduction in adult goats take precedence.

ADULT MOHAIR Frequency distribution of fibre diameter of summer and winter

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 YOUNG GOAT MOHAIR Frequency distribution of fibre diameter of summer and winter

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 KID MOHAIR Frequency distribution of fibre diameter of summer and winter

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EXTRACTED FROM: Effect of season on fible diameter M.A. Snyman1 & N.M. Kritzinger2

1 Grootfontein Agricultural Development Institute, P/Bag X529, Middelburg (EC), 5900, South Africa

2 Cape Mohair and Wool, P.O. Box 3314, Port Elizabeth, 6056, South Africa 

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