Effect of Season on Mohair Fibre Diameter
By Dr Mackie Hobson BSc(Agric),BVSc

1. Nutrition

Fibre diameter is an important price-determining variable of mohair and is important in determining the textile qualities and final manufacturing applications of mohair.

The fibre diameter of mohair produced varies according to:

• Nutrition
• Age of the goat at the time of shearing.
• Area of the fleece of individual Angora goats, with mohair from the neck usually stronger than that from the rest of the fleece.
• Varies considerably within a staple, as well as along the length of individual fibres.

Higher prices have traditionally been paid for summer than for winter kid mohair. The reason for this remains a controversial issue in the mohair industry in South Africa.

M.A. Snyman (Grootfontein) and N.M. Kritzinger (Cape Mohair and Wool) evaluated data to determine what influence the season had on the Fibre diameter of mohair produced.

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. 

Season accounted for more of the variation in fibre diameter traits of kid and young goat mohair than for adult mohair. This is due to an age effect, which is confounded with the season effect, as the first shearing of kids comprised the summer clip, while their second shearing comprised the winter clip. The same applied to young goats, where the winter clip is usually from relatively older goats.

Differences between producers accounted for more variation in the traits than the season.

Adult Mohair.

The Mean Fibre Diameter (MFD) of adult mohair differed among producers, ranging from 29.2 µm to 37.9 µm on average.

Overall, for all producers:

Summer adult mohair (33.56±0.04 µm) had a lower MFD than winter adult mohair (34.37±0.04).

The mohair produced by adult ewes during the summer season usually includes mohair produced during pregnancy and lactation. Those produced during the winter season includes mohair produced during the dry period and early pregnancy.

Reproduction generally suppresses the rate of mohair growth, and the demands of lactation are quantitatively more pronounced than those of pregnancy.  During late pregnancy and lactation, nutrition is often poor, and mohair production, especially fibre diameter and length, will suffer.

There are little differences in fibre diameter traits between the summer and winter clips for adult mohair.

Therefore, the processing properties of adult mohair should not be influenced by season.

Young goat Mohair.

Summer young goat mohair had a lower MFD than winter young goat mohair. As mentioned earlier, this could most probably be ascribed to an age effect.

There was also less variation in MFD along the length of the staple in summer compared to winter young goat mohair.

Kid Mohair.

Summer kid mohair had a lower MFD than winter kid mohair at all producers

As in the case of young goat mohair, differences between summer and winter kid mohair could be ascribed largely to an age effect. This could be due to the possible presence of birth coat fibres in the first fleece.

Variation in MFD along the length of the staple was also higher in summer kid mohair.

The first shearing of the kids (summer clip) includes mohair grown over periods of different feeding regimes, i.e. milk, then first roughage and then only roughage diets and the weaning period. All of these contributed to the higher variation in MFD among the length of the staple compared to the second (winter) clip, which is more even in terms of MFD.

The recorded differences in fibre diameter traits between the summer and winter mohair of kids could contribute to the price difference between summer and winter kid mohair.

Although seasonal effects the Fibre diameter of Mohair, the more pronounced effects of producer management, age, nutrition and reproduction in adult goats take precedence.

REFERENCE:

EXTRACTED FROM: Effect of season on fibre 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