Nutritional effects on fibre growth cycles and medullated fibre
production in Angora goats
A.J. Nixon, D.P. Saywell, M.D. Bown
MAF Technology, Whatawhata Research Centre, Hamilton, New
Zealand
Proceedings of the New Zealand Society of Animal Production.
1991, 51: 359-364
The effect of nutrition on fibre growth cycles and medullation
in skin of Angora goats was investigated by microscopy of transverse
sections of hair follicles. Samples of skin and fleece were taken at
regular intervals between August 1989 and August 1990 from non-
reproducing does fed either maintenance (MPA) or ad libitum (HPA)
pasture allowances. There were no differences in follicle activity
between nutritional treatment groups for any of the 11 sample dates.
Primary follicles grew and shed their fibres seasonally, with the main
growth period from September to May and the mean nadir of 26±6% in
August. Mean secondary follicle activity did not fall below 95% in HPA
goats, or below 85% in MPA goats, however, there was large between
animal variation. Primary central follicles grew kemp fibres. Primary
lateral follicles produced both kemp and gare fibres. Secondary
follicles grew mostly unmeduallated mohair, but gare fibres were grown
by some earlier developing secondary follicles. Goats on higher feed
intake had greater degree of medullation in fibres of lateral primary
follicles in October and February, and in secondary follicles in
February, March and May. These data suggest that nutritional effects on
kemp content of the fleece are achieved through a shift in fibre type
within all follicle types.
Keywords: NZSAPAB;
Angora goat; hair follicle; kemp; mohair; nutrition;
seasonality; shedding
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Last Updated 25-01-1997
