Winter - Classical Mileend Alpacas

crinkly type fl eece with high curvature (56
in her case) but there is no classic crimp.
Luis Chavez’s study of curvature makes
it clear that crimp can have several
appearances and still be associated with
fi neness.
THE IMPORTANCE OF KNOWING
THE PARAMETERS OF ALPACA FIBRE
CHARACTERISTICS
In the summer of 2004 North American
fi bre scientists Christopher Lupton PhD,
Robert Stobart PhD and Angus McColl,
fi nished work on their Alpaca Research
Foundation Grant that was a fi rst of its
kind study of alpaca fi bre. They sampled
606 huacayas from throughout the United
States. This study was unique in that
it is one of the fi rst large studies that
attempted to identify the parameters of
common fi bre properties and record both
the positive and negative correlations
between important fi bre characteristics.
For example, one of the study’s many
conclusions was ‘The intrinsic resistance
to compression of alpaca is low because
of the relatively low levels of crimp. Thus,
alpaca is not suited to end-uses that
require high resistance to compression
or bulk.’ It turned out that alpaca ranged
between 15.4 and 52.5 curvature
(deg/mm) and curvature decreased with
age. A low curvature in Merino sheep
is 50 deg/mm. When it comes to crimp,
sheep’s wool starts where alpaca stops,
so the species parameters are different
for each. This study established base line
data on age, body weight, sex, colour,
and last shearing date. This is important
base line data because it allowed these
researchers to assess the changes in
fl eece characteristic based on age,
weight, and region (which could be a
general indicator of infl uences of gross
diet).
CONCLUSIONS AND MAKING USE
OF SOPHISTICATED HISTOGRAMS
The study mentioned above has provided
valuable information for new areas
of inquiry and developed expanded
types of histograms that will allow
breeders to get directly involved in
their own correlations of objective fi bre
measurement. The fi rst version of the
article ran in the Summer 2004 issue
of Alpacas Magazine. The original
article has been revised and is awaiting
publication in the Small Ruminant
Research Journal. Here are some
conclusions from the study:
❍ Alpaca as a species has low
curvature compared to sheep breeds.
In alpacas the range in curvature in
the US was between 15.4 and 52.4
deg/mm, possibly meaning holding
alpaca to the same standard as
sheep may be counterproductive if
other desired qualities of alpaca fi bre
are compromised.
❍ For both worsted and woollen
spinning, AFD (micron), and
CV (coeffi cient of variation)
measurements are by far the most
important fi bre properties infl uencing
spinning performance…
❍ Average fi bre diameter (AFD) is
positively correlated with age, body
weight, clean yield, and staple
strength and negatively correlated
with average curvature and staple
length.
❍ Compared to wool of similar
fi neness, alpaca was shown to be
much higher yielding, more heavily
medullated, longer and considerably
stronger.
❍ Average level of fi bre curvature in
alpacas is quite low compared to
cashmere and fi ne wool. Average
curvature is negatively correlated to
age, body weight, fi bre diameter, and
clean yield and positively correlated
with staple length and resistance to
compression.
❍ Staple length: longer fi bres produce
more uniform heavier yarns that
have greater resistance to abrasion.
The mean staple length was 4.6
inches (12.4 cm), which is more than
adequate for processing.
❍ Most alpaca is medullated to varying
degrees. White and light colored
fi bres having a medulla greater than
60% of the width of the fi bre are
chalky in appearance and also appear
not to accept dyes readily. These are
referred to as objectionable fi bres.
(Only fi bre from white and light
fawn/beige animals can be tested for
medullation at this point in time. See
Figure 4).
❍ Ageing correlates to changes in fi bre
characteristics. Body weight, fi bre
diameter, staple strength, percentage
of medulla increase while curvature
and staple length decrease.
❍ Low AFD negatively corresponds
with staple length regeneration,
which is different than most sheep
breeds.
❍ Truly fi ne wool tends to have more
crimp than alpaca of the same
fi neness.
❍ Fine fi bres in alpaca tend to have
more crimp that results in positive
signifi cant correlations in resistance
to compression. However the
resistance to compression in alpaca
compared to sheep is low. Thus
alpaca is not well suited to end
uses that require high resistance to
compression (or bulk). To produce
alpacas with more resistance to
compression selection should favour
crimp. Less crimp in alpaca results
in leaner, smoother, less bulky yarns
and fabrics, which is an attribute for
the worsted process.
This study produced both sound data and
valuable tools for the breeder. We are all
familiar with laser scan histograms that
measure AFD, CV, SD and percentage of
fi bres over 30 microns. Yocom-McColl
Testing Laboratories can now expand
your histogram to include medullated
fi bres (in light coloured fl eeces only),
spin fi neness, mean curvature and SD of
Fibre Curvature
curvature. The overlapping profi les show
both the AFD distribution in one and the
medullation in the other. Curvature is
reported in mean curvature and standard
deviation of curvature.
I strongly suggest that anyone
interested in this topic test their own
animals to check the correlation of
curvature and microns to see how they
do or don’t match up with the data in this
article.
Many thanks to Angus and Margaret
McColl, owners of Yocom-McColl Testing
Laboratories, and Christopher Lupton PhD
of Texas A&M University, for their time
and expertise in reviewing this article. •
Alpaca World Magazine Autumn 2004/05 51