Alpaca Articles

ALIGNING FIBRE - Part 3 of a 6 part series

By Nic Cooper Southern Alpacas Stud

Part 3 - What else a mill wants - a study in uniformities.

Earlier articles set the scene for growers of fibre to develop a process that will help align their growing goals with those of processors and retailers. Part 2 then went on to address fineness goals and shear weight goals - weighting them commercially and indicating that the product you are producing for will dictate the micron level you breed for.

Part 3 deals with more mill requirements - mainly uniformity - and what the grower can do to best produce uniform fibre. Part 4 delves into some of things that alpaca breeders talk about as being "great" properties of alpaca, and investigates whether they truly mean much to the processors and retailers, and whether growers can meaningfully build breeding goals to address them.

Making things out of synthetic fibres is just so much easier for a mill. Synthetic fibres are inherently uniform. They react predictably and consistently in the mill process and produce an end product which can be predicted with confidence before processing.

Natural fibres are inherently diverse. They can create havoc with machinery set to tight tolerances and can make product very different from that predicted - or worse, different from that ordered by the client retailer.

Fortunately natural fibres have a niche with end buyers - so mills persevere with them. And with 2009 being the Year of Natural Fibres, there is an opportunity for alpaca to benefit.

But mills (and end buyers) do want to do everything possible to produce a product that best meets end consumer specifications, and which slips through the mill unnoticed by the machine mechanics and engineers.

Hence the importance of uniformity in mill input.

Micron, uniformity, spin fineness, cv and other measures

Micron determines 70% - 80% of fibre price for a given weight. The lower the micron the better, from a grower pricing point of view - although that is irrelevant to the mill.

What the mill seeks is uniformity of micron and uniformity of length across the fleece and amongst the fleeces in the batch going to the mill. Usually this is more determined in the shearing and the sorting than in the growing.

Shearing and sorting - whilst important - is not within the scope of this article. So let's look at the things the grower decisions can influence.

Co-efficient of Variation (CV) helps determine uniformity in the fleece. Merino breeders have found that a low cv also helps avoid fleece micron blow out with age (although drive the cv too low and weight suffers -  the fleece loses its “guts”).  As a rule of thumb, look for a cv that equals the micron you are producing (19 micron fibre, 19% cv).

A low cv fleece spins finer than a high cv one for the same micron. Hence higher micron, low cv fleeces can achieve similar results to lower micron fleeces with high cv. This is the concept of “Spin Fineness” - developed in the 1940’s in sheep and translated to alpacas in the hope that it translates (there is no research), and quoted on alpaca histograms.

Spin fineness is a good measure for growers to quote because it encompasses in one measure the concept of a fine, uniform micron which is what the processor seeks.

The example below shows how a histogram (left graphs) can belie uniformity, and the OFDA 2000 “along the line” graph (right graph) shows one important aspect of processor uniformity.

These two histograms display very similar statistics (micron, cv, spin fineness etc

However they are very different in their uniformity along the fibre length. 

259 varies from 18.5 micron to 24 micron, whereas Zarin is within 2 microns right along.

Fleece weight of course is measured by weighing the fleece. Factors that determine fleece weight are body size (surface area shorn), time of growth, speed of growth, follicle density per defined area of skin and – if we consider not all fleece but good usable fleece - the extent of that better fleece over the body area.

Body size is clearly important. Whilst we do not wish to breed llamas (and their fibre characteristics) we do want to maximise surface area. Big is good. However (from part 2) we know that large body size and ultra-fine fibre do not tend to go together. 

So maybe ultra-fine breeders need to tolerate lower shear weights and smaller (not necessarily less robust) alpacas, and those breeding for big frame alpacas need to tolerate a higher micron production

Length is an interesting concept, emphasised by some.

Given that processors want a clearly defined uniform length for their process input (and this is different for each process), then time of growth and speed of growth are factors in determining length. Getting to your required process length quicker means you will get one (maybe two) more shears off your animal in a lifetime. But it may also dictate non-seasonal shearing if you reach required length every (say) 10 months.

Whatever, it is important to avoid over long fleece. To quote one Italian mill (The Land, June 2005)

"We don't want SRS."  On a tour of four NSW properties, Claudio Lacchio, General Manager of Giovanni Schneider, said Italian millers were against the SRS concept "simply because the wool is too long and the crimp is definitely too bold".

"That performs through to the final stage - our clients don't want to see the very obvious SRS wool in the factory; we don't have a price for it," he said.

To be fair to SRS fleece, different mills have different opinions and Asian mills do process the SRS type fleece quite successfully.  All mills are different!

The length issue would be managed by non-seasonal shearing - but clearly hadn't been by the Australian sheep industry in 2002 when the Schneider comment was made.

The process machinery that mills use was originally designed around traditional sheep shear lengths – not the other way around. Alpaca will certainly have to “fit in” as we will never be significant enough for machinery to be developed for us.

However the most influential commercial factor in (usable) fleece weight is the extent of the good fleece that you get off a shear (also called uniformity). This can vary hugely – in our herd from 67% to 90% of total fleece weight.

Consider the maths.

A 2.8 kg fleece (the norm) is shown in the AGE distributions of fleece weight (printed in Part 2) as having a potential genetic gain of 0.5 kg. which at 23 micron = A$6. This benefit clearly comes from all the genetic weight factors combined.

However moving that fleece from 65% usable (the norm) to 90% usable gains 0.7kg in usable fleece which at 23 micron = A$8.50 additional income. 

Follicle density is clearly also an important factor in fleece weight. It is a measure many breeders may wish to consider as part of their breeding programme. SRS champions follicle density measurement - but does not have a monopoly on the measure.

In Summary

In considering all of the factors involved in getting a usable shear weight increase to enhance the value of the fleece, the two factors that stand out as having the most influence on commercial value are the alpaca’s body size, and the uniformity/extent of good fleece over the body.

As we suspect that body size has a negative correlation with fineness, maybe the prime breeding goal for increasing (usable) fleece weight is (at least initially) breeding for a greater uniformity of good usable fleece across the surface area of your alpaca.

Take home points

1. Uniformity is a huge issue for mills.

2. Uniformity (of good fleece across the body) has the greatest effect on usable shear weight.

3. CV is an indicator of uniformity, and low cv assists combating “blow out”. Spin Fineness combines micron and cv to indicate "processability".

4. Staple length is important - both for uniformity and meeting process target lengths.  However it can be a result of timing of shearing.

Updated July 2009