Mecardo Analysis - Staple strength and staple length

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By Andrew Woods | Source: AWEX, ICS

Key points

· Short staple fleece has a higher staple strength than longer fleece, on average.

· The higher staple strength in shorter wool is built into its price (it is an assumed characteristic by the buy side).

· The staple strength of shorter length wool varies more in some regions (as does the strength of longer wool).

Shorter staple length wool tends to have a higher staple strength. This combination of specifications is wrapped up together when valuing wool of different lengths, a pertinent point when considering shorter interval shearing. Staple strength is a function of the variation of fibre diameter along the staple (more variation means lower strength) so a question was asked about the regional variation in staple strength for short wool. This article looks at this question.

Different regions have different patterns of pasture, for example, north Queensland and south west Western Australia. Do the different pasture patterns lead to different staple strength levels for short staple wool? Figure 1 shows the annual average (a simple average of monthly measurements) staple strength for 66-70 mm long and 90 mm long Merino fleece by region in the 2018-2019 season.

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The first point to note is the substantially higher staple strength for the shorter staple length wool compared to the more standard 90 mm length wool. Secondly, while there is variation in the staple strength for the shorter staple length wool (ranging from 40 N/Ktx in south west Western Australia to 47 in northern South Australia), the strengths are all 40 N/Ktx and higher.

Figure 2 shows the annual average staple strengths for 66-70 mm length Merino fleece for northern NSW (which takes in the New England), south west Western Australia and Tasmania from the mid-1990s to the current season to date. As expected the staple strength of northern NSW has a lower variation compared to the other two regions. The message from Figure 2 is that when using prices for shorter staple length wool, consider the variation in staple strength possible for the region, as staple strength is important for lots in the 65-75 mm range. The effect on price of low staple strength will vary, depending on the price structure of the time, but low staple strength effectively means the lot will be downgraded in terms of quality for pricing.

The final graph in Figure 3 gives a feel for how staple strength and staple length interact. It shows the average staple strength by staple length for Merino fleece offered for sale last Thursday (eastern Australia). The length ranges in 5 mm increments from 52 to 117 mm. Average staple length starts at a high 50 N/Ktx and falls to around 87 mm where it steadies, around 33-34 N/Ktx.

What does this mean?

The strength of the cardings market in recent years has reduced the risk of receiving a heavily discounted price for short staple wool or low strength wool. With the weakness in the current market, especially in the cardings sector, this risk might increase in the coming years. Staple strength does vary for short length wool between regions and therefore the processing characteristics will vary and price will follow. Most quotes for shorter length wool are set for the average delivered to the market, so it might pay when doing budgets for shorter length wool to check on your expected staple strength and adjust prices accordingly.

www.mecardo.com.au