Position of Break (POB) is measured in conjunction with staple strength and is a measure of the position in the staple (base, mid or tip) where it will break given enough force.

Both sections of the broken staple are weighed after the strength test, with the results converted into values indicating whether the staple was broken in the base, middle or tip region.

The POB is useful in processing since it provides the processor with an indication of where fibres are likely to break, and thus the length of the broken fibre sections.

For example, if a staple breaks at the tip, then the broken fibres are either very short, (and probably lost as card waste or noil) or rather long. If the staple breaks in the middle, both fibre sections are of approximately equal length and both relatively short.

Although there is a tendency for low mid break wools to produce higher fibre losses during processing, they are usually preferred by processors as they give a longer average length in the top (hauteur).

This preference generally translates into longer wool tops receiving a higher price for the topmaker, which in turn means that greasy wool buyers are usually willing to pay premiums for low mid-break wool.

Current discounts for Position of Break have increased dramatically over the past 18 months, with price differentials seen across the entire clip. In fine wools, differences of around 150 cents can often be seen between a very low midbreak of single figures, and a midbreak in the 80 to 90% range. Most mills now specify a maximum midbreak for a delivery, therefore placing great importance upon this measurement for both the grower and the buyer.

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Wool position of break trends

The following charts display the trends for Position of Break discounts since 1995. Medium and high mid-breaks are shown as a discount when compared to low mid-break wools and are broken into fine and medium categories.

The two charts confirm that there are discounts in the marketplace for higher mid-break wool and that the discounts are more severe for the finer microns. After reaching historical highs in the 2000 to 2001 period, the discounts steadily contracted before making lows around 4 years ago.  Since then penalties have increased as buyers increasingly seek out the better specified wools in response to the demands of topmakers and spinners.

Point of Break - Fine Wool  

Point of Break - Medium Wool

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Wool position of break tips

There are generally two ways to reduce the number of mid-breaks in your wool.

The first is to manage the nutrition of the sheep throughout the year so that there is an even profile along the length of the fibre.

Break points usually occur when there are sudden changes in the nutrition, for example the winter "break" in winter rainfall areas. The key is to maintaining the supply of nutrients to the follicles during these stress times, particularly when they occur midway between shearing dates.

Supplementary feeding during these periods (and just prior to) may help to offset the effect of these seasonal breaks. Identifying the most appropriate times for joining can also help in keeping a constant nutrition plane for the animal.

The second management tool involves the date of shearing. If it is difficult to reduce mid break or increase strength via nutrition management techniques, the break can be managed by altering shearing dates. While a weak point will still appear in the wool, shearing at time near to when the break will occur will shift the break to either the tip or base.

If the break is within 10mm of either end of the staple, the likelihood is that the Length and Strength test will not break the staple at this point, which should increase the overall strength.

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