Feed Gaps and Fibre Variations. The development of along staple diameter measurement as a diagnostic tool for improved grazing management. 2004 Results

Abstract

This paper was produced as part of the 8x5 Wool Profit Program, funded by AWI.

The program is an integrated research, development and extension program to assist Tasmanian wool producers to achieve an 8% annual return on assets managed within 5 years through access to benchmarking, best practice information, group improvement initiatives and a State-wide wool profit awards program. The 8x5 Wool profit Program is a major new initiative in the Tasmanian wool industry jointly funded by Australian Wool Innovation Limited and the Tasmanian Institute of Agricultural Research.

This project is aimed at providing staple profile and strength information to wool producers on individual flocks of sheep on their properties. It will also provide data on some problem areas in wool growth for future research.

This report details the results of the second year of the project. The 2003 report can be found on the 8x5 web site  or on this website.  Like the previous year this, 2004 report is written to allow the producers involved to compare their results with others.

In 2004, one hundred and fifty individually identified mobs, (55 ewe, 56 wether and 39 weaner mobs) were sampled compared with ninety one mobs, (40 ewe, 33 wether and 18 weaners) in 2003.

The biggest difference in seasonal effects was the rainfall in January and February 2004. The total for the 2 months in 2003 and 2004 was 44 and 199 mm in Swansea, 12 and 201 in Bothwell and 9 and 115 in Ross, three Bureau of Meteorology recording sites within the wool growing
area.

Overall, the 2004 weaner wool was 4.5 N/ktex stronger with a lower range in maximum and minimum micron and over 30% of the mobs had a strength of 40 N/ktex or stronger compared with 11% in 2003.

Wethers were on average only 2 N/ktex stronger than 2003 and were similar in wool characters other than the position of break. In 2004 the break was closer to shearing time and over 25% of the mobs had a minimum micron position which would have been in the jaws of the ATLAS machine, resulting usually in a different position of break at a higher staple strength.

Ewes had an average staple strength of 40.1 N/ktex, an increase of 3.7 on 2003. The within mob micron range was lower than the previous year with a range of 3.1 micron compared with 3.8 in 2003.

The difference between ewes, and wethers and weaners was the difference in profiles in the 2 years. Unlike the wethers and weaners, in ewes there was a reduction in micron in many mobs in late summer.

One of the problems in wool measurement is the lack of a relatively easy and quick method of estimating staple strength. Having over 1600 individual ewe and wether and 1100 weaner OFDA data and measures of staple strengths allowed a number of comparisons of strength against OFDA measurements to be made. On an individual sheep basis there were no OFDA measurements which could explain much of the staple strength variability, while on a mob basis only the total coefficient of variation of fibre diameter (CVD) and across fibre CVD from the OFDA data were well related to staple strength and even then could explain no more than 30% of the variation in staple strength. This is consistent with Western Australian data.

The data from 2003 and 2004 were also used to investigate the relationship between individual sheep or mob staple strengths in consecutive years. With this preliminary data, in neither case was there a significant relationship, ie individuals or mobs which had high staple strength in 2003 did not necessarily have the same in the subsequent year.

Citation

"Feed Gaps and Fibre Variations. The development of along staple diameter measurement as a diagnostic tool for improved grazing management. 2004 Results", M Statham Senior Research Fellow Tasmanian Institute of Agricultural Research, Mt Pleasant Labs, PO Box 46, Kings Meadows, TAS 7249, May 2005