Relative economic value of wool processing parameters for New Zealand strong wool between 2003 and 2007
Price trends for a total of 147,416 lots of wool in the strong wool segment of the New Zealand clip sold at auction between 1 July 2003 and 30 June 2007 were analysed by multiple regression analysis to determine the effect on price of five key characteristics known to affect wool processing performance. Changes in exchange rate were allowed for by covariance against the exchange rate of the US dollar on the day of the auction. The residual standard deviation within the data set was 20.4 c/kg clean. Mean values of the slope of the regression, or relative economic value, were 0.4 ± 0.2 c/ kg clean/mm change in barbe length, -1.9 ± 0.9 c/kg clean/μm change in mean fibre diameter, 2.5 ± 0.5 c/kg clean/CIE Y value change in brightness, -5.0 ± 0.6 c/kg clean/CIE Y-Z value change in intensity of yellowness and -16.8 ± 3.0 c/kg clean/% change in vegetable matter contamination. These estimated values align closely with values estimated in 1991 for the New Zealand clip as a whole confirming that despite the significant changes that have occurred within the wool processing industry the economic significance of individual wool characteristics to wool processors have not changed.
Wool characteristics in the Meat and wool New Zealand Central Progeny Test flocks
The Meat and Wool New Zealand Central Progeny Test programme (CPT) was established to demonstrate the relative breeding merit of leading sires in the New Zealand sheep industry. Here we describe the wool grown over the summer by the 2007 born one-year-old ewes within the CPT. Within fleeces, staple strength varied between farms as shown by the mean difference of 23 N/ktex in offspring of the link sire. Staple strength correlated positively with midside fibre diameter (r = 0.26), medullation (r = 0.23) and negatively with fibre curvature (r = -0.61). Staple strength was similar on anterior (74 ± 24 N/ktex) and midside (75 ± 24 N/ktex) body-sites, but was weaker on the hindleg (64 ± 21 N/ktex; P <0.001). Overall mean staple strength was 72 ± 20 N/ktex, while individual fleeces ranged from 19 to 121 N/ktex. Ten percent of fleeces measured below 45 N/ktex leaving them prone to excessive fibre breakage during processing. Some fleeces varied up to 40 N/ktex across body-sites. Even within one flock, offspring of individual sires differed by a mean of 29 N/ktex, suggesting a consistent weakness of wool in the progeny of some highly ranked sires which will negatively affect processing and end-product performance.
Instrumentation and Automated Photometric Titration Procedure for Total Acidity Determination in Red Wine Employing a Multicommuted Flow System
An automated procedure for photometric titration of red wine and associated instrumentation is described. The procedure was based on the flow-batch approach implemented employing multicommutation. The photometric detection was carried out using a homemade LED-based photometer. The mixing device, LED, and photodetector were attached to the titration chamber in order to form a compact and small-sized unit. The flow system comprised an automatic injector and three-way solenoid valves, which were controlled by a microcomputer through an electronic interface card. The software, written in Quick BASIC 4.5, was designed with abilities to accomplish all steps of the titration procedure including data acquisition and real-time processing to decide about the course of titration in the following step and so forth, until the titration endpoint was reached. The usefulness of the proposed titration system was demonstrated by analyzing red wine samples. When results were compared with those obtained using the AOAC reference method, no significant difference was observed at the 95% confidence level. A relative standard deviation of ca  2% (n=9 ) was obtained when processing a typical red wine sample containing 7.3 gl -1 total acidity expressed as tartaric acid.