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.
Relative economic values of wool processing parameters
The wool described by the New Zealand Wool Board's auction data may be considered to be a vector space defined by axes which are the wool processing parameters. Analysis of this wool vector space gives indications of the relative economic values of the wool properties. Data from 1984 to 1990 has been analysed to give relative economic values and, ahbough short term values vary considerably, them appeartobesomelongertermtrends.WoolbulkaspredictedfromNZWBtypeshowsageneralincreaseinprium,andwoolcolour,~sc~~ by objectively measured yellowness and brightness, has shown increased importance for determining wool price, with brightness taking over from yellowness as the mote important of the two. 'Ibe correlation between parameters in the range of wools offered at New Zealand auctions not only makes it difficult to determine the relative economic importance of the wool properties but limits the range of blend specifications a wool processor can work with. Hence, altboughpremiumsamnotalwaysobvious,it isimportanttotheprocessorthatextremesofwoolpropertiesareavailabletoallowthem~um flexibility when making up parcels of wool for processing.
Effects of thyrotropin-releasing hormone and a thyrotropin releasing hormone analog on growth and selected plasma hormones in lambs.
An 8-wk growth trial was conducted to assess the effects of continuous infusion of thyrotropin-releasing hormone (TRH) and an active TRH analog less than Aad-His-Pro-NH2 (the less than Aad is L-pyro-alpha-aminoadipic acid) on growth trial performance, carcass composition and hormone profiles of growing lambs. Both drugs were infused at 600 micrograms X lamb -1 X d -1 with 16 lambs/treatment. Both TRH and less than Aad-His-Pro-NH2 decreased average daily gain (ADG; P less than .01) and increased feed conversion (FC; P less than .01) compared with saline infused controls. Average daily feed intake was not altered. Carcasses of lambs given TRH or less than Aad-His-Pro-NH2 contained fewer kilograms of moisture (P less than .05) and appeared to contain fewer kilograms of protein. Thyrotropin-releasing hormone and less than Aad-His-Pro-NH2 increased thyroid gland weights (P less than .05), but pituitary gland weights were not different. Plasma thyrotropin (TSH) concentrations were increased by both drugs compared with control lambs, peaking at 4 to 7 d after initiating infusion. However, by 14 d, TSH concentrations returned to control levels. Triiodothyronine (T3) and thyroxine (T4) were elevated by both drugs over the entire 8-wk trial, with peak levels reached at 10 d and maintained for the duration of the study. Both TRH and less than Aad-His-Pro-NH2 increased prolactin over the entire period. Growth hormone levels were not altered by either drug. The effects of less than Aad-His-Pro-NH2 infusion on growth trial performance, carcass composition and hormone profiles of growing lambs were very similar to TRH. The negative effects of TRH and less than Aad-His-Pro-NH2 infusion on ADG, FC and carcass protein appear to be the result of elevated T3 and T4 levels.