Contribution of objective and subjective attributes to the variation in commercial value of Australian mohair: implications for mohair production, genetic improvement, and mohair marketing

Abstract

A database collected in the years 1998–01, from 2 mohair-selling agents in Australia, was analysed using multiple regression analysis to determine the effect on commercial sale prices of year, selling season within year, agent, mean fibre diameter (MFD), coefficient of variation of fibre diameter [CV(D)], vegetable matter base (VM), Schlumberger dry yield, visually assessed staple length, visually assessed fibre style, incidence of kemp, other faults, and interactions of these effects. The database consisted of 557 objectively measured lots. The weighted means ± s.d. of attributes analysed were: MFD, 30.9 ± 3.7 μm; CV(D), 29.1 ± 2.6%; VM, 1.0 ± 1.0%; Schlumberger dry yield, 84.0 ± 2.7%; lot weight, 1186 ± 938 kg. The final model for the price of greasy mohair had fixed terms involving a combination of selling agent, selling period, MFD, VM, and visual classing grades. This model accounted for 98% of the variation of the logarithm of greasy mohair price. Agent and selling period combinations accounted for 22% of the variation. Terms involving MFD accounted for 59% of the variation not accounted for by agent and period combinations. Although the response of greasy mohair price to MFD differed greatly with period, in the second quarter of 1999 the maximum relative price of greasy mohair was reached at a MFD of about 25 μm. The relative price typically declined to about 50% of the maximum at 30 μm and to a price of 10% of the maximum at 36 μm. The increase in relative value from poor to superior style mohair was about 43%. There were large discounts for length (up to 48%), kemp (up to 87%), and light stained mohair (70%). Deviations due to length differ with time and MFD. The discount for fault lines was proportionally higher when MFD was low, and proportionally less serious when the mohair MFD was high. The discount was proportionally greater the more serious the fault. There was a curvilinear response to the presence of VM in mohair and an interaction of VM with MFD, but these terms only accounted for the last 0.5% of the variation. After allowing for the effects of selling, agent, visual attributes, MFD, and VM, neither Schlumberger dry yield nor CV(D) was related to greasy mohair price. CV(D) was related to length, kemp, fault, and MFD. Apart from the current practice of price reporting on a greasy basis, the information supplied by agents provides transparency in mohair transactions as the current objective measurements and visual appraisal explain 97% of the variation not explained by agent and period of sale.