Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. 17 THE EFFECT OF SEASON OF BIRTH, BREED AND PASTURE TYPE ON THE FIBRE STRENGTH OF WOOL FROM WEANER SHEEP GEOFFREY R. SAUL* 467 Fibre strength (FS) and position of break (POB) influences the price obtained for wool of a particular fibre diameter. However, there are few reports of the This paper reports effects of management decisions, or breed differences on FS. data on the effects of season of birth, breed and pasture type on FS. Experimental details have been published previously (Obst 1986). Mid-side wool samples were collected from 15 month old May/June or August/ September born, Merino (19~) and Comeback (21~) weaner sheep which had grazed either perennial ryegrass/subterranean clover (PRG) or lucerne/subterranean clover (Luc) for'12 months. Lambs born in May/June were weaned, shorn and placed ixi paddocks in mid September, and August/September lambs were similarly treated in December. Wool was collected from 8 randomly selected sheep per treatment and each sample tested for FS and POB. Results are shown in Table 1. Table 1 The effect of season of birth, breed and pasture type on fibre strength (N/Ktex) and summer live weight (kg) Oaten grain was offered if the condition score (Jeffries 1961, 1 = thin, 5 = fat) of 33% of sheep in a treatment fell to <1.7. August/September weaners required more grain than May/June weaners (167 vs 94 MJ/hd) and weaners on PRG The time at which the break in more than those grazing Luc (197 vs 64 MJ/hd). For May/June weaners, the wool occurred was determined from monthly dyebands. the wool break occurred before the opening rains, while grain was being fed to The wool PRG weaners and Luc weaners were grazing declining amounts of lucerne. break for August/September weaners was at or just after the opening rains. Analysis of variance (years as replicates) was used to test the effect of Wool from Comebacks was weaker (~(0.01) than wool from the treatments on FS. Also, wool from August/September born weaners was of Merinos (35 vs 41 N/Ktex). lower strength (~(0.01) than that from May/June born weaners (33 vs 43 N/Ktex), Pasture despite the higher amount of supplementary feeding to the former group. Provided the condition score of weaner species had no effect on fibre strength. sheep is maintained above 1.7, these management and breed effects are unlikely to However, cause price discounts for wool as all treatments were >30 N/Ktex. spring born Comeback weaners may have wool of marginal strength. The University of NSW tested the wool with financial assistance from the AWC. JEFFRIES, B.C. (1961). Tas. J. of Agriculture 32:19. OBST J.M. (1986). Proc. Aust. Soc. Anim. Pror 2: 52. *Department of Agriculture and Rural Affairs, Pastoral Research Institute, Box 180, Hamilton, Vic., 3300.
