Wool scoured colour is one of the features that must be improved in Uruguayan Corriedale wool. Yellow discolouration is the main problem and it is related to environmental conditions and individual susceptibility. The objective of this trial was to estimate the effect of season and staple length on wool colour through the application of an incubation technique in a Corriedale flock. 63 hoggets were sampled each 6 months during 2 years. 4 treatments were carried out considering staple length (short and long wool staples) and sampling season (winter or summer). A raw wool incubation technique was applied to predict coloration and pre incubation and post incubation clean wool colours (Y-Z) were determined. The results showed a significant increase in post incubation wool colour (Y-Z= 6.98 ± 1.93) with respect to pre incubation colour (Y-Z= 1.88 ± 1.72). The samples extracted in winter with short staple developed a significant lower colour (Y-Z = 5.69 ± 2.00) than those extracted in summer with 12 months growth (Y-Z = 8.93 ± 2.11) (P<0.01). Season of shearing and length of wool affect wool yellowness in this Corriedale flock.
