THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: WOOL PRODUCTION AND FLEECE CHARACTERISTICS

Abstract

Wool fibers grown on 2 cm2 of skin were removed from the shoulder region of 273 female yearlings born at La Pocatiere Experimental Farm over a period of 3 yr. The yearlings represented nine genetic groups, Finnsheep, DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. The traits studied were staple length, fiber density, clean wool percentage, fiber length and thickness and their variability. Grease fleece weight (GFW) was recorded at first shearing on the 273 yearlings and on an additional 90 female yearlings. GFW was subsequently recorded at yearly intervals up to the 5th shearing. GFW of Finnsheep (F) was 2.3 kg for yearlings and averaged 2.0 kg for older ewes compared to 2.3 and 2.8 kg for the DLS, respectively. The crosses showed positive deviations from the expected means of their parental breeds, the highest was expressed in the [Formula: see text] and 5/8F crosses, GFW exceeded in many crosses that of the better parental breed. The relationship between GFW and the proportion of Finnsheep in the genetic group was linear in second shearing and curvilinear for later shearings. Significant linear relations were also observed in fiber thickness and variability in both fiber length and fiber thickness, whereas significant curvilinear relations were observed in clean wool percentage and fiber length. Compared to DLS, Finnsheep had a higher fiber density (1950 vs. 1551 cm−2), fibers were longer (19.1 vs. 15.8 cm) more variable in length (SD = 4.66 vs. 2.96 cm), finer (20.5 vs. 25.5 μm, and uniform in fiber thickness (SD = 4.8 vs. 5.9 μm), these differences being statistically significant. Most of the crosses exhibited positive heterosis particularly in clean wool percentage, staple and fiber length. The highest heterosis was often manifested in the [Formula: see text] cross. Key words: Wool production, fleece characteristics, crossbreeding, heterosis, Finnsheep, DLS sheep