Fiber production and properties in genetically furred and furless rabbits

The objectives of this study were to describe and compare means and measures of variability of fiber characteristics and fiber production between genetically furred and furless rabbits and among classes of furless rabbits. An F₁ generation of rabbits was produced by mating New Zealand White does to a rare, furless Mini Lop buck. All F₁ offspring had normal coats of fur. Inter se random matings of the F₁ stock (barring full-sibling matings) were made to produce the F₂ generation that consisted of approximately 75% furred and 25% furless progeny. Furless animals were further subjectively classified into 3 distinct classes (1 to 3) having increasingly more fur. In yr 1, 17 furred and 20 furless rabbits (age 28 to 49 d) were randomly assigned to growing pens, and in yr 2, 17 additional furless and 9 additional furred rabbits were included to increase the size. After 6 wk, the rabbits were weighed, and a measured area of fur (approximately 20 cm²) was shorn from the left flank of each rabbit. This fiber was weighed and measured for staple length, fiber diameter, prickle factor (% of fibers >30 μm in diameter), and fiber curvature. Fiber production per unit area of skin was calculated and fiber production per animal was estimated. In yr 2, all of the furless and 2 of the furred rabbits were shorn over their entire bodies to obtain direct measurements of total fur weight. Furless rabbits were 9% heavier (1,941 vs. 1,783 g of BW, P < 0.01) and produced approximately 90% less fiber per unit area of skin than furred rabbits (1.74 vs. 15.83 mg/cm², P < 0.01). The fibers from furless rabbits were shorter (1.54 vs. 2.56 cm, P < 0.01) and coarser (15.8 vs. 14.5 μm diameter, P < 0.01) than those from furred rabbits and exhibited greater prickle factor (11.3 vs. 3.5%, P < 0.01) and curvature values (47.5 vs. 38.5 deg/mm, P < 0.01). Class 3 furless rabbits were heavier than rabbits of classes 1 and 2 (2,075 vs. 1,817 and 1,981 g of BW, respectively, P < 0.05). Means for actual total fiber production per animal for classes 1 to 3 were 0.64, 2.07, and 8.68 g, respectively, compared with 23.0 g for furred rabbits (P < 0.01). Although some similarities were present, several of the correlations involving fiber properties and BW were substantially different (e.g., BW vs. staple length and fiber diameter vs. weight of fiber per unit area) for furred and furless groups. These results, and those reported elsewhere from a series of experiments, support the potential for production of furless rabbits in arid and tropical environments.