Skin wrinkles of the sire adversely affect Merino and halfbred pelt characteristics and other production traits

Abstract

The wrinkles on the skin of Merino sheep and related breeds are retained during leather processing, and the skins are known as ‘ribby pelts’ in the leather trade. Merino sires with either no skin wrinkles (smooth, n = 7) or excessive wrinkles (ribby, n = 7) were allocated at random to mating groups of 22 Merino ewes mixed with 22 Romney ewes. The progeny of ribby sires were more ribby at docking (P<0.001), at shearing (P<0.001), in the fellmongery (P = 0.001) and as pickled pelts (P<0.001). Merino progeny were more ribby than Merino × Romney (halfbred) progeny at all stages. When professionally graded as pickled pelts, smooth-sired progeny produced more pelts without ribs in both Merino (5% v. 0%) and halfbreds (69% v. 38%) than ribby-sired progeny. Wool samples collected at 7.5 months of age were not significantly different between sire groups in mean fibre diameter (P = 0.27) or staple length (P = 0.60) but they were different in standard deviation of fibre diameter (P = 0.003). Liveweight was consistently greater in the progeny of smooth sires, although this difference did not reach significance until the progeny attained a mean liveweight of 28 kg for Merinos and 32 kg for halfbreds (P = 0.016). Breed differences were observed in other traits and these are discussed. Interestingly, there were few significant sire type breed interactions, the exceptions being yield of clean wool (P<0.001), standard deviation of fibre diameter (P = 0.003) and an additional pelt trait referred to as pinhole score (P = 0.003). In summary, choosing sires without skin wrinkles can improve pelt quality, wool quality and liveweight of Merino and halfbred progeny.