Fiber density and hair ducts in the skin of alpacas: Quantification, heritability, and genetic correlations

Alpaca fibers are used to create luxury garments, and simultaneous selection for optimizing fiber density and the density of hair ducts in the skin of alpacas could result in a more profitable product for breeders. The objective of this study was i) to quantify fiber density (FibDen), density of hair ducts (DenDuc), and the relationship between No. of fibers/No. of ducts (Fib/Duc) by age and sex, and ii) to estimate heritability and genetic correlation between FibDen and DenDuc. This study was conducted in the CEDAT (Centro de Desarrollo Alpaquero de Toccra) in the Department of Arequipa, Peru. A total of 1,813 alpacas of different sex and age with pedigree information were analyzed from years 2004–2018. The quantification of FibDen, DenDuc and Fib/Duc was estimated using Fiber-Den equipment in an area of 1 mm² in the middle rib region of the animal. The average FibDen, DenDuc and Fib/Duc was 24.75 ± 5.48, 7.83 ± 2.17 and 3.25 ± 0.55, respectively. The heritability for FibDen, DenDuc, and Fib/Duc was 0.48 ± 0.04, 0.53 ± 0.04, and 0.20 ± 0.03, respectively. The genetic correlation between FibDen and DenDuc was 0.87 ± 0.06. The estimated heritabilities of these traits in Peruvian alpaca population are moderate to high and indicate that these characteristics could be used as selection criteria in breeding programs.