Comparative evaluation of medullation types and their respective fiber diameter in alpacas from seven regions of Peru

Alpaca fibers may be classified according to the type of medullation, into fibers with strongly medullated (StrMed), continuous (ContMed), discontinuous (DiscMed), fragmented (FragMed), and fibers without medulla (NoMed). ContMed and StrMed may cause prickling and issues during dyeing and are less resistant in textile processing; therefore, they should be eliminated from fleece. Thus, to produce more comfortable alpaca fibers, it is essential to establish a baseline, and for this reason, this research aimed to evaluate the incidence of fibers according to medullation type and their respective average fiber diameters (AFD) in Peruvian regions. Samples of alpaca fibers were collected from Apurímac, Arequipa, Cusco, Huancavelica, Junín, Pasco and Puno, which were analyzed using the Fiber Med equipment of the Textile Fiber Laboratory of the Natural Fiber′s Tech SAC, a Technological Research and Development Center. Medullation and fiber diameter data did not have a normal distribution, then for statistical analysis, nonparametric techniques were applied. The means of the percentages of medullation and fiber diameters were: 61.87% and 19.12 µm; 16.84% and 22.62 µm; 7.56% and 24.87 µm; 13.23% and 28.56 µm; and 0.50 and 45. 69 µm for NoMed, FragMed, DiscMed, ContMed, and StrMed, respectively; showing greater variation in medullation types than medullated fiber diameter. The geographical region, owner type, and age of animals influenced the medullation types and their fiber diameters (p < 0.05). On the other hand, ContMed was similar by breed; the sex only influenced FragMed. AFD_FragMed and AFD_StrMed were similar by breed. AFD_StrMed was also similar by sex. The percentages of medullation and the fiber diameters of alpacas from the seven Peruvian regions maintain high variability by location, age, owner type, breed and sex. Furthermore, there is a positive correlation between the percentage of medullation and its fiber diameters, with ContMed and StrMed fibers showing greater diameters.