Reproductive status and age effects on Huacaya alpaca fiber medullation

Résumé

This study delved into the impact of environmental factors on the medullation of fibers (continuous (C), interrupted (I), fragmented (F), and non-medullated (NM)) in white female Huacaya alpacas. Utilizing records and fiber samples from 185 alpacas at the Research and Development Center for South American Camelids Lachocc, National University of Huancavelica (Peru), statistical analyses were executed employing the least squares method for unequal numbers in subclasses. The age of the alpacas exhibited a statistically significant influence on the type of fiber medullation, with the exception of fragmented medullated fiber. The regression equations generated facilitate predictive modeling for continuous, interrupted, and non-medullated medullae. Mean values (%) for continuous medullae were observed as 27.45, 27.98, 28.03; interrupted medullae as 33.15, 34.13, 35.41; fragmented medullae as 10.60, 8.11, 11.29; pigmented medullae as 16.27, 13.06, 16.87; and non-medullated as 29.99, 30.57, 29.51, respectively, for empty, pregnant, and lactating alpacas. It is noteworthy that reproductive status exhibited no statistically significant effect (p>0.05) on various forms of medullated fibers, highlighting the nuanced interplay between environmental factors and fiber medullation in Huacaya alpacas. Age significantly influenced medullation, except for fragmented fibers. Continuous medulla rose by 2% yearly, while non-medullated fibers dropped by 3.69%. Interrupted medullation peaked at 38.5% around 5.9 years. The study provides insights into the nuanced relationship between reproductive status and medullation in alpaca fibers.