Relationship between age and postnatal skin follicular development in three types of South American domestic camelids

Fifteen alpaca kids, comprising l0 huacaya and 5 suri, and l0 llama kids of chaku type, born on January 1998 at the "Alpaquero" Developing Centre of Toccra, located in the Arequipa Plateau, Caylloma Province (Peru), were chosen for determining the age at which all the secondary follicles reach the maturity, as well as for comparing the skin follicular structure and activity among these different types of Peruvian camelids. Skin biopsies were taken at 2,4,6, and l0 months of age in order to monitor four follicular parameters: i) follicular density (FD), ii) ratio of secondary to primary follicles( S/P), iii) percentage of medullated secondary fibres (PMS), and iv) percentage of active secondary follicles (PAS). As a general trend, three parameters, i.e. FD, PMS, and PAS, reached maximum values at the 2nd month, minimum values at the 6th month (i.e. during the winter season) and increased again until observations stopped at month 10. A slightly different trend was shown by the S/P parameter which, after having gained its maximum value at month 4, progressively decreased until the end of the observations. It is concluded that the South American camelids here investigated gained a complete and mature skin follicle apparatus at an early age and, hence, producers should practice an anticipated first shearing.