69 Is mating behaviour linked to fibre quality in alpacas in the Peruvian Andes?

Many of the inhabitants of the Andes are dependent on alpacas for their livelihood. The quality of alpaca fibre determines the market price; therefore, factors affecting fibre quality can have a marked negative effect on the household economy. It has been suggested that factors such as age, body condition score, and coat colour affect fibre quality. Another possibility is that high testosterone levels could be associated with coarser fibres but also with a higher proportion of successful matings, Therefore, the objective of this study was to assess the effects of mating success, male age, body condition score, and coat colour on fibre quality in Peruvian alpacas. Breeding data were collected during the breeding season; fibre samples were taken from males during September in the same year. Breeding records comprised notes made when each male and female were presented to each other; the female either accepted or rejected the male. Females who permitted mating were checked for receptivity again after 14 days. Females who spat at the male at this time (spit-off) were deemed to be pregnant whereas those who permitted this second mating were assumed to be nonpregnant from the first mating. Records were available for 3–4 mating attempts. The hair samples were analysed using a laser scanner, Optical Fibre Diameter Analyser 2000 Benchtop version (BSC Electronics). The video microscope magnifies and captures images of the individual fibres and measures the diameter of each fibre, coefficient of variation, comfort factor, curvature, and spinning fineness. To assess the body condition, alpacas were palpated over the back, near the last rib; the muscle mass was given a score from 1 to 5, with 1 being very thin and 5 being obese. Body condition scores of (BSC) 2.5–3.5 are considered healthy for a male (Australia Alpaca Association 2013). The age of the male was recorded. Colour was scored as white through various shades of brown to black (white, white chile, café con leche, light fawn, light brown, grey, coffee, brown, dark brown, black). Fibre samples were taken from both white (n = 137) and coloured (n = 57) alpacas. The white alpacas had significantly longer (P = 0.0093) and thinner (P = 0.0001) fibres than the coloured animals. Body condition had a significant impact on the length of the fibres (P = 0.0002). Animals with BCS ≥ 3.5 had the longest fibres; animals with BCS ≤ 2.5 had fibres longer than those of animals with BCS 3, but shorter than animals with BCS ≥ 3.5. Young alpacas had finer fibres than older males (P < 0.0001). There was no association between fertility (as assessed here in terms of willingness of the females to mate with a particular male) and fibre quality (P < 0.959). In conclusion, age, body condition score, and colour, but not mating success, affected fibre quality in male alpacas in Peru.

The authors express their thanks to the Minor Field Study Program at the Swedish University of Agricultural Sciences for funding.