Winter - Classical Mileend Alpacas

mating have been reported as low (Sumar 1985)
and less effi cient than other farm species (Wiepz
et al. 1985). However, there have been reports of
21 out of 28 (75%) female llamas pregnant after
two matings 4–8 hours apart (Adams et al. 1990),
a 46% parturition rate in single-mated llamas
(Condorena et al. 1988) and 34 out of 70 (49%)
females pregnant 60 days after a single random
natural mating (Vaughan et al. 2002). These rates
compare favourably with conception rates in other
domestic livestock and suggest that unsuitable
reproductive management, nutritional defi ciencies
and inbreeding contribute to low fertility (Parraguez
et al. 1997). The sperm concentration required
for successful fertilisation and pregnancy is not
known, but intracornual semen deposition of
semen during copulation may be an adaptation to
overcome relatively low sperm concentrations in
ejaculates (Brown 2000).
To maximise the number of sperm per ejaculate
and matings per day, it has been recommended
to select males with large testicular size on the
assumption that the direct relationship between
testis size and sperm production in other domestic
livestock also occurs in camelids (Sumar 1983,
Smith 1999c, Brown 2000, Galloway 2000). Mean
testicular length (the average length of left and
right testes) is correlated with testicular weight
(Galloway 2000) and may be used as a simple
means of assessing testicular size in alpacas.
Mean testicular length may be used to estimate
the likelihood of sperm production in alpacas
(Table 1; Galloway 2000).
TABLE 1 Development of testicular function
in alpacas with testicles of different sizes
(Galloway 2000)
Mean Proportion % testicular
testicular of males tissue producing
length (cm) (%) elongated spermatids*