Alpaca females reach sexual maturity between 12 and 18 months but should also have reached around 65% of their final body weight (say, 45kg) prior to mating. They will remain fertile for between 14 to 18 years. Alpacas, in common with cats and rabbits, are induced ovulators i.e. ovulation is stimulated by the mating itself, so they may be mated at any time. I practice, in the UK, breeders try to avoid births during winter months both because the risk of cria morbidity is higher if born in very cold weather, and because daylight is an important growth factor in young cria so those who experience long days in their early months tend to do better. As the gestation period is around 11.5 months this means most breeders are conducting their mating program in late spring or early summer.

Females are generally very reliable ‘presenters’ of their state of pregnancy (they recognise their own raised levels of progesterone). A female who is pregnant will reject the advances of a male either by running away, spitting, kicking, or a combination of all three. An open female should ‘kush’ (i.e. sit on all fours) when approached by an interested male. The male then mounts the female and the mating commences. Generally the female is calm and still throughout but the male will spend almost the entire period – usually about 20 minutes – ‘orgling’: a curious and very distinctive gutteral sound. With the exception of the orgling the mating is a very peaceful affair and interested outsiders – both alpaca and human – are tolerated well.

Ovulation occurs between 24 and 48 hours post mating.

Pregnancies are initially confirmed by successive rejections by the female. These are usually confirmed at about ten weeks by trans-abdominal ultrasound.

The foetus exhibits little growth for the majority of gestation with most growth occurring in the last six weeks. Thus it’s very difficult to tell visually whether an alpaca is pregnant.

Births are usually unproblematic, rarely require intervention, and generally occur in the morning. The female usually gives birth standing up and normal presentation is fore-legs and nose first. The cria will be standing within an hour or so, suckling shortly thereafter, and will be running unsteadily by the end of the day. Multiple births are rare and successful ones rarer still. Crias should weigh between 6 and 9kg, less than 6kg may indicate a problem cria and above 9kg could mean a birth which needs assistance. The rest of the herd will be very inquisitive about the new arrival, the mother, whilst protective, is generally tolerant of this interest.