Camelids
Mating & Castration:
Females can be bred from 12 months of age once they have begun the hormonal changes of puberty. The rule of thumb is that they should be over 12-months of age and weighing at least two thirds of their anticipated adult weight (>35kg). The gestation period of the alpaca is 11.5 months and most animals are bred in the spring/summer/early autumn, so that the cria are born during the more favourable climates of the English summer.
Following parturition, the female alpaca undergoes early uterine involution (returning the uterus to normal size) and is usually capable of successfully re-breeding as early as 10 days after giving birth. As a general rule we recommend re-breeding 14-21 days after unpacking.
Alpacas are induced ovulators, only shedding their eggs after mating with a male. They sit down to mate. A male may be run with a group of females (pasture breeding), or a single female may be mated with a male under observation (managed breeding). The latter gives better control and assistance may sometimes be given to guide the male penis into the vagina. In some circumstances, hormonal treatment may also be given to the female in a managed breeding programme to assist the establishment of pregnancy.
1 week after mating, the female should be put back with a male to see if she will “spit off”. “Spitting-off” is when the female is unreceptive to the male, causing them to reject the male advances by spitting. This can be used as a crude method of detecting whether the animal has held to the mating. Normally, females are re-introduced to the male at weekly intervals following mating and two positive spit-offs at weekly intervals are a good indication that the mating has held. Confirmation of pregnancy can be obtained by ultrasound scanning of the abdomen, which is a painless technique similar to that used in humans. Ultrasound scanning can detect pregnancies as early as 30 days, but we generally recommend using it between 40-60 days of pregnancy for the most reliable results.
Castration
Not all males will be suitable for breeding, and those that do not make the grade should be castrated between 18 months and 2 years of age. This may seem late in life, compared to other farm animals, but testosterone (produced by the testicles) is involved in closing the growth plates of the alpaca skeleton. Early castration can therefore cause failure of growth plate closure, resulting in deformities and elongated limbs. Castration is a veterinary procedure and must be conducted under anaesthesia. This may be full general anaesthesia, or using local anaesthesia under sedation. In our hands, we find that the latter method causes little stress to the animals and does not have the inherent risk of a general anaesthetic.
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Last Updated : 29 January 2008 (C) Larkmead Veterinary Group