With their big eyes and fluffy coats, crias (baby alpacas) are particularly cute.  They are also very valuable additions to the alpaca herd.  No wonder then that successful births are among the greatest joys of alpaca farming. 

The birth process is sometimes called ‘unpacking’ or ‘criating’, and while ‘unpacking’ might sound easy, breeding alpacas isn’t always as straightforward as it is with cattle and sheep. 

One of the oddities about alpacas is the fact that the females are induced ovulators, like cats. 

  • This means that they don’t have regular oestrus cycles but they are receptive to the male much of the time, with the intensity of receptiveness coming and going over a period of days. 
  • When they are sexually receptive they seek the attention of a male and adopt a sitting position for copulation, which may take some time.
  • The act of mating and possibly stimulation of the cervix provoke ovulation 24 to 48 hours later. 
  • Female alpacas can become sexually active from around 12 months of age if they weigh 40 kg or more.

Another alpaca oddity is that the males are born with the equivalent of a chastity belt! 

  • In young males, there are adhesions around the penis in the sheath that mean that the penis can’t be extruded completely. 
  • These adhesions break down over time and have gone by about 3 years of age. 
  • However, the adhesions mean that if a male younger than about 3 years old attempts to serve there is a risk that the penis will be damaged by the adhesions. 
  • In spite of this, males start to show sexual activity from about 8 months of age, and males as young as this have been known to mate successfully.

The size of the testicles is a good guide for evaluating a male’s performance.  Males with testicles longer than 3 cm are more successful sires. 

The male at mating makes characteristic gurgling roaring noises called “orgling”.     

Alpacas can breed at any time of year, but mating success tends to be most successful in spring and autumn.

Foetal losses

There is a fairly high rate of foetal death and resorption in alpacas, and most of the losses seem to occur before 60 days’ gestation.  The reasons are not always clear, but if the female seems unwell, infection is a possibility and veterinary treatment is important. 


The length of pregnancy is usually between 335 and 355 days but it can be as long as 390 days.  Generally, the pregnancy length of any one female is similar from one pregnancy to the next so it’s a good idea to keep breeding records for individuals.

Pregnancy testing

  • Seven days after mating, it is possible to test for pregnancy using a “spit-off” test.  If the female sees her suitor off by spitting, she is probably pregnant (84% likely). 
  • Ultrasound testing by your vet is the most accurate way of pregnancy testing up to 120 days’ gestation.  It can be done through the abdominal wall from about 60 to 120 days’ gestation and is relatively stress-free for the animals.

If your female is successfully pregnant and approaching full term, you can start to look forward to the birth.  The birth process itself is worthy of a whole article on its own, and that will follow next month.


Alpacas: A Basic Veterinary Reference. Peter Aitken BVSc. VetLearn, Massey University 2006.
AANZ Alpaca Conference Proceedings: The Alpaca Enigma. Alpaca Association New Zealand and NZVA, July 2007