A recent exchange of e-mails prompted me to write a three-part series about pregnancy testing in alpacas. The breeder with whom I exchanged e-mails is a regular reader of this blog. I’m sure she doesn’t need this information, but others might, so I sat down and started writing. What follows is my (current and subject to change) perspective based on my experience. I want to stress that I am relating opinion and not dispensing veterinary advice.

New alpaca owners are told that breeding alpacas is easy. “The females are induced ovulators.” the story goes, “Just put them in with the male and they’ll get pregnant.” You’ll hear stories like, “Oh, yeah, testing for pregnancy is easy. Just put the male in with the female. If she’s pregnant, she’ll spit at him. If she’s not pregnant, she’ll cush (lie down) to breed.”

If only it were so simple.

Alpacas are induced ovulators. Sex in alpacas generally does cause the female to release an egg. Female alpacas, however, do cycle, and they only have an egg ready for release most of the time. They aren’t always receptive to the male and even if they are, they don’t always have an egg ready to drop. If the female does ovulate in response to breeding, it takes a couple weeks to determine if she’s acting pregnant due to ovulation or acting pregnant due to actual pregnancy. (Then, there are the real reproductive complications that occur plus the failed implantations, inviable embryos, miscarriages, etc.)

Behavior testing for pregnancy in alpacas isn’t nearly so simple as it sounds, either. To a first approximation, the above statement about the female either cushing or spitting roughly accurate. If you put a male alpaca and a female alpaca together, the male will attempt to breed the female and she will either be receptive or she won’t. If she’s receptive, she will eventually cush and allow the male to breed. If she’s not receptive, she will attempt to reject the male’s advances and this rejection usually involves spitting.

Notice the words eventually and usually in the above statement. The key to effective behavior testing for pregnancy is knowing your animals and being able to read the females’ behavior while attempting to control a very excited male alpaca on the end of a lead – a male alpaca with twice as many feet as you have and who weighs about as much as you do who doesn’t want to take “no” from a female alpaca and isn’t about to take “no” from a mere human.

We had three females we bred enough times to get comfortable in our ability to read their behavior. One always the easy. She would either run from the male or cush. We never had any question about her pregnancy status. Another was easy for us to read, but only because we knew her well. She will cush for the male whether she is pregnant or not. The key to testing her is to watch her jaw. If her jaw is clenched, she’s pregnant and only cushing because she thinks she is supposed to. If her jaw is relaxed, she’s open. We’ve never had much problem reading her, but many breeders will insist she’s open when she is in fact pregnant. Our third female was the tricky one. We finally decided that if she was open, she would run in circles sniffing at the male and that if she was pregnant, she would run in circles spitting. She showed enough variations in these behaviors, however, that we were never quite sure.

All these behavioral differences and difficulties with behavior testing lead to many alpaca breeders relying on veterinary means of determining pregnancy. The two common methods are ultrasound and progesterone tests. Ultrasound is not as reliable in alpacas as it is in humans. For some reason, the accuracy of ultrasound in mid and late pregnant alpacas is very poor – some anatomical difference that I’m sure I don’t understand. The other problem with ultrasound is that many vets don’t have the equipment. A progesterone test takes only a blood draw, and all vets are equipped for that.

Which leads to progesterone tests as a very common way of testing for pregnancy in alpacas, something I’ll discuss in a near future blog.