I have used the Preg-Tone on my herd for 3 years now and it has been 100% accurate. I usually breed and confirm the female’s pregnancy using spit testing for the first 40 days.  I use the Preg-Tone to make sure that the female has not resorbed or aborted the fetus up to the last trimester. Through the last trimester, the pregnancy is visually confirmed by obsessively staring at the female’s belly, in anticipation!

From the Llama & Alpaca Neonatal Care book: “Three to four weeks following mating, the embryo finally attaches to the uterine wall and begins to develop a placenta.”

“More than 95% of the embryos migrate to the left horn of the uterus and attach there.”

“It is recommended that 28 to 60 days is a good time for an ultrasound confirmation of pregnancy. Transabdominal ultrasound does not work well until the fetus has grown sufficiently large enough to pull the uterus forward and down into the abdominal cavity. Up to this time the fetus is relatively small and the distance between the ultrasound head and fetus is less than 4 inches. From approximately 90 days until birth, the uterus is close to (or touching) the body wall and the fetus can be visualized across the body wall (transabdominal).”

“By 4 months of gestation the llama cria is approximately 8 ½ inches in length and weighs approximately 200 grams (less than ½ pound) , while the alpaca cria at the same stage of development will be somewhat smaller. From three or four months of gestation until birth, the primary fetal changes are completion of organ development and overall growth. During this period (four months of gestation to birth), body weight will increase fifty or sixty times, with the most dramatic growth occurring in the last third of gestation. ”

180 days gestation (6 months), alpaca cria weighs 1.3 lbs. 230 days gestation (7.6 months), cria weighs 5.5 lbs. 345 days gestation, cria weighs 19.8 lbs.  Total weight gain in the last 1/3 of gestation - 14.3 lbs!

From the Medicine and Surgery of the American Camelid book: “Compartment one of the stomach occupies the entire left side of the abdomen, so the pregnant uterus is diverted to the right side.”

Based on this information I can conclude that prior to 40 days there may not be a sufficient amount of fluid to be detected by the Preg-Tone. I begin by ultrasounding from the left side of the female prior to 60 days. From 60 days on I work from the right side. If you do not get good results from the left side try the right side, since the pregnancy might be in the right uterine horn.

On some females, you may need to shave a small area on the belly to get good contact. I used to routinely shave an area first, but have since found that by applying contact oil and smoothing the hair down, I can usually get good contact. The hair in the proper testing area is usually  fairly smooth and thinly distributed. I have used water based OB lubricants such as KY Jelly. Apparently, due to cold temperature, these products will trap air bubbles which affects the ability of the ultrasound to penetrate the skin. (Renco recommends mineral, vegetable or motor oil.) I now use mineral oil in a squeeze bottle. First I wrap a paper towel around the base of the probe to keep from drenching my hand with oil. I put a puddle of oil on the probe and smear this on the area of the belly I intend to test, smoothing the hair down with the oil. The idea is to eliminate air between the probe and skin so the ultrasound waves can be transmitted. Then, I apply another puddle of oil onto the probe and  place it in the same spot I just smoothed down. You should get a contact tone or a positive tone. If you do not get a tone, put another puddle of oil on the probe and keep trying until you realize why you wrapped that paper towel around the base of the probe!

With the female standing, I place the probe about six to eight inches down from the females udder. On maiden females, you may need to place the probe a little higher, about 5 inches from the udder. I don’t always get a contact tone (which is an intermittent beep). Often, the positive tone is immediate when good contact is made. I point the probe straight into the belly from the angle that is defined by the females shape. Sometimes, directing it up to a more vertical line. See drawing. It would be difficult to pick up the female’s bladder from this position without really pushing into the belly and directing the probe toward the rear.

Elsa is not a representative for Renco Corp. and has no interest in their product other than as a helpful tool that is successfully used on her alpaca herd.