The Girls

We all know now that alpacas are 'induced ovulators'. The physical act of copulation and the stud's ogling noise induces ovulation with the release of an egg from a mature follicle. They do not have an oestrus (sexual receptivity) cycle as most other domestic livestock (cats, rabbits, ferrets, mink and otters are similar) and a sexually mature female is either receptive to mating or non-receptive to mating. We can thus ask our alpacas to mate at any time of the year.

The uterus has a short body with two horns, which lead to the fallopian tubes down which the eggs travel from the two ovaries. Regardless of which ovary ovulates, most pregnancies will implant in the left uterine horn. Twin conceptions are rare, with twin full term births usually resulting in malformed or weak cria.

The most important parts of the ovary are the eggs, follicles and corpus luteum. We need to understand simplistically, their function. Starting with the eggs, under hormonal stimulation some of the cells surrounding them begin to develop and form into what are called follicles. These continue to grow in size, filling with estrogen hormone. The largest one eventually takes over from the smaller ones and becomes dominant. When it has reached a mature size (defined as being greater than 7mm in diameter) and if stimulated by the luteinising hormone (LH) they rupture and release the egg.

The required surge of luteinising hormone, stimulated by copulation, is released from the brain and peaks around 2-4 hours after mating. Ovulation then completes anywhere between 24-48 hours after mating.

Once the egg has been released from the follicle, the cells re-arrange and over a 3 to 6 day period continue to grow into a solid mass called the corpus luteum (CL), the producer of progesterone.

Meanwhile the egg starts its journey down the uterine tube towards the uterus. Sperm swim from the uterus up the uterine tubes and conception hopefully takes place. The fertilized egg completes its journey to the uterus over the next 5 to 7 days. Finally, it takes three to four weeks for the developing embryo to attach itself to the uterine wall and begin to develop its placenta.

Progesterone production is needed throughout the gestation period and any event that causes the CL to shrink will result in foetal abortion.

If ovulation fails to occur then the follicle shrinks and dies back. The growth and then shrinking of the follicle is called a follicular wave and has significance on the sexual receptivity of the female. The typical cycle is 3 to 4 days of growth to reach the mature size of 7mm where it remains mature for another 4 to 6 days, before shrinking back over the next 3 to 4 days. As there are two ovaries and therefore two dominant follicles each with separate waves, we end up with a 2 to 3 day period where the follicles are either too young or too old for a fertile mating to take place, and a 4 to 6 day period with good fertility and receptivity.

A small percentage of females may fail to ovulate after mating because of a LH deficiency. We do not recommend repeated daily matings as no further LH will be available for at least two days after a previous mating.

So how long to we have to wait for the new born cria. A long time is the only real answer. Officially within the range of 315 to 370 days. Yes that is an alarming just over ten months right through to over 12 months. On average though the vast majority will deliver at around 11.5 months. As the mating seasons roll by, your records might well show some consistency of gestation periods for individual alpacas. Some always coming early, some right on the dot and the others that always keep you waiting. (I have read somewhere that there is also some evidence that gestation periods are linked to seasonal mating times with spring matings having longer times than autumn matings)

Finally, at what age do we allow maidens their first experience. Certainly not before 12 months of age. There is some evidence that young pregnancies have higher rates of failure so we will wait for a body weight of at least 100 pounds and at least 12 months of age before we gently try with a not too aggressive male. If the female appears at all under stress or refuses to sit within a short period then we stop. Generally over a few weeks of short sessions we find most girls willingly sit.

Male

Our stud has what is called a fibro-elastic penis and two testicles held in a scrotal sac. He has the alarming ability to be able to move his testicles closer to his body to maintain optimal temperatures. So if you were sure your boy was well endowed when you bought him and then the next time you looked you could see nothing, don't panic !

The prepuce or sac which holds the penis, normally points backwards, but when he is aroused points forward and the penis extends from it. Prior to puberty the penis is attached to the prepuce so no extension is possible. We normally expect sexual maturity at around 2.5 to 3 years of age at which time the penis has become detached, sperm production is in full flow and sexual drive is evident. There are always the exceptions though, so it is wise to keep all entire males away from the girls after 12 months of age, and ideally after weaning.

During mating the penis extends and passes through the cervix up into the uterus. Sperm is ejaculated into both uterine horns as he moves his penis from one to the other. Around 2ml of viscous semen is ejaculated over a period of time which seems to vary from a quick 5 minute session to over 45 minutes, on average 20 minutes seems to do it.

We would normally allow healthy mature males two matings per day, usually in succession, as they are always on the look out for the next girl should she be standing close by. A third mating after a few hours rest seems to work. Young males beginning their stud duties are restrained to one.

Preparation

First we must decide on whether to use pen or pasture. It is our experience in a stud business that pen mating is the way to go. This facilitates close observation of both alpacas, accurate record keeping for date, length of time and any problems, correct entry into the female and without interference from tail or fleece. We will wrap the females tail to avoid the fleece from interfering with the mating.

Facilities

Pen mating will require a small secure area perhaps 10 - 14 ft square with a gate on one side. During fine weather small such pens can be easily created within a pasture using portable fencing, but these must be at least four feet high. Best of all, a small stable area with a clean grooved concrete floor for the boy's feet to grip on. Pasture mating will require an area that is new to both the boys and girls. One male can be run with up to a dozen females.

Alpaca Preparation

Make sure your stud is halter trained. If you have a rising star that you think might make the grade get the halter out and start the work. If you are looking to purchase your star stud make sure he walks happily on a lead.

And for the girls, fertility starts with good nutrition and a healthy body score. Under nourished or obese alpacas will make it all that much more difficult. When we receive visiting girls for mating that have been on an unspecific nutrition program we will routinely start them with a multivitamin and mineral preparation. Similarly, parasite control is most important , if no firm records can be found on last worming treatment, this will go on the list as well.

Next, is the girl a maiden. If so it is advisable to check for a clear entrance to the uterus. A gloved and lubricated finger gently inserted through the vaginal opening will detect any obstruction. Slight pressure will rupture the hymen. If a persistent obstruction is felt, it is time to call the vet.

And finally, to the rear end. Lift the tail. Look carefully for any evidence of infection at the vulva. An opaque discharge will need treating before you should allow your stud anywhere near. Typically we find Terraourcin LA antibiotic administered at the rate of 1ml/10kg IM does the trick. Leave for seven days after treatment and then check again.

While looking under the tail look at how long the fleece is. Especially under the tail at the base end and around the business area. The last thing needed is for our prize boy to become entangled in long fleece. Such events will certainly force a holiday for him and at worse cause permanent damage. Reach for the clippers and trim her up or wrap the tail.

Pasture Mating

Chose a field or pasture that is new to both the boy and his girls. Check that the girls are receptive by running past a male first, and ensure they have not been run with another male within the last 14 days to avoid uncertainty of sire. If you have more than one stud male to use, use only one at a time with the group of up to 12 females. Leave him with the girls to strut his stuff for about fourteen days which is long enough if he is going to be successful and not too long when you try and estimate the correct mating date.

After this starts the period of testing for conception, which is no different to that we use for pen mating, below. If some girls failed to conceive then we get to do this all again.

Pen Mating

We should have our group of females to be mated, or tested, assembled in one area, with good and easy connection to our mating area. The rampant stud close by, possibly tethered, or easily available to walk him in. Your clip board and pen in hand.

Run the female into the mating area (have you checked under the tail). Walk the boy in and release him. Now the observation starts. If the girl is open, or receptive, the experienced male will immediately know what is going on. Sometimes they will have a quick sniff to check all is correct before the ogling noise starts. Perhaps a short chase around if the girl fancies some foreplay, otherwise the boy will mount from the rear (on most occasions anyway) and shortly afterwards she will sit in the kush position. If the male shows no interest or the girl shows her contempt for him by spitting and or kicking we do not have a receptive girl.

Once she is down and our boy is starting his work, move slowly towards them, and reach in to pull her tail out to one side. Most males will eventually find their own way from now on, but since we do not have all day it is worth giving some guidance to him. Gently guide his sheath to the vaginal opening but do not grasp his penis.

Once you are happy he has penetrated and chosen the vaginal opening rather than the anus, let them get on with it. He will gradually draw up his rear legs as he penetrates fully, his eyes will have that fixed happy stare and the girl will be relaxed and unaffected. Make notes in your mating records.

Once our boy has decided enough is enough he dismounts, and quite often walks around appearing to say, 'so where is the next please'. Release the girl.

On rare occasions, our stud will take one look or sniff at his intended mate and say 'no thank you'. Sometimes this is because the 'look of death' has been sharply relayed, other times the smell is not right for him or body language is such that he knows to not even bother to try. Heavily fleeced animals can have this effect, uterine infections also. Other times it can only be put down to straight forward lack of affection or just the wrong time. Try again in a few days time perhaps or swap to another male if you have such an option. Switching to pasture mating can also bring success. Either way, make sure you carefully record your observations and solutions.

Day Seven after Mating

This is a good time to see if have had ovulation. A mature follicle has ruptured, released its egg which has perhaps been fertilized, the corpus luteum should have developed and started to produce progesterone. Checking is done with our stud again (or in fact any active male). So we repeat the same process as we did for the initial mating. Only this time we must watch the girl's body language carefully. Failure to willingly sit for the male is great news. This can be evidenced by spitting , kicking out at the boy, or desperate attempts by the girl to vacate the area. As soon as this is evident, restrain the stud and release the girl to avoid undue stress. Now becomes the difficult bit. If the girl was a maiden, or is weak in character compared to our prize winning stud, she might sit regardless. Only experience will help you in determining this condition but careful observation of her body language, in conjunction with the movement of her front legs are good clues. The so called rejection of the male or 'spitting-off' is the good news we are looking for and we mark the records accordingly.

Day Fourteen after Mating

This is the next milestone at which we test. Repeat as for the seven day testing and record the result, hopefully another spit-off.

Day Twenty one after Mating

Repeat as for day fourteen, recording the result.

Day Twenty Eight after Mating

Repeat as for day twenty one. Still spitting-off, things are looking very good. Mark the record book.

If you are fortunate to own ultrasound equipment you are thus able to start obtaining visual scans of pregnancy from around the 30 day post mating date. This provides invaluable confirmation of what our girl has been demonstrating to us. So from day 30 we swap our stud for the computer and run a new testing program with scans done at 30, 45, 60, 90 and 120 days. Achieving positive ultrasound scans is the only guaranteed way to confirm an expected pregnancy following a stud males rejection routine. There are some instances where spit-offs occur that do not result in pregnancies and it is so easy to waste time thinking we have a pregnancy. There is nothing more frustrating for an alpaca owner than waiting 11 months for this wonderful cria to arrive only to find she is empty, and probably has been so for a long time. The moral of the story is test, test and test.

So, the vast majority of veterinarians will be able to bring portable scanning equipment to your farm. Somewhere between 45 days and 60 days post mating is a good time frame to invite them down for some picture taking. Pregnancy determination at this time is easily seen.

Assuming you have received good positive results we would recommend returning back to using your stud for routine spit-offs on monthly intervals up to six months. Why six months. Aborted fetuses of this age are sufficiently large to be clearly seen in the pasture.

Testing for Failure

So what do we do if on the above plan, we do not get the spit-offs we were hoping for. I am assuming of course that our proud stud is in fact known to have sired other successful pregnancies and we were absolutely sure the first mating did in fact proceed according to plan and was executed properly. Good records play their part as do our initial observations and assistance.

Day Seven Test

If our prize female sits again she did not ovulate at the first sitting. So we just repeat the mating, mark our records and go round the loop once more. If this happens more than three times in weekly succession we reach for the drugs. Receptal is a luteinising and follicle stimulating hormone replacer (that is why we had to do the technical bit at the start of this article) that we use successfully on alpacas at a rate of 2ml IM regardless of alpaca weight administered at the time of mating. Rarely do we encounter ovulation failures following this treatment.

DayFourteen Test

If we got through the first seven day test, but now find our much loved female sits at day fourteen, it is clear she has failed to carry the fertilized egg. So we again go around the loop once more. Persistent failure at this stage brings two possible reasons to mind. Either the CL has failed to maintain the production of progesterone or perhaps there is an underlying uterine infection, which is killing the fertilized egg. These can be quite prevalent yet do not produce the external discharge we looked for in our pre-mating preparation. Outcome the drugs again. Terraourcin LA administered at the rate of 1ml/10kg body weight IM goes on the score card. Leave her for one week and then start the program once more. Once again, our experience shows that this is most likely to solve the problem.

Day Twenty One Test and Onwards

Repeated sitting for the male at this stage always brings with it some concern and plenty of disappointment. Sometimes it is just bad luck, other times it can be symptomatic of more difficult problems to resolve. Recently we have started a program of progesterone implants on a few females that repeatedly fail to carry. Any success for this is not yet recordable. As previously stated, poor body condition, poor diet and overweight can be underlying problems which just take time to resolve. Other times it can be nature dismissing an abnormal fetus or perhaps the female has been exposed to a traumatic shock causing absorption. Perhaps it is time to summon our friendly vet for help and advice.

Ultrasound Failures On occasion, our females can seem to proceed perfectly as planned, spitting-off the male like clockwork until we come to wheeling in the computer. Then we see nothing to support our theory that we have a pregnancy. No liquid filled uterus, no evidence of a fetus. Sometimes this is down to what is called a retained corpus luteum (retained CL). If the follicle fails to regress following a lack of fertilization or subsequent absorption of a newly formed embryo then progesterone continues to be produced. We have a phantom pregnancy. Our girl mistakenly thinks she is pregnant and continues to refuse the amorous advances of our stud. We blindly continue with our spit-offs until it is ultrasound time. Fortunately this happens only rarely and there is a solution. Drug time again. Estrumate is a synthetic prostaglandin that causes regression of the CL. Administered as a single 1ml IM injection it will allow return to normal receptivity. Do not administer however if there is doubt as to a possible pregnancy. Forced regression of the CL will terminate the natural supply of progesterone and terminate any pregnancy. Estrumate is also contra indicated for asthmatics. Leave administration to your veterinarian.

Hopefully all has progressed normally and we can safely say our females are confirmed pregnant. Progesterone testing is another method of trying to confirm a pregnancy. The rise in serum level of this hormone, produced by the CL, is associated with a pregnancy, but not exclusively so, as the retained CL condition can confirm. Background levels of progesterone will have returned following 14 days or so after mating and after a few days following a foetal abortion. Serum levels measured at greater than 1ng/ml after 20 days post mating are consistent with a pregnancy.

Following a mating, you might well notice a bloody discharge on the mating pen floor. Panic is not in order. The physical action of the mating can be quite brutal for the female causing some minor bleeding from the uterine wall; maidens might also demonstrate this result. You are unlikely to have ongoing problems but as always, regular inspections and observations will pick up on any infections.

If using small mating pens it is wise to remove any attendant cria, although it is quite a good idea if they can see their mom and watch through a fence or gate. Sometimes, the girls will become uncomfortable bearing the full weight of the male on her back and roll over onto her side. Provided penetration is maintained, continue as normal.

I have used the drugs mentioned here after proper consultation with our veterinarian. Their use of course remains off label for alpacas. Your veterinarian must be consulted at all times for up to date advice and suggestions.

Good luck, happy humming, observe and make good records.

 

Excerpts from: Alpaca Breeder's Reproduction Handbook.
By Ewen McMillan B.V.Sc(Hons), M.A.C.V.Sc, and Carolyn and Allan Jinks.