P. Walter Bravo
The gestation period of the female alpaca is long, at eleven months, and the owner is anxious to have a cria on the ground. There are some considerations that every alpaca owner and/or breeder should have in mind. They are: 1) nutritional needs of the dam, 2) vaccination and/or deworming, 3) changes in behaviour, and 4) parturition itself.
Nutritional needs of the late pregnant dam
In general terms, the late pregnant dam needs additional nutrients in her diet during the last 3.5 months of gestation. In fact, the fetus grows rapidly and in an exponential manner in terms of weight. By 7 months of pregnancy the fetus weighs 1.5 kg, but at time of parturition it has increased to 7-8 kg. This represents an increase of 6.5 kg on the last 3.5 months of pregnancy (Fig. 1). A second management consideration is weaning of the previous cria if that is the case. A cria which is seven months or older is going to suck milk and may heavily influence the condition of the pregnant dam and consequently the next cria. Therefore, weaning a cria at five to six months old is wise and makes sense considering that the dam may be pregnant again.
There are different ways to improve the nutrition of the late pregnant dam. One is providing more succulent pasture; another way is providing additional hay and grain. Some others prefer to give their dams alfalfa hay mixed with other grasses. Whatever is the method, the bottom line is to improve the nutritional status of the late pregnant dam. Experimental evidence in Peru indicates that crias weighed 9.6 kg at birth when their dams grazed improved irrigated natural pastures for the last 3.5 months of pregnancy. By contrast, the cria weight was 8.2 kg when their dams were maintained in native pastures and without any improvement - a difference of 1.4 kg. Note that in Peru, parturition is seasonal and dams with crias on the ground are maintained on dry pastures due to a dry and cold winter. In this particular case, the presence of water made pastures grow again and consequently pregnant dams had better quality pastures. The difference in quality of pastures made the difference. A word of caution is pertinent at this point, and it is a fact that some dams are extremely overweight due to excessive feeding. In this case, dams at parturition may not have enough milk and the mammary gland tissue that produces milk will have been replaced by fat. Consequently the dam does not have enough milk for her cria.
Vaccination and deworming
The protocol of vaccination and vaccines to use depends on the region, area and country where alpacas are raised, and your veterinarian is the person who should advise you. There are many vaccines used on other livestock animals but none has been approved for alpacas. Thus your veterinarian should determine the potential diseases that crias will confront and therefore diseases to be vaccinate against. In South America, most crias become sick to enteric pathogens that provoke diarrhea, either clostridiosis (Clostridium perfringens, type A) or colibacillosis (E. coli), and lung diseases (pneumonitis, from which Pasteurella multocida was isolated). In North America, clostridiosis has been also diagnosed. Lately outbreaks of salmonellosis have also been diagnosed, and prevention should consider the vaccination of pregnant dams. Currently there are many vaccines on the market, but a concerted effort between the veterinarian and owner is crucial to decide which vaccines to use, and also the frequency of vaccination. The main consideration is that vaccination should be done in time and preferably two to three months before the due date. This time frame is in the light of the fact that alpacas are sensitive to abortion. Waiting to the last minute or last month of pregnancy to vaccinate pregnant dams may provoke abortion and then disappointment for the owner. A second consideration about vaccination is that alpacas transfer antibodies (proteins that are going to fight diseases in the neonates) through the colostrum. Thus, vaccination should be done in good time so that the dam will have plenty of time to develop antibodies that will passively immunize the neonate.
Deworming also should be considered before parturition. The veterinarian in charge of the health management is the best person to determine the product to be used. It is sad to see females giving birth and with a body condition 2 or 1 (1 meaning skinny and 5 overweight) and at fecal analysis they are loaded with parasite eggs. They may have little or most likely no colostrum and consequently no milk for the neonate.
Changes in behaviour: A late pregnant dam acts and even walks differently from open or non pregnant dams. When the due day is close, dams isolate themselves from the rest of the herd, they seem to find a spot to give birth, and they walk slowly and at close examination the movement of the fetus within the abdominal cavity may be distinguished. When females are relaxing and taking a nap during a sunny day, the mammary gland is clearly noticeable by its pink colour especially at the teats. Teats appear turgid and the wax that seals the opening is readily visible. In addition, the two main veins that drain blood from the mammary glands are observed protruding from the abdominal cavity and in a sinuous fashion. All of these are accompanied by the enlargement of the abdomen, especially discernable in shorn animals (Fig. 2). On the day of parturition, dams urinate frequently, they roll repeatedly, lying down in a lateral position and the vulva is enlarged, pink and sometimes turgid at manual palpation.
The process of parturition is continuous and academically has been divided into three events: Dilation of the cervix, fetal expulsion and placenta expulsion. A female with impending signs of delivering a cria lies down and gets up frequently, accommodating the cria for delivery. When the cria is being expulsed, its head and anterior legs comes first. Every push by the parturient female makes the fetus head come first and then the front legs. Sometimes when a female has a narrow vestibule the head may take some time to come out. In this case, grabbing the head by the jaw may help it to come out easily. On some other occasions, the fetal membrane that covers the fetus is not ruptured and the person assisting the delivery process pinches the membrane and the head and front legs are exposed. The process of fetal expulsion in a normal delivery is rapid and takes approximately 10 to 15 minutes. It is my personal preference not to rush the process of parturition and I strongly believe that the head should be hanging down for some minutes while the female is giving birth in a standing position. This awkward posture is natural and gives the cria an opportunity for to get rid of any fluid that may be present in the mouth, pharynges and the upper respiratory organs. At close inspection, liquid drops may be seen which again is beneficial to clear the air passage in and out of the lungs. When a female gives birth in the lateral position, it is wise to swing the neonate a couple of times to make sure that any liquids from the upper respiratory organs are expelled. This may be differentiated by the sounds that the neonate makes during breathing. If it looks as if the cria is snoring, swinging the cria from the rear legs makes fluids come out. Most females do not make sounds while giving birth; however, I have witnessed at least two females that emitted a loud sound like barking and/or screaming. Some females though, hum during the process of birth.
Once the cria is out the afterbirth or placenta should be expulsed in a matter of one to two hours.
The specific day of parturition is unpredictable, and the estimated due date should be taken cautiously. Sometimes people like to predict and pronounce the day of birth; however, I have witnessed people betting for a day and then nothing happens for a week, two weeks or even a month. In a strange situation a female gave birth four months after her due date. Naturally there was a mistake in recording the date of breeding or maybe the female was left alone with a male for breeding purposes and consequently the breeding date was unknown. Or even, if field breeding is practiced a female may become pregnant, undergo an early embryonic death and then become pregnant right away. Be aware and plan to be away from the farm after the dam has had a cria.
In conclusion, there are some management measures that late pregnant dams should undergo. It is a definite plus to increase the nutritional status, improving the quality of the pasture and the developing fetus then should not compromise the pregnant dam. Vaccination and deworming should be done at the proper time. The diseases to vaccinate against depend on the area or country where alpacas are raised. It is wise to consult with your veterinarian to determine the type and frequency of vaccination. There are some changes in behaviour and shape of the abdomen of the late pregnant dam. Signs of impending parturition are urination and lying down repetitively. Do not be surprised if there are no signs of parturition and then an hour later you have a cria on the ground. The process of fetal expulsion is rapid and hopefully no human intervention will be necessary. The next article will deal with the care of the neonate and the postpartum dam. In the meantime enjoy your dams with crias.
P. Walter Bravo, DVM, MS, PhD