(Sounds Like JelloWood)

Developing the Premier Colored Huacaya Alpaca Herd in the World

The Health of the Female Alpaca

Gestations - George Davis

Reproductive Problems - Brad Smith & Pat Long

Longer Gestations and Smaller Birth Weights in Spring-Born Alpacas

George Davis, M. Ag. Sci.

The breeding of alpacas in South America is planned so that parturition occurs during the rainy season from late November to April, summer and autumn in the Southern Hemisphere. However, there they are considered to be nonseasonal breeders because the females have active ovaries throughout the year. They are able to breed, conceive, and give birth at any time of the year (Smith, Peter, and Pugh, 1994).

Female alpacas can produce an egg (ovulate) 15 days after parturition (Bravo, 1994), and those that do not hold to service usually return to estrous 12 days after ovulation (Fernandez-Baca, Hansel, and Novoa, 1970). Thus, alpacas conceiving at the first mating after giving birth must have a gestation length less than 350 days if they are to remain in a 12-month reproductive cycle. Multiple births are extremely rare (Smith, 1985), and barrenness levels are high.

In a survey by Bryant, Florez, and Pfister (1989), Peruvian alpaca farms were classified as having high, medium, or low technological input according to a number of factors, including improved pasture, fertilizer use, fencing, mechanization, herd recording, and genetic selection. Barrenness levels were generally high but were lowest where technological inputs were highest. The barrenness levels on low-, medium-, and high-technological-input farms were 47 percent, 42 percent, and 38 percent, respectively, which shows that many females failed to produce crias in successive years.

Estimates of the gestation length of alpacas vary markedly. In a Peruvian study, San-Martin et al. (1968) recorded mating date and parturition date in 169 huacaya alpacas farmed on the altiplano 14,000 feet above sea level in Cuzco and found that the mean gestation length was 341.6 days with a range of 325 - 358 days. They did not report the season of mating, but reference to the breeding season implies that the matings were carried out in summer. Some other estimates of the gestation length of alpacas on the South American altiplano are 320 - 345 days (Smith, 1985), 343 days (Novoa and Wheeler, 1984), and 341 days (Velasco et al., 1981). Females therefore have few opportunities to be mated after parturition if they are to give birth at about the same time in successive years.

Research Herd Established

In 1989, eighty-six female and fourteen male huacaya alpacas were imported from Chile for the Ministry of Agriculture and Fisheries (now AgResearch) to study their production in the high country of New Zealand’s South Island. Because livestock raising in New Zealand is almost entirely pasture based, the aim was to maximize the number of births in the spring as this best matches the seasonal pasture growth pattern in this environment, where winter pasture growth is negligible. This paper reports gestation lengths and birth weights recorded in these imported animals and their New Zealand-born progeny mated at different seasons. The statistical analysis of the data has been described in detail elsewhere (Davis et al., 1997).

Herd Management

Seventy-five alpacas were farmed at the Tara Hills High Country Research Station, where the climate is quite similar to that in the alpaca’s native altiplano of South America. Tara Hills is situated at latitude 44^o32’S; the area where the alpacas were grazed is 1,600 feet above sea level, the annual temperature ranges between 12^oF and 94^oF, and there is an average of 150 ground frosts per year. The other twenty-five alpacas were located in a very similar environment on a nearby commercial farm located at latitude 45^oS and 1,000 feet above sea level. The imported alpacas were aged from 2 to 4 years at the beginning of the study. Records from sixty of their New Zealand-born female progeny at Tara Hills were also analyzed. The postpartum weights of females were 152 and 144 pounds for spring and autumn births, respectively.

At Tara Hills spring pasture growth begins in September, so spring matings were carried out from mid-October to mid-December to ensure that the subsequent births and lactation were timed to coincide with the peak of pasture growth. However, at the time of importation many of the females were already pregnant from autumn matings in Chile. In order to quickly build up the herd size, we carried out a second period of mating in autumn, from mid-February until late April. Early studies of alpaca mating behavior at Tara Hills showed that pen-mating was more successful in terms of the numbers mated than paddock-mating (Pollard, Moore, and Littlejohn, 1991), and thus a system of pen-mating was used for both the spring and autumn breeding seasons. Pen-mating involved placing the male and female together in a pen measuring 20 x 17 feet, and when the female was receptive they were allowed to mate once. This procedure was repeated every 2 weeks during both spring and autumn breeding seasons. Pen-mating also enabled the mating date to be accurately recorded for all pregnancies. The alpacas were weighed monthly so that mating weight could be estimated.

The fourteen imported males were used in both the spring and autumn mating seasons and were assigned to females on the basis of fleece color. Throughout the study some females switched from spring-conceived to autumn-

conceived pregnancies because all females not conceiving in one season were remated at the next season. The alpacas were shepherded daily around the time of parturition so that birth dates could be accurately assigned to all crias. All crias were weighed at birth.

Data were analyzed from a total of 162 pregnancies recorded from matings carried out between spring 1989 and autumn 1992, and the resulting births from spring 1990 until autumn 1993.

Gestation Lengths

Gestation lengths summarized in Table 1 were recorded for 60 pregnancies from spring matings and 102 pregnancies from autumn matings. The mean spring mating date was November 14, with a range from October 16 to December 18. The mean autumn mating date was March 6 and ranged from February 11 to April 30. Pregnancies resulting from autumn matings, which resulted in autumn births, averaged 336.4 days, which was 12.5 days less than those from spring matings and the subsequent spring births, which averaged 348.9 days.

The mechanisms controlling parturition in alpacas are not well understood. The observation in South America that births almost always occur in daylight hours, mostly in the morning and seldom during bad weather, suggests that alpacas can delay parturition in unfavorable conditions (Reiner and Bryant, 1983). This pattern of the timing of parturition has also been observed at Tara Hills (Davis et al., 1991). However, this effect appears to be independent of the large effect of season on gestation length observed in this study. Knight et al. (1995) recorded mean gestation lengths of 350.1 days where conception and birth were in spring and 340.2 days where conception and birth were in autumn for alpacas on the North Island of New Zealand at latitude 40^o14’S. The larger difference recorded in the present study, where alpacas were located at 44^o32’S, and the absence of any reports of this effect in South America, where alpacas are mainly farmed, between latitudes 11’ and 21’S (Novoa and Wheeler, 1984), is consistent with a latitude effect.

Looking at the proximity of the mating date to the longest day of summer revealed that at common day lengths at mating (i.e., the same number of days before [spring] or after [autumn] the summer solstice) there was still an effect of season with pregnancies from autumn matings (338.9 days), 6.5 days less than those from spring matings (345.4 days).

Within spring, when day length is increasing, for each day later the female was mated there was an increase in gestation length of 0.11 day, whereas in autumn, when day length is decreasing, for each day later the female was mated the gestation length was reduced by 0.24 day. Gestation length increased with day length at mating by about 2 days for each extra hour of day length. Dam weight did not have a significant effect on gestation length. The within-dam repeatability of gestation length was 0.42, which is moderately high. In other words, some individuals tended to regularly have shorter gestation lengths while others had longer gestation lengths.

In our study the spring matings occurred closer to the summer solstice than did autumn matings; and because day length varies less per day for days closest to the solstice, any photoperiodic stimulus is likely to have been weaker for the spring matings. Thus, if the observed differences in gestation length are in response to changing day length, the regression of gestation length on mating day would be shallower in spring than in autumn. The observation that gestation length changed by 0.11 day per day of mating in spring compared with 0.24 day per day of mating in autumn is consistent with the changing day length hypothesis. The precise time of implantation in alpacas is unknown, but ultrasonography and oestrone sulphate measurements suggest that it begins at 20Ð22 days after breeding (Bravo, 1994). The possibility that delayed implantation is involved in the difference in gestation length between autumn and spring matings should be investigated.

Age and Sex Effects

There was no significant difference in gestation length between female (343.4 days) and male crias (341.9 days) or between yearling (343.1 days) and multiparous females (342.2 days). The incidence of barrenness in the imported adult females after a 6-week mating period was 40.9 percent (38/93) following spring matings and 33.6 percent (49/146) following autumn matings.

Seasonal Effects On Weight

Postpartum weights of dams were 152 pounds and 144 pounds for spring and autumn births respectively. Female crias averaged 17.9 pounds at birth, which was 0.8 pound less than males (18.7 pounds). The longer gestations in spring were not reflected in heavier birth weights. Autumn birth weights were 2.2 pounds heavier than spring birth weights (19.4 versus 17.2 pounds) after adjusting for gestation length and dam weight. The unadjusted difference was 0.9 pound in favor of autumn births. Within season, birth weight increased 0.11 pound for each extra day of gestation. Thus, birth weight appears to increase with increasing gestation length within season but decreases with increased gestation length between seasons.

Birth weight also increased 0.03 pound for each extra pound of dam weight. The postpartum weights of dams, 152 pounds and 144 pounds for spring and autumn births respectively, were about 20 - 29 pounds heavier than the high-input herds identified by Bryant, Florez, and Pfister (1989). However, birth weights remained in the same range as those observed in medium- and highÐinput herds.

Birth weights of alpacas are affected by management. Records from herds in Peru classifying herds according to the level of technological input showed that birth weights increased from 15.4 pounds in low-input herds to 17.6 pounds in medium-input herds and 19.8 pounds in high-input herds (Bryan, Florez, and Pfister, 1989). These birth weights were associated with dam live weights of 99, 110, and 123 pounds respectively. Mean birth weights of only 14.6 and 15.0 pounds have been recorded in two Californian herds (Hoffman, 1992). It might be worth mentioning, however, that these animals had been in the United States for only a short while and been subjected to a great deal of transportation and stress. Subsequent birth weights of established herds on the same properties under similar dietary conditions have risen to 18 pounds on average. Perhaps an established herd without a great deal of stress factors occurring during pregnancy is more prone to producing full-term crias and thus higher live weights.

If dam weight were ignored there would be an effect of parity, with crias from first-parity females (17 pounds) weighing 2 pounds less than those from multiparous females (19 pounds). However, inclusion of dam weight showed no significant difference in birth weight between crias from first and later pregnancies. That is to say, alpacas only had smaller crias following their first pregnancies because the mothers weighed less.

Nevertheless, our results showed that birth weights in autumn were 2.2 pounds heavier after adjustment for gestation length and dam weight, which suggests that the critical day length signals affecting the rate of maturity of the developing fetus and the timing of parturition are experienced well in advance of the time of parturition. Clearly, further research is required to elucidate the mechanisms by which season affects gestation length.

Seasonal Effects In Other Species

An effect of season on gestation length in the dromedary camel (Camelus dromedarius), which like the alpaca belongs to the Camelidae family, has been reported in Israel by Elias, Degen, and Kam (1991). During winter to spring (Northern Hemisphere, December to March), when day length is increasing, gestation length was 0.33 day shorter for each day mating was delayed. In sheep there appears to be a relationship between seasonality and latitude. For example, within sheep breeds the length of the breeding season may be modified by latitude (Haresign and McLeod, 1985). Differences of 2 to 3 weeks in the onset of the breeding season between the north and south of New Zealand have been attributed to latitude effects (Kelly, Allison, and Shackell, 1976).

Practical Implications

The combination of reduced sexual behavior in spring (Pollard, Littlejohn, and Moore, 1995) and long gestation lengths (349 days) make the maintenance of a spring mating/birthing pattern in the Tara Hills environment quite difficult, as there will be a tendency for mating and births to occur later with each successive pregnancy. This has been our subsequent experience with most of the herd now in an autumn pattern. In contrast, because gestations following autumn matings are 12.5 days shorter, there is the opportunity for alpacas returning to service after the first postpartum estrous to have a second chance to conceive while still maintaining a 12-month reproductive cycle. This extra opportunity for mating plus the enhanced sexual activity in autumn (Pollard, Littlejohn, and Moore, 1995) makes autumn matings the preferred option for high reproductive performance, which is consistent with the observed lower barrenness following autumn matings. Thus, in this environment there is a conflict between best matching feed demand to feed supply (spring births) and maximizing reproductive performance (autumn matings).

Knowledge of the effect of season on gestation length will assist breeders with herd management, but the large variation in gestation length in both seasons means that even after allowance for seasonal effects, the time of parturition still cannot be predicted with the precision that is possible for other livestock species, such as sheep and cattle. Two-thirds of spring pregnancies occurred in the range of 342-356 days, and two-thirds of autumn pregnancies occurred in the range of 330-342 days. The moderately high repeatability of gestation length indicates a tendency for some animals to be consistently ranked as having shorter or longer gestations within seasons. The heritability of this trait is unknown; and with major emphasis on selection for fleece characteristics, which can be accurately measured in both sexes, it is unlikely that breeders will apply direct selection pressure to gestation length. However, selection of females that continuously maintain a 12-month breeding interval or less may indirectly select for shorter gestation length, particularly those in a spring birth pattern.

The finding that gestation length differs by 12.5 days between seasons was unexpected. The equivalent northern latitude of Tara Hills is approximately Corvallis, Oregon, and it is likely that the effects observed at Tara Hills will occur in

alpaca herds from at least Corvallis north. This effect has been confirmed by prominent alpaca breeders Jim and Janet Faiks, who farm alpacas in Alaska at latitude 61^oN. Incidentally, they have observed that getting their alpacas pregnant in the spring is more difficult than in fall, which has also been my experience with the AgResearch herd.

Summary

Gestation lengths and birth weights were measured in 162 pregnancies in huacaya alpacas farmed in the high country of the South Island of New Zealand. A comparison of pregnancies from spring and autumn matings showed that gestation lengths were 12.5 days longer in spring (348.9 days versus 336.4 days). For each day later in spring that a female was mated there was an increase in gestation length of 0.11 day, whereas for each day later in autumn the gestation was reduced by 0.24 day. There were no significant effects of sex of cria or age of dam on gestation length. After adjustment for gestation length, crias born in autumn weighed 2.2 pounds more than those born in spring (19.4 pounds versus 17.2 pounds). Female crias weighed 0.9 pound less than males at birth. The results suggest that in this southern environment maintaining spring-mated females in a 12-month breeding cycle will be difficult.

References

Bravo, P. W. 1994. Reproductive endocrinology of llamas and alpacas. Veterinary Clinics of North America: Food Animal Practice 10(2):265-79.

Bryant, F. C., A. Florez, and J. Pfister. 1989. Sheep and alpaca productivity on high Andean rangelands in Peru. Journal of Animal Science 67:3087-95.

Davis, G. H., K. G. Dodds, G. H. Moore, and G. D. Bruce. 1997. Seasonal effects on gestation length and birth weight in alpacas. Animal Reproduction Science 46:297-303.

Davis, G. H., T. Wuliji, G. H. Moore, and G. D. Bruce. 1991. Growth, reproduction and fiber production of alpacas imported from Chile. Proceedings of the New Zealand Society of Animal Production 51:255-58.

Elias, E., A. A. Degen, and M. Kam. 1991. Effect of conception date on length of gestation in the dromedary camel (Camelus dromedarius) in the Negev Desert. Animal Reproduction Science 25:173-77.

Fernandez-Baca, S., W. Hansel, and C. Novoa. 1970. Corpus luteum function in the alpaca. Biology of Reproduction 3:252-61.

Haresign, W., and B. J. Mcleod. 1985. Physiological criteria in genetic selection for seasonality. In Genetics of Reproduction in Sheep, ed. R. B. Land and D. W. Robinson, 291-300. London: Butterworths.

Hoffman, E. 1992. Alpaca crias: What’s different about them? Llamas 6(7):60-67.

Kelly, R. W., A. J. Allison, and G. H. Shackell. 1976. Seasonal variation in oestrous and ovarian activity of five breeds of ewes in Otago. New Zealand Journal of Agricultural Research 4:209-14.

Knight, T. W., M. Ridland, I. Scott, A. F. Death, and T. K. Wyeth. 1995. Foetal mortality at different stages of gestation in alpacas (Lama pacos) and the associated changes in progesterone concentrations. Animal Reproduction Science 40:89-97.

Novoa, C., and J. C. Wheeler. 1984. Lama and alpaca. In Evolution of Domesticated Animals, ed. I. L. Mason, 116-28. London: Longmans.

Pollard, J. C., R. P. Littlejohn, and G. H. Moore. 1995. Seasonal and other factors affecting the sexual behaviour of alpacas. Animal Reproduction Science 37:349-56.

Pollard, J. C., G. H. Moore, G. H. and R. P. Littlejohn. 1991. The sexual behaviour of alpacas imported to New Zealand from Chile. Proceedings of the New Zealand Society of Animal Production 51:43-46.

Reiner, R., and F. Bryant. 1983. A different sort of sheep. Rangelands 5(3):106-8.

San-Martin, M., M. Copaira, J. Zuniga, R. Rodreguez, G. Bustinza, and L. Acosta. 1968. Aspects of reproduction in the alpaca. Journal of Reproduction and Fertility 16:395-99.

Smith, C. L., A. T. Peter, and D. G. Pugh. 1994. Reproduction in llamas and alpacas: A review. Theriogenology 41:573-92.

Smith, T. M. 1985. Reproduction in South American camelids. Iowa State University Veterinarian 47(2):110-15.

Velasco, J. A., W. Condorana, D. D. Kress, P. J. Burfening, and R. L. Blackwell. 1981. Breed characteristics, color and weight inheritance in alpaca. Journal of Animal Science 53: supplement 1, abstract 73.

About the Author

George Davis is a senior scientific officer at New Zealand’s AgResearch Invermay Agricultural Centre and has published 150 papers on sheep, cattle, and alpaca breeding and production based on 28 years’ experience in New Zealand and Korea. In 1994 he received the prestigious McMeekan Memorial Award from the New Zealand Society of Animal Production for outstanding service to agriculture. He has been an invited speaker, primarily on subjects related to breeding and fiber production in alpacas, at four Australian Alpaca Association national seminars and was a guest speaker in the United States at the 1995 AOBA conference, 1996 AlpacaFest International, and the 1998 Alpaca Fiber Symposium organized by AOBA, ARI, and ALSA. He has his own herd of seventeen alpacas in which he puts theory into practice.

Reproductive Problems in the Alpaca
Part 1: Assessing Reproductive Problems in Proven Alpacas

"Say, doc, you know that beautiful animal we bought at the auction last fall? Well, we’ve been trying to get her pregnant for the last six months, and she just isn’t settling. Think you had better take a look at her."

"Remember Megasuri Suzie, that gorgeous suri we bought pregnant three years ago and her daughter Megasuri Suzie II? Suzie had another baby the following year but has been open since then. Think we need your help on this one."

These, and variations on the theme, are some of the most common calls that alpaca vets receive. Sometimes the problems are with maidens who fail to conceive, are unreceptive to the male, or have other problems. All too frequently, however, the problem animals are not maidens but mature females who have had one or more successful pregnancies. This group of animals can be particularly frustrating to work with because the problems are often subtle in nature and not easily identifiable. Compounding the diagnostic challenge is the apparent good health of many animals in this group. These are the focus of this article - alpacas who once were mothers but are now unable to conceive or carry a pregnancy to term. The second article in this series will focus on what happens if you are unable to resolve the problem and the vet needs to begin a more extensive medical workup of the problem.

Before reviewing specific approaches to fertility problems in the alpaca, we would like to highlight a couple of caveats and considerations.

First, the methodology we use for evaluating fertility problems has been the most successful for us. It is not, however, the only way to deal with these issues. As a result, your vet may have different ideas about how to manage the infertile or subfertile female. The only thing that matters is the result: another successful pregnancy.

Second, diagnosing fertility problems in the alpaca works best when it is approached as a partnership between you and your vet: You handle the easy problems and pass the difficult ones on to your vet, making sure to provide the animal’s complete medical history (Figure 1).

The key issues in approaching fertility problems in the alpaca are (1) that they be handled in a careful, systematic manner, and (2) that you and your vet look for the obvious before searching for the unusual. To paraphrase a line from an instructor in vet school, "If you hear hoofbeats and a whinny, think horses - not zebras."

In a surprisingly large percentage of cases, just making sure that the basics are covered - such as working toward the appropriate body condition of the female and breeding to a male of known fertility - will resolve the problem. Only after the simple things have been checked and eliminated should the more unusual causes of infertility be considered.

Considerations and Problems

The animal’s history often provides some of the most important, and frequently overlooked, clues to the cause of the problem. Some of the most important pieces of information are these (Figure 2):

Age: Is the animal too old?

While we don’t have good information about when fertility naturally declines in the alpaca, empirical observations suggest that fertility normally begins to decrease somewhere between 12 and 16 years of age. Although there are numerous stories of animals delivering annually up to age 20 or 22, these are the exceptions rather than the norm. Unfortunately, methods for determining the age of mature alpacas are extremely unreliable. For example, while tooth appearance and eruption times can differentiate the 1-, 3-, and 6-year-old animals, that is not the case with 8-, 12-, and 18-year-old animals. Age is a particularly important issue with some of the animals from early importations. Many of these were reported as 3 years plus at the time of importation and today may be 8 or 18 years of age. The important issue to consider is that some animals may have reached reproductive senescenceÐÐthat is, the reproductive equivalent of a human female of 50-plus years. In these cases no reasonable amount of treatment is going to restore fertility.

Reproductive history

Another critical piece of information in evaluating reproductive problems is the animal’s own history. Key questions include:

Has she had a cria before?

Has she ever had a dystocia (difficult birth)?

Has she had a uterine or vaginal tear? Uterine infections? Unusual vaginal discharges?

These questions are important because the alpaca is more susceptible to reproductive problems than many other domestic livestock species. If the animal has had a cria, you know that at one time she had a properly functioning reproductive system. If, however, she has not, the animal’s inability to conceive or carry a pregnancy full-term may be due to any of a surprisingly large number of anatomic reasons.

The issue of dystocias is important because significant damage to the reproductive system will occur in some percentage of cases. Of particular concern are dystocias resulting in damage to the cervix and/or vagina. A history of uterine infections and vaginal discharges is important because of possible uterine scarring and/or con-

tinuing problems. If the animal has a history of reproductive problems and/or a noticeable vaginal discharge, it’s time to call the vet.

Also consider where the animal has lived for the past few years. The animal who has lived on your farm for the past 5 years and has had two crias is a known entity; the animal purchased at auction is more of a black box. Of particular concern is the animal who has had multiple owners in the past 3 to 5 years. Experience suggests that the probability of unresolvable problems goes up exponentially as a function of the number of previous owners.

Other medical problems: Does the animal have a history of other ongoing medical problems?

Important problems would include any condition that caused the animal to be significantly debilitated. It is not worth spending significant amounts of time working on reproductive problems until the other medical problems are resolved.

The male: One variable that can easily be eliminated is the male.

Are you using a proven male? If the male is not settling other females, switch studs.

Is the female receptive to the male being used? The alpaca, more than almost all other domestic species, appears to exhibit preferencesÐÐthat is, some females don’t seem to like certain males and vice versa. If the female only reluctantly kushes and/or the male shows only modest interest in the female, try switching males.

Body condition

Poor body condition is one of the more common problems in older females, particularly the best milkers. If the female is lactating, consider weaning the cria if it is old enough. For both the lactating and nonlactating female, increase the caloric intake and get the dam into better body condition before rebreeding. In addition, check the teeth to make sure that the female is able to adequately grasp and chew food.

Behavior

The dam’s behavior when introduced to the male provides an important window into her reproductive physiology. Important questions to ask:

Does she readily kush for the male?

Does she show a normal pattern of receptivity to the male, followed by spitting him off 3 to 4 days later?

The female’s response to mating and a subsequent period of rejection together provide important clues about the animal’s reproductive status. If the female has a mature follicle and accepts the male, she will typically ovulate approximately 24 hours later. Following ovulation, the follicle is transformed into a CL (corpus luteum) and will be producing significant amounts of progesterone by 3 to 4 days after mating (Figure 3). If the animal has ovulated but not conceived, the CL will die and progesterone concentrations will decline to baseline concentrations by about 12 to 15 days after mating. In contrast, the animal who ovulates and conceives will maintain elevated progesterone concentrations until shortly before delivery.

The issue of the male’s kushing is important because it indicates that the female is probably having at least some follicular development. While the issue is still not completely resolved, it appears that the combination of estrogens produced by the developing follicle and the absence of progesterone production from a CL are the key factors in the female’s receptivity. A lack of sexual receptivity suggests either insufficient follicular development and/or progesterone production by a CL.

The typical animal who ovulates but does not conceive will accept the male at the time of copulation, reject the male from day 3 or 4 post-mating until day 10 to 15 after mating, and then accept the male again approximately 2 weeks following the initial breeding. This information provides two important pieces of information: (1) the ovaries are probably functioning normally and the animal is developing a CL; and (2) the animal is failing to conceive with normal implantation.

The presence of a CL is important for a couple of additional reasons. One uncommon but significant cause of infertility is a persistent CLÐÐa corpus luteum that did not regress (die) after the female lost the pregnancy. In this case the CL continues to produce progesterone after the female has lost the pregnancy, causing her to reject the male even though the animal is not pregnant (open). The second and far more important reason is that one of the major causes of "infertility" in the South American camelids is pregnancy. Illustrating this point, pregnancy was one of the leading causes of owner-reported infertility problems in a recent review of llama cases presented to Oregon State University.

For estrogen-stimulated receptivity to occur, there has to be sufficient follicular development in addition to the absence of significant concentrations of progesterone. If the ovaries are not being adequately stimulated by the pituitary (a gland at the base of the brain), the follicles will not develop and the animal will usually not be receptive. While the lack of follicular development (hypoplastic ovaries) is very rarely a problem in the mature animal, it is a more common in the animal who has never had a cria.

Another less common but important breeding pattern is the continuously receptive female. The best example was reported by an owner who observed that the female had accepted the male every day for the previous 23 days. While clearly abnormal, the situation also provides some important clues to the nature of the problem. In this case, the continuous receptivity without a period of spitting off suggests that a large follicle was present but not rupturing following copulation. If a large follicle is confirmed by ultrasound, your vet can use various drugs to induce ovulation and stimulate resumption of normal ovarian activity.

Season

The llama and alpaca are classified as nonseasonal breeders under North American conditions, with crias born throughout the year. While this classification is generally accurate, recent work does suggest that there may be a partial seasonality in breeding patterns for some animals. Dr. Norm Evans suggests that fertility rates may be lower in the llama during winter months, and work at Oregon State University has produced similar results. As part of an ongoing research effort evaluating factors involved in the dam’s recognition of pregnancy (and reasons early embryonic losses are such a problem in the cam-elids), we have been collecting llama embryos from our research herd for the past 2 years. While most of the llamas produce embryos throughout the year, a few animals regularly produce embryos throughout the spring, winter, and early fall but slow or cease embryo production during late fall and winter. Further support for the existence of subtle but important seasonal effects is the shorter gestational length in fall compared to spring deliveries. The important consideration is to give the "winter infertile" female a second chance and work with the animal again during the spring and summer months.

Summary

The bad news first: Reproductive problems in older alpacas are relatively common. The good news: With a careful, thoughtful approach, many of these problems can be resolved and the animal returned to the breeding pool. The key issue is to make sure that the basics are covered. Once these problems are addressed, in many cases the reproductive issues will go away.

As a first step, resolve the "fixable" problems and then start a program of breeding using a male of known fertility. Watch the behavioral response of the female to the male at breeding, after its progesterone concentrations have risen in response to ovulation, and again when she is receptive if she has not conceived. If you have not been successful after the third round of breedings, it’s time to call the vet.

What This Article Has Not Discussed

One of the questions that almost invariably arises is, "So, doc, can you give her a shot to get her pregnant?" The answer is no - that’s up to the male. In certain cases, however, there are various treatments that can stimulate ovarian function or clear up uterine infections, and there are surgeries that can help certain physical problems. These are aggressive steps that need to be handled by your veterinarian and will be the focus of the second part of this article, to be published in the next issue of the Alpaca Registry Journal.

About the Authors

Brad Smith, DVM, PhD, is the head of the camelid research program at Oregon State University (OSU). His primary research interests are reproduction and internal medicine. He has been working with llamas and alpacas for 15-plus years and started the OSU camelid research herd in 1985. Since then the herd has grown to almost 100 animals (approximately 80 llamas and 20 alpacas) and is used by the OSU faculty, staff, and students for teaching, research, and public relations. He is also coauthor of the book Llama and Alpaca Neonatal Care with Pat Long, DVM, and Karen Timm, DVM, PhD.

Pat Long, DVM, owns and runs Eastgate Veterinary Clinic in Corvallis, Oregon. He has been treating llamas and alpacas since 1984 and spends about half of his time in the field with camelids. In addition to his professional duties, he is a medical editor for Alpacas magazine, serves on the board of the Alpaca Registry Foundation, and helps review research grants for the Willamette Valley Llama Foundation. International