Breeding management of alpacas and llamas vary, depending on the production system in place; however, it is the goal of most producers for each female to produce one cria per year. In South America, the breeding season is restricted to the summer months because of weather and available forage and because the animals are housed on native pastures at high elevation. In North American management systems, breeding may be planned for early summer or fall to avoid the females giving birth during the cold winter months or the very hot summer months, which would place added stress not only on the female in late gestation and labor but also on the neonatal cria which is very sensitive to ambient temperature. It should be noted, however, that alpacas and llamas kept in good health and body condition will cycle year-round and that pregnancy is possible at any time.
Selection of females for breeding is covered elsewhere in this text; however, it should be noted that a complete breeding soundness examination should be performed on any maiden female prior to breeding. This examination is performed to assess for any congenital abnormalities of the reproductive tract and to demonstrate cyclicity in preparation for breeding. Alpacas and llamas seem to have a higher rate of congenital defects compared with other domestic species, and identifying any abnormalities that may cause or contribute to infertility will save not only the female from repeated matings but also the producer time and effort in the breeding pen. It is important to emphasize that breeding management starts with a sound nutritional and herd health program. These aspects are detailed in other chapters of this publication.
Prospective herd sires should be selected on the basis of strict guidelines for conformation, production, and absence of congenital diseases. Males should be examined at birth for any obvious abnormality and then monitored for growth.
Studies on sperm production capacity and factors affecting semen quality are still not as developed in alpacas and llamas as they are in other species. Testicular size remains one of the most important factors in the selection of males. All males should undergo periodic examinations for testicular growth (Box 16-1). A complete breeding soundness examination should be scheduled before intended use. Although owners may be starting males as early as age 2 years, a great proportion of these males will not pass the breeding soundness examination at this age. A final decision on the male’s reproductive ability should be made by 3 years of age.
Studies on the appropriate frequency of use of the male or the male-to-female ratio are lacking. Studies have shown that male llamas and alpacas can sustain a relatively heavy breeding schedule for 2 weeks, but thereafter they need to be replaced or rested. Scientific data on the appropriate frequency of mating of young males are not available.
Male fertility should be monitored closely in relation to the early pregnancy status of all mated females. Breeding records should be maintained in detail and include dates, durations, and results of all breedings.
Female alpacas and llamas undergo puberty as early as age 4 to 6 months, when they attain the ability to develop follicles and show signs of receptivity. In our experience, several females have become pregnant at age 4 months when accidentally mated in a pasture situation. It is not rare for a llama to become pregnant at age 9 months, although this is not recommended because mating this early in life results in a very high rate of early embryonic loss or abortion, and most of these young females with early matings will exhibit stunted growth and poor conformation. The adequate age to mate a female for the first time is when it reaches 63% to 65% of its adult body weight and height.1 This age varies from 12 to 14 months; however, most North American producers will plan a first mating at 15 to 18 months of age. Growth and development of the female camelid is dictated by level of nutrition, although care should be taken to ensure that they do not grow too fast or attain a high body condition, as this may lead to orthopedic or metabolic diseases, which may impair fertility. The ideal body condition score (BCS) for a maiden female is 2.5 to 3 on a scale of 1 to 5.
Once a female has reached an appropriate age and size, a breeding soundness examination must be performed to ensure that the female is suitable for breeding. Persistent hymen is a condition that should be assessed and treated. Transrectal ultrasonography will demonstrate the level of activity present in ovarian follicles. If a dominant follicle is present at the time of evaluation and the female is physically suitable to be bred, it may be teased to the male and mated, if receptive.
If no dominant follicles are present or if the producer chooses to breed the animal at a later date, the best way to detect receptivity on the farm is by teasing. The female is teased to a breeding male over a fence, or in a small paddock if each animal is restrained by a handler with a halter and lead rope. If the female spits or kicks at the male, it is not receptive. If it sits, it either has a dominant follicle within the ovary, or in some cases, it may have no significant hormonally active structures within the ovary. The behavior of nonreceptivity is correlated to the presence of a corpus luteum in the ovary and high serum progesterone levels. However, behavior is not always correlated to ovarian activity or serum hormone levels, which underscores the importance of veterinary ultrasonographic examination for accurate determination.
All camelids are induced ovulators, although a very small percentage of females ovulate spontaneously. It is our personal observation that a maiden female may present to the veterinarian with a corpus luteum in the ovary, even without mating. This stresses the importance of a breeding soundness examination, as females that ovulate spontaneously may tend to do so over their lifetime, and breeding management of these animals may require more intense monitoring.