Reproduction of Llamas and Alpacas – Exotic and Laboratory …

Relative to body size, the nonpregnant reproductive tract of SACs is relatively small. Uterine morphology is similar to that of a mare, with relatively short horns and uterine body. The cervix can be felt on rectal palpation and has two or three cartilagenous rings. The urethra opens onto the floor of the vagina. A suburethral diverticulum is present.

Ovarian activity typically begins at 1012 mo of age. Camelids are induced ovulators. At the onset of puberty, follicular waves occur, with a dominant follicle developing every 1214 days. Because of the small size of females and the potential for dystocia associated with early breeding, females are usually not bred until they are >18 mo old and weigh 40 kg (alpaca) or 90kg (llama). When a female is truly receptive, she will usually assume a position of sternal recumbency (cushing) within seconds to a few minutes after introduction of a male and allow the male to breed. While mounting, the male will typically begin a vocalization described as orgling. The volume of the ejaculate isrelatively small (25 mL) and is mostly deposited directly into the body of the uterus after cervical dilation. Ejaculation occurs over an extended period of time. An ovulation induction factor in the semen stimulates reflex ovulation ~2430 hr after mating. A functional corpus luteum (CL) is present 23 days after ovulation. The fertilized oocyte is usually found in the uterus by day 7 after mating, with implantation occurring by ~30 days of gestation. The type of placentation is diffuse epitheliochorial, developing in both horns. Although ovulation occurs from either ovary, uniquely, ~95% or more of the pregnancies are carried in the left horn. Live births of twins are extremely uncommon, with most twin pregnancies being resorbed or aborted early in gestation.

A female with a functional CL will aggressively refuse the males efforts to mount. An indication of pregnancy is the females rejection of the male if he is reintroduced >15 days after the initial breeding. Progesterone concentrations of >1 ng/mL are typical in females with a functional CL and can be used for confirmation of both ovulation at 69 days after mating and of pregnancy at >21 days after mating. Persistent CL are periodically seen and account for most false-positive results when using serum progesterone for pregnancy confirmation. Rectal palpation for pregnancy diagnosis is practical in llamas at >45 days of gestation. It is usually not possible to safely perform rectal palpation in alpacas, unless the palpator has small hands. Pregnancy can positively be diagnosed by transrectal ultrasound from ~28 days of gestation, although it is possible to be suspicious as early as 1012 days based on presence of fluid and to be reasonably sure by day 21 when a hyperechoic embryo is seen. Ultrasonographic transabdominal approach from 4560 days can be expected to produce positive results.

Normal gestation in camelids is ~342 10 days, with alpacas being somewhat shorter. Most normal births (>70%) occur in the morning. Dystocias due to excessively large crias are rare. There are few reliable indications of pending delivery. Stage I labor typically lasts 16 hr and may be accompanied by increased frequency of urination, increased humming, and separation from the herd. Stage II labor is rapid (typically <30 min), with delivery of a cria weighing 5.58 kg (alpaca) or 1116 kg (llama). Stage III should be complete within 46 hr. All stages are usually longer in a first-time delivery. Retained placentas are rare. Uterine involution begins shortly after birth, and most females can conceive within 1421 days after delivery. Females have four teats and do not exhibit significant mammary enlargement during the prepartum period. Mastitis is rare.

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Reproduction of Llamas and Alpacas - Exotic and Laboratory ...

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