Camelid reproduction

Question 1

Are South American Camelids classed as seasonal breeders? When would their breeding season be in the UK?

Answer 1

• South American Camelids are not classed as seasonal breeders. However, they breed seasonally if the environment or climate requires it (as in their harsh natural habitat). In the UK they are bred and give birth in the summer (gestation is 11-12 months).

Question 2

Briefly describe the key facts about the ‘oestrous cycle’ in South American Camelids

Answer 2

• South American Camelids are induced ovulators so do not have regular oestrus cycles, but repeated and overlapping follicular waves (in the absence of mating). Overlapping follicular waves result in persistent elevated levels of Oestradiol-17β and prolonged periods of receptivity to the male, with only short periods when the male is rejected. Mounting and intromission stimulates an increase in GnRH and LH resulting in ovulation in 24-48 hours.

Question 3

You are called to see an alpaca breeder who has 10 females and 2 males in order to perform pregnancy diagnosis. When asked how many months gestation the foetus should be, the breeder starts to give you dates regarding ‘last seen cushing’ and ‘spitting off’. What do these terms mean and how do they relate to the reproductive cycle. What is the gestation length of llamas and alpacas? The breeder also states that he keeps the males separate from the females during the last trimester of gestation. Why is that?

Answer 3

• ‘Cushing’ and ‘Spitting off’ are behaviours displayed by camelids during breeding. Females will ‘cush’ (assume sternal recumbency) if they are receptive to the male at the time of breeding (if there is a pre-ovulatory follicle) and will usually ‘spit off’ if they are not receptive (no pre-ovulatory follicle/pregnant). Gestation length of llamas and alpacas is 11-12 months. Males should be kept separate from females during the last trimester of gestation as placental oestrogen production may lead to inappropriate mating attempts.

Question 4

You are called to an abortion outbreak affecting alpacas of mid to late gestation. What are the most likely causes of abortion in alpacas and what samples would you take?

Answer 4

• There are various causes of abortion in camelids, and as in other species they may be infectious or non-infectious. Of the infectious causes, bacterial infections are most common (Leptospira, Chlamydia, Listeria, Campylobacter), but there are also viral causes (such as BVDV) and protozoal causes (such as Neospora). Non-infectious causes of abortion in camelids include twinning, foetal abnormalities and environmental stressors. Sampling is similar as for other species, and ideally a whole foetus with placenta should be submitted. If this is not possible, samples of placenta (both cotyledons and inter-cotyledonary areas), foetal fluid, foetal stomach contents and foetal liver or spleen can be submitted. Sampling should be discussed with the lab prior to submission where possible.

Question 5

You are presented with a 3 year old female alpaca who is in cria, but at an unknown gestation as the owners only purchased her 6 months previously. She is showing signs of colic and is rolling and crying out and has been for 2 hours. On physical examination she is in good body condition, with dark pink mucous membranes, capillary refill time of 3 seconds, heart rate of 120 beats per minute with minimal compartmental contraction. The fetus can be seen moving excessively against the maternal side. The vagina is swollen and moist. What are your differential diagnoses for an animal that presents in this way? Please consider all body systems. What diagnostic tests would you perform in order to confirm your diagnosis? Examination ultimately results in a diagnosis of uterine torsion being made. What is the underlying reason for the development of this condition very commonly in South American Camelids? How can it be corrected?

Answer 5

Differential diagnoses include:
* Uterine torsion – commonly occurs at 8-10m gestation (in comparison to cattle where it occurs at term)
* Mechanical obstruction: intussusception, entrapment, foreign body
* Peritonitis – ruptured ulcer, uterine tear
* Enteritis (viral, bacterial, parasitic)

Diagnosis
Uterine torsion can be diagnosed on rectal palpation or exploratory laparotomy. Many torsions are pre-cervical, and so cannot be detected on vaginal examination. The direction of the torsion (clockwise or anti-clockwise) can be ascertained by palpating displacement of the broad ligament towards the opposite side of the pelvis to the gravid horn. Bloods or imaging could be used to investigate other potential causes of colic in the absence of a uterine torsion.

Risk factors for uterine torsion include large foetal size, right horn pregnancies and excessive rolling in late gestation.

Treatment
Uterine torsion can be corrected surgically or non-surgically. Non-surgical corrections include rolling the dam to untwist the uterus, or transvaginal correction (if the cervix is sufficiently dilated). If these are unsuccessful, surgical correction can be carried out, as described in the resource attached to this session.