Alpaca Castration

Author: Peter Aitken BVSc MACVSc MRCVS

Castration is a common practice in machos' not required for breeding purposes. It is a procedure that can be done from 8 months of age onwards, but many owners prefer to wait until after skeletal height maturity has been reached (12-18 months). The procedure is undertaken for many potential reasons including behavioural and management. It will help to reduce aggression between males and means that castrated males and females can be kept together without unintended consequences.

Problems associated with early castration have been discussed in North American literature1 and involve prolonged long bone growth plate closure resulting in elongated limbs, in particular in llamas where lateral patellar luxation and early onset of degenerative osteoarthritis of the stifle joints have been seen due to the development of a tall straight legged stature.

Should castration be done prior to 12 months of age; the only limiting factor is that both testicles are present in the scrotum. Provided that the owner is aware (albeit very small in alpacas) of the above potential complications, this is a decision that they can make based on the aforementioned requirements for management and behavioural reasons as best suits the situation; which will vary from one property to another and may depend on safety/handling, space and reasons for having the animals.

Castration can be safely performed under local anaesthesia and suitable restraint. Suitable restraint I find is to have one person holding the head of the animal and a second person holding the tail for me, chukkering (physical restraint using a soft rope tied around the animals' waist in the cush position) can also be used if required. General anaesthesia is not required although some larger or more aggressive individuals may require some sedation.

Following suitable preparation of the perineum using surgical scrub techniques, local anaesthetic is infused in a line over each testis (the volume will depend on the size and age of the animal). In a full grown male approximately 2-3ml is infused under the skin over each testis and a further 1ml is injected into the body of each testis. Pre-operative anti-inflammatories can also be given at this point.

The skin is then incised over the testis and through the overlying fat pad. The testicle, epididymis and ductus deferens are then exteriorised within the common tunic (closed technique) and the surrounding fat and fascia separated away. The ductus deferens and other vessels are then clamped and ligated before cutting. This procedure is then repeated for the other testicle.

Following removal of both testicles, the incisions are stripped of any fat or tissue that may be hanging out and are left open to heal by secondary intention. Providing strict asepsis has been observed, and appropriate vaccinations have been used prior to the castration antibiotics are not indicated. Minimal bleeding should occur post-operatively.

Complications that can arise include bleeding, swelling and infection. They are very uncommon but should be attended to promptly should they occur and veterinary attention should be sought immediately.

By using the above technique it is possible to make castrations a quick and relatively stress free event for the animals whilst placing both animals and handlers at minimal risk also.

References
1. Barrington GA, Meyer TF, Parrish SM. Standing castration of the llama using butorphanol tartrate and local anesthesia. Equine Pract 1993;15:35-39.