‘Principally in reply to Tom Cade’s points:
1. I agree, with Tom, that whatever the scientific/genetic arguments, in these conservation times in which we live, I believe our efforts should be towards sterilisation of hybrids before they are flown free.
This has a number of implications; firstly, it will need to be done at a young age, well before sexual maturity, at which stage the organs are small and surgery (if that is the method of choice), is not so easy. Yes, it will need to be done by a vet if it is surgical, and it will have to be certified by the vet as having been done. For the certificate to be legitimate, the bird will have to be identifiable, e.g. identichip.
2. I agree that I currently have a tendency against surgical castration as it might affect rate of muscle development etc. Air sac walls will repair very quickly following surgery. Bob Altman is due to present a paper to the European Association of Avian Vets in London (May 1997), on the radiological sterilisation of pigeons. [...] Essentially, if any testicular material is left behind, it can regenerate. However, in the pigeons on which he operated, post mortem histopathology (carried out 1-5 months later) failed to show any vestigial testicular tissue in 9 birds (including 6 sexually immature birds), whilst four were not successfully castrated. None of the 11 female birds were effectively castrated by this method.
3. Recommended surgery would involve removal of the oviduct (at least 75% of its length, rather than simple transection.) This is a recognised standard procedure, routinely carried out by
39 | P a g e experienced avian vets on birds as small as cockatiels. At present, surgery is being carried out via a left caudal celiotomy, but has also been carried out in larger birds (e.g. flamingos) via endoscopy. Endoscopic surgery has major advantages, as there is a smaller area of feather removal, less muscle sectioning, hence quicker healing and less effect on flight training at a young age. It is certainly technically possible. but it would remain a procedure for specialised avian vets to carry out, rather than the street corner cat and dog, or even camel vet.
With respect to male birds, sectioning of the vas deferens is certainly the method of choice. Again, surgery could be done by endoscopy, the main problem that I have experienced to date is finding the vas in a young (non sexually mature) bird. The position of the vas in relation to the caudal lobe of the kidney, and the ureters, does vary with respect to species. No doubt with more practice, we can come up with some more definite recommendations on surgical approach.
The only way of addressing whether the question as to whether castration as opposed to vasectomisation has any effect on flying ability, is to carry out a number of each (at least 6 and probably more), and to assess their ability in a blind trial (i.e. the trainer/falconer would not be aware of which bird had had which procedure carried out.)
As to whether the vas deferens would reconnect, if radio surgery were used (which would be the easiest anyway) and a number of sections were made this is highly unlikely.
Cost - could be a problem as it is a specialist technique, and will have to be carried out at the site of the breeder rather than in a specialist falcon hospital say in the UAE. What may be a greater problem is actually locating enough vets with the necessary equipment, experience and bottle to carry it out.
4. If sex steroids or other chemicals were to be fed, one would have to be certain that the effect was permanent, the same applies to chemical implants. Other chemicals such as cadmium certainly can be studied, but who is going to certify that the bird is sterile, i.e. that the correct amount for the correct period was given? I regret that I feel that there are plenty of breeders who would rather state that they had given the chemical when in fact they had not.
5. Imprinting - again, is variable; if done wrongly can be an absolute disaster, i.e. the effects are not in my mind consistent although apparently reliable if done correctly.
I will investigate the surgical side in greater depth and report back. I will also check with the RCVS to ensure that the procedure would not be termed a ‘mutilation’ (i.e. a surgical procedure not carried out for the animal’s best personal interests) and hence ethically unacceptable in the UK, although I cannot personally see much difference between this and castrating any cat/dog/horse.
NEIL FORBES FRCVS
To all interested parties, copy of Dr Bob Altmans paper on radiosurgical castration of pigeons. Please be aware that this paper is not due for presentation until May 22 1997 and hence is not for general release as yet. Feel free to contact Bob on his E mail if you want to raise any points. The paper does not discuss the safety of the technique utilised.
I personally still feel vasectomy / salpingohysterectomy is the way forward, in time by endoscopic keyhole surgery.
40 | P a g e Neil Forbes FRCVS
NEUTERING MALE PSITTACINE BIRDS