VN July 2023

Vetnews | Julie 2023 39  A secure nest site – which may be anywhere in the house or case where the bird has established territoriality. o Treatment  Environmental modification  Re-establish normal diurnal rhythms. In some cases it may be necessary to drastically reduce daylight hours artificially (to 8 hours or less) until the egg laying behaviour has stopped, and then bring the bird up to normal rhythms. Note that in species where daylength has little effect on breeding (eg Zebra Finches and budgerigars), changing daylength will have little effect on reproductive behaviour.  Remove nest sites (if possible). If the bird chooses an unconventional nest site e.g. on the floor of the cage, re-arranging the area may effectively remove its attractiveness as a nest site  Change the bird’s environment e.g. new or re- arranged cage furniture; re-position the cage on an irregular basis. This induces a certain amount of environmental stress and reduces territoriality. o Behavioural modification  If appropriate (and possible), remove the companion bird  Establish a normal relationship between human and bird through the introduction of basic behavioural training and client education. The client must be taught what behaviours sexually stimulate the bird, e.g. stroking the bird’s back.  Removing the eggs of an indeterminate layer, such as a cockatiel, will induce further egg-laying. Leaving the eggs in the ‘nest’ or replacing them with artificial eggs will often result in a hen laying a normal-sized clutch and then brooding the eggs. This shuts down (temporarily) the production of eggs. o Nutritional modification  Reduce fat and sugar in the diet by: • Conversion to a formulated diet • Removal of fruit from the diet • Introduce foraging behaviour. Typically wild birds spend 80% of their day foraging for food, leaving 20% of the day to groom, socialise and ‘nap’. In captivity, this time allocation is nearly reversed, with birds only having to spend a small amount of time looking for food. By introducing foraging activities, the less time there is for pair bonding and other reproductive activities. o Hormonal manipulation  Hormonal therapy does not work in isolation. Unless the modifications in environment, behaviour and diet are instituted beforehand or concurrently, there will be minimal or no response to the use of hormones.  Drugs that have been used include: • Deslorelin (Suprelorin 4.7mg implant) • Leuprolide acetate 100 – 700 ug/Kg every 2-4 weeks • HCG – 500–1000 IU/Kg every 2-4 weeks. Antibodies to HCG develop quickly, limiting its efficacy. It has been suggested to give dexamethasone concurrently to suppress the production of these antibodies, but this raises the spectre of generalised immunosuppression. • Medroxyprogesterone Acetate. 5-25 mg/Kg every six weeks. Side effects (diabetes, obesity, and hepatopathies) limit its use. o Surgery  Salpingohysterectomy has been proposed as a means of controlling egg production. Unfortunately, it appears that, by itself, it does not stop reproductive behaviour and subsequent ovulation – which then results in yolk peritonitis.  Surgery should therefore be reserved as a ‘last resort’ therapy only. This article is sponsored by V-Tech Technical I Article