Avian reproduction Flashcards
Successful reproduction requires a combination of:
External (proximate) stimuli to trigger the…
… internal (ultimate) hormonal cascade required to induce the necessary physiological reproductive response
Discuss Behavioural seasonal reproductive disorders?
–Misplaced natural ‘wild’ reproductive behaviour e.g.
–Pair bonding (often with an owner/self/inanimate object)
–Courtship regurgitation
–Cavity seeking and nest building
–Territorial aggression
Behaviour – seasonal reproductive disorders
Which leads in turn to maladjusted behaviour within the home ‘flock’ these behaviours can be?
–Aggression
–Territoriality
–Biting
–Excessive vocalisation – screaming!
–Feather plucking
–Regurgitation
–Self-mutilation
–Masturbation
»Leading to Prolapse cloaca
What is the treatment for reproductive disorders in the bird?
•Treatment
–Isolate (and remove) the “Hormone Button”
- What is initiating the hormonal cascade?
- What is flicking on the ‘proximate’ switch?
–Adjust the photo period
»Birds start to get into breeding mode when light increases – but this isn’t true for majority of birds in Britain, it isn’t the increase in light, it’s the decrease in light in autumn – just takes about 4 months to work!
–Curtail cavity seeking
–Prevent nesting stimuli
»Remove shredable material -
–Downgrade the amount and calorie (fat) level of food
–Increase exercise and foraging time (Take their mind off sex!)
»Give them something else to do!
What (if anything) is the owner doing to incite the trigger
What do we see here?
The bird – its missing feathers and toes – so chewing things! This bird has an issue and could well be that this issue is to do with unrequited love!
It’s having mating behaviour with it’s owner.
What is making the bird behave like this?
- What is initiating the hormonal cascade?
- What (if anything) is the owner doing to incite the trigger
–Stroking and petting (inducing copulation soliciting)
»Keep off the erogenous zones!! Back of the neck (a lot of nerves there) and base of the tail (if its bum comes in the air, its copulatory)
»Going to excite the bird! Then you put the bird in the cage and the bird is frustrated and this can lead to other behaviours
–Mouth to mouth feeding (inducing copulation soliciting)
–Carrying around on shoulder! (inducing bonding … etc)
»When birds are interacting, they sit side by side for eye to eye contact and they mutually groom and feed
ADJUST/MODIFY the owners approach to handling etc
How should you treat abnormal reproductive behaviour?
- Modification should be the primary approach
- Hormonal Control (Last resort in most cases)
- Synthetic GnRH antagonists (Lupron)
- Deslorelin implants
What are the reproductive problems diagnostic methods?
Bloods
•Birds (females) that are in reproductive mode tend to have:
–Increased serum proteins (mainly globulins)
–Increased TOTAL (not ionised) Ca levels
–Increased uric acid levels
–Increased cholesterol
Be aware of these when interpreting (all) bloods – especially if you are testing for something else!
(Know the sex of your patient!)
- Increased medullary bone can often be seen on X-ray
- in reproductively active female birds
Discuss chronic egg laying?
–Chronic egg laying (esp. Cockatiels, lovebirds, budgies) occurs when, without regard to the presence of a mate or accurate breeding season, a hen lays:
•Multiple clutches
–Removing the eggs as they are laid can ‘induce’ the bird to lay more – ‘double clutching’
–Pigeons lay 2 eggs, usually one of each sex
–Canaries lay 3, 4 or 5
–Chickens lay one a day
Discuss Determinate and Indeterminate layers?
- Determinate – a set number
- The amount they lay is often due to their brood patch
- Parrots are indeterminate, so if you keep removing the eggs, they often keep laying
- Large number of eggs in succession can lead to: (issues)
–Uterine inertia – Prolapse
–Calcium depletion
»Egg binding
»Yolk ceolomitis
»Osteoporosis (fractures)
Discuss Predisposing factors to chronic egg laying:
- Increased photoperiod (approximate)
- Food type availability (High fat) (prox)
- Presence of actual or perceived mates
–Toys, owners, mirrors, other birds (prox)
Chronic egg laying
–Treatment options?
Environmental changes
–Move cage*
»Why would this make any difference? Potentially differing light. It has a territory, feels settled where it is, if you move somewhere – its lost nesting site and has to keep reprograming, if you keep doing this – bird will think something has gone wrong with breeding cycle and hormone cascade changes
–72hrs continual light then decrease photoperiod (8-10 hrs) (Q: Why/how might this work?)
»It’s the decreasing daylight that makes them breed, at end of summer – birds have that much light that they become refractive and they stop – deplete whole of the GnRH and take them back to square 1 – photorefractive
–Remove all nesting material
–Rearrange the cage ‘furniture’
»Move food bowls, take mirror away, give it another toy to chew up
Behavioural modification
–Remove real/perceived mates
–Discourage territorial behaviour*
–Prevent ‘petting’
Allow?? a limited period of brooding – because of determinate and indeterminant layer, if we allow to brood – prolactin kicks in, responsible for milk production in pigeons (crop milk) and male birds get prolactin. Stimulate for prolactin is brood patch, pressure here sends signal to pit gland – so limited amount of brooding is okay
Discuss further treatment for chronic egg laying?
Diet modification (Prox)
–Important to ensure health
–Reduction of high fat foods–seeds
Pharmacological actions (Ult)
–GnRH antagonists
»Deslorelin
Surgical salpingohysterectomy
–Ovaries regress on their own – remove uterus
What can cause –Abnormal eggs – soft-shelled; abnormal shell texture; small size?
- Reproductive tract abnormalities
- Nutritional – Deficiencies Ca; Vit A; Vit D; trace mins
- Chronic oviductal pathologies
Case scenario:
7 y.o single pet hand-tame African Grey, Charlie, presented as an OOH emergency.
Main presenting symptoms: Owners came home to find Charlie on cage floor gasping; legs splayed behind it and wings out; mild tremors
What would be your DD?
–Respiratory/Cardiovascular
–Neurological (Undoubtedly but is it primary?)
- Trauma (cage injury – free-flying?)
- Toxins
–Heavy metals – Pb; Zinc; Teflon; Plant
- Hypocalcaemia
- Terminal seizures (e.g.– granuloma, TB, Asper, aBV)
–Bleed – abdomen/cerebral
•Stroke (common for birds)
–Reproductive
- Egg-binding etc.
- We have an acute problem but could be a chronic cause!
Assess you treartment priorities for this case?
–Oxygen – Air-sac tube?
–Antibiotics
–Food
–Fluid
–Pain relief
–Warmth and quiet
–Other? (Anticonvulsants?)
–Diazepam is an easy go to for parrots – anti-convulsant
You need a basic history – what questions?
- Sex of bird – is it known?
- Diet
- Previous problems
- Is the bird allowed out of the cage unsupervised?
Have the owners taken the bird anywhere recently?
What does a BCS of 4/5 look like?
What does a BCS of 3/5 look like?
What does a BCS of 5/5 look like?
What does a BCS of 2/5 look like?
What does a BCS of 1/5 look like?
Look at this image of a normal and imploded egg?
What is going on here?
Ventrodorsal radiograph of a cockatiel hen with reproductive-associated coelomitis.
Note the severely enlarged fluid/soft tissue density, cranial displacement of the grit-filled ventriculus, obliteration/compress-ion of the caudal thoracic and abdominal air sacs, and increased density of both femurs
Discuss Prolapsed phalluses?
•The only birds with an intromittent phallus are
–Ratites (ostrich, emu etc), Tinamous, and Anseriformes (ducks, geese)
•Most commonly seen in Anseriformes during the breeding season
Discuss leg and toe abnormalities in the paediatric patient?
Leg and toe deformities
•Metabolic bone disease (common)
–Poor nutrition of parent or hand rearing formula
–‘Plastic pot’ rearing places undue pressure on legs
–Severe cases easily diagnosed as have
»Folding fractures (tibiotarsal)
»Postural problems
–X-rays will reveal extent
–Consider quality of life and euthanasia – painful!!
–Re-fracture and pin
–If mild and bird can perch possibly leave alone
Discuss Beak malformations in paediactric patient?
•Trauma
–Siblings
–Self
–Parents
–During hand feeding
•Scissor beaks
–Imbalanced Calcium
–Genetic
•Mandibular prognathism (Underbite)
–Correction of the above conditions can be tried with acrylics to correct bite or more elaborate surgery
Pic shows scissor beak
Discuss crop stasis in the paediatric patient?
Primary
–Infections mainly yeasts (Candida)
»Crop wash to confirm
»LOOK AT HUSBANDRY HYGEINE feeding protocols, brooder temperature
»Treat by use of antifungals; crop acidifiers – cider vinegar; improve husbandry; Ensure crop emptying at each feed; use pre-digestive enzymes to permit thinner hand rearing formula (Avizyme)
–Crop atony due to overstretching
»Crop bra
