Avian Flashcards
Which ovary and oviduct regress in birds and at what point?
The right at day 10
Which gonadal region receives more germ cells?
The left
What does FSH and LH do?
FSH -> regulates follicular growth
LH -> promotes ovulation
When does ovulation occur in regards to laying?
After the previous egg is laid
What produces oestradiol and androgens?
Thecal cells of small follicles
What produces progesterone?
Granulosa cells of large follicles under stimulation of LH (not luteal cells)
What structure do birds not form?
A corpus luteum
What does progesterone feed back positively on?
LH
What are follicles suspended by?
A stalk with smooth muscle, blood vessels and nerves
Describe the process of a primary oocyte becoming a secondary oocyte
Primary oocytes mature to secondary oocytes and a polar body a few hours before ovulation
What happens to the oocyte post ovulation?
It undergoes a second maturation to an ovum and second polar body in the oviduct after fertilisation
How long is the infundibulum present?
15-30 minutes to catch the egg
What is the purpose and structure of the magnum?
To deposit albumen over 3 hours
Enlargement of mucosal folds - longest and most coiled part of oviduct with tubular glands
How long is the egg in the uterus and what for?
18-20 hours for outer shell deposition, calcification and pigmentation
Watery solutions added in first 8 hours
What is the structure of the infundibulum?
Funnel shaped with thin wall
Chalaziferous region - thicker wall and mucosal folds to lay day chalazae
Fertilisation occurs here
What is the structure and function of the isthmus?
Short and less prominent folds than magnum
Produces soft shell membranes
First section no glands, remainder has tubular glands
Describe the structure of the uterus - or shell gland
No separation from isthmus
Short
First short and narrow ‘red’ region and larger pouch region
Manufactures calcereous shell
Describe the structure of the vagina
Separated from uterus by sphincter
Contains spermatic fossulae and stores sperm for 10-14 days
S shaped
Thin and low mucosal folds with thick muscle wall and no secretory gland
Where are the lipids and proteins formed for egg formation and how are they transported?
liver - transported via blood to granulosa cells
What organises the lipids and proteins and what do they form?
the primary oocyte
Into the yolk sphere and fluid
What is the purpose of chalazae?
Added to poles of the yolk to keep embryonic disk orientated
what is added in the isthmus?
Protein added to albumen and addition of shell membranes (inner + otuer)
How long does the process of vitellogenesis last?
23-27 hours
What are the testis suspended by?
The mesorchium
What are the testis surrounded by?
The abdominal air sac (not cooled by this)
What increases with sexual activity in the male?
The length and diameter of seminiferous tubules and number of interstitial cells
What do males not have compared with other species?
No pampiniform plexus
What do the sertoli cells do?
Provide mechanical support for germ cells + produce steroid hormones
What do leydig cells do and where are they?
Produce androgens
Between tubules
What is the rete testis?
Thin, irregular channel on dorsomedial aspect of testis adjacent to epididymis - not present in all species
which is the homogametic sex?
Males - females determine sex of offspring
Describe the epididymis
No distinctive head, body or tail and relatively small compared to mammals
Efferent ductules along whole length
Where do the ductus deferens go?
From epididymis to cloaca, entering cloaca at urodeum
Describe the phallus
Not found in all species - others copulate by everting cloaca
Intromittent or non-intromittent (chickens, turkeys)
Describe endogenous factors for seasonal breeding
Captive birds - can have these turned off
Migratory birds - go to where climate is right
Tropical - need warmth
Describe exogenous factors for seasonal breeding
Ultimate factors - for survival
Proximate factors -> social cues, behaviour (vary from year to year), climate, mate availability
Describe exogenous factors for seasonal breeding
Ultimate factors - for survival
Proximal factors - vary each year (climate, loss of nesting site, mate availability)
What chromosomes do females and males have?
Female - ZW
Male - ZZ
How can we karyotype birds?
Blood granulocytes
Feather pulp cells
How can we surgically determine sex?
Laproscopic exam of gonads - requires anaesthesia
How can lovebirds sexual behaviour be described?
Sexually monomorphic - homosexual pairing is common
What is the difference in male and female lovebirds tails?
Females have straight across tail
males have rounded tails
How can we feather sex at birth?
Females - remiges longer than coverts
Males - short remiges under coverts (in first day)
What are 5 reasons for reproductive poor performance?
- Husbandry problems
- Problems with copulation
- Female infertility
- Male infertility
- Poor hatchability
List 4 examples of husbandry problems
- Unsuitable nest sites
- Overstocking
- visual and audible threats
- incorrect photoperiod
List 4 reasons for issues with copulation
- Swinging perches
- Obesity
- Bullies
- Arthritis
List 4 reasons for female infertility
- Obesity
- Metritis
- Uterine polyps
- Chromosomal issues
List 4 reasons for male infertility
- Incorrect photoperiod
- Obesity
- Neoplasia
- Size disparity
List 4 things causing poor shell quality
- Long length of lay
- Increased temperature
- Stress
- AM eggs worse than PM eggs
List 5 avian reproductive diseases
- Chronic egg laying
- Egg binding + dystocia
- Prolapsed oviduct
- Egg yolk peritonitis
- Phallus prolapse
What breed is chronic egg laying common in?
Budgies
List 3 methods to reduce chronic egg laying
- Eliminate sexual stimulation
- Decrease photoperiod to 8-10 h/d
- Leave artificial eggs in nest
List 3 treatments for chronic egg laying
- Medroxyprogesterone - cause obesity, FI liver, PU/PD
- Leuprolide acetate GnRH agonist –> budgies every 12 days, cockatiels every 18 days and cockatoos every month
- Salphingohysterectomy - some hens will still ovulate
Define egg binding
Failure of an egg to pass through the oviduct at a normal rate
What are 5 causes of egg binding/dystocia?
Hypocalcaemia Large mis-shapen eggs Old hen Oviduct tumours hyper/hypothermia
What can egg binding cause for the bird? (4)
- Circulatory disorders
- Nerve paralysis
- Cessation of normal defecation and urine flow
- Pressure necrosis of oviduct layers
What is used to treat egg binding?
Prostaglandin -> with warmth, fluids, calcium and glucose
Gel applied to utero-vaginal sphincter 0.1mg/100g
Expelled in 15 minutes if egg not adherant to oviduct
Can oxytocin treat egg binding?
No -> does not relax utero-vaginal sphincter
What are 2 methods of assisted delivery?
Ovocentesis -> shrink egg size by removing fluid resulting in uterine damage by shell pieces (soft shell eggs deliver easily)
Surgery -> ventral laparotomy/hysterectomy
What is egg yolk peritonitis?
Yolk enters the abdominal cavity causing inflammation
What are signs of egg yolk peritonitis?
Distended abdomen
Dyspnoea
Pink fluid on abdomenocentesis
How do we treat egg yolk peritonitis? (4)
Drainage, fluids, hystorectomy, Leuprolide (GnRH agonist)
What is a phallus prolapse?
Phallus protrudes from cloaca
Clean, lubricate and return to cloaca +/- purse string suture
