Avian reproduction

Question 1

Explain the role of yolk and albumen

Answer 1

Yolk –
- Provides a food source (1) for the developing embryo (1)

Albumen –
- Protective fluid (1) prevents adhesion of the embryo to the shell (1) / protects the embryo or yolk (1)
- Additional nutrition (1) to support the growth of the embryo (1)

Question 2

Describe how photoperiod effects egg production in chicken

Answer 2

Reduced daylight (1) reduces egg production (1)
- Increased daylight (1) increases egg production (1)
- Increased levels of hormones (1) stimulates egg released (1)

Question 3

The role of extraembryonic membranes in an egg

Answer 3

Layer around the embryo for gaseous exchange, yolk sac food source provides nutrients

Question 4

How many ovaries does a female have

Answer 4

One

Question 5

Parts of the avian oviduct

Answer 5

Infundibulum
Magnum
Isthmus
Uterus
Cloaca

Question 6

Site of fertilisation in a chicken

Answer 6

The infundibulum

Question 7

Four factors that affect egg production in chickens

Answer 7

Light availability, diet, type of breed, age

Question 8

Ideal incubation conditions for chickens eggs

Answer 8

Temperature- 37-39
Humidity- 60% first 18 days 70% for the last 3
Ventilation- allow oxygen to enter shell, increases as egg hatches
Turning at least 3 times per day

Question 9

Process of fertilisation in birds

Answer 9

Copulation- male places sperm into the cloaca via the papillae
Sperm can live in oviduct for up to three weeks
Sperm have full fertilising capacity for up to 6 days
The egg develops in the oviduct before it’s laid
Egg are developed over approximately25 hours

Question 10

How an egg is formed through each stage of the oviduct

Answer 10

Yolk is released from the ovary into the infundibulum, ovum spends 15 mins in the infundibulum where it is fertilised by sperm, the fertilised ovum moves into the magnum where the albumen is disposed and layered over the yolk in approximately 3 hours, inner and outer shell membranes are then added in the isthmus where the egg stays for around an hour, the egg moves into the uterus where it spends around 21 hours- water is added to thin the outer white of the egg, the shell material and pigments are added, the egg shell is made of calcium carbonate, the egg moves into the cloaca where it is laid

Question 11

Seasonal breeding

Answer 11

Due to the effect of light levels on the brain
Timing birth to coincide with spring when nutritional and climate conditions are optimum for lactation and growth of offspring