Lecture 37 Evolution & Domestication - Poultry Flashcards
Birds evolved from
Small, predatory dinosaurs
Bird transition from dinosaurs involved: (4)
-transition from Dino-fuzz to flight feathers
-loss of teeth (modification of beak/tongue)
-loss of tail
-fusion and modification of skeletal elements
Characteristics uniquely adapted for flight: (7)
-reduction, loss and fusion of vertebrae and bones of pelvic girdle
-reduction in overall body size
-outer cortex of bones are thinner but more dense (light but strong)
-bones are hollow or have trabeculae
-larger sternum and central keel
-forelimbs longer than hind limbs (running to flight)
-teeth were lost repeatedly in various lineages
The central keel is used
As an anchor for flight muscles
Gallus domesticus
Domestic chicken
Chicken is domesticated from
Red jungle fowl
Domestication of chickens occurred around
8000 years ago with multiple origins of domestication
Chickens were originally likely domesticated for
Cockfighting
Multiple chicken origins of domestication in (4)
-China
-Laos
-Burma
-India
Domesticated chickens differ from wild jungle fowl (3)
-less active
-fewer social interactions
-less aggressive
Domesticated chickens: (5)
-increased adult body weight
-reach sexual maturity earlier
-egg production starts earlier
-more frequent laying
-larger eggs
Broiler chickens (7)
-meat
-~660 million produced annually
-reach slaughter weight at 5-7 weeks of age
-reach ~2kg in 35 days consuming only 3.2kg of feed
-genetic selection for improved performance and decreased time to market
-skeletal structure cannot support rapid weight growth
-enlarged breast (pectoral muscles)
Layer hens (4)
-Australorp and White leghorn
-production peak at ~26 weeks of age
-physiological limits of an egg a day
-Australian consumer preference for tinted eggs
