Factors Affecting Animal Growth: Genetics - Breeds & Sex Flashcards
Within a species, animal breeders have placed selection pressure on different traits that have led to many different breeds. What are some of these traits?
1) Strength
2) Meat
3) Disease Resistance
4) Milk
Within breeds selected for meat and milk production, what else has cattle been selected for? What did that result in?
- Also been selected for size
- Resulted in some breeds having very large skeletons and small skeletons.
What are cattle breeds called when they have a very large skeleton?
Large-framed cattle
What are cattle breeds called when they have a small skeleton?
Small-framed cattle
How do you determine the frame size of an individual animal?
Determined by a frame score given for a particular age range
What is a frame score based on?
Based on the height over the hips
What is the height or “frame” of cattle of a given age closely related to?
Maturity type
What is the frame size, frame score, growth potential, muscle, and carcass weight when the maturing type is early?
- Framed size: Small
- Frame score: 1 and 2
- Growth Potential: Low/Lack rapid
- Muscle: Good
- Carcass weights: 150-180 kg
What is the frame size, frame score, growth potential, muscle, and carcass weight when the maturing type is moderate?
- Framed size: Average
- Frame score: 3, 4, and 5
- Growth Potential: Average
- Muscle: Good
- Carcass weights: 200-350 kg
What is the frame size, frame score, growth potential, muscle, and carcass weight when the maturing type is late?
- Framed size: Large
- Frame score: 6, 7, and 8
- Growth Potential: High
- Muscle: Lean
- Carcass weights: 350-450 kg
What is the frame size, frame score, growth potential, muscle, and carcass weight when the maturing type is very late?
- Framed size: Extreme
- Frame score: 9, 10, and 11
- Growth Potential: Extreme
- Muscle: Extremely lean
- Carcass weights: >450 kg
Because small-framed animals grow relatively quickly, they are called….
Large-framed cattle = Later-Maturing Animals
- Small-framed cattle = Early-Maturing Animals
At the same chronological age, large-framed animals are __________________ ___________ than small-framed animals.
physiologically younger
What comparisons can we make between later-maturing and early-maturing animals if they are at the same chronological age or same weight?
Later-maturing animals are leaner, while earlier-maturing animals are fatter and more physiologically mature
Cattle can be compared at the same ___________ or _____________ endpoint. What are these endpoints?
In this case, large-framed, later-maturing cattle can be _____________ to small-framed cattle.
- Physiological or compositional
- puberty, 5% intramuscular fat in the longissimus muscle, and 19% fat trim
- Equivalent
Selection for muscle is ___________ related to milk production.
Inversely
What happened to fat distribution regarding selection for milk production?
Selection for milk production has shifted the fat distribution on the carcass
In matur meat cattle, how is carcass fat distributed?
Carcass fat is evenly distributed between the intermuscular and subcutaneous depots
Dairy cattle have _______ subcutaneous fat but _______ prerenal fat than beef cattle.
Less, more
True or False: Growth and composition are dependent on the sex of the animal.
True!
What are intact males capable of compared to castrates and females?
Are capable of > body weights than castrates and females
When do intact males attain compositional maturity compared to castrates and females?
They attain compositional maturity at later chronological ages than castrates and females
Are intact males generally heavier or lighter at any given chronological age?
Heavier
When do intact females mature compared to castrates?
Intact females mature earliest of the sex classes, whereas castrates are intermediate
