Growth and Development

Question 1

What Factors Affect Growth of Meat Animals?

Answer 1

Physiological Age/stage of maturity
Genetics/Epigentics (choosing genetics and how different breeds mature)
Gender/Hormones (females are earlier maturing, intact males are leaner and heavier at older ages)
Nutrition (feeding right things; energy, protein, other nutrients)
Environment (temperature, sunlight, space)
Exogenous Agents (steroid hormones’, beta agonists/blockers (growth/milk), immunological approaches (probiotics and antibiotics), gut-active compounds)

Question 2

Sigmoid (S-Shaped) Growth Curve

Answer 2

Lag Phase - seed germinantion and losing weight
Log Phase - slow growth into rapid growth in early to middle life
No Growth - near end of life, weight loss, and death

Question 3

How to Change Shape of Growth Curve?

Answer 3

change average daily gain
change mature size (hormones, decreasing or increasing nutrition and genetics)
earlier maturing = chronological age
later maturing = physiological age

Question 4

How do Breed Classifications Affect Growth?

Answer 4

Materal Breeds, Terminal (Sire) Breeds, Dual Purpose

Question 5

Maternal

Answer 5

Reproductive Efficiency (cattle = one calf/year starting at two, swine = litter size, sheep = multiple births, and out of season breeders)
Milking Ability
Longevity of how long they’re reproductive
Fatter to withstand the physiolocial stress of lactation, marbling and quality are often higher, but meat quantity is low

Question 6

Terminal (Sire) Breeds

Answer 6

growth rate
carcass traits (high lean:fat ratio)
heat quantity high, while quality may be low

Question 7

How does Sex affect development?

Answer 7

uncastrated males grow faster, are leaner and more efficient
Cattle - bull (later), steer, heifer (earlier)
Swine - boar, gilt, barrow
Sheep - ram, wether, ewe

Question 8

Why do we Castrate?

Answer 8

Managements (animals are aggressive, damage to themselves, each other, humans, equipment)
Meat Quality (decreased tenderness, less marbling, bad odor/taste)

Question 9

Nutritional Effects

Answer 9

Protein (more muscle potention = more protein, later maturing animals need more protein, need a higher protein diet % during period of rapid muscle growth
Energy (limited energy = slower growth, decreased fat deposition, and less protein, limited energy during fat deposition reduces it)

Question 10

Economically Important Tissues

Answer 10

muscle (good for eating)
fat (good for slavor)
bone (holding animal upright)
nervous, organce, connective (collagen), blood

Question 11

Nutrition Priorities in Order

Answer 11

Nervous System (brain and spinal function and move)
Skeletal Development (building foundations of your body)
Muscle (nutrients for your muscle)
Fat (excess consumption of nutrients turns into fat)

Question 12

Relative Rates of Deposition

Answer 12

Muscle - slow, than rapid, then maturity and declines
Fat - slow, than rapid, inclining slightly
Bone - slow incline whole life, little increases earlier in life

Question 13

4 Locations of Fat Deposition

Answer 13

Internal (heart, pelvic, kidney) - protects organs
Subcutaneous (back fat) - insultation, protects during storage and handling, increases shelf life
Intermuscular (between muscle; seam fat)
Intramuscular (marbling) - palatability, quality, taste, flavor

Question 14

Fat

Answer 14

Measured at 12th rib - cattle and sheep
Measured at 10th rib - pigs

Question 15

Purpose of Fat

Answer 15

Excess energy storage beyond maintenance and production
Insulation
Protection
Optimum amount to ensure eating quality
Subcutaneous for storage and handling (stops water loss and shrinkage)