Growth And Development

Question 1

What is ADG?

Answer 1

Average Daily Gain
Delta W/ Delta T (days)

Question 2

4 ways growth occurs

Answer 2

1. Hyperplasia - increase cell numbers (prenatal)
2. Hypertrophy - increase cell size (postnatal)
3. Atrophy - decrease cell size
4. Tumors - abnormal localized cell growth without normal control mechanisms

Question 3

3 phases of prenatal growth

Answer 3

1. Blastocyst
   - after fertilization
   - nutrients from uterine secretions and egg
   Zygote dividing
2. Embryonic
   - cell differentiation
3. Fetal
   - increase weight and composition
   - nutrients from maternal bloodstream (placenta)

Question 4

5 factors influencing prenatal growth

Answer 4

Number of fetuses
Uterine implantation site
Dam; size, nutrition, disease status

Question 5

What is the shape of the postnatal growth curve

Answer 5

Sigmoid shape

Question 6

3 points on postnatal growth curve

Answer 6

1. Self-accelerating
2. Inflection point - puberty
3. Self-inhibiting

Question 7

Thyroxin (from where, to where, why)

Answer 7

From thyroid
To all body tissues
Sets metabolic rate

Question 8

Insulin (from where, to where, why)

Answer 8

From pancreas
To all body tissues
Promotes cell division

Question 9

Adrenal corticoids (from where, to where, why)

Answer 9

From on top of kidneys
Minerals= regulate concentrate of electrolytes
Glucose= regulate conversions and metabolism of carbohydrates

Question 10

Thyrotopin (from where, to where, why)

Answer 10

From ant. Pituitary gland
To thyroid gland
To release more hormones

Question 11

Adrenocorticotropic hormone (ACTH) (from where, to where, why)

Answer 11

From ant. Pituitary gland
To adrenal cortex

Question 12

Gonadotropins (from where, to where, why)

Answer 12

Follicle Stimulating Hormone - FSH
Luteinizing Hormone - LH

From ant. Pituitary gland
To ovaries and testicles

Question 13

Somatotropin (growth hormone) (from where, to where, why)

Answer 13

From ant. Pituitary gland
To all body tissues
To grow

Question 14

How do genetics limit growth?

Answer 14

Genetics set the maximum size and rate of growth. Nutrition, disease, and parasites determine the proportion of the maximum that will be obtained.

Question 15

What are the 4 phases of postnatal growth?

Answer 15

1. Short time of birth
2. Early growth
3. Middle growth
4. Late growth

Question 16

Short time of birth (body parts and tissues?)

Answer 16

All head, neck, and legs
Tissues: bone, muscles, vital organism

Question 17

Early growth (body change and tissue)

Answer 17

Length
Tissue: bone, muscle, vital organs

Question 18

Middle growth (body change and tissue?)

Answer 18

Increase Depth and width
Tissues: bone, muscles, fat

Question 19

Late growth (body parts and tissue?)

Answer 19

Loin and hind quarters
Tissue: muscle, fat

Question 20

What happens to percent fat in older and heavier animals?

Answer 20

Percent fat increases
% muscle decreases
% bone decreases

Question 21

Influence of sex on mature size

Answer 21

M > F

Question 22

Influence of sex on rate of growth

Answer 22

M > CM > F

Question 23

Influence of sex on rate of fattening on cattle and sheep

Answer 23

F > CM > M

Question 24

Influence of sex on rate of fattening in swine

Answer 24

CM > F > M

Question 25

Influence of sex on feed efficiency

Answer 25

M > CM > F

Question 26

Carcass characteristics (lean and fat)

Answer 26

Lean: M > CM, F
Fat: F, CM > M
Testosterone keeps animal lean

Question 27

Priority system of use of nutrients

Answer 27

1. Nervous tissue and vital organs
2. Skeletal
3. Muscle tissue
4. Fat
5. Reproduction
   - explains why a female may not show heat
   - except ranked 2 for pregnant female

Question 28

How to tell stunted growth and naturally small animal apart?

Answer 28

Stunted animals have large heads

Question 29

When switching from as-fed basis to dry matter expect percentages to

Answer 29

Increase, except for moisture