Abbey's Franken-notes for Phys 2

What is unique about the growth curve for growth over time?

the curve is sigmoidal but also has a stair shaped pattern because growth is sporadic.

The self-accelerating phase is at the _______________ (cumulative growth)

beginning of the curve before the point of inflection

The self-inhibiting phase is at the __________________ (cumulative growth)

ending of the curve after the point of inflection

What are the characteristics of the self accelerating phase?

- Characterized by exponential growth

- Each cell divides into two daughter cells at a constant rate

- rapid growth but with little complexity

- The velocity of growth increases because there are more cells available to divide

- At some point, the velocity will begin to slow because there is not enough nutrients to maintain that growth speed --> gowth becomes linear at this point

What are the characteristics of the point of inflection in the cumulative growth curve?

- Maximum growth velocity after which the animal will continue growing, but at a decreasing rate

- occurs at PUBERTY

Maximum growth velocity = _________

• period of greatest ADG

• occurs at puberty

What are the characteristics of the self-inhibiting phase in the cumulative growth curve?

- animal approaching maturity at a decreasing rate of growth

- diminished intake of food until they reach they maintenance requirement

Reduced growth rate is controlled by many signals including the secretion of _______________ by the hypothalamus.

a. GnRH

b. GHRH

c. GHIH

d. yo mom

c. GHIH (somatostatin)

What are the characteristics of the asymptote in the cumulative growth curve?

- point at which food intake matches maintenance

- mature body weight

• top of the cumulative growth curve where it levels out

The time at which an animal reaches mature body weight can depend on _____________ (3 reasons)

available food

reproductive cycle

season

Growth is measured as a compared function of

1. chronological age

2. physiological age

What different types of curves can describe growth over time?

1. cumulative growth

2. absolute growth

3. relative growth

Cumulative growth is a plot of an animal’s _____________ over time.

weight

chronological age is measured in what unit?

age in absolute time units ( days, months, years)

What four factors can alter the shape of the growth curve?

1. Nutrition

2. disease

3. stress

4. Activity level

What four factors does physiological age refer to?

1. height

2. weight

3. composition (muscle to fat)

4. Puberty

Different types of animals might reach the same stage of physiological maturity at very different _____________________.

chronological stages

What does the absolute growth rate curve plot?

gain per unit of time against time

What is the equation for average daily gain?

ADG = (final weight - initial weight ) / (final time - initial time)

Is the absolute growth rate curve really the true growth rate of the animal?

No, an animals growth rate changes as an animal grows, ADG is only accurate for short measures.

What are the characteristics of a relative growth rate curve?

- growth in relation to total weight

- can be used to describe whole body or individual tissue growth

- GREATEST DURING INITIAL STAGES OF DEVELOPMENT BECAUSE THE ANIMAL IS STILL SMALL.

What is whole body growth?

whole body growth curves represent a sum of growth of many different tissues that develop at dramatically different rates.

What body components develop first?

the ones that are physiologically more important: nerve, bone, muscle, and fat.

Extremities develop first (legs, arms, etc)

What is allometric growth?

the study of how body parts change in size as an animal develops.

There is a _________ relationship between the log of the crab and the log of the claw weight

linear

in positive allometric growth where b>1 then

The tissue component rate is growing faster than the body as a whole and has a higher growth impetus

late developing

In isometric growth where b=1

then the tissue and body size are growing at a similar rate and the body has an average growth impetus

in negative allometric growth where b<1

then the tissue is growing slower than the body, and the body has a lower growth impetus

early developing

does allometric growth explain all growth?

no, it only explains proportions, muscle, and fat deposition

What were the findings of the study that restricted nutrient intake during growth?

when nutrition was limited, the tissues had a different priority for nutrients based on the sequence in which they had developed and on their functional priority.

Why might a pig have a higher b value on their neck and back than a sheep?

pigs are rooting animals, so they spend a lot of time digging with their nose. This causes late muscle deposition.

_______ and _________ composition of the body changes throughout growth.

tissue and chemical

What is absolute basis?

cumulative weight gain over time

What is percent basis?

proportion of the total body weight over time

the absolute growth curve resembles the

sigmoidal growth curve

What chemicals are bone, muscle, and fat composed of?

water, protein, lipid, ash

What does percentage growth describe muscle, bone, and fat as?

a percentage of the whole body

fat becomes a _____ proportion with age as muscle and bone become a _________ proportion

larger, smaller

water and protein become a ___________ proportion over time

smaller

what are some genetic factors that affect growth?

- genotype

-heritability

-carcass composition

-species

-breeds

-sex

species definition

organism capable of interbreeding and producing offspring

How does growth between species vary?

deposition of different tissues

relative proportion of each body part

Natural selection differences between species varies a lot from man made selection because man made selects for

production and not survival

How does muscle distribution in cattle compare to other domestic species?

ruminants have increased muscle in their front legs to bear the weight associated with grazing for long periods.

domestic ruminants have increased muscle mass around the abdomen to digest the large quantity of feed they consume

Species is a ____________________ in the deposition of fat.

major determinant

Breed definition

within a species, placed selection pressures on different traits that have led to many different breeds

what are examples of large framed cattle breeds?

Chianina (meat)

Holstein ( milk)

What are some examples of small framed cattle breeds?

angus (meat)

jersey (milk)

What is given to determine the frame size of an animal?

frame score, use hip height measurement

Do large framed animals reach a heavier or lighter weight at physiological maturity?

heavier

Do larger-framed or smaller-framed animals reach physiological maturity earlier?

smaller framed animals mature faster

At the same chronological maturity larger-framed animals are physiologically __________ than small-framed animals.

younger

cattle can be compared at the same _____________ OR ________________

physiological, compositional

Comparing large-framed and small-framed animals on composition can be ______________ to small-framed cattle?

equivalent

Selection for muscle is ___________ related to milk production

inversely

True/False: Selection changes the muscle distribution in beef vs dairy cows

false

Are intact males more or less capable of a greater body weight than castrated males or females?

more

In pigs do intact females mature earlier or later than barrows?

Later, it could be due to estrogen enhancing muscle development

where do intact males have the greatest proportion of muscle?

in the forequarter - secondary sex characteristic

Where do females have the hight propertion of muscle?

in the hindquarter

no balls =

intermediate muscle deposition beween in tact and female

What hormone stimulates epiphyseal plate closure?

a. estrogen

b. testosterone

c. pregnenalone

d. GHSH

a. estrogen this is why intact males tend to be taller than females because their bones grow more before closure

____________ and ____________ are hormonally regulated through sex steroids with dramatic effects

lipogenesis, lipolysis

What environmental factors affect growth?

- stress

- disease

- nutrition

- activity

What are the essential nutrients in a diet?

- amino acids

- carbohydrates

- fatty acids

- vitamins

- minerals

What is the effect of consuming nutrients in excess of maintenance?

allows for growth, production, and reproduction; the balance of nutrients consumed determines the composition of growth

List the nutrient partitioning in order of least to most importance

fat<muscle<placenta/fetus<brain/CNS

organ systems:

• nervous

• circulatory

• respiratory

• digestive

• reproductive

tissues:

• skeleton

• muscle

• adipose

adipose deposition

• mesenteric (located in the abdomen in association with the git)

• perirenal (located around the kidneys

• subcutaneous / intermuscular

• intramuscular

An effect of positive energy balance is

nutrients are plentiful enough for body maintenance as well as growth and fattening

an effect of negatve energy balance

nutrients enough for the maintenance of vital organs and causes weight loss

What is compensatory growth?

refers to an animal's growth after a period of nutritional stress

How are abnormally high growth rates achieved so that nutritionally compromised animals can catch up?

1. Low basal metabolism during nutrient restriction due to decreased visceral weight

2. increased feed intake during realimentation contributes to increased growth

What can influence how much compensatory growth occurs?

Severity of nutrient restriction

can also permanently stunt growth

is dietary protein more important in monogastrics or ruminants? why?

monogastrics, ruminant can use microbial crude protein for some amino acids.

What effect does a diet have on growth if there is sufficient energy but insufficient protein?

increased fat deposition

animals with increased requirements for protein include:

1. genetically selected animals

2. Working animals

3. males

4. Hormone treated for growth enhancement

Dietary energy definition

is the energy required for maintence and growth of new tissue, also increases with size of the animal

Energy required for growth depends on?

genetics, sex class, location on growth curve, hormone treatments

true or false: microorganisms from the environment have a negative effect on the growth of domestic animals

true, the nutrient and energy cost of the immune response required to protect against microbes takes resources away from growth

Breeding for growth and performance has ___________ selected against immunity

inversely

How do we protect animals in production from pathogens ?

low dose antibiotics in their feed can act as growth promoters.

How does stress affect growth?

physical and social stresses significantly affect the hypothalmo-pituitary-adrenal axis

Chronically stressed animlas suffer from elevated concentrations of what hormone that is known to inhibit growth?

glucocorticoids

What are aspects of transportation that can increase stress levels?

temperature/ wind

novel social group

abscence of feed and water

motions

What is specific stress free housing?

raising animals in the same group from weaning to slaughter so they are less stressed, this reduces injury and improved growth

Why does physical activity have an effect on growth?

1. requires more energy to move muscle and supply oxygen

2. burns energy reserves and uses energy for movement instead of growth

How does physical activity impact muscle protein synthesis?

Resistance exercise increases muscle protein synthesis

endurance exercise does not increase muscle protein synthesis but can decrease synthesis if nutrients are insufficient

how does exercise impact bone?

increased activity during development increases bone mass, density, and size

How does exercise impact fat?

fat provides a vital energy substrate for physical activity, especially aerobic exercise

What two hormones does exercise induce the release of?

GH and IGF-1

Gh is secreted in a pulsatile fashion after exercise.

The amount of hormone depends on the exercise intensity

GH release with exercise is greatest in what stage of life?

a. old bitches

b. middleaged bitches

c. newborn bitches

d. adolescent bitches

d. adolescent bitches

What are the characteristics of the innate immune system?

- an ancient system present in all organisms

- exists pre-infection

- exists in broad specificities

- early response to infection

what are the characteristics of the adaptive immune system?

- exists only in vertebrates

- matures on exposure

- is remembered (anamnestic)

Cells associated with the innate immune system are:

- macrophage

- dendritic cell

- mast cell

- granulocytes

Cells associated with adaptive immunity are:

- B cell

- T-cell

- antibodies

Cells associated with both the adaptive and innate immune system are the:

T- cell

natural killer t cell

Where do cells of the immune system come from?

1. Hematopoiesis in the bone marrow (myeloid and lymphoid immune cells)

2. Maturation of lymphocytes occurs in the central lymphoid organs (bone marrow of mammals for B cells, Thymus for T cells)

What is hematopoeisis?

The process that allows for the production of blood cells in red bone marrow

How do T cells mature as they move through the thymus?

Move from the outer cortex in towards the medulla before being pushed out into the blood.

95% of thymocytes do not survive

What are the 2 types of adaptive immune responses?

1. Humoral immunity ( block infections and eliminate extracellular microbes)

2. Cell-mediated immunity (kill the bad cells)

Where do immune responses happen?

1. lymph nodes '

2. spleen

3. cutaneous immune system

4. mucosal immune system