Animal Growth and Efficiency of Growth Factors - Exam 4

when food is plentiful, what 3 things does the body recieve nutrients for

1. maintenence

2. growth

3. fattening

what food is limited, what 3 tissues are affected

1. fat and muscle

2. bone

3. organs

how has feed efficiency changed in the past 50 years

feed to gain ratio has decreased

what are the 6 essential nutrients

• carbohydrates

• protein

• fats

• minerals

• vitamins

• water

what are carbohydrates

• a nutrient that provides the cheapest source of calories

• supplied by corn, silage, and hay.

what are proteins

Nutrient comprised of amino acids

what are fats (lipids)

• provide energy

• produced in the liver and absorbed from the diet.

what is water

the most limiting nutrient

what are minerals

inorganic elements established as necessary for life and bodily balance

what are vitamins

organic compounds that are needed by the body in very small amounts

what do changes in environment cause

reduced feed efficiency (may need to consume more)

what are hormones

a chemical substance produced in one area of the body that is transported in the blood to another area where it influences the activity of a target organ.

what are 4 groups of hormones

• polypeptide

• steroid

• tyrosine-derived

• prostaglandins

what are 6 types of polypeptide hormones

1. growth hormone

2. insulin

3. glucagon

4. leptin

5. cholecytokinin

6. opiates

what are growth hormones

• released from the anterior pituitary gland

• stimulates production of insulin-like growth factors

what is insulin

• secreted from the pancreas when glucose is high

• regulates glucose

what is glucagon

• secreted fron the pancreas when glucose is low

• move glucose and fatty acids to be stored

what is leptin

• produced by adipose tissue

• sends signals to the hypothalamus to

  • decrease food intake

  • increase energy use

what is cholecystokinin

• brain and intestinal polypeptide

• reduces feed intake

what are opiates

brain polypeptides that stimulate feed intake

what are 3 steroid hormones

1. testosterone

2. estradiol-17B

3. glucocorticoids

what is testosterone

• produced by testes

• increases protein accretion

what is estradiol-17B

• produced in the overies

• increases protein synthesis

what are glucocorticoidsI

• secreted by the adrenal cortec

• “stress hormones'“

• suppress immune function

  • (stressed animals get sicker)

what are tyrosine derived hormones

• produced and secreted by thyroid gland

• they maintain metabolic rate in animals

what is the main group of tyrosine-derived hormones

catecholamines

what are 2 types of catecholamines

1. epinephrine

2. norepinephrine

what is epinephrine

• “flight or flight”

• raises heart rate

what is norepinephrine

raises blood pressure

what does cattle eat most of their lives

grass

when do cattle recieve more grain

for the final 100-140 days before harvest

what 4 things does grain feed do for cattle

• increases growth

• increases marbling

• more beef in less time

• more tenderness

what 5 things does grass feed do for cattle

• slower growing

• less beef in more time

• less fat

• costs more

• more antioxidants

what is somatoptropin

a growth hormone

what is somatotrophin in pigs

• impractical

• naturally produced in anterior pituitary gland

• decreases fat depth and carcass fat

what is bovine somatotropin (bST)

• when injected into dairy cows it increases milk production

• when injected into beef cattle it decreases fat depth and yield + quality grades

what does the growth hormone releasing hormone (GHRH) do

causes release of GH from anterior pituitary gland

what 4 things does the CCK (cholecystokinin) immunization do

• increases feed intale

• increases growth rate

• increases carcass protein

• increases lipid content

what are beta-adrenergic agonists

• they are medications used to relax smooth muscles

• increase protein synthesis and accretion

• increase lipolysis

what are paylean beta-adrenergic agonists

• approved for use in swine

• pigs may be more suceptible to stress

what are optaflex beta-adrenergic agonists

• approved for use in cattle

what are zilmax beta-adrenergic agonists

• approved for use in cattle

• increases live and carcass weights

• improves dressing percentage

what are lubabegron beta-adrenergic agonists

• in cattle

• labeled to remove ammonia gas emissions

what are steroid implants

• used to greatly improve growth and efficiency

  • more aggressive implants (like testosterone) may alter tenderness and marbling

what does all food contain

hormones

what hormones are not approved for use in pork and poultry

steroid hormones

what are antibiotics used for

to treat and preveny illness

what are ionophores

• a class of antibiotics used to modify rumen microflora

  • helps move ions across cell membrane

  • improves feed efficiency

what is the myostatin gene

• causes increase in muscle hypertrophy

• results in “double muscling” (lots of muscle)

• rarely seen in humans

what is the callipyge gene

• muscular hypertrophy in sheep

• increased toughness in meat

• ewes have trouble lambing