Growth and Carcass Composition Flashcards by Sydney H

skeletal muscle

contractile tissue
long multinucleated muscle cells
colour related to Mg concentration

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80% of muscle cell volume is taken up by

myofibrils

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muscle fiber number is ________ at birth

fixed

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how does postnatal muscle growth occur

hypertrophy of muscle fibers
90% of skeletal muscle

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nuclei in muscle fibers are not able to divide so how does hypertrophy occur

satellite cells

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satellite cells work by

supplying DNA to individual muscle fibers for growth

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what are satellite cells

mononucleated cells located between basal lamina and sarcolemma of the fiber

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can satellite cells divide

yes

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muscle satellite cell numbers

decease in number during post natal growth
require stimulation to proliferate (exercise or injury)

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how is satellite cell proliferation regulated

family of myogenic regulatory factors (myostatin and IGF-1)

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how do double muscled cattle happen

gene mutation that limits myostatin expression
myostatin should limit muscle fibers present at birth
therefore extra muscle fibers present at birth
hyperplasia of muscle cells
hypoplasia of fat cells

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2 types of adipose tissue

white: energy store, slow mobilization
brown: rapid metabolism for fast energy

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what makes adipocytes mature

fibroblasts and vascular cells

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brown adipose

small cells with abundant cytoplasm
many mitochondria
fat stored as small droplets in cytoplasm
generate heat via non shivering thermogenesis

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white adipose

single round cells with nucleus
restricted cytoplasm
interior of cell fills with triglyceride
storage vesicle of fat

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adipose hyperplasia vs hypertrophy

unlike muscles
adipocytes reach max size
can create more adipocytes though (HYPERPLASIA)

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SC vs IM adipocyets

SC are larger wit greater volume
IM are more numerous

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4 major adipose depots

internal or body cavity fat
external or subcutaneous fat
inter muscular fat
intramuscular fat

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internal or body cavity fat locations

kidney
stomach
intestinal
pelvic or channel

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intermuscular fat

between muscles
seam fat

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intramuscular fat

marbling
within muscle (around and between fibers)
functions as localized energy source

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4 growth stages and which body tissue is most abundant

conception
birth- bone
puberty- muscle
maturity- fat

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order of fat deposition
why is this important in feedlot

perirenal
intermuscular
subcutaneous
intramuscular
since this is fairly set you need to fill 3 previous steps before you can get marbling

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as an animal grows

DMI/d increased
CP requirement decreases
calcium “
phos “
energy requirement increases

what food sources do acetate and glucose come from

acetate- fermentation of carbs glucose- VFA routes to liver and converted to glucose

frame score range and how are they calcualted

2-9 from hip height and age

frame size and fat relationship

at the same body weight a larger frame animal will have lower fat you need to finish to fat content not BW because of this

in general large frame cattle will (6)

grow faster deposit more muscle over a longer time frame older and heavier at puberty fatten at heavier weight heavier mature weights heavier at birth (longer gestation)

what is compensatory growth

ability of animal to recover growth after periods of underfeeding that restricted growth often associated with higher than normal growth rates

outcomes of compensatory growth

full compensation partial compensation no compensation

why would a feedlot consider compensatory growth

have a large opportunity for growth without putting a whole bunch into the animal

factors affecting compensatory growth

age of animal during restriction severity of restriction duration of restriction quality of feed post restriction

carcass definition

portion of the animal's body that remains following slaughter and the dressings out procedure of the abattoir

parts of body to be removed

hide (NOT IN PIGS) GI tract and contents viscera fat organs feet head blood

dressing % =

carcass weight / live weight x 100

hot yield is

dressing % calculated using hot carcass weight following slaughter

cold yield is

dressing % calculated using weight morning after slaughter`

steer and heifer dressing percentage goal

55-62%

cow dressing percentage

40-50%

lamb dressing percentage

52-54%

pigs dressing percentage why is it different

75-80% hide stays on

factors affecting live weight and carcass weight

cattle age and class diet (shrink and organ size) transport time

shrink will be worst

loading in afternoon hot ambient longer time on truck

carcass weight vs quality

weight is economically important quality is the function of carcass composition

most tender cuts

tenderloin rib loin sirloin

least tender cuts

walking muscles round

carcass is composed of 3 major tissues

bone muscle fat

carcass value depends on (3)

amount of each tissue type proportion of each tissue type distribution of each tissue type

functions of carcass bone

primary support for issues and organs protection for organs mechanical levers operated by muscles and tendons immune system, RBC formation

proportion of bone in swine cattle and sheep

swine 9-11% cattle 16-17% sheep 19-20%

factors influencing proportion of muscle in carcass

stage of growth/age- inverse relationship with fat content diet genetic potential for growth- breed and gender

gross composition of muscle

fat tissue (intramuscular) connective tissue muscle tissue

gross morphology of muscle

1- muscle- epimysium connective tissue 2- muscle bundle- perimysium connective tissue 3- muscle fiber- endomysium connective tissue

functions of connective tissue

support muscle fibers, prevent over extension and damage to contractile elements provides framework for vascular and nervous systems

3 categories of connective tissue

epimysium perimysium endomysium

collagen

major component of connective tissue (95%) tough with little elasticity (inextensible) negative association with tenderness converts to gelatin under moist heat

as animal ages cross links in tropocollagen strands of collagen become _________ making them ____

non reducible tougher

elastic fibers

<5% of connective tissue negative association with tenderness walls of vessels, ligaments, skin minor muscle component

proportion of fat in a carcass is influenced by

stage of growth/age level of nutrition- high plane=early onset=rapid fattening other- sex, frame size, breed, management