Muscle Growth and Carcass Development Flashcards
Whats the objective of growth and carcass development? (3)
-a high proportion of lean tissue
-minimum bone
-only as much fat as the market demands
When the animal is fed Adlib what do we see with growth?
What happens when the animal is mature size?
Linear
Starts to drop off as mature size is approached
What are influenced by breed and sex?
Growth rate and point of decline
(Charolais> Angus, Bulls > Steers > Heifers)
What has a crucial influence on growth rate and in most systems,
Why is growth usually not linear?
What sort of growth plays an important role when this occurs?
Level of feeding
Growth is non-linear due to variations in supply and quality of feed
Compensatory growth
When does Compensatory growth occur?
It occurs when cattle are underfed in winter but grow faster when they are unrestricted to reach mature size at the same time as cattle fed ad libitum over winter
What sort of animals has complete linear growth?
Pigs and Poultry
Ruminants dont
When is most growth complete in cattle?
Birth to 15 months of age
After an animal increases its growth rate after a year what growth becomes a priority?
Muscle growth and then following this fat deposition- The tissue changes (muscle growth)
When maximising lean your only putting out as much fat as the market desires when it pleatues what happens?
thats when you slaughter because growth rate and feed conversion efficiency is very important
FCE=
DMI/Gain
-You want your growth to suppress your feed input costs for your farm to be profitable
Is FCE efficient from birth to slaughter?
NO
How much will a 750kg animal eat of its body weight ?
1-2%
While the animal gets older, the GR gets slower and the FCR changes due to….
The animal having fewer nutrients available to deposit towards growth as it has bigger maintaince requirements
What optimises production profit and lean meat yield ?
Selecting stock at the correct growth stage optimises production profit and lean meat yield
Where is Energy intake is first directed to?
bone growth, then lean muscle (meat)
Once bone and muscle is formed what happens to energy intake?
The animal stores energy as fat
What does excess fat require?
Excess fat requires up to six times the energy needed to deposit lean
What is the order in which cattle put on fat?
1- Skeletal (Bone)
2- Muscle
3- Fat
Until it reaches maturity and then it goes from muscle to fat deposition
What are the 2 main principles to carcass development?
- Bone achieves its maximum growth first, followed by muscle and then fat
- Partition of nutrients goes first to bone and muscle, over fat
What is the order that fat is deposited in the carcase?
1-Kidney channel fat
2-IntERmuscular fat
3-Subcutfat
4-IntRAmuscular fat
What are above market requirements have a detrimental effect in carcass quality?
KCF, IntERmuscular fat and Subcut fat
What has beneficial effects on meat quality?
IntRAmuscular or marbling fat
1-At birth what tissue is the heaviest and gains faster than other tissues?
2-As the animal approaches maturity what is there an increase in ?
1-At birth muscle is the heaviest tissue and it gain faster than other tissues during juvenile growth.
2-Increase in muscle: bone ratio
As the animal approaches maturity a fattening phase takes over
What is the order that the development of muscle takes place in?
Developed at Birth:
1- Limbs
2- Tongue
3- Intercoastal muscles for breathing
After this :
4- Upper limb muscle
5- Spinal column development
Last muscle group to mature:
6- Abdominal wall muscles
What is the last muscle group to mature ?
is the abdominal wall muscles
Does breed and sex have an impact on carcass composition?
Substantial impact on carcass composition
When does the main effects of breed get underway?
Fattening phase
What breed animals are early maturing ?
Angus / Hereford : early fattening phase= early maturing
What animals are late maturing breed animals?
Limousin/Charolais: Late fattening phase = Late maturing
What breeds have a better muscle to bone ratio?
( Limousin/Angus > Charolais)
What does the effect of sex mainly influence ?
The amount of lean tissue , driven by androgens
Bulls> Steers> Heifers
Slaughter at the same age as equivalent steers, bulls produce carcase at least what % heavier and yet are still leaner
10% heavier yet are still leaner
Bulls have a high GW of what % more and percent kill out than heifers?
30%
What does KO% equal to?
High carcass yield and economic value
What is one of the key carcass intentions?
Kill out
What is the kill out%?
The weigh of the animals carcass minus the weight of the :
-Hide/Skin - Head - Feet - Stomachs and Intestines
Fill out % formula:
Cold carcass weight/ Unfasted final weight x 100%
What does killout % typically range from ?
50-60%
What have effected kill out %? (4)
- Heat of carcass
-2% higher KO% when carcase is hot vs cold - Dressing Specification
-2% lower if KCF is removed - Gut fill
- Breed
-Continentals > KO% than traditional breed
Breed Effects on Carcass weight :
1-Herford
2-Limousine
3-Simmental
4-Charolais
1- 100kg
2- 100kg
3- 105kg
4- 107kg
What animal has much better meat yield potential that traditional?
Continental- high fat deposition
Whats the % weight difference between chaorloais and traditional breeds?
5-7% difference in weight
When you compare continental breeds with traditional breeds is there a big difference with LWG?
Not a massive difference
What are the 3 key regions that interplay when it comes to hormones that control growth:
- Brain
- Gut
- Liver
What does the brain, gut and liver use?
Stimulatory effects - a key driver of growth in an animals is the growth hormone (IGF1)
What is the growth hormone and what does it do?
IGF1
Drives all growth
What does the growth hormones generally work on?
What is the No1 anabolic growth promotor in the animals body?
Works on the liver to release IGF1
IGF1
If the animal is growing well…
It will have high IGF1 present - its a key stimulator
What does IGF1 do in the body? (4)
1- Enhances muscle growth
2- Stimulates muscle cell proliferation
3- Drives cellular growth
4- Has impact locally in the tissue and systemically throughout the body from the liver
What can impact IGF1?
Diet
Whats the key role of insulin in the animals body?
Does insulin have a positive or negative effect on IGF1?
What is INSULINS key role in growth?
Glucose uptake by cells
Insulin has a positive effect on IGF1
Insulins key role in growth is fat deposition , laying down fat and inhibiting the IGF1 hormone.
Can insulin shut down the IGF1 hormone?
yes
What has a key interplay with growth:
Stress and immunity- animals cant bet stressed when they are growing
What happens when animals are stressed?
High cortisol levels - weakening of the immune system - this is a stress response
This inhibits ACHT and a reduction in growth hormone
Stress indirectly and directly impacts the animals growth
If you have a stress challenge,,,
You have an immune challenge which means you have a muscle and fat deposition challenge
Whats the key role of the growth hormone?
Actions through IGF1
Key anabolic