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
What is the role of fat and insulin?
To promote fat and storage for adipose tissue
What does Hormone Growth Promoting stimulate ?
HGP Stimulate growth
What do HGP revolve around?
Revolve around a 100-day implant thats placed in the animal
Over 400 days how often is there a new implant going in ?
after 100 days a new implant goes in
An animal with HGP improved there growth by what % which is equivalent to how many kilos?
20%
30-40 kilos
What does the hormonal implant ensure?
-efficiency
-transformation
-greater growth deposition
Hypertrophy definition
increase in tissue size
Hyperplasia definition
Increase in muscle/skeletal/fat cells
What is muscle mainly- hypertrophy or hyperplasia ?
hypertrophy
What is fat mainly- hypertrophy or hyperplasia ?
you can have both
Androgen
Make sex hormone
leads to anabolic hormones
Oestrogen
Female sex hormone
leads to anabolic hormone
Anabolic
constructive metabolism eg. adding muscle and bone
Endogenous
produced by the body
Exogenous
derived from outside the body
Xenobiotic
Synthetic hormone
What are hormone implants ?
They are both:
Oestrogenic
Androgenic
What do Hormone Growth Promotant implants form in the animal?
naturally-occurring oestradiol and testosterone or as the equivalent manufactured xenobiotics—zeranol and trenbolone acetate (TBA).
How are hormones from HGP released into the animal?
From a pellet implanted under skin in the animal ear
What is the increased feed conversion efficiency by using HGP’s?
What is the increased carcase leanness using HGP’s?
5-15%
5-8%
Muscle composite definition (ICBF):
Width at withers, loin development, development of hind quarter, thigh width
What do trained inspectors do?
*Trained inspectors evaluate the animals muscularity and skeletal traits by allocating a score on a linear scale (i.e. 1-15)
*Scores are subsequently analysed and can be used to formulate an index –also contribute to sire index
What are the 3 main categories that the animal is inspected ?
-Muscularity
-Skeletal Functional capacity (correctness)
-Fatness
What are the 3 genetic correlations for scoring?
–Around 0.7
*between linear scoring at weaning on farm and Carcass Grade for young bulls (10-15 studies)
–0.8 to 0.9
*between linear scoring and Carcass Grade for young bulls in ProgTstation (Renand1986, Fouilloux, 2000)
–0.3 to 0.6
*between linear scoring and Dressing percentage for young bulls in ProgT station(Fouilloux, 2000
The higher the correlation of the co-efficient between muscle and conformation and meat percentage…
The better the prediction
What s another measurement on how to get muscle and fat measurement ?
Ultrasound: Sound of a frequency above that perceived by the human ear.
*Diagnostic ultrasound lies in the 1-10 MHz region.
How can an ultrasound tell the amount of muscle/fat ?
*Animal tissues have different densities, characterized by differing velocity of propagation through the tissues
*Therefore these differences allow the use of ultrasonics to characterize these tissues for different purposes
What is the scanning procedure for an ultrasound?
Locate area between 12thand 13thrib. Cover skin with echogenic oil –i.e. vegetable oil
The probe is placed along a plane that will be parallel to the area between the 12th and 13th rib
What is used to measure the fat dep’t, muscle depth and muscle area of the animal when getting an ultrasound?
Internal callipers
Physical location –between 12th and 13th rib
Why is a good idea to scan animals when they are young?
Early life measurements of muscle are very good for muscle potential , weather its live animal weight or carcass conformation scanning measures to the animal.
The scanners basic function is to process the image acquired by the transducer and display it on the screen
What are goof indicators of carcass confirmation?
Visual muscular scores
What time of the animals lifetime is almost as efficient as at slaughter?
Weaning time scoring
When was the UE beef classification scheme introduced and what was its two functions?
It has two functions:
1.It provides a common beef classification system for producers (farmers), processors (meat plants) and retailers across the EU.
2.It acts as the basis for payment for different carcase type
*Each beef carcass is inspected and classified using a mechanical grading machine at the weighing scales on the factory slaughter line.
*The carcass is stamped to indicate the appropriate category.
*The factory is obliged to transmit relevant classification data to the farmer
Under EU Legislation, approved abattoirs slaughtering over a minimum ?? number of cattle per week must provide carcass classification
75
Cold carcass weight calculation:
hot weight x 0.98
What is the classification criteria for mandatory beef carcass classification?
- Cold carcass weight
-Sex
-Confirmation
-Fatness
What is the confirmation class describes ?
the development of carcass profiles, in particular the essential parts (round, back and shoulder)
has a major effect on carcase price
What are the five conformation classes are defined:
E,U,R,O,P.
*Grade E-is an exceptional double muscled-type bullock
*Grade U-is a good continental bullock
*Grade R-includes the better Friesian and Hereford crosses
*Grade O-includes the bulk of Irish Friesian cattle
*Grade P-poorly shaped bullocks and cows or underfinished cattle and cows
What is a Fat Class?
*Fat class describes the amount of fat on the outside of the carcase and in the thoracic cavity.
*It is determined using the mechanical grading machine
*Five fat classes are defined, representing by the number 1,2,3,4,5 (may subdivide L or H)
What do the fat classes range from?
This ranges from 1 which denotes least fat to 5 denoting most fat.
*Fat scores 3 and 4L are the most desirable.
*Animals with fat scores 4H may be penalise
1(low)- None to low
2(slight)- Slight, fat most places
3(average)- Except round and shoulder everywhere covered with fat
4(high)-More cover than 3 , fat seams prominent on round
5(vhigh)-Entirely covered, round covered so seams no longer visible
What words do you use to describe muscle groups?
Convex
Concave
What is the minimum and maximum fat cover due to chilling?
To meet market value what are crucially important?
minimum= 2+
maximum= 4-
Weight and fat cover
Beef carcasses have a meal yield of generally what %?
70%
Cute from what area are 2 times the value ?
Ribes and start of hind quarter (200)
Medium value cuts price
100
Low medium value cuts :
80
What does the price of meat depend on?
the tenderness
Where are prime cuts from?
Round
Sirloin
Striploin
Rib Roast
What do integrated results in the Irish genetic evaluation generate?
EBV’s
Whats the challenge with “retails power”
Retailers and Consumers are the drivers of “specification
To maximise revenue what is the ideal carcass weight range?
280-400kg
Whats the average carcass weight from Irish steers?
338.3kg
What % of steers and what % of heifers fall into the combines confirmation classes of O and R?
87% steers
91% heifers
85% of young bulls had carcass conformation scores of U and R what does this show?
shows that they are mainly late-maturing breed crosses
What % of steers and what % of heifers were in fat classes 3 and 4?
87% steers
85% heifers
The fact that 40% of these young bulls have fat scores of 2 what does it indicate?
indicates the potential to carry them to heavier carcass weights
Whats the average confirmation class from irish steers?
R, clostly followed by O
this accounts for 85% of classes
What is fatness dominated by, whats the average fat classes?
Average fat classes 3-4 (94%)
Why is the average confirmation class R and then O?
High percentage of our beef comes from Friesian crosses and many of our beef animals have half Friesian/Holstein breeding in them so even Charolais cross animals can fall into the ‘O’ category for conformation
What has the suckler herd increased the use of?
An increased use of Holstein will have what sort of an impact on beef market?
Suckler herd increased use of continental bulls should lead to an improvement in conformation
But increased use of Holstein will have a negative impact on the beef merit of the Friesian breed
What breed is the best and worst in terms of confirmation?
Best- Continental
Worst - Frisians
What sex is the best and what age ?
What are the worst?
Young bulls (best), then steers, then heifers and the cows (worst)
How much kg’s will improve confirmation by 1 score?
70kg (105kg live weight) from an O to and R
What has a great effect on conformation when it comes to nutrition level?
Severe restriction during the store period has a greater effect on confirmation
What is the pricing grid developed by?
What is it based on?
What can meat yield vary from % of carcass weight ?
What does meat yield increase with?
*Developed from carcase dissection trials.
*Based on recorded meat yields related to conformation and fatness grading.
*Meat yield can vary from 60% to 75% of carca/wt
*Meat yield increases with increased conformation
What is carcase value calculated as a sum of?
Commercial value of individual meat cuts
What did the development of pricing grid propose?
Proposed a pricing system based on meat yield and market outlet would result in a price improvement for animals of good conformation
Was the 5 point grid accurate?
Was the 15 point classification accurate?
5 Point Grid did not adequately describe carcases.
15 Point Classification is accurate & efficient predictor of meat, fat & bone
How many meat cuts are in the hind quarter?
13 meat cuts
How many meat cuts are in the fore-quarter?
11 meat cuts
What are the steps to a carcass dissection? 4 steps
*Bones removed from cuts (where applicable) & scraped clean
*All visible fat removed from each cut
*Weight of each cut& total weight of fat trim, lean trim & bone recorded for hind-quarter & fore-quarter
*Lean trim added to meat cuts to give meat yield
How do you get the carcass value sum?
sum of wholesale values of individual meat cuts & lean trim with a small deduction for bone
What needs to be reviewed?
Carcass pricing structure
Emphasis on breeding goals could be placed on improving carcass meat yield and distribution in addition to meeting the higher export market
Study Recommendations :
1-Conformation & fatness grading on 15 point scale.
2-Price differential on conformation of 6c / kg on 15 point scale.
3-Deduction of 2.5 c / kg on 15 point scale for fat score above 3+
In Ireland what payment system do we have?
What can we predict from this?
15-point grid on market value
Methane yield on any animal in Ireland
Are carcass classification scores (15-point scale) relatively accurate predictors of carcass meat, fat and bone proportions?
yes
When was the mechanical grading system introduced?
2004
*All systems use Video Image Analysis (VIA)
*Cameras capture images
*Image analysis software extracts data-dimensions, areas, volumes, angles etc.
*Measure curvature and 3D shape
*Data analysed to predict classification
*Can also predict saleable yield etc
From trials completed by the mechanical grading system what where the findings?
its robust 91-97% of carcasses are graded in their letter score; fat is where the issue comes in
At best 70-80% were correct for fat scores
Which means 20-30% weren’t values properly with meat
What is the ICBF Sensory Analysis ?
Ranks meat from 1-9
anything above 6 is a good grade for meat quality
In ireland what do we pay for?
weight and meat
what 2 countries pay for meat quality?
US
Australia
what does current IBD chip V3 (17K) contain?
Contains meat quality related genes: Calpain1, Calpastain, Myostatin
In the genomic ere what is king
Phenotypes
Is EUROP grading related to palatability?
unrelated to palatability
In Australia what is the approach for quality grading?
all elements are given a score based on what is implemented - critical control points throughout the whole chain in Australia
The score thats good is 4-5, its not cut specific its all elements of the supply chain
