Food Animal - Body Composition & Growth Promotion Flashcards
What is a vet’s role in meat production?
Breeding advice
Procedures (eg castration)
Production system & nutrition
Optimising slaughter weight /age
Manipulations (eg growth promotion)
What factors influence composition of meat animals?
Breeds/genotypes
Sex status
Feeding/nutrition
Slaughter at optimum weight
Growth promotion
What are the slaughter ages for different meat animal species?
Pigs = 6 months
Sheep = 5 months - 1+ year
Cattle = 10 months - 3 years (30 months)
Broiler chicken = 42 days
What can be a consequence of breeding a large sire breed to a small dam?
Dystocia (difficult birth)
How does bone/muscle/fat composition compare in young & old animals?
Young = high bone, low muscle, low fat
Old = low bone, high muscle, very high fat
What are the 2 types of maturation in cattle?
Early maturing - put fat on quicker (need sufficient nutrients), but are less heavy (native breeds)
Late maturing - take longer to reach 15-20% fat targeet. but kill out heavier (continental breeds)
What does ‘maturing’ mean in terms of composition & development/growth?
“The likelihood of putting on fat with increasing Energy Density of Diet”
What effect do sex steroids have on maturation in cattle?
Heifers mature earlier than steers, which mature early than bulls
oestrogen vs testosterone
What is the ideal beef carcass classification?
4LR
What does the final live weight determine?
Optimum tissues composition & carcass weight
Affects price of carcass
What is allometry?
The relationship of the growth of one part of an organism to the growth of another part/the growth of the whole organism
What does it mean when the allometric growth coefficient (b) of one part of the animal is <1?
The part is growing slower than the whole body - better cuts of meat
What does it mean when the allometric growth coefficient (b) of one part of the animal is =1?
The part is growing at the same rate as the whole body
What does it mean when the allometric growth coefficient (b) of one part of the animal is >1?
The part is growing faster than the whole body
How does body composition compare between bulls, steers & heifers?
Bulls heavier, leaner & less fatty than steers
Steers heavier, leaner & less fatty than heifers
What is the feed conversion ration (FCR)?
=kg feed / kg weight gained
How can marbling fat in meat be increased?
Feeding low protein diets in the later stages of growth (85-110kg)
Why are growth promoters used?
Economic gain (meat
Clinical therapy (debilitated animals)
What are some methods of growth promotion?
Selective breeding
Optimised husbandry
Alter GIT flora (diet, probiotics, antibiotics)
Affect hormone balance (eg somatotropins, sex steroids)
What is the effect of growth promoters?
Change growth rate
Change feed conversion
Alter body composition
What are some examples of growth promoters?
Growth hormones - bovine somatotropin (bST)
Sex hormones - oestrogens & androgens (behind the ear implant in cattle)
Catecholamines - beta-adrenergic agonists (clenbuterol)
Antimicrobials (affect gut flora)
Porcine somatotropin (PST)
