Factors Affecting Animal Growth Flashcards
(28 cards)
Animals grow according to interactions between the _____ they inherit (genotype) and the ________________ _________ they are exposed to.
This relationship can be expressed by the formula…
- Genes, environmental factors
- Genotype + Environment = Phenotype
How would you describe the genotype among species?
Species = different chromosome number and genetic code
How would you describe the genotype among breed?
Breed = same chromosome number but different genetic code
What is the definition of genetics?
Genetics = the science of heredity, which the process of passing along genes from one generation to the next
How did genetic differences come about? What is that the result from?
- Evolution
- Results from a selection of mutations that arise in genes
How does genetics impact the animal industry?
Natural selection and artificial selection!
What are the components of natural selection?
- “Survival of the Fittest”
- If the animal has characteristics to survive, it reproduces
- No human intervention
- Very long term
What are the components of artificial selection?
- Humans control which animals reproduce based on the presence of desirable characteristics
- Short term
What is the definition of a genotype? What are its characteristics?
- Genotype = refers to the unique set of genes that an animal possesses in its genome
- Characteristics:
- an organism’s genetic code
- represented as a special pattern of letters (R/W)
What is the definition of a phenotype? What are its characteristics?
- Phenotype = the outward expression of a genotype (physical)
- Characteristics:
- observable
- physical characteristics
What are heritability values?
Heritability Values = reflects the ability of an animal to pass a particular gene or sets of genes to the next generation.
What does it mean when a heritability value (H)…
H > 0.5
Highly heritable trait (more likely to be passed on to the next generation)
What does it mean when a heritability value (H)…
0.2 > H > 0.5
Moderately heritable trait
What does it mean when a heritability value (H)…
H < 0.2
Low heritable trait
Traits associated with carcass composition are ____________ heritable.
Moderately
What does “species” refer to?
A species refers to organisms capable of interbreeding and producing fertile offspring
__________ ___________ has played an important role in the development of different species or speciation.
Natural selection
Animals have also been selected by human for thousands of years for ____________ ________.
Desirable traits
What is the species-muscle distribution?
It is the relative distribution of muscle that has been altered by selection and/or domestication.
What is some general knowledge about the species-muscle distribution between wild animals and domesticated ruminants?
- Wild species have a greater % of muscle located in the upper portion of their hind legs.
- In wild animals, there is likely a selective advantage to hind-leg muscles to enhance animal speed and agility to escape predators.
- Domesticated ruminants have a greater proportion of muscle weight in abdominal muscles because of the extensive rumen.
Muscles in different species have evolved for _______________ __________.
Specialized functions
How does muscle distribution in domestic cattle (ruminants) compare to other domestic and wild species (pigs)?
- Pigs - increased muscles around the spinal column, which extend the backbone for the footing action of pigs
- Ruminants have increased muscle in front legs to bear weight associated with grazing for long periods of time
How does muscle distribution in domestic cattle (ruminants) compare to other domestic and wild species (wild ruminants)?
- Wild ruminants have increased muscle in their rear legs to travel long distances and escape predators
- Domestic ruminants have increased muscle mass around the rumen to digest the large quantities of feed they consume.
Species is a major determinant in the deposition of ____.
FAT
