Growth Physiology
Nutrition
Proper nutrition to control fat deposition
Key for producing good quality products
Can bu used for compensatory growth if managed correctly
Increased growth and efficiency following a period of nutrient restriction
Effects all stages of development
Can be used to influence time to puberty and/or maturation
Genes
Determines maximum size
Genotype and phenotype
Genotype: potential of animal
Phenotype: expression of that potential
Control growth at a cellular level
Heritability
Likelihood of a trait to be passed on
Selection for favorable traits such as size and early maturity
Hormones
Hypothalamus
Restless releasing hormones to act on the pituitary or thyroid
GHRH for GnRh release from AP
TRH fro TSH release to act on the thyroid
Anterior Pituitary
Prolactin secretion for mammary secretion
Release of ACTH for glucocorticoid release
Stimulated to release GH to a variety of tissues to stimulate growth
Growth
Post pubertal development
Muscle deposition slows
Continued fat deposition. Often to increase marbling (intramuscular fat)
Depends on diet
Bone elongation ceases
Body weight continues to increase
Prepubertal Development
Bone growth
extension of growth plate
ossification of cartilage
Muscle growth
Muscle fibers increase in length and diameter
Fat deposition
Abdominal, subcutaneous, intermuscular and intramuscular
Prenatal growth and development
Zygote develops in the uterus
All tissues and organs develop from 3 germ layers
Endoderm
Lining of digestive tract, pancreas, and lungs,
Ectoderm
Nervous system
Mesoderm
Bones and Muscle
Hatching and rapid growth to maturity
Bone elongation
Muscle growth
Environment
Determines outcome
Influenced by temperature, humidity, nutrition, etc.
Phenotype may be effected by the environment
Development
Functional Maturation
Change in organ shape
Change in organ form
Deterioration with age
poor reproductive function
Less elastic collagen
Wrinkles
Blood vessels may collapse or bust
Decrease in muscle strength and speed
Cellular differentiation
Cells differentiate to perform specific functions