Ch. 1 Flashcards
What is genetics?
the scientific study of how genes control the characteristics of plants and animals
What is animal breeding?
controlled propagation of domestic animals in order to improve desirable qualities
What is animal breeding (2nd defintition)
the process by which young animals, birds, etc., are produced by their parents. The activity of keeping and caring for animals or plants in order to produce more animals or plants of a particular kind.
Why sex?
Perpetuation of the species and genetic recombination
trait
an observable or measurable characteristic of an individual
phenotype
an observed category or measured level of performance for a trait in an individual
Genotype
the genetic make-up of an individual
equation
P=G+E
Environmental effects
are non-genetic factors that affect performance (phenotype)
Exs. of environmental effects
physical environment
fixed resources and management
economics
common physical environmental effectors of livestock phenotypes
temp., humidity, level of nutrition, disease exposure, hygiene, elevation, light exposure
fixed resources
size of farm, facilities, ability to grow supplemental feed, available labor
management
level of supplemental feeding, health care, culling rates
cost of inputs
feed, labor, supplies, interest rates
price of outputs
animals, meat, milk, eggs
interactions
components within animal systems will interact
ex. herd health program, pathogens, cost of vaccines, natural resistance to pathogen (genotype)
genotype by environment interaction
occur when the difference in performance between multiple genotypes changes from environment to environment.
From a breeding standpoint, the most revealing interaction.
seedstock producers
elite breeders and multipliers. traditionally purebreds (registered)
Commercial producers
Commondities (milk, meat, eggs, wool hides, etc.) for consumption.
Terminal crosses common.
