Obj: Discuss reproductive management terms used in the animal science industry.

Natural Selection  No human intervention  Survival of the fittest  Based on an organism’s ability to SURVIVE and pass on its GENETIC information to its offspring

Artificial Selection  HUMANS control which organisms pass their GENETIC information (reproduce)

Phenotype VS. Genotype PHENOTYPE GENOTYPE  Observable PHYSICAL characteristic Phenotype=Black  An organism’s GENETIC code (genes) Genotype=BB or Bb (Pattern of letters representing the genes for color)

Terms in Genetics  Genes: Factor that control traits  Alleles: Different forms of genes Paired (AA or Aa) & represented by a letter

Terms in Genetics  Adaptability: The ability of a BREED to become SUITABLE to conditions

Terms in Genetics  Type: a group of ANIMALS that are grouped together according to the PRODUCTS they produce Examples: Beef type cattle, Dairy type cattle,

Terms in Genetics  Species: a group of similar organisms that can produce fertile offspring CanineEquine

Terms in Genetics  Breed: animals having a common ORIGIN and CHARACTERISTICS different from animals within the same SPECIES Labrador Chihuahua Australian Shepard Quarter Horse Clydesdale Arabian

Terms in Genetics  Purebred Individuals within a BREED Must have all of the required CHARACTERISTICS Recorded PEDIGREE

Terms in Genetics  Dominant alleles Represented by capital letters This trait is the one expressed  Recessive alleles Represented in lower case letters Only expressed if both parents donate recessive genes for a trait

Terms in Genetics  Homozygous: Alleles express the same trait type (BB dominate) OR (bb recessive)  Heterozygous: Two different alleles for the same trait (Bb)

Punnet Square  A method of calculating the chances of inheriting a specific trait Bbbb Bbbb B b b b Holstein Cattle Black & White Bb Red & White bb

Your Turn!  Solve the genetic problems using a Punnet Square

Breeding Systems How to design a breeding system: 1. Set Goals 2. Choose measurable traits 3. Select parents according to goals

Breeding Systems Traits to breed for:

Breeding Systems How to measure traits  Qualitative Traits Controlled by SINGLE pair of genes Not altered by environment Example: Coat Color  Quantitative Traits Controlled by SEVERAL pair of genes Can be altered by environment Examples: Weight gain, growth rate, backfat depth, etc.

Breeding Systems  Breed only animals that are purebred with registration papers  Goal: To produce high quality animals to sell as breeding stock

Breeding Systems  Breed purebred sires to commercial females  Replacement females are kept and bred back to the purebred sire  GOAL: To produce progeny resembling the purebred sire and SAVE $$ Most common in the livestock industry!!!

Breeding Systems  The mating of animals of different breeds  GOAL: To take advantage of hybrid vigor and hopefully have offspring inherit good traits of both parents Hybrid vigor: crossbred offspring exceeds the average of the two parental breeds

Breeding Systems  Mating of related individuals- sires and dams that share at least one ancestor  Necessary when creating new breeds or when you need to isolate genes for chosen traits  GOAL: Isolate unique/rare genes and perpetuate them

Breeding Systems  Increase uniformity of offspring  Could result in the surfacing of deleterious genes  Reduction in performance because what use to be hidden by recessive genes is now expressed Deleterious gene: Could cause undesirable effects on an individual’s viability, productivity and/or economic value

Examples of Deleterious Genes “Lethal White” gene in Paints:  Foals carried full term  All white or mostly white coats  Look & seem fine at birth  BUT colon is non functioning. They show symptoms of colic and die within 48 hours.  Gene is carried on the overo color gene  Recessive gene was perpetuated as overo paints were bred

Breeding Systems  A minor form of inbreeding with the attempt to keep a relationship to a highly regarded ancestor Elite Sire X Half Sisters Son of Elite Sire X Daughter of above Females Grandsire X Granddaughters

Create Your Own Breed  Every breed of animal that we are familiar with today was once developed through generations of selective breeding to isolate specific traits unique to the breed.  You will now choose traits you like in a certain species to create you own new breed!