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

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natural selection
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
Artificial Selection
  • HUMANS control which organisms pass their GENETIC information (reproduce)
phenotype vs genotype
Phenotype VS. Genotype
  • Observable PHYSICAL characteristic


  • An organism’s GENETIC code (genes)

Genotype=BB or Bb

(Pattern of letters representing the genes for color)



terms in genetics
Terms in Genetics
  • Genes: Factor that control traits
  • Alleles: Different forms of genes
    • Paired (AA or Aa) & represented by a letter
terms in genetics1
Terms in Genetics
  • Adaptability: The ability of a BREED to become SUITABLE to conditions
terms in genetics2
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 genetics3
Terms in Genetics
  • Species: a group of similar organisms that can produce fertile offspring



terms in genetics4
Terms in Genetics
  • Breed: animals having a common ORIGIN and CHARACTERISTICS different from animals within the same SPECIES


Quarter Horse






terms in genetics5
Terms in Genetics
  • Purebred
    • Individuals within a BREED
    • Must have all of the required CHARACTERISTICS
    • Recorded PEDIGREE
terms in genetics6
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 genetics7
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
Punnet Square
  • A method of calculating the chances of inheriting a specific trait



  • Holstein Cattle
  • Black & White
  • Bb
  • Red & White
  • bb



your turn
Your Turn!
  • Solve the genetic problems using a Punnet Square
breeding systems1
Breeding Systems

How to design a breeding system:

  • Set Goals
  • Choose measurable traits
  • Select parents according to goals
breeding systems2
Breeding Systems

Traits to breed for:


Coat Color

Weaning weight


Speed Index

# Born Alive

Birth Weight

breeding systems3
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 systems4
Breeding Systems


  • Breed only animals that are purebred with registration papers
  • Goal: To produce high quality animals to sell as breeding stock
breeding systems5
Breeding Systems

Grading Up

  • 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 systems6
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 systems7
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 systems8
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
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 systems9
Breeding Systems

Line Breeding

  • 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
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!