1. Traditional (historical) Breeding
Gradual (but dramatic) genetic change over long time periods through observation and selective breeding (Instinctive Selection)

2. Modern Breeding
Economic pressures for rapid genetic change over short periods via optimal utilization of available breeding tools
Co-improvement of technologies on nutrition, management crossbreeding and genetic improvement

3. What Animal Breeding is?
Where to go? Breeding Goal
How to get there? Quantitative Genetics
Selection Theory
Genetic Evaluation
Crossing Theory
Reproductive Technology
Tools
Getting There Implementation

4. What tools are available?
Visual assessment

5. What tools are available?
Visual assessment
Pedigree Information

6. What tools are available?
Visual assessment
Pedigree Information
Performance information
- simple, traditional measures
Ex: growth, fertility, calving easy

7. What tools are available?
Visual assessment
Pedigree Information
Performance information
- simple, traditional measures
Ex: growth, fertility, calving easy
-Advanced measures
Ex: Ultrasound (IMF%, RE area, feed intake)

8. Basic Genetics and Cytogenetics
Inheritance: May be defined as a tendency of parents to generate offspring with similar characteristics.
Variation: May be defined as every environmental or germinal differences between organisms related by ascendance. It can be due differences on the environment (nongenetic) or on the genotypes (genetic)

9. Some Definitions
Gene: The basic unit of heredity consisting of a DNA sequence at a specific location on a chromosome
DNA: Deoxyribonucleic acid, the molecule that forms the genetic code
Chromosome: One of a number of long strands of DNA and associated proteins present in the nucleus of every cell
Homolog: One of a pair of chromosome having corresponding loci
Locus: The specific location of a gene on a chromosome
Allele: An alternative form of a gene
Multiple alleles: More than two possible alleles at a locus
Nucleus: contains bodies known as chromosomes which carry the primary material involved in heredity (genes). Genes consist of deoxyribonucleic acid (DNA).
Cytoplasm: includes the cell mass other than the nucleus. The amount of cytoplasm varies among cell types. Sperm cells have essentially none. The entire yolk of an unfertilized hen's egg is cytoplasm. Contains organelles with special functions:
Golgi apparatus: involved in carbohydrate synthesis.
Ribosomes: involved in protein synthesis.
Mitochondria: generate energy for cell functions.
The cytoplasm contains a relatively small amount of genetic material (called cytoplasmic DNA), primarily in the mitochondria. Mitochondrial DNA in mammals consists of a single circular piece of DNA.
Inheritance of mitochondrial genes does not follow Mendelian laws, because the material (genes) does not exist in pairs.

10. Some Definitions
Genotype: The combination of genes at a single locus or at a number of loci*
Homozygote: A one-locus genotype containing functionally identical genes
Heterozygote: A one-locus genotype containing functionally different genes
Segregation: The separation of the homolog chromosome during meiosis
Germ Cell or Gamete: A sex cell – a spermatozoid (sperm) or ovule (egg)
Meiosis: The process of germ cell formation
Mitosis: The process of cell multiplication:
Embryo: An organism I the early stages of development in the shell (birds) or uterus (mammal)
Nucleus: contains bodies known as chromosomes which carry the primary material involved in heredity (genes). Genes consist of deoxyribonucleic acid (DNA).
Cytoplasm: includes the cell mass other than the nucleus. The amount of cytoplasm varies among cell types. Sperm cells have essentially none. The entire yolk of an unfertilized hen's egg is cytoplasm. Contains organelles with special functions:
Golgi apparatus: involved in carbohydrate synthesis.
Ribosomes: involved in protein synthesis.
Mitochondria: generate energy for cell functions.
The cytoplasm contains a relatively small amount of genetic material (called cytoplasmic DNA), primarily in the mitochondria. Mitochondrial DNA in mammals consists of a single circular piece of DNA.
Inheritance of mitochondrial genes does not follow Mendelian laws, because the material (genes) does not exist in pairs.

11. Cells are classified into two types
1. Gametes (sex cells)
sperm cell
ovum or egg
1n chromosome number at maturity
2. Somatic cells (non-sex cells)
2n chromosome number at maturity

12. Chromosomes Located in nucleus of cell.
Each is a huge molecule, consisting of DNA and proteins called histones.
Occur in pairs in somatic cells, but as singles in gametes. E.g., in humans:
Somatic cells have 46 chromosomes (23 pairs).
Gametes have 23 chromosomes.
2n = 46, 1n = 23
The two chromosomes of a given pair are said to be homologous to one another.
Chromosomes:
- thread-like bodies in the nucleus, composed of deoxyribonucleic acid (DNA) and proteins called histones. The DNA portion of the chromosome is the primary hereditary material.
- present in pairs in somatic cells of higher animals. The two chromosomes of the same pair are called homologous chromosomes. Each somatic cell contains one pair of chromosomes involved in determination of sex, called sex chromosomes (XX or XY in mammals). Non-sex chromosomes are called autosomes.

13. Chromosomes X and Y are known as sex chromosomes; others as autosomes.
Female:
somatic cell contains X X
ovum contains X
Male:
somatic cell contains XY
sperm contains X or Y
Genes determining gender are located on the sex chromosomes
Humans have 46 chromosomes (2n = diploid number = 46); 44 autosomes and 2 sex chromosomes; 23 pairs of chromosomes (1n = haploid = 23).
Sex cells, called gametes (sperm and ova), contain only one member of each pair ("half pairs") of chromosomes, or 1n, number of chromosomes. When an ovum is fertilized by a sperm cell, the chromosome number of the resulting zygote is 2n.

14. Chromosome Number for Selected Species (2n)

15. Chromosomes- Chromatin and DNA
DNA – Genetic Code for Protein Synthesis DNA – Polymer of Nucleotide Bases Nucleotide Sequence –Amino acid Sequence of the Protein (Shape and function)
Chromosomes- Chromatin and DNA

16. I - DNA is the Genetic Code for Protein Synthesis Proteins can be Enzymes, Hormones, Transcription Factors, Structural, etc. Nucleotide Sequence –Amino acid Sequence of the Protein Shape Determine the function/effect)

17. Genetic Code for Protein Synthesis

18. DNA Replication - Complementary Bases

19. What are alleles?
Alternative gene forms that occupy the same locus on homologous chromosomes.
e.g., black (B) / red (b) coat color gene in cattle B
___._____________ b
Can have at most 2 alleles in an individual, but more than 2 in a population (A/B/O blood-type).

20. Law of random segregation
a random sample half of each gene pair of an individual is transmitted to a gamete (and offspring)
parent
B/b
1/2
1/2
gametes /b B/

21. Law of Independent Assortment
Segregation of alleles at one locus is independent of segregation at other loci.
Black, polled
Bb Pp
parent
Segregation of B versus b at the color locus does not affect and is not effected by the segregation of P versus p at the polled/horned locus.
Note: linkage is an exception to independent assortment. Loci located on the same chromosome are said to be linked.
With complete linkage, BP//bp parent produces only two combinations in gametes, BP and bp.
We’ll discuss linkage more later. B P B p b P b p
gametes

22. Terminology Dominant versus recessive Homozygous versus heterozygous
black (B_) dominant to red (bb)
Homozygous versus heterozygous
BB or bb versus Bb
Summary
BB = homozygous dominant
Bb = heterozygous
bb = homozygous recessive

23. Genetics = Heredity X Environment
Heredity: transmission of genetic or physical traits of parents to their offspring.
Environment: the sum total of all external conditions which effect the life of the animal

24. Terminology
Heritability: describes what fraction of the differences in a trait is due to differences in genetic value rather than environmental factors.
Hereditary variation: variation caused by the heredity.
Environmental variation: variation caused by the environment.

25. Heritability Estimate
Heritability estimate: hereditary variation due to additive gene action.
effects the rate of improvement
low heritability lends to slow rates of improvement
high heritability estimates yields faster rates of improvement

26. Economic Important Traits
205 day adjusted weaning weight
Yearling weight
Birth weight
Rib eye area
Intramuscular fat
Milk production
Average daily gain
Feed efficiency
Calf crop %

27. Heritability Estimates for economical important traits
Rate of Gain (feedlot cattle)
40-68%
Ribeye Area
50-70%
Calving Interval (Fertility)
10 %
Weaning Weight
30 %
Birth Weight
40 %
Fat Thickness
45 %
Pasture Gain
30 %
Cancer-eye Suscept.

28. Terminology
Prepotency: the amount that an offspring looks like the parent.
Nicking: when genes of the dam and sire complement each other.
Heterosis: the improvement that the offspring has over its parents.

29. Production Testing and Selection
Performance testing- testing of the individual
Progeny testing- testing of the offspring
Pedigree selection- using the reputation or records of animals for breeding selection

30. Multiple Trait Selection Systems
Tandem- looking at intensifying on one trait at a time
Independent Culling- using minimal criteria to select for two or more economic important traits
Selection Index- using the combination of two or more economic important traits by observing an index to make selections for breeding

31. Selection Differential, Estimated Breeding Value and Expected Progeny Differences
Definition of S.D.= the difference between animals selected to be parents and the average of all animals in the herd for selection for a specific trait
EBV = ave. of animals selected minus the ave. of all animals X heritability
EPD = EBV X .5

32. Expected Progeny Differences
Definition – the expected performance of an individual’s offspring relative to the average individual of the entire breed.
Examples – birth weight, weaning weight, yearling weight, scrotal circumference, ribeye area, etc.
Understanding a Sire Summary

33. Types of Breeding Purebreeding systems:
Outcrossing: the mating of relatively unrelated animals within the same breed.
Inbreeding: production of offspring from parents more closely related than the average of a population
Line breeding: a form of inbreeding in which an attempt is made to concentrate the inheritance of some ancestor in the pedigree.

34. Crossbreeding Systems
Crossbreeding: the mating of animals of different breeds.
two-breed cross
two-breed backcross
three-breed rotational cross
three-breed terminal cross

35. Frame size vs. production vs. type
Size - frame
grazing area vs frame
market size vs frame
nutrition vs frame

36. Genetic/Repro Problems in Cattle
Freemartins-hormonal influence
Dwarfism – genetic influence
Dark cutters / more environment
muscular hypertrophy (double muscling)
increase in size of muscle fibers
Quality vs quantity vs performance

37. Genetic Defects Tibial hemimelia (TH)
Pulmonary Hypoplasia with Anasarca (PHA)
Bovine Arthrogyrposis Multiplex Congenita (AM) aka curly calf
Neuropathic Hydrocephalus (NH)
Dwarfism (Angus mutation, DW1)
Osteopetrosis (OS) aka marble bone
Contractual Arachnodactyly (CA)- aka Fawn Calf Syndrome