1. Genetics

2. What is Selection? Mating animals to produce certain characteristics
Low Birthweight
Heavier Weaning Weight
Color
Horned or Polled
Temperment

3. What makes an animal they way that they are?
Animals are the result of Feed, Health, and Inheritance (genetic material)
Feed is fastest to correct
Genetics last longest

4. What is Genetics?
All body cells contain “Blueprints” with instructions as to how an animal will look or act etc.
One Gene comes from each parent (pairs)
Genes are divided into sections (Chromosomes) that carry genes
Sex chromosomes: male = XY, female = XX

5. What are Dominant Genes?
Dominant Genes = one gene overshadows the other
Angus Cattle: black is dominant, red is not (Bb)
Hereford: white face is dominant (Ww)
Hampshire Hog: white belt is dominant
Horns are dominant (Pp)

6. What are Recessive Genes?
The gene that is overshadowed by a dominant gene
Recessive genes can only express themselves if both genes are recessive
Polled vs Horned (Pp) (pp)
Black wool vs white (Ww) (ww)
Dwarfism vs normal size (dd)
Albino

7. Punnet Square P = horned p = polled
If a homozygous horned cow (PP) is mated to a homozygous polled bull (pp), what percent of the calves will be horned, polled?

8. Punnet Square

9. Punnet Square
If a homozygous horned cow (PP) is mated to a heterozygous horned bull (Pp), what percent of the calves will be polled?

10. Punnet Square

11. What are Sex Linked Genes?
Some recessive genes are attached to the X and Y chromosomes
Humans: Colorblindness and Baldness are on the X chromosomes
In Men, traits expressed anytime present
In Women, must have two recessives to show trait
Children get baldness from mothers

12. Punnet Square: What sex will the offspring be?

13. If Dad is bald, will you be bald?

14. Baldness is carried by the mother

15. What is Mom is bald?

16. What is Incomplete Dominance?
If both genes express themselves
Shorthorn Cattle: Red male mated to a White female = Roan calf
RR + WW = RW

17. Punnet Square Shorthorn Cattle R = Red W = white RW = roan
If a red bull (RR) is mated to a white cow (WW), what color will the calves be?

18. Shorthorn: Red X White

19. Punnet Square
If a red bull (RR) is mated to a roan (RW) cow, what color will the calves be?

20. Shorthorn: Red X Roan

21. What if Both Parents are Roan?

22. Undesirable Characteristics
Dwarfism
Monorchid = only one testicle descends
Cryptorchid = no testicles descend
Short ears & tails

23. What is a Mutation?
Dramatically different from what is expected genetically
Horned calf from polled parents
Loss of some or extra body parts
Lethal Mutation: causes death at birth
Sublethal Mutation: limits animals ability to grow to maturity
Beneficial Mutation: loss of tail in lambs

24. What is an Abnormality?
Similar to a Mutation, only it is caused by something in the environment
Siamese twins

25. What is Heritability? Chance that traits will be inherited
Low: multiple births, fat covering
Medium: birth wt, wean wt, milk, wool grade, carcass wt, rate of gain
High: Loin eye area, fleece length & quality

26. Heritability Currently have ewes that wean 70 lb lambs
Want to raise weaning wt to 110 lbs
Select a ram with a wean wt of 110 lbs
Heritability of weaning wt is 30%
What can you expect new lamb crop to weigh at weaning?

27. Heritability
What is the difference in current weaning wt and that of the new ram?
= 40 lbs
Heritability % x difference
30% x 40 = 12 lbs
Can expect a gain in weaning wt of 12 lbs
70 lbs + 12 lbs = 82 lbs

28. Mating Systems
Random Mating: all males have an equal opportunity to mate with all females
Outcrossing: mating purebreds with unrelated purebreds
Inbreeding: mating related animals
Linebreeding: parents mated to offspring
Crossbreeding: mating animals of same species but different breeds

29. What is Hybrid Vigor? Offspring will outperform either of the parents
Corn Breed A yields 100 bu/acre
Corn Breed B yields 100 bu/acre
Crossbreed A & B yields corn that yields 200 bu/acre
Vigor only expressed in crossbreeding
Donkey mated to a horse = Mule
mule is sterile

30. What are Exotics? Animals not common to United States
Difficult to define today
New breeds are exotics

31. Genetic Terms Genotype: genetic makeup (Bb)
Phenotype: physical appearance (Black)
Heterosis: Genes are different, Dominant & Recessive (Bb)
Homozygous: both genes are the same (BB or bb)