2. Breeding Systems AgriScience 2 Animal Reproduction

3. Why is improving organisms important to agriculture? Three main factors driving this goal: –Rising World Population –Urbanization –Fewer people in production agriculture

4. What methods are used in agriscience to improve organisms? Two major approaches are used: –Controlled breeding –Genetic manipulation.

5. Controlled breeding Breeding plants or animals to achieve certain characteristics in the offspring. Considered a natural method of improving plants and animals. –Scientists control the natural breeding process.

6. Kinds of controlled breeding: Selection –Choosing a few parents with the desired traits with the intent of increasing the amount of desired qualities in the offspring.

7. Genetic manipulation Artificial means of producing desirable traits. Genes can be moved from one species to another. Gene splicing is the moving of hereditary characteristics from one organism to another often unrelated organism.

8. Hybridization Crossing of two different plants or animals Combines the traits of different parent strains. Many hybrids are not able to reproduce.

9. Straight breeding Inbreeding- close breeding purebreeding

10. Inbreeding-mating closely related animals Parent to offspring and siblings 1/2 brother and sister Uncle x niece Nephew x aunt 1/2 uncle to niece Cousin to cousin 25% inbred 12.5% inbred 6.25% inbred 3.125% inbred

11. Closebreeding- mating animals that share some common ancestors

12. Purebreeding- mating animals that are not related but of the same breed.

13. Crossbreeding- mating animals of different breeds.

14. Crossbreeding Systems

15. Cross breeding- Criss-Cross F1 - 1/2 B 1/2 L

16. Criss-cross F1 1/2B 1/2L Brahman F2 1/4L 3/4 B

17. F2 3/4B 1/4L Limousin F2 5/8L 3/8 B Criss-Cross

18. Rotational Breeding-1st Cross F1 - 1/2 C 1/2 D ColumbiaDorset

19. Rotational Breeding-2nd Gen F2 - 1/4 C 1/4 D 1/2 H F1- 1/2C 1/2 D Hampshire

20. Rotational- 3rd Generation F3 - 1/8 C 1/4 H 5/8 D F2 - 1/4 C 1/4 D 1/2 H Dorset

21. Rotational Breeding

22. Terminal Cross

23. Roto-Terminal Cross

24. 3 breed roto cross Hampshire Terminal boar 1/2 Hamp, 1/2 white blend

25. Review / Summary Discuss the importance of improved organisms to agriculture. Identify methods used in agriscience to improve organisms. Identify breeding systems used in animal science.