1. Chapter 11 Animal Reproduction

2. Animal Reproduction Overview • Perhaps most important part of animal industry • Animals must reproduce efficiently • Complicated process • Requires systems to work together • Occurs sexually

3. Production of Gametes • Spermatogenesis (sperm) • Oogenesis (egg)

4. Spermatogenesis • Testes produce sperm • Four-step process • Replication • Chromatids pair (synapsis) • Cell divides, chromosome separate • Cells and chromatids separate

5. Oogenesis • Ovaries produce egg • Process similar to spermatogenesis • Difference • One egg • Three polar bodies

6. Male Reproductive System

7. Female Reproductive System

8. Mating Process • Estrus occurs at about ovulation • Female allows male to mate • Females may be aggressive • Males may be belligerent • Act of mating deposits sperm in female’s tract

9. Fertilization • Sperm and egg join in fallopian tube • Egg secretes attracting chemical • Many sperm dissolve egg membrane • One sperm enters • Fertilization membrane forms • Processes ensure female stays pregnant

10. Artificial Insemination Basics • Process • Collect sperm • Deposit in female reproductive tract • Advantages • Use/select superior males at low cost • Greater reliability • Lower disease occurrence

11. Semen Collection • Animal mounts dummy • Animal ejaculates • Semen collects in ampule • Semen is inspected • Semen is processed via extender • Semen is placed in straws

12. Process of Artificial Insemination • Female comes into estrus • Semen is thawed immediately prior • Straw placed in tubelike instrument • Instrument placed in female tract • Technician releases semen

13. Embryo Transplant Basics • Transplant embryos between females • High-quality females have many offspring • Inferior females carry • Most feasible with cattle

14. Estrus Synchronization • Transfer embryo from donor to recipient at once • Process • Get donor and recipient in estrus • Donors undergo superovulation • Donors/recipients brought into estrus • Donor bred or artificially inseminated

15. Embryo Transfer Process • Prostaglandin is injected • Estrus about ~48 hours later • Fertilization occurs • Embryos are collected/examined • Recipient brought into estrus • Embryo placed in recipient uterus

16. Cloning • Make genetically identical offspring • Process • Multiply one egg • Remove another egg’s nucleus/DNA • Inject second egg from culture • Transfer cell after division

17. Summary • Beginning to understand animal reproduction • Through understanding can increase efficiency of: • Animal reproduction • Food production