Animal Reproduction and Genetics

1. Animal Reproduction and Genetics

2. Estrus Cycle • Time during which the female will accept the male for breeding • Length of estrus cycle in both cattle and swine is about 21 days • The actual time a cow is in heat is about 16-18 hours, sow about 2 days

3. Estrus Cycle http://www.hyperionfarm.com/Estrous.htm

4. Estrus Cycle • There are several signs of heat including swelling of the vulva, frequent urination, nervousness or restlessness, mounting other animals and letting other animals mount.

5. Estrus Cycle • Best indication that a cow is ready to breed is when she stands when mounted by another cow

6. Ovulation • Number of young that animals gives birth to at one time is indication of number of eggs released or ovulated • Sows: 1-15 • Cows generally 1

7. Ovulation-Fertilization http://www.visembryo.com/baby/stage1.html

8. Ovulation • At ovulation, fertilization will take place and the animal will become pregnant if the animal is bred so that the egg cell and live sperm are present at the same time

9. Fertilization http://www.visembryo.com/baby/stage2.html

10. Artificial Insemination • Placing sperm in the female reproductive tract using other than natural processes

11. Artificial Insemination • Cow: person’s hand is inserted into the cow’s rectum to grasp the cervix, and then then inseminating tube or rod is used to deposit the bull semen from the middle of the cervix to just into the body of the uterus when the cow is in heat

12. AI- transfer gun http://www.agtechinc.com/store/products.cfm?action=showThumb&start=1&DeptCode=38

13. Artificial Insemination • Advantages • Wider variety of superior bulls • Increases number of cows bred to superior bulls • Reduces the spread of diseases • Don’t have to keep bulls on the farm

14. Artificial Insemination • Disadvantages: • Requires a trained inseminator • Requires more time and herd supervision

15. Embryo Transfer • Superovulation of donor with hormones • Artificial insemination • Flush embryos and remove with catheter • Isolate and classify embryos

16. Embryo Transfer • Store embryos in liquid nitrogen • Transfer embryos to recipient cows • Diagnose pregnancy 1 to 3 months later • Birth 9 months after transfer of embryos

17. Embryo Transfer • Advantage: • Genes of the female (dam) can be passed to more offspring faster than natural breeding

18. Embryo Transfer http://www.agtechinc.com/overview/

19. Cloning Cattle Using Nuclear Transfer • Process: • Flush and remove embryos with catheter same as regular ET • Filter the flushed liquid to remove embryos • Remove genetic material from recipient oocytes

20. Cloning Cattle Using Nuclear Transfer • The nuclei are removed through microsurgery • The nuclei are separated and each one is transferred to an unfertilized egg cell that has had its nucleus removed (thus the term nuclear transfer)

21. Nuclear transfer http://www.roslin.ac.uk/library/

22. Cloning Cattle Using Nuclear Transfer • Plugs with 3 or 4 embryos are placed in oviducts for 5 to 6 days to develop to the 32 to 64 cell stage • Embryos are removed and placed into surrogate mothers, frozen for long term storage or used to produce another generation of cloned embryos

23. Stages of Nuclear transfer http://www.roslin.ac.uk/library/

24. Cloning Cattle Using Nuclear Transfer • Advantages: • Increased herd uniformity • Increase herd quality • Produce genetically identical animals

25. Parturition Process • Begins when increased estrogen causes the uterus muscles to contract • First water bag appears, enlarges and breaks open

26. Parturition Process- water bag breaking http://www.lapc.cc.ca.us/usr/shapirls/Parturition_in_the_horse.htm

27. Parturition Process • Soon afterwards, the second water bag containing the fetus breaks open and the presentation of the animal begins

28. Parturition process- amnion sac http://www.lapc.cc.ca.us/usr/shapirls/Parturition_in_the_horse.htm

29. Parturition Process • Normal position of the fetus at birth is front feet first, followed by the nose, then the head, shoulders, middle, hips, rear legs, and feet

30. Parturition process- foaling http://www.lapc.cc.ca.us/usr/shapirls/Parturition_in_the_horse.htm

31. Parturition Process • Several hours later, the placenta and other membranes (afterbirth) are expelled. • Afterbirth must be expelled or the animal will become sick

32. Parturition process- placenta http://www.lapc.cc.ca.us/usr/shapirls/Parturition_in_the_horse.htm

33. Parturition Process • Any presentation that does not have the order as previously stated is abnormal and could cause problems such as death of the young or the mother

34. Body Conditioning • Important because it affects conception in cows, and the goal is to have each cow give birth and wean a calf every year • Underconditioned or thin cows are the major cause of all reproductive problems

35. Timing • Size is the most important consideration when breeding heifers that are sexually mature (550-750 pounds) • Age is second (2 years calve) • Calving in the herd should occur during a 40 to 60 day period

36. Synchronization of Estrus • Use of hormones to cause all the female sin a herd to come into heat in a short period of time • Shorter breeding and calving seasons are advantages

37. Multiple farrowing • Arranging the breeding program so that groups of sows farrow at regular intervals throughout the year • The number in the group should match facilities

38. Advantages • Higher average prices for hogs sold because sales are spread throughout the year • Spreading income throughout the year • More efficient use of facilities

39. Disadvantages • Requires better management • Requires a year-round labor supply

40. Other considerations • Because the producer needs to make maximum use of farrowing facility capacity, it is very important that conception rates and litter sizes be the best possible

41. Other considerations • Disease prevention and control, proper boar to sow ratio and breeding each sow at least twice during each heat period (multiple breeding) increase conception rates

42. Reproduction Practices in Poultry • AI is used for large, heavy breeds of turkeys because of low fertility rates and eh large size of males (toms) used for natural breeding

43. Reproduction Practices in Poultry • Since chickens and turkeys come from fertile eggs, reproduction efficiency involves the eggs being fertile, the incubation process and control of diseases

44. Reproduction Practices in Poultry • In breeding flocks, eggs are gathered several times each day and packed with the large end up to protect the air cell • Hatching eggs are fumigated with chemicals to help prevent the spread of egg-borne diseases

45. Palpation • The process of diagnosing pregnancy by feeling the reproductive tract of a cow • Experience is necessary for accuracy because the person doing the diagnosis compares the feel and size of different parts of the tract to determine the stage of pregnancy

46. Palpation • Good website http://www.animal.ufl.edu/hansen/protocols/palpation.manual.htm http://www.breeders.umn.edu/ansc3023/ai/sld011.htm

47. Palpation • Must use plastic sleeves and lubricant to palpate in the rectum • Breeding records are used to indicate when the cow was bred and when to check for pregnancy

48. Genotype • Kinds of gene pairs the animal has

49. Genes • Dominant: hides or dominates the effect of the other gene in the pair and is indicated by upper case letters • Recessive: is hidden or covered by the gene in the pair and is indicated by lower-case letters

50. Gene pairs • Homozygous carries two genes for the same trait (uppercase letter or lowercase letter) • Heterozygous carries two different genes for the same trait (uppercase letter and lowercase letter)