Animal Reproduction

1. Animal Reproduction Zoology Springport High School 2015

2. Outline • Female Reproductive System • Male Reproductive System • Semen Dilution & Storage • Estrous Cycle & Fertilization • Breeding, Determining Pregnancy & Gestation

3. Female Reproductive System

4. Quick Facts • The female provides half of the chromosomes • The female nourishes the young in her uterus & after birth until weaning

5. Functions • Ovaries • Primary organ of reproduction in the female • Contains many follicles in which eggs are produced • The follicles secrete the female hormone estrogen • After ovulation, the follicles rupture & become a corpus luteum • The corpus luteum secretes the hormone progesterone

6. Functions • Fallopian Tubes (Oviducts) • Two tubes that carry eggs from the ovaries to the horns of the uterus • Uterus • Consists of the body, neck & two horns that are connected to the oviduct • Fetal development occurs in the body & horns

7. Functions • Cervix • The neck of the uterus that separates the uterus from the vagina • It is tightly closed except during estrus & during parturition (birth • Vagina • Passageway between the cervix and the vulva • Urethra • Carries urine from the bladder to the vagina

8. Functions • Clitoris • The sensory & erectile organ of the female located just inside the vulva • Vulva • External opening of the reproductive & urinary tracts • Infundibulum • Fnnel-shaped end of each oviduct that covers each ovary

12. Male Reproductive System

13. Quick Facts • The males role is less complex than the females • The male contributes half the chromosomes • After mating the role of the male is complete

14. Functions • Scrotum • Contains the testes • Maintains lower temperature needed for sperm production • Testes • Produces sperm cells • Produces testosterone

15. Functions • Epididymis • Storage site for immature sperm until they mature • Store up to 200 billion sperm at a time • Vas Deferens • Long tube that connects the epididymis with the urethra

16. Functions • Spermatic Cord • Consists of the vas deferens, smooth muscle, blood vessels & nerves • Enclosed in a fibrous protective sheath • Seminal Vesicles • Secretes seminal fluid into the urethra • The seminal fluid functions as a form of transportation for the sperm

17. Functions • Prostate Gland • Produces an alkaline secretion that give semen an odor • Cowper’s Gland • Small, paired gland that secrets a fluid similar to seminal fluid • It is secreted before ejaculation & its purpose is to neutralize and clean the urethra • Ureter • Tube connecting the kidney & bladder

18. Functions • Urethra • A tube connecting the bladder to the end of the penis • Semen • Fluid consisting of sperm, accessory fluids from seminal vesicles, Cowper's and prostrate glands • Sheath • Protective covering of the penis

19. Functions Penis • External organ that deposits sperm cells within the female • Two types • Fibro-Elastic: A sigmoid flexure allows the penis to be extended for mating. The retractor muscle pulls the penis back in the sheath. • Example: Bulls, boars & rams • Vascular: Does not have the sigmoid flexure & retractor muscle • Example: Stallions

21. Artificial Insemination

22. Why Breed Artificially • Maximum use is made of outstanding sires • Uniformity of offspring is increased • Certain physical handicaps to mating may be overcome • Sire cost is reduced • Danger & cost of keeping a sire is eliminated

23. Why Breed Artificially • Cost & delays involved in using infertile sire are reduced Better health is maintained • Breeding herd records are improved • Profits are increased • Pride of ownership is increased

24. Limitations of Artificial Insemination • Skilled technicians are required • Physiological principles must be followed • Sire market may be limited • Diseases may be spread

25. Limitations of Artificial Insemination • May be subject to certain abuses • May accentuate the damage of a poor sire • Artificial breeding organizations require large investments of capital and competent management

26. Sanitary Precautions in Artificial Insemination • All semen collection equipment should be clean & sterile • All glassware for semen dilution & storage should be clean & sterile • Follow strict refrigeration regulations for handling semen both after collection & before insemination

27. Sanitary Precautions in Artificial Insemination • The inseminator-technician should make certain that all equipment used in the insemination process is completely sterilized • Disposable equipment such as palpation sleeves & inseminating tubes should be placed in a suitable receptacle to avoid possible contamination of other animals on the farm

28. Animal Health Precautions in Artificial Insemination • Don’t breed back too soon • Avoid breeding diseased females • Have males inspected at regular intervals • Have females inspected that have not conceived after three breedings • Keep records of heat periods & note irregularities

30. Semen Collection

31. Quick Facts • Preparation of the bull is important • Electrodes are used in some collection methods

32. The Collection Process • A teasing period results in an improvement in the quality and quantity of semen • Teasing allows the bull to mount a female but note to ejaculate

33. Two Methods of Collection • The Artificial Vagina • Two attached tubes • An outer layer of heavy rubber • An inner layer with a thin lining of rubber • The space between the tubes is filled with warm water (110-130°F) • One end is open to permit the penis to enter • The other end leads to a test tube to collect the semen

34. Two Methods of Collection • The Electro-Ejaculator • Developed to produce and electrical impulse • Stimulates the nervous system causing erection & ejaculation • How it works • Electrodes attach to a probe are inserted into the rectum after the feces are removed • Low power stimulation is given intermittently & gradually increased to obtain extension & erection of the penis

39. Semen Volume & Sperm Number for Farm Animal Species

40. Semen Dilution & Storage

41. Quick Facts • Milk & egg yolks are used to dilute • Sperm that is not diluted will die within 24 hours

42. Sperm Dilution & Storage • The diluents are added a few minutes after the semen is collected • Sperm should never be cooled suddenly • By adding diluents and cooling slowly sperm can be kept fertile for a week • Sperm can stay fertile and can be stored for months or even years

43. How Does It Work? • The diluted semen is put into a plastic straw called a French Straw • Each straw is identified with the sire’s name, registration number, a code & collection date • The straws are sealed at 40°F & five straws are placed in a tube

44. How Does It Work? • Two tubes are clipped to a metal device called a cane. This allows for vertical storage making it easy to store many canes in a small area • Finally, the packaged semen is frozen using liquid nitrogen to -320°F

45. Semen Diluters

46. Estrous Cycle & Fertilization

47. Quick Facts • Sperm can survive in the female for up to 96 hours • An unfertilized egg lives for about 12 hours • A sow is ready to breed at 4 months while a horse isn’t ready until she is 24 months of age

48. The Estrous Cycle • The reproductive cycle of a female animals measured from the beginning of one heat period to the beginning of the next heat period.

49. Ovulation • The process of releasing eggs from the ovaries to the fallopian tubes. Occurs at different times during and after the estrus period.

50. Estrus • Signs of Estrus: 1. noise and aggressive behavior 2. swelling of the vulva 3. females will mount each other • Hormones control the entire estrous cycle • The estrous cycle begins with the secretion of follicle stimulating hormone (FSH) which is released from the pituitary gland.