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 1.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 2.The Electro-Ejaculator Developed to produce and electrical impulse Stimulates the nervous system causing erection & ejaculation How it works 1.Electrodes attach to a probe are inserted into the rectum after the feces are removed 2.Low power stimulation is given intermittently & gradually increased to obtain extension & erection of the penis

39. Semen Volume & Sperm Number for Farm Animal Species Animal Ave. Semen Volume Per Ejaculation (ml.) Sperm per ml. of Ejaculation (1,000’s) Sperms per Ejaculation (millions) Potential number of females bred AI per Ejaculation (fresh semen) Boar25010058,00015-17 Bull41,0009,600800-1,500 Rooster0.6-0.83,5001.8-2.415-20 Ram13,0002,00040 Stallion7012010,00020-25

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? 1.The diluted semen is put into a plastic straw called a French Straw 2.Each straw is identified with the sire’s name, registration number, a code & collection date 3.The straws are sealed at 40°F & five straws are placed in a tube

44. How Does It Work? 4.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 5.Finally, the packaged semen is frozen using liquid nitrogen to -320°F

45. Semen Diluters Type of DiluterType of AnimalComments Egg Yolk – CitrateBull, Ram Mix 1 part fresh egg yolk w/ 3 parts 2.9% sodium citrate dehydrate in distilled water Egg Yolk – PhosphateBull, Ram, Stallion Mix equal parts fresh egg yolk w/ chemically pure sodium hydrophosphate-hydrate or another appropriate phosphate solution Homogenized Whole Milk Bull, Ram. Boar Boil fresh homogenized whole milk for 5-10min, cool to body temp & dilute w/ equal parts of distilled H 2 0 Glycine-Containing Diluents Boar Mix 50% of a 4% glycine solution & 42.5% skim milk w/7.5% egg yolk

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.

51. Estrus continued: FSH stimulates the ovary to produce a blister like structure called a follicle The follicle secretes estrogen. It is the messenger that stimulates the rest of the reproductive system to prepare for the reception of the egg. in the follicle, oogenesis occurs. Oogenesis is the process of egg production in the female.

52. The follicle then expels the egg into the oviduct The expulsion of the egg results in yellow cells that develop into the corpus luteum. The development of the corpus luteum(aka ovulation) is caused by luteinizing hormone.

53. The end of Estrus. A ripened follicle ruptures and secretes the hormone progesterone. The 4 functions of progesterone 1.Stimulate the uterus to implant and nourish the embryo. 2.Prevents other eggs from maturing. 3.Maintains pregnant condition 4.Assists in the development of mammary glands.

54. If an egg does not unite with sperm, the corpus luteum dies, allowing another follicle to ripen and the estrous cycle to continue. Why is it important to know when ovulation is occurring?????? To determine the correct time for artificial insemination Cows- breed toward the end of estrus. Ewes and Goats- breed in the middle of the heat period.

55. Mares – breed on the 2 nd day and every other day thereafter throughout the heat period. Fertilization: union of egg and sperm. Takes place in the oviducts. Ejaculation: The process of depositing sperm and semen into the vagina of the female. In each ejaculation, millions of sperm are deposited. Why so many? 1.Not all sperm are hardy enough to make the journey.

56. 2. Many sperm are needed to float around the cell and secrete and enzyme that helps break down the cells surrounding the egg. The semen provides two functions. 1. to provide a means for the sperm to move. 2.To provide nourishment for the sperm.

57. The journey of Sperm Sperm are deposited into the vagina, travel through the cervix, into the uterus and into the fallopian tube (oviduct) One sperm will form a tube-like connection with the egg. The head is the only part that enters the egg. Once the nucleus of the sperm enters the egg, the egg releases carbohydrates and protein to form a protective layer, the Fertilization Membrane, which does not allow anymore sperm to enter.

58. Breeding, Determining Pregnancy and Gestation

59. Breeding, Determining Gestation, and Pregnancy Quick facts: 1.And elephant is pregnant for 624 days 2.A hamster carries her young for 16 days Breeeding age- the age at which the female is ready to conceive offspring. Age varies among species. Gestation- the length of time from conception to birth.

60. The average age at puberty (in months) Mare* 10-12 Cow * 8-12 Ewe* 4-8 Sow* 5-7 The average at breeding (in months) Mare* Cow* 14-16 Ewe* Sow*

61. The average length of gestation (in days) Mare* 336 Cow* 281 Ewe* 150 Sow* 112