Basic Animal

1. Basic Animal Reproduction

2. Basic Animal Reproduction Objectives • To label and identify male and female reproductive anatomy • To describe the structures and functions of male and female reproductive anatomy • To understand the animal reproductive process, including the estrous cycle, ovulation, gestation and parturition

3. Basic Animal Reproduction Hormones Reproduction is closely related to the action of several hormones called Gonadotropins • Produced by pituitary gland • follicle stimulating hormone (FSH) • luteinizing hormone (LH) • Release is controlled by gonadotropic releasing hormones or (GnRH) produced by the brain

4. Estrogen Basic Animal Progesterone LH Reproduction FSH Hormones • FSH • stimulates follicle development • produces estrogen in the ovary • FSH and LH combined • prepares the follicle for ovulation • LH • causes ovulation • Progesterone • maintains pregnancy changes in the hormones secreted by the ovary and pituitary gland during estrous cycle

5. Male Anatomy Functions production of Sperm storage deposition Produce male sex hormones Is a passageway for expelling urine

6. Male Anatomy Testes (testicles) • Are paired, oval shaped organs • Produce sperm cells • Produce testosterone(male sex hormone) • Have seminiferous tubules coil throughout testes • Have interstitial cells (Leydig) lie between seminiferous tubules causes development of secondary sex characteristics and sex behavior site of sperm production and maturation produce testosterone

7. Male Anatomy Scrotum • Protects and supports the testes • Protects sperm • Regulates temperature • Lie within the wall of the scrotum • Raise or lower the testes to maintain constant testicular temperature cremaster muscle spermatic cord tunica dartos muscle Temperature should be 4 – 6° below body temperature for normal sperm development

8. Male Anatomy Epididymis • Is a coiled tube, attached to each testis • Is responsible for further maturation, storage and transportation of sperm cells Vas deferens (ductus deferens) carries urine from the bladder carries sperm and fluid from accessory sex organs • Transports sperm from the epididymis to the urethra Because location of testes vary among livestock species, location of the epididymis varies

9. Male Anatomy Accessory Glands sperm plus the added accessory fluids • Provide 95-98% of total ejaculate • Include: • seminal vesicles (vesicular glands) • secrete fluids providing energy and buffers to sperm • prostate gland • secretes a thick, milky fluid high in inorganic ions • bulbourethral glands (Cowper’s glands) • secrete fluids before ejaculation to clean urethra

10. Bull Ram Boar Male Anatomy Penis • Is a passageway for semen and urine • Deposits semen in the female reproductive tract Fibroelastic Penis Primarily composed of connective tissue and depends little on blood for erections Stallion Vascular Penis Supplied with blood vessels

11. Male Anatomy Sigmoid Flexure • Has a s-shaped curve • Allows for penis retraction • Stallions and humans do not have sigmoid flexure Retractor Penis Muscles • Extends the penis upon sexual excitement Sheath • Protects penis from injury and infection

12. Poultry Anatomy Both the male and female poultry reproductive systems vary compared to other domesticanimal species Note • How Male Anatomy Differs • Testes are located within the abdominal cavity, produce sperm and seminal fluid • Papillae emit semen and are considered the copulatory organs of the rooster • Cloaca serves as passageway for urinary, digestive and reproductive tracts • Androgen is the male sex hormone produced by the testes

13. Female Anatomy Functions To produce the eggs or ova to be fertilized by sperm To serve as as receptacle for the penis during copulation To house and nourish the fetus until parturition

14. Female Anatomy Ovaries • Produce eggs • Produce female hormones • estrogen • progesterone stimulates the development of secondary sex organs and sexual receptivity maintains uterine lining during pregnancy keeps estrus from occurring causes mammary system to develop

15. Female Anatomy Ovaries • Follicle • blister-like mass on the surface of an ovary containing a developing ovum(egg) follicle ovum

16. Female Anatomy secreted from follicle to signal the remainder of the reproductive tract to prepare for ovulation Ovaries • Follicle • functions • hold the growing ovum • produce and store estrogen • at ovulation, the follicle ruptures, expels the ovum, enters the infundibulum and awaits fertilization in the oviduct

17. Female Anatomy Ovaries • Corpus Luteum (CL) • forms after ovum is released from the follicle • function • produce progesterone

18. Female Anatomy Oviducts • Transport eggs from ovary to uterus • Are site of fertilization Infundibulums • Pick eggs at ovulation and direct them into the body of the oviducts process of discharging an ovum from the mature follicle of an ovary

19. Female Anatomy Uterus • Consists of horns and a body • uterine horns • uterine body • Is site of embryonic growth • Is site of placental and fetal development • Varies in shape among species A sow has a very long uterus and a mare has a very short uterus

20. Female Anatomy Vagina • Is receptacle for the penis during copulation • Serves as birth canal at parturition • Is separated from uterus by the cervix • Is passageway for expelling liquid wastes major barrier and protection of the uterus and developing fetus

21. Female Anatomy Vulva • Is external portion of the female reproductive tract • Serves to: • protect internal system from infection • initially receive the penis at copulation • act as passageway for urine Clitoris • Sensory erectile organ

22. Poultry Anatomy Both the male and female poultry reproductive systems vary compared to other domesticanimal species Note • How Female Anatomy Differs • Mature female poultry have only one functional ovary and oviduct (left ovary) • Ova produced in ovary are developed into egg yolks • Oviduct has five parts • funnel: receives yolks from ovary and stores sperm cells • magnum: secretes thick white of egg • isthmus: adds two shell membranes • uterus: adds thin white and outer shell • vent: opening where egg is laid

23. Reproductive Process Estrous Cycle • Reoccurs and repeats itself as long as the female is not pregnant • Is controlled by hormones preparing the reproductive tract for ovulation and pregnancy • Includes two phases • follicular phase • luteal phase short phase; period from regression of the CL to ovulation long phase; period from ovulation to CL regression

24. Reproductive Process Estrous Cycle • Is categorized by frequency of occurrence throughout the year • seasonally polyestrus— cycles occur only during certain times of the year Long-day breeders cycle when day length increases Short-day breeders cycle when day length decreases

25. Reproductive Process Estrous Cycle • Is categorized by frequency of occurrence throughout the year • monoestrus— one cycle per year; estrus periods last for several days Example: dogs • polyestrus—uniform, regularly occurring estrous cycles throughout the year Example: cattle and swine

26. Reproductive Process Stages of the Estrous Cycle • Proestrus • begins after CL regression and ends at the onset of estrus, period of follicle growth • Estrus • period of sexual receptivity; sometimes referred to as “heat” • Metestrus • early postovulatory period; CL begins to develop • Diestrus • begins approximately four days after ovulation and ends with the regression of the CL

27. Reproductive Process release of egg cell from ovary; occurs near the end of estrus period Ovulation • Before ovulation • egg cell is contained in follicle • During ovulation • follicle breaks, releases the egg into the oviduct • if sperm is present, egg may become fertilized • After ovulation • CL forms on ovary and releases progesterone If egg is not fertilized, CL does not grow, allowing another follicle to grow and another estrus period to occur

28. Reproductive Process Ovulation • Functions of progesterone • prepares uterus for implantation of the embryo • stops other eggs from forming • maintains pregnant condition • develops mammary glands which produce milk to feed young after they are born

29. Reproductive Process time in which female is pregnant Gestation • Fetus develops in uterus and is surrounded by a watery membrane • Blood vessels in umbilical cord supply nutrients, oxygen and carry off waste products • Placenta is connected to the fetus by the umbilical cord and lies along wall of uterus • Food, oxygen and wastes are exchanged between mother and fetus through the placenta

30. Reproductive Process Parturition process of giving birth • Near the end of the gestation period, the CL decreases its production of progesterone • Increased estrogen levels, cause uterine muscles to contract, beginning the birthing process • Sequential set of events: • cervix widens (dilates) • pelvic region relaxes • uterus begins contractions • fetus passes through the cervix, pelvic region and finally the vagina

31. Reproductive Cycles COW Estrus 10 – 26 hrs. (18 hr avg.) Estrous Cycle 18 – 24 days (21 day avg.) Ovulation 4 – 16 hrs. post estrus Gestation 283 days Estrus 20 – 42 hrs. (30 hr avg.) Estrous Cycle 15 – 18 days (17 day avg.) Ovulation 12– 18 hrs. estrus onset Gestation 150 days EWE SOW Estrus 1 – 4 days (2 day avg.) Estrous Cycle 16 – 25 days (21 day avg.) Ovulation 16 – 48 hrs. estrus onset Gestation 114 days (3 months, 3 weeks, 3 days)

32. Reproductive Cycles GOAT Estrus 2 – 3 days (2.5 day avg.) Estrous Cycle 15 – 24 days (21 day avg.) Ovulation Near end of estrus Gestation 151 days Estrus 20 – 42 hrs. (30 hr avg.) Estrous Cycle 15 – 18 days (17 day avg.) Ovulation 12– 18 hrs. estrus onset Gestation 150 days POULTRY MARE Estrus 4 – 9 days (5 day avg.) Estrous Cycle 15 – 24 days (21 day avg.) Ovulation 1 – 2 days before end of estrus Gestation 336 days

33. Assessment • Which part of the male reproductive anatomy is responsible for further maturation, storage and transportation of sperm cells? • What female hormone prepares the uterus to maintain implantation of the embryo? • What term is used for the process of giving birth?

34. Assessment • Which specie discussed has the longest gestation length? • Gonadotropins are produced by which gland? • What male hormone is responsible for the development of secondary sex characteristics?

35. Assessment • Name two functions of the scrotum? • Accessory glands provide what percent of the total ejaculate? • Which part of the female reproductive tract is the site of fertilization?

36. Assessment • Which part of the female anatomy serves as the birth canal at parturition? • Name the two phases of the estrous cycle? • Animals cycling when day length increases are considered to be what type of breeders?

37. Acknowledgements Pond, Kevin R., and Wilson G. Pond. Introduction to Animal Science. John Wiley & Sons, Inc., 2000. Reece, William O., Physiology of Domestic Animals. College of Veterinary Medicine, Iowa State University. Williams & Wilkins, 1997. Sam Prien, Ph.D. Texas Tech University Health Sciences Center Production Coordinator Clayton Franklin Executive ProducerProduction Manager G.W. Davis Geoff Scott ©MMIII, MMIV CEV Multimedia, Ltd.