1. Cattle Reproduction

2. Introduction
Reproduction is the process by which animals produce offspring for the purpose of continuing the species.
The process of reproduction begins with copulation, which is the mating of a male and female of the species.
Sperm cells from the male are deposited in the female reproductive tract and try to unite with an egg cell.
When fertilization (a sperm cell and egg cell unite) occurs, an embryo begins to develop.
The embryo attaches to the wall of the uterus where it is protected, receives nourishment, and develops.
When the new offspring reaches the end of the gestation period, it is delivered from the female reproductive tract in a process called parturition.

3. Hormones Male Female Testosterone- critical for sperm development
Estrogen- critical for follicle development
Progesterone- sustains pregnancy and inhibits new follicle development
Relaxin- causes ligaments around birth canal to relax
Oxytocin- causes milk letdown

4. Structure and Function of the Male Reproductive System

5. The major functions of the male reproductive system include:
Production, storage, and deposition of sperm cells,
Production of male sex hormones,
Serve as passageway for expelling urine from the urinary bladder.

6. Male Reproductive System
Testicles-
Site of sperm production and testosterone synthesis
Sperm contain ½ of genetic makeup
Epididymis-
Sperm storage and maturation
Scrotum-
Protects testes and regulates temperature

7. Male Reproductive System
Vas Deferans-
Transports sperm from epididymis to urethra
Urethra-
tube inside of penis transports sperm or urine exterior
Penis-
organ of copulation

8. Scrotal Circumference
Gives an indication of a bull's ability to produce sperm and is related to younger age at puberty.
Breeds differ somewhat as to scrotal circumference, but 32 centimeters is generally accepted as the minimum size for yearling bulls to be sound breeds.

9. Secondary male characteristics include coarse hair, horns that are long and large at the base, a deep voice, and pronounced muscularity.
Photo from IMS.

10. Structure and Function of the Female Reproductive System

11. The functions of the female reproductive system include:
Produce egg cells (ova),
Serve as receptacle for the penis during copulation, and
House and nourish the fetus until parturition.

12. Female Reproductive System
Ovaries-
Produce egg
Egg contains ½ of genetic makeup
Oviducts-
Site of fertilization
Transport embryos to uterus
Uterus-
Site of embryonic development during gestation

13. Female Reproductive System
Cervix-
Connects uterus and vagina
Serve as barrier during pregnancy
Vagina-
Female organ of copulation at mating
Opening of bladder
Vulva-
External opening of reproductive system

14. Terms of Reproduction
Puberty- Age at which reproductive organs become functional
Female- Reproduction process occurs within
Estrous cycle- Repetitive cycle occurring when pregnancy does not
Estrus- “Heat” or receptivity to mating
Fertilization- Egg & Sperm unite
Gestation- Length of time of pregnancy
Parturition- Act of giving birth

15. Age of Puberty Estrous Cycle Cattle: 6 to 12 Months
Cattle: Polyestrous (cycle throughout year)

16. Duration of Estrus Cycle
Length of Estrus Cycle
Cattle: 19 to 23 Days
Duration of Estrus Cycle
Cattle: 12 to 18 Hours

17. Signs of Estrus Swollen vulva Mucous discharge Restless behavior
Female receptivity to male
Visually active mounting

18. Gestation Length
Cattle: Days

19. Signs of Parturition Distended abdomen
Mammary development & milk secretion
Swollen vulva and relaxed pelvic ligaments
Mucous discharge
Relentlessness and separation from group
Labor and Contractions

20. Signs of Parturition Appearance of placental membrane
Expulsion of fetus
Expulsion of placental membrane
Bonding behavior of offspring and mother (will vary between species)

21. Transfer of Sperm Two different ways
Let the male and female naturally engage.
Male seeks out female in Estrus
All controlled by male and female interaction
Artificial Insemination (AI)
Human transfers semen past female cervix
Human is in control of male product and female interaction
No contact between male and female

22. Artificial Insemination

23. Artificial Insemination (AI) Pros
Conception rate is high
Extends use of superior males
One ejaculate can fertilize many females
Reduce incidence of venereal diseases
Individual straw per female
Improves record keeping and mgt.
Know exactly who the father is
Can accelerate genetic improvements
Conception rate is high
Extends use of superior males
One ejaculate can fertilize many females
Reduce incidence of venereal diseases
Individual straw per female
Improves record keeping and mgt.
Know exactly who the father is
Can accelerate genetic improvements

24. Artificial Insemination (AI) Cons
Need to know Estrus Cycle of animal
Cost intensive
Pay for someone to AI animals