1. Animal Reproduction Ashlee Gibson 3025A, 3025M, 3025N

2. Hormones Male Testosterone- critical for sperm development Female 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

3. Events 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 Only real male contribution is the sperm Gestation- Length of time of pregnancy Parturition- Act of giving birth

4. Age of Puberty Cattle:6 to 12 Months Sheep:5 to 7 Months Swine:4 to 8 Months Horses:12 to 15 Months Humans:9 to 16 YEARS

5. Estrous Cycle Driven by hormones produced in the brain Follicle Stimulating Hormone Follicles on ovaries develop and mature Lutenizing Hormone One follicle out matures Triggers ovulation Mature follicle erupts and releases the ovum (egg)

7. Estrus Cycle Pregnant Corpus luteum produces progesterone Signals animal is pregnant and stops estrous cycle Not pregnant Prostaglandin released from uterine wall Causes Corpus Luteum to regress

8. Estrous Cycle Cattle: Polyestrous (cycle throughout year) Sheep: Seasonal (Decreasing light, Fall) Swine: Polyestrous (cycle throughout year) Horses: Seasonal (Increasing daylight, Spring)

9. Length of Estrus Cycle Cattle:19 to 23 Days Sheep:14 to 19 Days Swine:19 to 23 Days Horses:10 to 37 Days

10. Duration of Estrus Cattle:6 to 27 Hours Sheep:24 to 36 Hours Swine:48 to 72 Hours Horses:3 to 8 Days

11. Ovulation Cattle:10 to 14 Hours after estrous Sheep:18 to 26 Hours after estrus started Swine:24 to 30 Hours after start of estrous Horses:1 to 2 Days before estrous ends

12. Signs of Estrus Swollen vulva Mucous discharge Restless behavior Female receptivity to male http://www.goodecattle.com/spot.htm

13. Specific Signs of Estrus Cattle: Visually active mounting Sheep: Few external signs Swine: Brace with pressure to back, vocal grunting Horses: Tease with Stallion and will go nose to nose

14. Gestation Length Cattle:285 Days Sheep:147 Days Swine:114 Days Horses:336 Days