Estrous Cycle
Download
Report
Transcript Estrous Cycle
Animal Reproduction
Ashlee Gibson
3025A, 3025M, 3025N
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
Events of Reproduction
Puberty- Age at which reproductive organs become
functional
Female- Reproduction process occurs within
Fertilization- Egg & Sperm unite
Estrous cycle- Repetitive cycle occurring when
pregnancy does not
Estrus- “Heat” or receptivity to mating
Only real male contribution is the sperm
Gestation- Length of time of pregnancy
Parturition- Act of giving birth
Age of Puberty
Cattle:
Sheep:
Swine:
Horses:
Humans:
6 to 12 Months
5 to 7 Months
4 to 8 Months
12 to 15 Months
9 to 16 YEARS
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)
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
Estrous Cycle
Cattle: Polyestrous (cycle throughout year)
Sheep: Seasonal (Decreasing light, Fall)
Swine: Polyestrous (cycle throughout year)
Horses: Seasonal (Increasing daylight,
Spring)
Length of Estrus Cycle
Cattle:
Sheep:
Swine:
Horses:
19 to 23 Days
14 to 19 Days
19 to 23 Days
10 to 37 Days
Duration of Estrus
Cattle:
Sheep:
Swine:
Horses:
6 to 27 Hours
24 to 36 Hours
48 to 72 Hours
3 to 8 Days
Ovulation
Cattle:
Sheep:
Swine:
Horses:
10 to 14 Hours after estrous
18 to 26 Hours after estrus
started
24 to 30 Hours after start of
estrous
1 to 2 Days before estrous
ends
Signs of Estrus
Swollen vulva
Mucous discharge
Restless behavior
Female receptivity
to male
http://www.goodecattle.com/spot.htm
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
Gestation Length
Cattle:
Sheep:
Swine:
Horses:
285 Days
147 Days
114 Days
336 Days