Transcript Estrous Cycle

Animal Reproduction
Ashlee Gibson
3025A, 3025M, 3025N
Hormones
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Male
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Testosterone- critical for sperm development
Female
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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
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Puberty- Age at which reproductive organs become
functional
Female- Reproduction process occurs within
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Fertilization- Egg & Sperm unite
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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
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Follicles on ovaries develop and mature
Lutenizing Hormone
One follicle out matures
 Triggers ovulation
 Mature follicle erupts and releases the ovum
(egg)
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Estrus Cycle
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Pregnant
Corpus luteum produces progesterone
 Signals animal is pregnant and stops estrous
cycle
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Not pregnant
Prostaglandin released from uterine wall
 Causes Corpus Luteum to regress
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Estrous Cycle
Cattle: Polyestrous (cycle throughout year)
 Sheep: Seasonal (Decreasing light, Fall)
 Swine: Polyestrous (cycle throughout year)
 Horses: Seasonal (Increasing daylight,
Spring)
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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:
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Swine:
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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
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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
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Gestation Length
 Cattle:
 Sheep:
 Swine:
 Horses:
285 Days
147 Days
114 Days
336 Days