normal breeding habits – sheep. normal breeding habits – does statusmeanrange estrous (d)2017-24...
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Normal Breeding Habits – Sheep
Age at puberty 5 –12 mo.
Estrous cycle (heat to heat)
14 – 19 days @ = 16.5 d
Length of estrus (heat period)
20 – 42 hours @ = 30-35 h
Gestation 143 – 152 days @ = 147 d
Ovulation Near the end of estrus
Normal Breeding Habits – Does
Status Mean Range
Estrous (d) 20 17-24
Estrus (hr) 30 16-30
Ovulation (hr) 33 30-36
Gestation (d) 150 144-155
Normal Breeding Habits – Billy
Status Mean Range
Sperm production (b)
6.0 4.8-7.2
Ejaculate volume (ml)
1 0.5-1.5
Concentration (b/ml)
3.0 1.5-5.0
Puberty First estrus vs. First
Ovulation
Foster, D. L., 1994
Pubertal Transition
• LH pulses are present, but frequency is low
• During puberty, estradiol’s inhibition on GnRH decreases
• High frequency rhythm of GnRH is then expressed
• This leads to the follicular phase and the 1st LH surge occurs
• Animal then ovulates Foster D.L., 1994
Production Optimum stage
score
Breeding 3 – 4
Early - Mid Gestation 2.5 – 4
Lambing (singles) 3.0 - 3.5
Lambing (twins) 3.5 – 4
Weaning 2 or higher
Estrous Cycle
PGF2α Ovulation
Some Goats are Short Day Breeders
Perc
en
t D
aylig
ht
June
Perc
en
t Ew
es
in E
stro
us
Daylight
Ewes in estrous
DARK
light
Pineal Gland
Hypothalamus
Pituitary
Melatonin
GnRH
FSH
LH
To ovary
