Small Ruminant - MT Flashcards
Where is the semen deposited in ewe when doing AI?
Internal os of the cervix
What are the conception rates using fresh semen?
Frozen semen?
- 70-75% conception rates w/ fresh
- 5-15% conception rates w/ frozen
Depositing semen into the _______ vagina of the ewe results in a conception rate of 50-60%.
Anterior vagina
What affects puberty/onset of puberty in small rumis?
- Age
- Nutritional status
- Exposure to rams
- Seasonality ⇒ photoperiodicity
Sheep are ______ day breeders?
Short day
Describe Photoperiodicity’s effects on the ovine.
short day length ⇒ increase melatonin⇒
**increased GnRH = cyclicity **
(increased sensitivity to ovarian estradiol ⇒FSH & LH pulses ⇒Follicle development & ovulation)
What is “Flushing/Flush Feeding”?
Why do we do it to ewes?
- Feeding high energy meals 2-3 wks before breeding season
- Increases ovulation rate
How long is the estrous cycle in the doe?
18 - 22 days
(Doe = female goat)
What is the gestation length of the ewe and doe?
5 mo.
(145 - 150 d)
How long does it take the ova to move to the ewe’s uterus?
72 hrs
(3 d)
When does implantation occur in the ewe?
begins ~ d. 18
The ewe’s CL is the primary progesterone source until what day?
~day 70
Is the first heat often “visible” in the ewe?
NO
1st heat is usually “Silent”
What must you have in place in order to establish a “Lambing Season”?
- Estrus Synchronization program
- Estrus detection
- Adequate sire/ AI
Why do they use Synchronization programs in
small rumis?
- Timed period of lambing/kidding
- To induce estrus during the non-breeding season
- Maintain continuous milk supply from dairy herds
- Allow for optimal nutritional management of dam & youngs
What is the Ram/Buck Effect?
Rams/bucks isolated from ewe/does for 4-6 weeks
Introduction of a teaser male or breeder male into an all female herd will induce estrus w/in 3-4 days due to the pheromones produced by the male.
What must be done in order for the Ram/Buck Effect to be successful?
- Females should have no contact w/ males 3-4 wks prior
- Males used should be isolated for 1-2 months before
- Can use a “Buck Rag”
How long are CIDRs or Impregnated Sponges/Pessaries placed into the anterior vagina of the ewe? the doe?
What hormone do they utilize?
- 12 - 14 days ⇒ ewe
- 18 - 21 days ⇒ doe
- Progesterone
In what phase of the estrous cycle is PGF2a effective?
Luteal phase
Describe how PGF2a can be used to
synchronize ewes & does.
- Ewes → 2 injections of PGF2a or Cloprostenol IM 8-9 days apart → estrus w/in 2-3 days
- Does → 2 injections of PGF2a or Cloprostenol IM 11-12 days apart → estrus w/in 2-3 days
How can you bring transitional ewes into estrus?
- Place vasectomized ram w/ ewes → estrus w/in 6-12 d.
- Give PGF2a or Cloprostenol IM, followed be eCG
What is the uterine transport time in the sheep?
2 to 4 days
When does maternal recognition of pregnancy occur in the ewe?
**Day 12 **
(Interferon-t and rapid elongation of trophoblast)
When does implantation of the embryo occcur in the doe and ewe?
d. 18 of gestation