Equine Breeding Management Flashcards
Treatment with ____ is the most common management tool in equine reproduction.
Prostaglandin
The interval between prostaglandin injection and ovulation is determined by…
the size of the follicle at the time of treatment
Mares with (small/large) follicles can have unexpected ovulations if the mare is not examined prior to treatment.
large
Universal birthday for horses?
January 1st.
Breeding Management factors (ie MF, SF) are (multiplicative/additive)?
multiplicative.
Repro Management Keys to obtain good fertility:
1. 2. 3. 4. 5. 6.
- Normality of the estrous cycle
- Pre and Post breeding therapies
- Timing of insemination
- Place of insemination
- Number of sperm in the inseminate
- Volume of the inseminate
Formula for Pregnancy Rate?
of Mares Pregnant divided by # of Mares Bred
Target Pregnancy Rate:
- Per Cycle (14-16 days)?
- Per season?
- > 60%
2. > 90%
What equine breed can breed between 2 to 4 times / day with the only limiting factor being libido?
TBs
What regimen is recommended to get the maximum number of sperm collected from stallions via AI?
Take every other day throughout the season
Uterine Edema:
- First appears when?
- Starts to decrease when?
- Most mares will ovulate with a (low/high) degree of endometrial edema?
- early estrus
- as mare approaches ovulation
- low
Describe a Grade 2 Endometrial Edema:
- Cervix?
- Follicle size?
- Folds?
- relaxed and edematous = fishbone
- 30-35 mm or 40+ mm preovulatory
- some folds easily observed with yperechoic centers in folds
What distinguishes a Grade 4 endometrial edema?
The folds! They are thicker, with a hypoechoic center and hyperechoic wall. They are more prominent at the uterine body but maintain architecture with a “cart wheel
appearance
Describe a Grade 5 endometrial edema
- folds?
- surface area?
- follicles?
- VERY THICK endometrial folds cause loss of normal u/s architecture
- Increased
- Follicles variable, but often are preovulatory or recently ovulated
Two Broad kinds of Breeding Methods:
1.
2.
- Natural cover
2. AI
- Two kinds of natural cover breeding methods?
2. Three kinds of AI breeding methods?
- Pasture breeding and Hand breeding
2. Fresh semen, cool shipped semen, frozen semen
Breeding method: Inseminate how long before ovulation?
- For natural breeding?
- For fresh semen?
- For fresh cooled semen?
- For frozen semen?
- 72-48 hours.
- < 48 hours
- 24 - < 36 hours
- < 12 hours
What breed cannot do AI?
TBs
Fertility Rates per cycle in horses wit hadequate semen quality:
- Natural cover?
- Fresh AI?
- Cooled AI?
- Frozen AI?
- > 60%
- > 60%
- > 50%
- > 40%
Timing of Breeding depends on what three factors?
- 2.
3.
- Type of semen used
- Susceptibility of the mare to infections or inability to evacuate uterine fluid
- Proximity of AI to ovulation
T/F: Natural breeding is a cheap alternative to AI
FALSE
Preparation of the mare for breeding:
1.
2.
3.
4.
- Bandage tail
- Wash and rinse vulva and perineum
- Dry washed area
- Proper mare restraint
Definition of PROPER artifical insemination:
Deposition of good quality semen (.5-1.0 x 10^9) into the uterus of a clean mare at the right time (0-24 hours pre-ovulation) via the uterine body
Advantages of AI;
1. 2. 3. 4. 5.
- Maximize efficiency of stallion usage
- Increase genetic pool due to increased availability of stallions
- More regular evaluation of stallion semen
- Reduce risk of sexually transmittable diseases
- Increases safety of animals and handlers
Sperm transport:
- Natural mating has how many sperm deposited in the uterus?
- How long to get in the oviduct? How long do they stay there?
- 2-15 billion
2. .5-4 hours. Can stay for hours or days
Sperm transport:
- _____ is responsible for eliminating excess fluid from the uterus.
- Maximal colonization appears to be achieved after how long?
- myometrial contractions
2. 4 hours
Put these types of mares in order of least to most fertile:
- Mares with foal
- Barren mares
- Mares > 8 years old
- Mares < 7 years old
- Maiden Mares > 8 years old
- Mares with foal
- Barren mares
- Maiden mares < 7 years old
T/F: Evidence has suggested 2x AI pre and post ovulation has a better result than a single AI
True
Advantages of Deep Horn Semen deposition:
1. 2. 3. 4. 5. 6.
- Increase the # of mares bred per ejaculate
- Maximize frozen semen usage
- Increase the efficiency of sexed sperm AI
- Utilize stallions with sub-optimal semen quality
- Reduce the incidence of post-breeding endometritis
- Increase fertility in some mares
What are the three assisted repro techniques used when a mare does not become pregnant after being bred with good semen under excellent management?
- ICSI - intracytoplasmic sperm injection
- ET - embryo transfer
- OT - oocyte transfer
Embryo Transfer:
- Typical donor?
- Typical recipient?
- How old of an embryo?
- Older competition animal
- Young healthy animal
- 7-8 days
Indications for Embryo Transfer:
1.
2.
3.
4.
- Young mares in competition
- Mares with severe uterine problems
- More than one foal a year
- Biopsy for desired outcome
Indications for intra-cytoplasmic sperm injections (ICSI)
1.
2.
3.
4.
- Old mare where it is not possible to retrieve an embryo
- Oviductal disease
- Mares that have died
- Use of stallions with very limited amount of semen available.
Describe the ICSI procedure:
Perform Transvaginal oocyte retrieval of severeal immature oocytes, Allow in vitro oocyte maturation. Inject a single sperm into oocyte, and culture in vitro to check for cleavage. If they reach the morula stage, freeze them or transfer them to a recipient
Indications for Oocyte transfer:
1.
2.
3.
- Old mares where it is not possible to retrieve an embryo
- Oviductal disease
- Mares with unexplained infertility
Describe the oocyte transfer procedure
Perform transvaginal aspiration of a mature oocyte, and aspirate an oocyte from recipient.
Transfer the oocyte into the oviduct of the previously bred recipient mare, and let it carry to pregnancy
