Equine Breeding Management Flashcards
when/how to breed a mare? (3)
- Firstly, the mare’s owner decide when he/she want the foal to arrive, the date of foaling determine when to breed the mare.
- Secondly, the mare’s owner decide the potential use of this mare in the
coming breeding season (normal breeding, ET doner, ET recipient) - Thirdly, the mare’s owner decide which stallion he/she wants for his/ her mare and method of breeding (natural cover/artificial insemination).
difference between early foals vs spring foals vs late foals and what they are good for
- Early Foals (Jan–Feb): foal is for racing. Mare artificial lighting to induce early estrus. Cold weather, and logistical foaling difficulties.
- Spring Foals (May–July): Ideal for natural breeding cycles. good weather, abundant pasture, and reduced feed costs.
- Late Foals : Less optimal.. hot weather, limited pasture, weaning difficulties.
reasons to breed vs not to breed
To Breed
* Cyclic? Stage of estrous?
* Preparing the mare’s reproductive system
* Ordering stallion semen
* Inducing ovulation
* Performing insemination
* Managing post-insemination care
* Diagnosing pregnancy
Not To Breed
* Not cyclic yet?
* Diagnose/ treat mare’s infertility
* Change stallion plan
what is the standard goal of breeding management
To deliver viable spermatozoa into a healthy reproductive tract of the mare very close to the time of ovulation.
duties of the clinician/breeding manager (3)
- Plan for breeding.
- Coordinate mare fertility window / availability of stallion semen.
- Decide when to start the process
what questions do you have to consider when determing how to breed a mare? (7)
- Mare’s age, value, reproductive status, and breeding history
- Breed registry regulations,
- Preference of the stallion owner and/or mare owner,
- Location and availability of the stallion and mare,
- Cost,
- Safety concerns,
- Experience of personnel, and many other factors
what is the only breeding technique allowed in order to register thoroughbred foals with the jockey club
natural service
natural service pasture breeding; when its done, pros, cons
- A stallion + 15-20 mares for 60-90 days, starting in April
- Check for pregnancy 14 days after the stallion leaves the herd.
Pros:
- Reduced horse handling.
- Lower expenses for personnel and breeding.
- Stallion detects estrus naturally.
Cons:
- Risk of injury to stallion or mares.
- Inability to detect reproductive issues in stallion or mares during turnout.
- Potential spread of diseases within the herd.
- Lack of accurate conception dates, making foaling date predictions difficult
natural service in-hand breeding; when its done, pros, cons
- Both the stallion and mare are handled and restrained in a designated breeding area.
- Mating every other day during heat
- or once per estrous cycle. Frequent examinations to determine the optimal breeding day + Hormones (e.g., hCG, GnRH agonists like deslorelin) to induce ovulation.
Pros:
- Breeding can be scheduled.
- Pre-breeding examinations…follicle size, edema pattern, and repro health.
- Post-breeding examinations; ovulation and check for reproductive abnormalities.
- Lower risk to the stallion compared to pasture breeding.
Cons:
- Time-consuming for mare examinations and teasing.
- Requires multiple personnel.
- Risk of injury to personnel
artificial insemination; pros (8)
- Semen Testing: Semen checked for quality and problems spotted and fixed early.
- Increased Efficiency: One semen ejaculate can breed multiple mares
- Helps Older Stallions: with poor semen quality to still breed successfully.
- Less Infection: Reduces uterine infections, in older mares, with added antibiotics.
- Safer Method: Using dummy reduces the risk of injury to people, mares, stallions.
- Flexible Breeding: mismatched sizes, mares not in strong heat, or mares with disabilities.
- Global Genetics: breeding with stallions worldwide using cooled or frozen semen.
- Cost-Effective: Saves money by avoiding mare transport and boarding costs
breeding management for AI; what needs to be done and why
- Fresh, cooled, frozen semen
- Examination of mares by ultra-sonography and judicious use of hormone therapy has allowed veterinarians to:
1. Closely monitor the mare reproductive tract
2. Determine optimal date(s) to collect semen, inseminate the mare and induce ovulation
follicular dynamics and ovulation; waves, how many per cycle, growth and timing to functionality
- Minor waves (no deviation follicles >30mm).
- Major waves (secondary, starts early diestrus, primary, starts in mid-estrus).
- 1-2 major follicular waves develop per cycle
- The dominant follicle of secondary major wave (OV ±) The dominant follicle of Primary major wave preovulatory of next cycle(OV +).
- Ovarian growth 2-4 mm/day (av. 3 mm/day)
- By day 5 after ovulation, the CL is fully functional can respond to PGF
when do you deliver sperm into the mare
very close to the time of ovulation
viability of equine gametes in different forms of semen storage
- Fresh semen …….. 48 hours;
- Cooled semen…… 24 - 48 hours;
- Frozen semen …… ~12 hours;
- Oocyte ….. ……… 6-12 hours
what are some normal ovarian ultrasound features
Normal ovarian structures routinely observed with ultrasound are various sizes of ovarian follicles, corpora hemorrhagica, corpora lutea, and multiple small follicles
grading of endometria edema (5)
- Edema score 0: No edema. The uterus has a homogeneous structure, and no distinct
endometrial folds are visible. - Edema score 1: Mild edema. Distinct endometrial folds are present but not visible throughout
the entire uterus. - Edema score 2: Moderate edema. A cartwheel pattern uterus, with folds appearing slightly hypoechoic in the center.
- Edema score 3: Strong edema. Endometrial folds are prominent, a distinct hyperechoic border and increased thickness.
- Edema score 4: Excessive edema. hyperechoic borders and hypoechoic centers. Free fluid is often detectable
once the mare approaches ovulation, the ____ of the edema starts to _____
intensity; decrease
how to stop vs start ovulation in the mare
Brake (ovulation induction)
1. Deslorelin (1.8 mg, IM) ovulation in 40 h.
2. HCG (2,500 IU, IV) induce ovulation in 36 h, (≥35 mm Pre-ov. follicle)
Accelerator (Luteolysis and Short-Cycling)
1. Cloprostenol 250 μg, IM (1 ml)
2. Dinoprost tromethamine 10 mg, IM (≥5 days old CL + not pregnant mare)
how to determine if its ready for ovulation induction and AI; mare side vs stallion side vs logistics
Mare Side
* ≥35 mm Pre-ov. follicle + healthy uterus (relative pattern of uterine edema + free of fluids)
* Ovulation induction agent (Deslorelin, HCG).
Stallion side
* Semen type and availability
* Stallion collection dates (schedule, even or odd days of month, or a Mon-Wed-Friday).
* Time of semen arrival
* Booking, Cancel/confirm polices.
Logistics
* Shipping options (overnight courier (arrive next day) counter-to-counter (arrive same day)
* Weather patterns can interfere with semen shipments.
* Scheduled national holidays
fresh semen AI; viability, breeding strategy, semen dose, two factors for breeding management
- Sperm Viability : remains viable in the mare’s reproductive tract for at least 48 hrs.
- Breeding Strategy: at least one insemination within 48 hrs before ovulation.
- Semen Dose: at least 500 million PMS, 1:1 with a semen extender + antibiotics (don’t use raw semen)
Breeding Management:
1. Stallion low demand/ young mare healthy uterus, AI every other day until go out of heat.
2. To limit inseminations/ stallion high demand, the estrous cycle monitored via US on the
second day of heat, followed by checks every 24-48 hrs. Once ready, ovulation induction+ AI on the same day!
cooled semen AI; sperm viability, breeding strategy, semen dose
Sperm Viability
-Sperm cooled for 24 hrs remains viable an additional 24 - 48 hrs after
AI.
Breeding Strategy
-At least one insemination within 24 - 48 hrs before ovulation.
Semen Dose
-At least one billion PMS at packaging. 1:3 with a semen extender. Good if PMOT% is at least 50% after 24 hours of cooling
when to induce for cooled semen AI? (3)
- At the Time of Semen Order:
- Frequent practice, reduces interval insemination and ovulation (counter-to-counter)
- Risk: If semen is unavailable or delayed, ovulation may occur without insemination. - When Semen Arrives at the Breeding Farm:
- Results in a longer interval between insemination and ovulation (36–40 hours).
- Safest option to prevent ovulation without insemination. - When Semen Shipment is Confirmed:
- Common practice in the breeding industry (overnight courier… next day arrivals)
- Reduces most risks but does not prevent issues if semen is lost in transit
frozen semen AI; sperm viability, semen dose, breeding strategy (4)
- Sperm Viability : remains viable in the mare’s reproductive tract for ~ 12 hrs.
- Semen Dose: Breeding dose ≥ 300 million PMS, Good if PMOT% ≥ 35% after thawing.
Breeding Strategy
1. The timing of insemination and ovulation must be very tight when using frozen semen.
2. The estrus monitored via US on the second day of heat, followed by checks every 24-48 hrs. Once ready, ovulation induction, keep checks every 8 hrs.
3. If single dose available, inseminate immediately after ovulation is detected.
4. If 2 doses available, one dose within 12 hours prior to the expected ovulation and second dose within 6 hours after ovulation has been detected
post breeding care of mares (3)
- Confirm ovulation
- Manging Persistent breeding- induced endometritis
- Pregnancy check day 15 ( or day 14 in case of suspecting twins)
