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26 Cards in this Set
- Front
- Back
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Key facts about horse breeding |
-Man has superimposed January 1st birth date for foals in the northern hemisphere -This "universal birthday" is used by many breeds like Thoroughbreds & Quarter Horses |
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Horses are not selected for fertility but for |
performance |
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Thoroughbred breeds prohibits |
artificial insemination |
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Reproductive anatomy of the mare |
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Seasonally polyestrous |
-Mare has a normal biologic breeding season from late March to early September -The use & desires of the impending offspring may dictate an earlier foal than the normal cycle would allow -Alteration in lighting can change the time a mare will cycle |
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Estrous period |
-Typically 5-7 days (early season 10-12) -Also referred to as "follicular phase" -Mare exhibits outward signs of receptivity to the stallion -Outward signs called "heat" shown by squatting to urinate, "winking" vulva, & putting rear by stallion -Ends with ovulation |
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Diestrus period |
-Also referred to as "luteal phase" -Period after ovulation & prior to next estrus period -Usually lasts about 15 days -No outward signs of receptivity, sometimes hateful toward stallion -Period associated with development of corpus luteum at site of ovulation -The CL will produce progesterone |
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Pregnancy |
-Upon ovulation & fertilization, conception may occur with development of an embryo -Once entry is made into uterus, the embryo is very mobile rolling from side to side |
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Embryo will stay in the oviduct until |
day 6-7 (before entering the uterine area) |
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At 12-14 days |
initial pregnancy examination by ultrasound |
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Evaluation for urine pathology |
twins & fluid are assessed |
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If twins are determined to be present |
-"pinching" may be performed -In a high # of cases, twins do NOT result in live healthy foals at the end of gestation |
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Implantation occurs |
day 16-17 |
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At 25-30 days, post ovulation, what can be observed? |
A fetal heartbeat |
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At 45-60 days, post ovulation, what can easily be observed? |
A fetus |
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Average gestation |
338-343 days (Normal gestation can range from 320-380 days) |
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Gestation period |
-Good judgement should be used when moving/hauling a pregnant mare -Provide fresh water, high quality pasture/hay, & grain/supplements -Continue deworming -Allow exercise on regular basis -Administer vaccine for Equine Rhinopneumonitisat (3), 5, 7 and 9 months of gestation |
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During gestation remove pregnant mare from all fescue sources at least 3 months prior to foaling. Why? |
-Agalactia (failure to produce milk) -Prolonged gestation -Retained placenta -Thickened placenta |
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Last month of gestation |
-Many physical & hormonal changes will occur to the mare preparing for the upcoming delivery -Open Caslicks (sewing up mares vulva to prevent infection) if one in place, 2-4 weeks prior to foaling |
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Pre-foaling vaccinations |
should be given 4-6 weeks prior to the foaling date (tetanus, EEE, WEE, WNV, rhino, rabies), these booster the antibody level in the mares colostrum |
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Assisted reproductive techniques |
-Cooled or frozen semen techniques -Embryo transfer -Follicle recovery |
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Prepuce |
Smegma- sebacious gland secretion in the area of the prepuce |
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Penis |
"Bean" a small pellet of waxy debris in the penile fossa & sinus |
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Scrotum |
-2 testicles (testes) site of spermatozoa production -Epididymus associated with each testicle -Spermatic cord associated with each testicle |
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Stallion semen |
-Stallion breeding may be bred by "live" cover or by collection into an artificial vagina -The type of breeding is a multi-factoral decision & may be dependent on breed, stallion, & owner preferences & stallion physical health |
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If semen is collected into an AV, the semen may be |
-Extended with semen extender, & breed mare on sight -Extended with semen extender, & cooled for shipment -Centrifuged, extended & breed mare or cooled for shipment -Centrifuge, & frozen for long-term storage: 0.5ml straws, 500 million progressively motile sperm per insemination |
