2 TERMINOLOGY BOOK BOOKING FEES STUD FEE FOAL GUARANTEE Live Foal Return ColorWET/DRY CAREBREEDERThoroughbredOther breedsDEATH & SALES CLAUSECHUTE FEE
3 Stallion Physiology Onset of sexual maturity 10-24 mo Life span of sperm in female tract2-4 daysSurvival time with fertilizing capacity1-2 daysSperm outputSemen volume/ejaculatemlSperm concentration X 106ml# sperm/ejaculate X 1096
4 Sperm Production Sperm Output and Production is influenced by: Season Testicular sizeAgeFrequency of ejaculationBehavior
5 Number of Sperm Depends On: Seasonal Influences (Photoperiod)Effected AreasEjaculate volumeSperm numbersTotal sperm/ejaculateSperm motilityWillingness to breedMounts before breedingScrotal sizeTestosterone production
6 Mare Anatomy Vulva Vagina Cervix Uterus Oviducts Ovaries Left Ovary Ovary – 2X1.5” in diameter. Located on pinched in face of ovary is ovulation fossa – unique anatomical feature of equine ovary.Oviducts = ~8-12”long.Uterus – Body & 2 horns. 8” wide X 3” wideCervix – 2-3”. Longitudinal foldsVagina – 7-9” long & 4-5” diameterLeft UterineHornUterine Body
7 MARES TERMS Anestrus Pregnant Diestrus Open Estrous Barren Estrus MARE CLASSIFICATIONPregnantOpenBarrenMaidenWetDryTERMSAnestrusDiestrusEstrousEstrusAnestrus – The period when most mares show no signs of reproductive activity at all.Diestrus – The period when the mare is not receptive to the stallion (usually lasts days)Estrous – Entire reproductive cycle. The average length of the estrous cycle is days (from one ovulation to the next).Estrus – Refers to “heat”, the period when the mare is receptive to the stallion (usually lasts 5-6 days).
8 The Open Mare Evaluate reproductive history Establish the time of year to breedMare Plan:Diagnose possible problemsImplement problem managementEstablish estrus calendar
10 Photoperiod EffectReproductive activity in spring is stimulated by an increasing photoperiodMechanismAlteration of hormone secretion by the pineal gland and hypothalamus
11 J F M A M J J A S O N D Increasing day length Decreasing day length Receptors in eyeNeuropathwayNeuropathwayPineal glandDecreasing melatoninIncreasing melatoninHypothalamusIncreasing GnRHDecreasing GnRHPhotoperiod EffectReproductive activity in spring is stimulated by an increasing photoperiodMechanismAlteration of hormone secretion by the pineal gland and hypothalamusAnterior pituitaryDecreasinggonadotropinsIncreasinggonadotropinsOvaries
12 Transition PeriodIncreased photoperiod stimulates the hypothalamus and pituitaryPituitary hormones (especially FSH) induce follicular development
13 Transition 1-3 waves of follicles develop & regress Estrogens produced by developing folliclesIrregular/prolonged estrus exhibited1 follicle eventually ovulatesThereafter, mares ovulate at ~21-day intervalsIncreased photoperiod stimulates the hypothalamus and pituitaryPituitary hormones (especially FSH) induce follicular developmentNote – Multiple follicles on ovary.
15 Estrous Cycle Sun Mon Tue Wed Thu Fri Sat 1 2 3 4 5 6 7 8 9 10 11 12 13141516171819202122232425262728293031Note:5 days estrus. To estimate the next cycle, count 21 days from the 1st day of estrus or 15 days from the last day of estrus.
16 Estrus Follicular Development & Ovulation Anterior Pituitary – FSH - follicular growthPituitary – LH – maturation of follicle & ovulationFollicles reach mm in diameter, secrete estrogen.
17 Prediction of Ovulation Number of days in heatGrowth rate of largest follicleAverage 3-5 mm/daySize of largest follicleSoftness of preovulatory follicleUltrasound imageOvulation normally occurs when follicle reaches 4-5 cm
18 Diestrus Corpus Luteum Formation Corpus luteum - secretion of progesterone.Progesterone - responsible for keeping the mare out of heat and for maintaining pregnancy.Prostaglandin ReleaseProstaglandin (PGF) - released from the uterus of a non-pregnant mare days after ovulation
19 Postpartum Estrus Foal Heat Fertile as compared to other species. Breeding may be necessary to maintain the 12 mo. Foaling interval.May be necessary to back up foaling.
20 Signs of Estrus Most consistent Other supporting signs Elevated tail raiseWinkingOther supporting signsLeaningSquattingStanding stillUrinating
22 Light Stimulus16 hrs daylight per day30-60 days
23 Progesterone or related compounds Regumate – most commonNormalization of estrusRegulation of estrusEstrus synchronizationLong-term suppression of estrusDelay foal heatPregnancy maintenanceNormalization of estrus in the early breeding season.Control of estrus in mares exposed to artificial light.Regulation of estrus in cycling mares.Appointment breeding.Estrus suppression in performance mares.Delaying foal heat.Pregnancy maintenance.
24 PGF2 Lutalayse or Estrumate Shorten the interval between estrous periodsTreatment of a maintained corpus luteumAfter foal heatEstrous synchronization with prostaglandins
26 Cooled Shipped Semen ADVANTAGES Cost Genetics Disease DISADVANTAGES Technology/managementStallion variabilityCommon ProblemsInability to obtain semenPoor quality semenReordering semenFailure to predict ovulationADVANTAGESCostNo mare care or shipping expensesGeneticsPotential access to higher qualityDiseaseDecreased transmission of std’sDISADVANTAGESCost & shipmentVeterinary/technician expensesTechnology/managementCompetent individualsStallion variability DISADVANTAGESStallion variability
27 Frozen Semen Success of Frozen Semen Maximum Success Fertility of stallion’s semenFertility of the mareSkill of the veterinarian/technicianMaximum SuccessClient communicationChoose ideal candidateHistory of stallion
28 Embryo Transfer Synchronization of donor and recipient mare Embryo flushingEmbryo transfer procedure
34 Late Pregnancy Abdomen greatly enlarged Ventral edema Mammary gland enlargement – 2-4 wkGluteal muscles relax – 7-10 dTeats fill with milk – 4-7 dWaxing of teat ends – 1-4 dVulva soft & relaxed – 1-2 d
35 Stages of Parturition Stage 1 Stage 2 Onset: initial uterine contractionsEnd: rupture of chorioallantois (water bag)Stage 2Onset: rupture of chorioallantoisEnd: delivery of fetus
36 Stages of Parturition Stage 3 (< 3 hrs) Onset: delivery of fetus End: passage of the fetal membranes
37 Foals and Immunity Colostrum (first milk) - antibodies 1-2 pts of high quality colostrumIf adequate passive transfer occurs there will be over mg/dl IgG in foal’s bloodTakes ~ 12 hours for all antibodies ingested in colostrum to show up in the blood
38 Key pointsFirst two weeks- lay the groundwork by ensuring adequate colostrumPreventative health program in placeAppropriate nutritionProblems must be addressed rapidly when they arise. No time for a “wait and see” attitude