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Equine ReproductionEquine Reproduction
LACP LACP
Chapter 6, pages 157-165Chapter 6, pages 157-165
Equine Breeding DataEquine Breeding Data
Type of estrous cycleType of estrous cycle Seasonally polyestrous (long day breeder)Seasonally polyestrous (long day breeder)
Age of female at puberty Age of female at puberty 10 to 24 months 10 to 24 months
Age of male at puberty Age of male at puberty 10 to 24 months10 to 24 months
Time of first breeding Time of first breeding Varies (2 to 3 years)Varies (2 to 3 years)
Estrus cycle frequency Estrus cycle frequency 15 to 26 days (21d)15 to 26 days (21d)
Duration of Estrus Duration of Estrus 2 to 12 days (Average 4 to 7)2 to 12 days (Average 4 to 7)
Equine Breeding Data (cont’d)Equine Breeding Data (cont’d)
Time of ovulationTime of ovulation Last 48 hours of estrusLast 48 hours of estrus
Optimal time of breedingOptimal time of breeding Every 24 to 48 hours while the mare is in heatEvery 24 to 48 hours while the mare is in heat
Gestation period for light breedsGestation period for light breeds 335 to 340 days335 to 340 days
Birth weightBirth weight Varies by breedVaries by breed
Litter sizeLitter size One (twins are rare and undesirable)One (twins are rare and undesirable)
Weaning ageWeaning age 4 to 7 months4 to 7 months
Selecting a Mare and StallionSelecting a Mare and Stallion
MareMarePhysical Physical
characteristicscharacteristicsTemperamentTemperamentAthletic potential Athletic potential Evaluate previous Evaluate previous
foals, reproductive foals, reproductive abilityability
StallionStallionThe four “P’s”The four “P’s”PhenotypePhenotypePerformancePerformancePedigree- proves Pedigree- proves
parentage not parentage not qualityquality
ProgenyProgeny
Breeding Soundness ExaminationBreeding Soundness Examination
Used on both males and femalesUsed on both males and femalesUsually performed near the beginning of Usually performed near the beginning of
the breeding season.the breeding season.A physical exam must be performed firstA physical exam must be performed first
Male Evaluation Female EvaluationMale Evaluation Female Evaluation
PenisPenis Prepuce/sheathPrepuce/sheath ScrotumScrotum TesticlesTesticles Semen analysisSemen analysis Venereal diseaseVenereal disease Physical examPhysical exam
Rectal palpationRectal palpation Ultrasound exam of the Ultrasound exam of the
ovaries, uterus, and cervixovaries, uterus, and cervix Visual exam of the vagina Visual exam of the vagina
and cervixand cervix Uterine cultureUterine culture Possibly a endometrial Possibly a endometrial
biopsybiopsy
Puberty of the MalePuberty of the Male
This is the age when a male can This is the age when a male can impregnate a female.impregnate a female.
10 – 24 months of ages10 – 24 months of agesCastration or Gelding …Castration or Gelding …
Males in General for Breeding Males in General for Breeding purpose purpose
Most males must be restrained for the breeding Most males must be restrained for the breeding examination. examination.
Approach with CAUTION!Approach with CAUTION! Never turn your back on a stallion.Never turn your back on a stallion. Most males tend to resent handling of the genital Most males tend to resent handling of the genital
areas.areas. Consistency!- same handlers, same routine, same Consistency!- same handlers, same routine, same
equipement for breeding , train to collect/breed equipement for breeding , train to collect/breed properly (should start with first breeding)properly (should start with first breeding)
Do not associate breeding with painDo not associate breeding with pain
Preputial and Penile Cleaning:
Routine care of the penis is a must in all male horses, regardless of castration. Smegma is a combination of secretions from sebaceous glands, sweat glands, dead cells, and dirt.
Keep in mind that Houston gets Keep in mind that Houston gets hot-hot-hot!hot-hot-hot!
Three masses of smegma “beans”. These Three masses of smegma “beans”. These beans can become the size of walnuts.beans can become the size of walnuts.
Beans are bad!Beans are bad!
The beans can compress the tip of the The beans can compress the tip of the urethra and make urination difficult and urethra and make urination difficult and very painful.very painful.
Sheath CleaningSheath Cleaning Gloves should be worn.Gloves should be worn. Extract the penis manually or Extract the penis manually or
with the aid of tranquilization.with the aid of tranquilization. One hand holds the penis, the One hand holds the penis, the
other actually does the cleaning other actually does the cleaning with warm water, mild soap and with warm water, mild soap and cotton or gauze.cotton or gauze.
Antibacterial ointment can be Antibacterial ointment can be applied to lesions if found.applied to lesions if found.
Stallion PhysiologyStallion Physiology
Onset of sexual maturity 10-24 mo (18)
Life span of sperm in female tract
2-4 days
Survival time with fertilizing capacity
1-2 days
Sperm output
Semen volume/ejaculate 20-100 ml
Sperm concentration X 106 30-800 ml
# sperm/ejaculate X 109 6
Sperm ProductionSperm Production Sperm Output and Sperm Output and
Production is Production is influenced by:influenced by: SeasonSeason Testicular sizeTesticular size AgeAge Frequency of Frequency of
ejaculationejaculation BehaviorBehavior
Number of Sperm Depends On:Number of Sperm Depends On:
Seasonal Influences (Photoperiod)Seasonal Influences (Photoperiod) Effected AreasEffected Areas
Ejaculate volumeEjaculate volume Sperm numbersSperm numbers Total sperm/ejaculateTotal sperm/ejaculate Sperm motilitySperm motility Willingness to breedWillingness to breed Mounts before breedingMounts before breeding Scrotal sizeScrotal size Testosterone productionTestosterone production
Semen CollectionSemen Collection
Quality and quantity of spermQuality and quantity of spermEvaluate diseases of the male Evaluate diseases of the male
reproductive tractreproductive tractAI=artificial inseminationAI=artificial insemination
Semen Collection and StorageSemen Collection and Storage
Artificial vagina collection most commonArtificial vagina collection most common Avoid contact with air, sunlight, and Avoid contact with air, sunlight, and
extreme heat and cold extreme heat and cold FreshFresh
Use within 24 hoursUse within 24 hours FrozenFrozen
0.5-ml straws0.5-ml straws500 million progressively motile sperm per 500 million progressively motile sperm per
inseminationinsemination
Breeding phantom (Phantom) for semen collection. Can be adjustedto a comfortable height for the stallion
After mounting the mare the artificial vagina is introduced to The stallion for ejaculation collection.
AV=Artificial vaginaOptimal temperature inside the AV is
approximately 113°F (48°C)
Colorado Style
Missouri
French INRA model
Roanoke model
http://video.google.com/videoplay?docid=2375536614971713657&ei=ntI-SrarDpj0qAPFvP2WCg&q=stallion+semen+collection&hl=en
http://www.youtube.com/watch?v=ySUq0xHIBig
General Semen AnalysisGeneral Semen Analysis
AppearanceAppearanceVolumeVolumeConcentration of spermConcentration of spermNumber of spermNumber of spermSperm morphologySperm morphologyLive sperm %Live sperm %Sperm motilitySperm motilitypH (7.2-7.5)pH (7.2-7.5)
Artificial InseminationArtificial Insemination Inseminate pipette into the uterusInseminate pipette into the uterusMultiple inseminations 24 to 48 hours Multiple inseminations 24 to 48 hours
apart apart Common to use ultrasound to monitor Common to use ultrasound to monitor
follicular growthfollicular growth
ExtendersExtenders
Milk based liquid- contains sugars, Milk based liquid- contains sugars, electrolytes and antibioticselectrolytes and antibiotics
Protection, prolonged sperm survival, Protection, prolonged sperm survival, optimal pH and osmotic pressure, optimal pH and osmotic pressure, protection against cold shock. protection against cold shock.
Hormones- testosterone and estogenHormones- testosterone and estogen Leydig cells of the testes produce testosterone Leydig cells of the testes produce testosterone
under the influence of LH (pituitary) under the influence of LH (pituitary) Sertoli cells produce estrogen under influence Sertoli cells produce estrogen under influence
of FSH (pituitary) - not well understood – of FSH (pituitary) - not well understood – regulation and secretion of other hormones regulation and secretion of other hormones “nurse cells”“nurse cells”
Testosterone necessary for spermatozoa Testosterone necessary for spermatozoa productionproduction
Female Reproductive SystemFemale Reproductive System
Mares are seasonally polyestrous, meaning that Mares are seasonally polyestrous, meaning that during the breeding season they cycle repeatedly.during the breeding season they cycle repeatedly.
The natural breeding season centers around the The natural breeding season centers around the period of long day length-light!period of long day length-light!
January 1January 1stst is the designated birth date for all is the designated birth date for all horses in the northern hemisphere. This means horses in the northern hemisphere. This means that a horse born in January and a horse born in that a horse born in January and a horse born in June will both be considered 1 yr old the following June will both be considered 1 yr old the following January. Welcome to the horse world!January. Welcome to the horse world!
CTVT pg. 381
Mare AnatomyMare Anatomy
VulvaVulvaVaginaVaginaCervixCervixUterusUterusOviductsOviductsOvariesOvaries
Left Ovary
Oviduct
Left UterineHorn
Uterine Body
CervixVagina
Female Reproductive SystemFemale Reproductive System
Cost-effectively mares are tricked into Cost-effectively mares are tricked into perceiving that the days are lengthening by perceiving that the days are lengthening by providing artificial lighting and mimicking a providing artificial lighting and mimicking a 16 hour daylight period.16 hour daylight period.
This can be done either indoor or outdoor. This can be done either indoor or outdoor. This should be done in the evening and not This should be done in the evening and not the morning.the morning.
CTVT pg. 381
Reproductive Physiology of the MareReproductive Physiology of the Mare
Estrus Cycle: 15-26 days (21)Estrus Cycle: 15-26 days (21)Estrus: 4-7 daysEstrus: 4-7 daysOvulation: last 48 hrs. of estrusOvulation: last 48 hrs. of estrusGestation: 11 months (330-345 days)Gestation: 11 months (330-345 days)
light breeds (305-365 days)light breeds (305-365 days)
LACP pg. 157
Mares Cycle
0
20
40
60
80
100
120
J F M A M J J A S O N D
% Mares ovulating % Mares in estrus
Perc
ent
Mare Reproductive PhysiologyMare Reproductive Physiology
FSH- follicular recruitmentFSH- follicular recruitmentLH- follicular maturation (with low LH- follicular maturation (with low
progesterone), or aids in production of progesterone), or aids in production of estrogen, ovulation, luteinization of CLestrogen, ovulation, luteinization of CL
Estrogen- released from growing follicle, Estrogen- released from growing follicle, initiates standing heat, relax cervix and initiates standing heat, relax cervix and vulva, increases smooth muscle vulva, increases smooth muscle contraction, negative feedback on FSH, contraction, negative feedback on FSH, positive on LHpositive on LH
Mare Reproductive PhysiologyMare Reproductive Physiology
Progesterone- secreated from CL, tightens Progesterone- secreated from CL, tightens cervix, readies uterus for pregnancy, cervix, readies uterus for pregnancy, decreased receptivity to stallion, decreased receptivity to stallion, decreases smooth muscle contraction, decreases smooth muscle contraction, negative feedback on LHnegative feedback on LH
PGF2PGF2αα – shortens CL life span – shortens CL life span
Photoperiod EffectPhotoperiod Effect
Reproductive activity in Reproductive activity in spring is stimulated by an spring is stimulated by an increasing photoperiodincreasing photoperiod
16 hrs daylight per day16 hrs daylight per day 30-60 days30-60 days Mechanism Mechanism
Alteration of hormone Alteration of hormone secretion by the pineal secretion by the pineal gland and hypothalamusgland and hypothalamus
Hormonal ManipulationHormonal Manipulation
Administer PGF2Administer PGF2αα to shorten life of CL to shorten life of CL (Lutalyse, Estrumate, Equimate)(Lutalyse, Estrumate, Equimate)
Estrus will be 2-4 days later (lasts 4-7days), Estrus will be 2-4 days later (lasts 4-7days), breed at 7-12 daysbreed at 7-12 days
Progesterone administration- maintains a long-Progesterone administration- maintains a long-term estrus suppression, maintain pregnancy, term estrus suppression, maintain pregnancy, suppresses LH and blocks ovulationsuppresses LH and blocks ovulation
When taken off 4-7 days to estrus, 7-12d to When taken off 4-7 days to estrus, 7-12d to breed (Regumate)breed (Regumate)
TransitionTransition
1-3 waves of follicles 1-3 waves of follicles develop & regressdevelop & regress
Estrogens produced by Estrogens produced by developing folliclesdeveloping follicles
Irregular/prolonged Irregular/prolonged estrus exhibitedestrus exhibited
1 follicle eventually 1 follicle eventually ovulatesovulates
Thereafter, mares Thereafter, mares ovulate at ~21-day ovulate at ~21-day intervalsintervals
Prediction of OvulationPrediction of Ovulation
Number of days in heatNumber of days in heatGrowth rate of largest Growth rate of largest
folliclefollicleAverage 3-5 mm/dayAverage 3-5 mm/day
Size of largest follicle Size of largest follicle Softness of preovulatory Softness of preovulatory
folliclefollicleUltrasound imageUltrasound image
Signs of EstrusSigns of Estrus
Most consistentMost consistentElevated tail raiseElevated tail raiseWinkingWinking
Other supporting signsOther supporting signsLeaningLeaningSquattingSquattingStanding stillStanding stillUrinatingUrinating
Equine BreedingEquine Breeding
Successful breeding and Successful breeding and pregnancy in female horses is pregnancy in female horses is not often easy to accomplish.not often easy to accomplish.
Mares do not readily accept Mares do not readily accept the male.the male.
Timing must correspond to Timing must correspond to ovulation.ovulation.
Mares usually breed and Mares usually breed and conceive in the spring and conceive in the spring and summer with deliver about 11 summer with deliver about 11 months later in the spring or months later in the spring or early summer.early summer.
Video..Video..
LACP pg. 281
Pregnancy DiagnosisPregnancy Diagnosis
Rectal palpationRectal palpationDiagnostic Ultrasound, per rectumDiagnostic Ultrasound, per rectumDiagnostic Ultrasound, TransabdominalDiagnostic Ultrasound, TransabdominalExternal PalpationExternal PalpationAbdominal RadiographsAbdominal RadiographsLaboratory TestsLaboratory Tests
Preparation of the Perineum/vulvaPreparation of the Perineum/vulva
Both areas should be Both areas should be cleansed so that you do cleansed so that you do not contaminate the not contaminate the vagina, cervix and uterus vagina, cervix and uterus with fecal material and with fecal material and other debris.other debris.
Tail should be wrapped Tail should be wrapped or bandaged.or bandaged.
LACP pg. 282
Cleaning Cleaning You can use a mild soap, You can use a mild soap,
povidone-iodine scrub, or a povidone-iodine scrub, or a chlorhexidine scrub with warm chlorhexidine scrub with warm water and rolled cotton.water and rolled cotton.
Clean the anal area first Clean the anal area first removing all fecal material. removing all fecal material. Scrub the lips of the vulva and Scrub the lips of the vulva and gradually working a circular gradually working a circular fashion, include the perineum, fashion, include the perineum, anus, and inner aspect of the anus, and inner aspect of the buttocks. Repeat the process buttocks. Repeat the process until cotton shows no until cotton shows no evidence of residue.evidence of residue.
A vaginal speculum examination being A vaginal speculum examination being performed on a mare using a disposable performed on a mare using a disposable
speculum.speculum.
A uterine biopsy instrument being inserted A uterine biopsy instrument being inserted through the vagina and cervix into the through the vagina and cervix into the
uterus.uterus.
Diagnostic Diagnostic UltrasoundUltrasound
An ultrasound image of the black appearance of multiple follicles on an
equine ovary.
An ultrasound image of a 14-day
pregnancy in an equine uterus. This
method can detect a fetus as early as 10 days old and is more reliable than rectal
palpations.
*video
Diagnostic UltrasoundDiagnostic Ultrasound
Twin embryos at 12 days. The equine uterus is not designed to support and nourish more than one fetus; competition for space and nutrition usually results in the death and abortion or stillbirth of both twin fetuses.
TwinsTwinsOccasionally, one twin may be born alive Occasionally, one twin may be born alive
but is typically weak and small, and it but is typically weak and small, and it faces a high mortality rate.faces a high mortality rate.
Birth of living twins is rare, and survival of Birth of living twins is rare, and survival of both is even rarer. When twin embryos or both is even rarer. When twin embryos or fetuses are detected, the vet needs to fetuses are detected, the vet needs to advise the owner of options to either advise the owner of options to either terminate the pregnancy or to terminate terminate the pregnancy or to terminate only one of the embryos in hope that the only one of the embryos in hope that the other may survive.other may survive.
RECTAL PALPATION RECTAL PALPATION
Most common, rapid methodMost common, rapid method
As early as 18 days post ovulationAs early as 18 days post ovulation
Increase uterine tone, presence of vesicular bulgeIncrease uterine tone, presence of vesicular bulge
External PalpationExternal Palpation
External abdominal palpation as used in External abdominal palpation as used in small animals is not possible in large small animals is not possible in large animals.animals.
You place both fists against the lower flank You place both fists against the lower flank area on the mare and rapidly press area on the mare and rapidly press inward; this displaces the pregnant uterus inward; this displaces the pregnant uterus (if present) and rebounds back into the (if present) and rebounds back into the original position by “bumping” against your original position by “bumping” against your fists. This method lacks accuracy and is fists. This method lacks accuracy and is not typically done.not typically done.
Abdominal RadiographsAbdominal Radiographs
Not useful for large animals, but Not useful for large animals, but commonly used in small animals.commonly used in small animals.
““Wee-Foal-Checker”Wee-Foal-Checker”Urine pregnancy test for maresUrine pregnancy test for mares
Laboratory TestsLaboratory Tests
Used when rectal exams are inconclusive or Used when rectal exams are inconclusive or impossible to perform.impossible to perform.
Can be difficult to interpret and have limited Can be difficult to interpret and have limited usefulness. You usually can only perform usefulness. You usually can only perform these during the later stages of pregnancy.these during the later stages of pregnancy.
Progesterone assay- (16-24d) nonspecific, Progesterone assay- (16-24d) nonspecific, high values may mean functional CLhigh values may mean functional CL
Estrogen- (60-100d) higher then during Estrogen- (60-100d) higher then during estrusestrus
Natural Breeding vs. Artificial Natural Breeding vs. Artificial InseminationInsemination
More efficient use of More efficient use of semensemen
Reduce transmission Reduce transmission of diseases from of diseases from stallion to marestallion to mare
Reduce risk of Reduce risk of breeding injuries in breeding injuries in maremare
Success of AI Success of AI requires greater requires greater knowledge and skillknowledge and skill
Increased costIncreased cost Greater risk of human Greater risk of human
injury during injury during collectionscollections
ADVANTAGES: DISADVANTAGES:
Embryo Transfer, Why?Embryo Transfer, Why?
Foals from older, Foals from older, injured, or sub fertile injured, or sub fertile maresmares
Access to wider gene Access to wider gene poolpool
Increase production Increase production and profit on and profit on genetically superior genetically superior maremare
Get embryo from Get embryo from mares who foal late in mares who foal late in seasonseason
Foals from 2 year old Foals from 2 year old maresmares
Foals form mares in Foals form mares in competitioncompetition
Embryo Transfer, why not?Embryo Transfer, why not?
ExpensiveExpensive Need trained Need trained
personellpersonell Embryo recovery can Embryo recovery can
be lowbe low Lack of commercially Lack of commercially
available embryoavailable embryo
Lack of interest by Lack of interest by many registriesmany registries
Many breed Many breed organization do not organization do not accept accept
Harder to Harder to superovulatesuperovulate
Embryo TransferEmbryo Transfer Synchronization of Synchronization of
donor and recipient donor and recipient maremare
Embryo flushingEmbryo flushing Embryo transfer Embryo transfer
procedureprocedure
PGFPGF22
Lutalayse or EstrumateLutalayse or Estrumate
Shorten the interval Shorten the interval between estrous periodsbetween estrous periods
Treatment of a maintained Treatment of a maintained corpus luteumcorpus luteum
After foal heatAfter foal heat Estrous synchronization Estrous synchronization
with prostaglandinswith prostaglandins
Embryo TransferEmbryo Transfer
Ultrasound or palpation for follicular Ultrasound or palpation for follicular development development
Prepare donor mare Prepare donor mare Induce ovulation Induce ovulation Flush 7 to 9 days after ovulationFlush 7 to 9 days after ovulationEmbryos collected in filter cup Embryos collected in filter cup ViewedViewedTransferred within 12 to 24 hoursTransferred within 12 to 24 hours
Recipient MareRecipient Mare
Good health and BCSGood health and BCS Easy to handleEasy to handle Similar in body size to Similar in body size to
donordonor 4-10 years old4-10 years old Sound breeding Sound breeding
conditioncondition Responsive to teaserResponsive to teaser Regular cyclingRegular cycling cheapcheap
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