equine reproductive techniques

Equine Reproduction

Tad Thompson, DVMSheridan, IN

Topics For Tonight– Mare

• Anatomy & Physiology• Prebreeding Plan

– Months, Weeks & Days• Breeding Plan

– Stallion • What's The Options

– Complications– Embryo Transfer– Gestation

• Now What?– How Long & How Much

Mare Anatomy & Physiology

What are the reproductive organs of the mare?• Pineal Gland• Hypothalamus• Pituitary Gland• Reproductive Tract

– Ovaries, Ovaducts, Uerine Horns, Uterine Body, Cervix, Vagina, lymph

• Mare’s Udder

– Take home message: Endocrinology is a big player in reproduction

– Because of this complexity of the endocrine system, mares are considered to be ______ ______ Breeders


–Long Day Breeders• Responsive to the photo period to induce estrus

– Photic information is received by the retina, transferred to the hypothalamus, which instructs the rest of the endocrine organs.


Mares require day light at least 14.5 hours per day to start vernal transition from anestrus.

Recommend 18 hours per day of artificial lighting• Best to extend lights in the evening • Rule of thumb can you sit in the darkest corner of the stall

and read a newspaper?


? What are the seasonal stages of the mares cycle?– Winter months (Anestrous)– Early Spring (Vernal Transition)– Later spring through summer (Estrous)– Fall (Transition)

– All mares will go through a transitional period of 6-8 weeks– Naturally early April is first heat cycle, on average – What does it mean for your mare to be “Transitional”?

• Her cycle will not progress to the breeding stage.


? What are the stages of the mares estrus cycle?– Estrous (follicular phase)– Diestrus (luteal phase)

Estrous defined as the period in which the mare is sexually receptive to the stallion, the genital tract is prepared to accept and transport spermatozoa, and ovulation occurs.

Average cycle length for mares = 21 days.


Estradiol increases during estrus- Produced by the

Follicle- Rapidly declines at

ovulation- Creates the “Edema”

seen on ultrasound- Relaxation of cervix- etc……


Progesterone is produced by the CL and increases post OVD

-Maintains pregnancy

-Regumate is a synthetic progesterone source.

PGF2alpha is a natural prostaglandin that causes the CL to regress

-Estrumate & Lutalyse are prostaglandins

Methods Of Synchronization

• PGF2a (Lutalyse, Estrumate)

• Combine exogenous progesterone (Regumate) with PGF2a

• P & E with PGF2a

• All followed with hCG or Deslorelin to induce ovulation. Goal is to induce ovulation within 48hrs.

Mare Anatomy

Good Challenging

Prebreeding Plan

1. Determine foaling date goal.

2. Does the mare need under lights?

3. Any history of prior complications?1. If so start early – more to come

4. Select stallion.1. Determine shipping options – more to come

5. Make sure paper work is in order..

Breeding PlanOnce mare is cycling what do I do?

Rectal ultrasound

Uterine culture and cytology

Cervix evaluation

Tools that help guide us in optimizing the breeding.

Breeding Plan

Rectal ultrasounds “Making since of the Black & White”

What are we looking at?

A. Cervix

B. Uterine body

C. Both uterine horns

D. Both ovaries

– Cross section of a uterine horn

Breeding Plan


– Mares in estrus will have the following ultrasound characteristics

– Uterine body & horns • Pin Wheel Appearance

» No Free Fluid

– Ovaries – Large Follicule » Black in color with a clear internal structure

– Cervix is soft and open

Breeding Plan


– Mares in anestrus will have the following ultrasound characteristics

– Uterine body & horns will have no edema• Homogeneous look

» No Free Fluid

– Ovaries • CL or corpum lutem

– White structure – Producing Progesterone

– Cervix is tight & closed– Progesterone affects

Breeding Plan

• The StallionA. Live Cover?

B. Artificial Insemination? – Semen Type

• Fresh • Cooled • Frozen

– Semen Quality• Concentration• Motility • Morphology

How Do We Get Her Bred?

We will evaluate each sample prior to insemination

Breeding The Mare

• Standard breeding management apply– Sterile prep of rectal and vaginal area – Sterile OB sleeve, pipette and lube – Semen is deposited inside internal os of cervix unless

frozen semen– Frozen semen

• Breeding close to OVD• Deep horn insemination• Pre & post OVD

Questions???So Far!

Complications– Abnormal conformation

• Urine pooling• Fecal contamination

– Uterine infection• Semen infection

– Poor uterine clearance of fluid• Poor lymphatic drainage• Cervix issue

– Cervical incompetence• Failure to open & close• Higher rate of yeast & fungal infections

– Anovulatory follicles• More frequent in transitional mares but

may occur mid summer

No Bugs Needed

Complications– Abnormal conformation– Uterine infection– Poor uterine clearance of fluid

• Culture & cytology– Know what you are dealing with

• Uterine lavage – solution to pollution is dilution

• Oxytocin• +/- Antibiotics

– Cervical incompetence• If no infection topical medication to soften cervix

– Anovulatory follicles• Time • Later prostaglandin

Transcervical Uterine Lavage

Questions

• My Padawan Learners

History of Embryo Transfer

• What species was the first ET preformed on?

• Rabbit

• What year was the first ET preformed?

• 1891

Embryo Recovery • Mare are bred in the same fashion • Embryos can be recovered b/w day 6-9

– Embryo enters uterus around @ 6.25days post OVD– Older mares slower embryo transient time

• Optimal recovery time varies based on goals– i.e. fresh transfer vs. vitrification – Recovery rates of 70-80 % can be expected @ day 7-

8 post ovulation – Transfer of larger day 9-10 embryos is possible but

less reliable • Increased Size and Fragility • Use modified technique

Transcervical Uterine Lavage

Recovered Fluid

• Filter cup emptied into sterile girded search dish– Rinse filter with flush media

• Fluids examined with stereomicroscope– 10-15x magnification – Day 7 embryo’s 300-600 um dia. – Large embryo’s (~8day) often visible with

naked eye

Staging Embryo

Grading Embryo

Grade 1

Grade 3

Transfer Process

• The single most rate limiting step in the success of the ET program

» The Transfer!!!

• This process is achieved in a manor similar to artificial insemination with a success rate ranging from 60% to 80% – Technique experience very important

Summary of Success

• If stallion and mare factors optimized – Good donor candidate

• 75% embryo recovery • 75% pregnancy rate at 14 days • 5-10% early pregnancy loss• Approx. 50% success or 1 out of 2 flushes

– National averages– On the conservative side

Gestation

– Pregnancy check at 14-16 days post OVD• Prior to implantation – twin reduction• Return to estrus for rebreeding

– Recheck ultrasound 30-45 days• Early embryonic loss• Breed back

– Recheck at 90-120 days - optional • Fetal sexing – variable results, fetal size and position

– Recheck 300 day or 10 month - optional • Early placentitis diagnosis

– Low frequency

Gestation

Main causes of abortion in mares• EHV – 1 : single most important infectious cause

– Viral respiratory infection of the mare followed by transplacental migration and ultimate anoxia of foal

– Variable duration of infection and abortion

• Bacterial & Fungal Infection – Most commonly ascending through cervix

– Placentitis – inflammation of placenta• Generally bacterial infection • Clinical signs include

– Premature mammary development with milk production– 300 day ultrasound may help catch 50-60% of these case resulting in a

live foal

Gestation

– Vaccination schedule • EHV – 1 at months 3, 5, 7, 9• Prefoaling boosters 30 days prior to delivery

– Rhino/ Flu, WNV, EWT, Rabies– Improves colostrum quality

Take Home Message

Reproduction is all about the

“half percenters”

!They soon add up to a significant difference!

How Long & How Much

Breeding Plan

A. Live cover

B. JVC manages from A-Z

C. Mare owner hauls in

D. Difficult mare has prolonged stay

Many variables can affect duration and cost of breeding

How Long & How MuchBoard Dry Mare = $29

Wet Mare = $32

Uterine Culture = $75

Uterine Cytology = $66

Ultrasound (In Clinic)

- first one of the year $52

- followup $29

Semen Evaluation = $19

Artificial Insemination Fresh semen = $49

Frozen semen = $80

Uterine Lavage = $72

Uterine Infusion = Varies based on antibiotic

How Long & How Much

Prebreeding Workup

-Uterine culture & cytology

-Ultrasound exam

Average cost $190

Uncomplicated Breeding

-Mare arrives in estrus

-No treatments needed

-We manage A – Z

-4 days in clinic

Average cost $450

Uncomplicated Breeding Hauled In -Less board at JVCAverage cost $475

Complicated Breeding-Based in reason & number of treatmentsAverage cost is highly variable

-can double base costs

Embryo Transfer-Collection at JVC $410-Recipient mare off site $?

Questions???

317-758-4865janssenvetclinic.com

Tad Thompson, DVM

equine reproductive techniques

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