selection and preparation of the mare and stallion for breeding

Selection and Preparation of the Mare and Stallion for Breeding

Abdelsalam TalafhaDVM, Diplomate American College of Theriogenologists

School of Animal and Veterinary SciencesThe University of Adelaide, SA 5371

Australia

Introduction - selection criteria

Criteria and techniques used in selection for reproductive competence

Goal: To produce healthy offspring with minimal danger to life and well-being of dam

Selection of the MareBreeding Soundness Examination “BSE”

Components of BSE

Reproductive and general history / Records

General physical examination

Reproductive tract examination

Reproductive history : Age

• 18 - 24 months

Puberty

• Higher embryo mortality rates• Demands of maintenance, growth,

pregnancy

Breeding at puberty

Reproductive history: Age

Maiden mares over 12 y of age

• Reduced fertilization & embryo survival rates• Poor ova viability• Embryonic defects• Increase in age-related endometritis

• Exposure to uterine infections

Reproductive history: Age

• Abnormal estrous cycles• Corticosteroids and anabolic steroids

effects• 6-18 months rest period to settle

down into non-athletic state

Mares in peak athletic condition demonstrate

Reproductive history : Age

Ideal age to breed a maiden mare

5–6 y. old

Not normally advisable to breed

Over 20 y. old

Reproductive history / Records

Length of estrous cycle / estrus

Regularity of estrous cycles

Showing characteristic signs of estrus

Beginning and length of breeding season

Reproductive history / Records

• Early embryonic death• Abortion • Twins• Dystocia

Problems during previous

pregnancies

• Rejection of foals• Foal birth weight / growth

rates• Uterine infection• Mammary gland inflammation

Post foaling problems

General history

VaccinationParasite controlUmbilical hernia

Respiratory problemsVaginal prolapse

LaminitisNavicular disease

Tendonitis

General physical examination

All body systems

Blood analysis

Urinalysis

Fecal egg count

Evaluation of conformation

Reproductive tract examination

Perineal conformation

Vaginal speculum exam

Rectal palpation

Ultrasound examination

Uterine cytology

Uterine culture

Uterine biopsy

Reproductive tract examination of

Uterine biopsy: category and predicted foaling rate (%)

I: 80–100%

II A: 50–80%

II B: 10–50%

III: < 10%

Selection of the StallionBreeding Soundness Examination

Components of Stallion BSE

Reproductive and general history

General physical examination

Reproductive tract examination

Observation of libido and mating ability

Examination for venereal disease

Semen collection and evaluation

Reproductive history / Records

Start and end of his season

Previous breeding performance

Results of prior fertility evaluations

Reproductive-tract infections

General history

Hind limbs injuries

Injuries to genitalia

Systemic infections

Vaccination

Parasite control

General physical examination

All body systems

Blood analysis

Urinalysis

Fecal egg count

Evaluation of conformation

Reproductive tract examination

Examination of the external and internal genitalia

Libido and mating ability

Immediate interest and interaction with a mare in estrus

Erection within 2 min.

Mount readiness within 5 to 10 sec. after erection

Ejaculation on 1st mount

Total breeding time of 2 to 5 min.

Examination for venereal disease

Normal nonpathogenic bacteria flora

Potentially harmful bacteria

Klebsiellapneumoniae

Pseudomonas aeruginosa

Venereal bacteria

Taylorellaequigenitalis

Venereal viruses

Equine herpes virus 3

Equine viral

arteritis

Semen collection and evaluation

Semen collection using artificial vagina

Ejaculate should be filtered

Gel: 10 - 300 ml

Gel free semen: 20 - 80 ml

Semen evaluation

• Watery grey to creamy white

Color of normal

ejaculate

• 7·2 - 7·7Normal semen

pH

Semen evaluation: Motility

• Scale of 0 to 4

Velocity

• > 60%• PM < 40% are likely to compromise

fertility

Progressive motility (PM)

Semen evaluation: Concentration

100 – 500 x 106 sperm /ml

4 – 14 x 109 sperm / ejaculate

Semen evaluation: Morphology

Morphologically normal (MN) > 70%

Calculation of PM – MN sperm: Example

A stallion produces 90 ml semen

Gel-free sperm = 75 ml

[ Sperm ] = 220 x 106 /ml• 75 ml x (220 x 106) = 16·5 x 109 / ejaculate

Assuming PM = 75%• Total # PM = (16·5 x 109) x 0·75 = 12·37 x 109

Assuming MN: 50% of PM • Total # PM-MN sperm= (12·37 x 109)x 0·50 = 6·18 x 109

Daily Sperm Output (DSO)

Number of sperm that a stallion can produce on a daily basis

To achieve 75%, 45-day pregnancy rate in 40 mares by natural cover or 120 mares by AI during a typical breeding season of 135-150 days

• Minimum of 2 x 109 PM-MN sperm in 2nd of 2 sperm collections taken 1 hr apart after 1 week of sexual rest

BSE - Interpretation

• Pass all tests of BSESatisfactory

• A problem that precludes his classification as satisfactory

• May pass BSE at a later dateQuestionable

• A problem that is not expected to improveUnsatisfactory

Types of semen

• Intended for AI at premises other than that on which it was collected

Transported semen

• Not extended• Must be used within 10 minRaw semen

• Extended semen • Maintained at ~ 22°C • Used within 4 hrs of collection

Fresh semen

Types of semen

• Mixed with extender• Cooled to between 5-10 °C• Used within 36 hrs after

collection

Chilled (cooled) semen

• Processed and maintained in liquid nitrogen (-196°C) for long periods

Frozen semen

Semen preservation: semen extender

• Protect sperm against cold shock by stabilizing cellular membranesLipoproteins

• Source of energy for spermGlucose

• Eliminate bacteria growthAntibiotics

• 350 mOsm/LOsmolarity

• 6.5 to 7.2pH

Semen preservation: Chilled Semen

• Within 2 - 5 min after ejaculationSemen mixed with 37°C extender

• Dilution 1:1 extender : semenFor immediate AI

• Dilution 4:1Semen storage > 2 - 4 hrs

• 25 - 50 x 106

sperm / mLFinale conc. in extended semen

Insemination volume (IV) for fresh extended semen

IV (mL) = PMS dose ÷ (SCe x %PM)

PMS dose: 100 – 500 x 106

SCe: sperm concentration in extended semen

(25 - 50 x 106 )

%PM: progressively motile sperm in ejaculate

Insemination volume (IV) for fresh extended semen

Example: [ sperm ] = 220 x 106 /ml, PM = 75%

IV = 500 x 106 ÷ (50 x 106 x 0.75) = 13.3 ml

(500 x 106 ÷ 220 x 106 ) 2.3 ml semen : 11 ml

extender

= dilution 1 ml semen : 5 ml extender

Typical IV 10 – 30 ml

Semen preservation: chilled semen

• Refrigerated temp: 24 - 48 hrs• 72 - 96 hrs (highly fertile stallions)

• Room temp: 12-24 hrs

Extended semen fertilizing capacity

• No adverse effects of on sperm motility, morphology, or fertility

• Mares delivered normal foals at term

Airport security x-ray at 10 μSv

Semen Preservation: Frozen semen

Insemination

Thawing

Storing

Freezing

Packaging

Freezing extender

Dilution and centrifugation

Semen Preservation: Frozen semen

• Stallion identification• Breed registry• Registration number• Semen-processing location and date• Freezing extender used

0.5-mL straw labeled with

Longevity of sperm motility

• Room temp. • PM > 10% at 6 hrs

Raw semen

• Stored at 5°C• Examined at 6, 12, 24 and 48 hrs• PM > 40% when warmed to 37°C after 24 h

Chilled extended semen

• Thawed at 38°C• PM > 15% after 2 hrs

Frozen sperm

Minimum standards for stallion semen for AI by “World Breeding Federation for Sport Horses (WBFSH)”

• Minimum of 300 x 106 PM

Fresh Semen

• Sperm dose: Minimum of 300 x 106 PM at time of portioning

• AI: within 12 hrs of collection• PM: > 35%• Storage conditions maintained

Chilled Semen: Extended / Fresh

Minimum standards for stallion semen for AI by WBFSH

• Sperm dose: minimum of 600 x 106 PM at time of portioning

• Max. volume: 40 cc • AI: 24 - 36 hrs after collection• PM: > 35%• Storage conditions maintained

Chilled Semen: Extended / Transported

Minimum standards for stallion semen for AI by WBFSH

• Minimum of 750x106 PM per AI dose post-thawing

• Volume dose: dependent on manufacturing process (0.5 or 5 ml straws)

• PM: > 35% post-thawing

Frozen Semen

Back to our Example using WBFSH standards

Gel-free sperm = 75 ml, [ sperm ] = 220 x 106 /ml, PM = 75%, Total # PM in ejaculate = 12·37 x 109

This ejaculate can be used for

Fresh and fresh extended semen =(12.3 x 109) ÷(300 x 106 ) = 41 mares

Chilled transported semen =(12.3 x 109) ÷ (600 x 106 ) = 20 mares

Back to our Example using WBFSH standards

Frozen semen= (12.3 x 109) x 0.35 post-thaw

motility ÷ (750 x 106 ) = 6 mares

If you want to be more hard on stallion, consider

% MN sperm in your calculations, i.e. 20, 10 and

3 mares, respectively, assuming 50% MN sperm

in ejaculate

Timing of insemination

• 24 - 36 hrs pre-ovulation

Fresh semen

• 12 - 18 hrs pre-ovulation

Chilled semen

• 6 - 12 hrs pre-ovulation• Up to 6 hrs post-ovulation

Frozen semen

Preparation of the Mare and Stallion for Covering

Body Condition

Ideal body condition score (BCS) at mating

• 5-6 (scale 1 - 9)• Good covering of flesh• Ribs, vertebrae, backbone felt with some

pressure

Mare and stallion Preparation - ManagementIntroduction to breeding surroundings &

proceduresExercise

Social interaction

Hoof care

Dental care

Parasite control

Vaccination

Introducing Stallion to Covering

• 1st breeding 3 years

• 50 mares / season• Inconsistent fertility

rates and libido

4 years

• 50–100 mares / season

• Up to 3 mares / day

5 y until his 20s

Introducing Stallion to Covering

During 1st season• Limited to 10 - 15 mares spread out over

season• Not more than 1 mare / day

References

Juan C. Samper, Jonathan F. Pycock, Angus O. McKinnon. Current Therapy in Equine Reproduction. 2007. Saunders Elsevier, St. Louis, Missouri.

Juan C. Samper. Equine breeding management and artificial insemination. 2nd edition. 2009. Saunders Elsevier, St. Louis, Missouri

Steven P. Brinsko et al. Manual of equine reproduction. 3rd edition. 2011. Mosby Elsevier, Maryland Heights, Missouri

www.vetmed.lsu.edu/eiltslotus/theriogenology-5361/ www.equine-reproduction.com www.drostproject.org www.ivis.org

THANK

YOU

Petra -JORDAN