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