1. Equine Reproduction
LACP
Chapter 6, pages

2. Equine Breeding Data Type of estrous cycle Age of female at puberty
Seasonally polyestrous (long day breeder)
Age of female at puberty
10 to 24 months
Age of male at puberty
Time of first breeding
Varies (2 to 3 years)
Estrus cycle frequency
15 to 26 days (21d)
Duration of Estrus
2 to 12 days (Average 4 to 7)

3. Equine Breeding Data (cont’d)
Time of ovulation
Last 48 hours of estrus
Optimal time of breeding
Every 24 to 48 hours while the mare is in heat
Gestation period for light breeds
335 to 340 days
Birth weight
Varies by breed
Litter size
One (twins are rare and undesirable)
Weaning age
4 to 7 months

4. Selecting a Mare and Stallion
Physical characteristics
Temperament
Athletic potential
Evaluate previous foals, reproductive ability
The four “P’s”
Phenotype
Performance
Pedigree- proves parentage not quality
Progeny

5. Breeding Soundness Examination
Used on both males and females
Usually performed near the beginning of the breeding season.
A physical exam must be performed first

6. Male Evaluation Female Evaluation
Rectal palpation
Ultrasound exam of the ovaries, uterus, and cervix
Visual exam of the vagina and cervix
Uterine culture
Possibly a endometrial biopsy
Penis
Prepuce/sheath
Scrotum
Testicles
Semen analysis
Venereal disease
Physical exam

7. Puberty of the Male
This is the age when a male can impregnate a female.
10 – 24 months of ages
Castration or Gelding …

8. Males in General for Breeding purpose
Most males must be restrained for the breeding examination.
Approach with CAUTION!
Never turn your back on a stallion.
Most males tend to resent handling of the genital areas.
Consistency!- same handlers, same routine, same equipement for breeding , train to collect/breed properly (should start with first breeding)
Do not associate breeding with pain

9. 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.

10. Keep in mind that Houston gets hot-hot-hot!

11. Three masses of smegma “beans”
Three masses of smegma “beans”. These beans can become the size of walnuts.

12. Beans are bad!
The beans can compress the tip of the urethra and make urination difficult and very painful.

13. Sheath Cleaning Gloves should be worn.
Extract the penis manually or with the aid of tranquilization.
One hand holds the penis, the other actually does the cleaning with warm water, mild soap and cotton or gauze.
Antibacterial ointment can be applied to lesions if found.

14. Stallion 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 ml
Sperm concentration X 106 ml
# sperm/ejaculate X 109 6

15. Sperm Production Sperm Output and Production is influenced by: Season
Testicular size
Age
Frequency of ejaculation
Behavior

16. Number of Sperm Depends On:
Seasonal Influences (Photoperiod)
Effected Areas
Ejaculate volume
Sperm numbers
Total sperm/ejaculate
Sperm motility
Willingness to breed
Mounts before breeding
Scrotal size
Testosterone production

17. Semen Collection Quality and quantity of sperm
Evaluate diseases of the male reproductive tract
AI=artificial insemination

18. Semen Collection and Storage
Artificial vagina collection most common
Avoid contact with air, sunlight, and extreme heat and cold
Fresh
Use within 24 hours
Frozen
0.5-ml straws
500 million progressively motile sperm per insemination

19. Breeding phantom (Phantom) for semen collection. Can be adjusted
Good footing, correct height, can use with a teaser mare, can use AV inside dummy. Collect every other day allows maximum harvest with minimal labor/risk of injury
Breeding phantom (Phantom)
for semen collection. Can be adjusted
to a comfortable height for the stallion

20. After mounting the mare the artificial vagina is introduced to
The stallion for ejaculation collection.

21. Optimal temperature inside the AV is
AV=Artificial vagina
Optimal temperature inside the AV is
approximately 113°F (48°C)

22. Colorado Style
Missouri

23. French INRA model
Roanoke model

24. http://video. google. com/videoplay

25. General Semen Analysis
Appearance
Volume
Concentration of sperm
Number of sperm
Sperm morphology
Live sperm %
Sperm motility
pH ( )
Volume mL Motility-(use warm slide) normal 75-80%, Concentration x10^6 per dose, concentration X volume= total # of sperm, morphaology- 90% or better,

26. Artificial Insemination
Inseminate pipette into the uterus
Multiple inseminations 24 to 48 hours apart
Common to use ultrasound to monitor follicular growth
Extenders- protection, increased insemination volume, prolonged sperm survivial, enhanced fertility, optimal pH and osmotic pressure, protection against cold shock

27. Extenders
Milk based liquid- contains sugars, electrolytes and antibiotics
Protection, prolonged sperm survival, optimal pH and osmotic pressure, protection against cold shock.

28. Hormones- testosterone and estogen
Leydig cells of the testes produce testosterone under the influence of LH (pituitary)
Sertoli cells produce estrogen under influence of FSH (pituitary) - not well understood – regulation and secretion of other hormones “nurse cells”
Testosterone necessary for spermatozoa production

29. Female Reproductive System
Mares are seasonally polyestrous, meaning that during the breeding season they cycle repeatedly.
The natural breeding season centers around the period of long day length-light!
January 1st is the designated birth date for all horses in the northern hemisphere. This means that a horse born in January and a horse born in June will both be considered 1 yr old the following January. Welcome to the horse world!
CTVT pg. 381

30. 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” wide
Cervix – 2-3”. Longitudinal folds
Vagina – 7-9” long & 4-5” diameter
Left Uterine
Horn
Uterine Body

32. Female Reproductive System
Cost-effectively mares are tricked into perceiving that the days are lengthening by providing artificial lighting and mimicking a 16 hour daylight period.
This can be done either indoor or outdoor. This should be done in the evening and not the morning.
Also hormone use to induce ovulation,
CTVT pg. 381

33. Reproductive Physiology of the Mare
Estrus Cycle: days (21)
Estrus: 4-7 days
Ovulation: last 48 hrs. of estrus
Gestation: 11 months ( days)
light breeds ( days)
LACP pg. 157

34. Mares Cycle
Percent

36. Mare Reproductive Physiology
FSH- follicular recruitment
LH- follicular maturation (with low progesterone), or aids in production of estrogen, ovulation, luteinization of CL
Estrogen- released from growing follicle, initiates standing heat, relax cervix and vulva, increases smooth muscle contraction, negative feedback on FSH, positive on LH

37. Mare Reproductive Physiology
Progesterone- secreated from CL, tightens cervix, readies uterus for pregnancy, decreased receptivity to stallion, decreases smooth muscle contraction, negative feedback on LH
PGF2α – shortens CL life span

38. Photoperiod Effect
Reproductive activity in spring is stimulated by an increasing photoperiod
16 hrs daylight per day
30-60 days
Mechanism
Alteration of hormone secretion by the pineal gland and hypothalamus

39. Hormonal Manipulation
Administer PGF2α to shorten life of CL (Lutalyse, Estrumate, Equimate)
Estrus will be 2-4 days later (lasts 4-7days), breed at 7-12 days
Progesterone administration- maintains a long-term estrus suppression, maintain pregnancy, suppresses LH and blocks ovulation
When taken off 4-7 days to estrus, 7-12d to breed (Regumate)

40. Transition 1-3 waves of follicles develop & regress
Estrogens produced by developing follicles
Irregular/prolonged estrus exhibited
1 follicle eventually ovulates
Thereafter, mares ovulate at ~21-day intervals
Increased photoperiod stimulates the hypothalamus and pituitary
Pituitary hormones (especially FSH) induce follicular development
Note – Multiple follicles on ovary.

41. Prediction of Ovulation
Number of days in heat
Growth rate of largest follicle
Average 3-5 mm/day
Size of largest follicle
Softness of preovulatory follicle
Ultrasound image
Ovulation normally occurs when follicle reaches 4-5 cm

42. Signs of Estrus Most consistent Other supporting signs
Elevated tail raise
Winking
Other supporting signs
Leaning
Squatting
Standing still
Urinating

43. Equine Breeding
Successful breeding and pregnancy in female horses is not often easy to accomplish.
Mares do not readily accept the male.
Timing must correspond to ovulation.
Mares usually breed and conceive in the spring and summer with deliver about 11 months later in the spring or early summer.
Video..
LACP pg. 281

44. Pregnancy Diagnosis Rectal palpation Diagnostic Ultrasound, per rectum
Diagnostic Ultrasound, Transabdominal
External Palpation
Abdominal Radiographs
Laboratory Tests

45. Preparation of the Perineum/vulva
Both areas should be cleansed so that you do not contaminate the vagina, cervix and uterus with fecal material and other debris.
Tail should be wrapped or bandaged.
LACP pg. 282

46. Cleaning
You can use a mild soap, povidone-iodine scrub, or a chlorhexidine scrub with warm water and rolled cotton.
Clean the anal area first removing all fecal material. Scrub the lips of the vulva and gradually working a circular fashion, include the perineum, anus, and inner aspect of the buttocks. Repeat the process until cotton shows no evidence of residue.

47. A vaginal speculum examination being performed on a mare using a disposable speculum.

48. A uterine biopsy instrument being inserted through the vagina and cervix into the uterus.

49. Diagnostic Ultrasound
An ultrasound image of the black appearance of multiple follicles on an equine ovary.

50. An ultrasound image of a 14-day pregnancy in an equine uterus
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

51. Diagnostic 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.

52. Twins
Occasionally, one twin may be born alive but is typically weak and small, and it faces a high mortality rate.
Birth of living twins is rare, and survival of both is even rarer. When twin embryos or fetuses are detected, the vet needs to advise the owner of options to either terminate the pregnancy or to terminate only one of the embryos in hope that the other may survive.

53. Rectal Palpation Most common, rapid method
As early as 18 days post ovulation
Increase uterine tone, presence of vesicular bulge

54. External Palpation
External abdominal palpation as used in small animals is not possible in large animals.
You place both fists against the lower flank area on the mare and rapidly press inward; this displaces the pregnant uterus (if present) and rebounds back into the original position by “bumping” against your fists. This method lacks accuracy and is not typically done.

55. Abdominal Radiographs
Not useful for large animals, but commonly used in small animals.

56. “Wee-Foal-Checker” Urine pregnancy test for mares

57. Laboratory Tests
Used when rectal exams are inconclusive or impossible to perform.
Can be difficult to interpret and have limited usefulness. You usually can only perform these during the later stages of pregnancy.
Progesterone assay- (16-24d) nonspecific, high values may mean functional CL
Estrogen- (60-100d) higher then during estrus

58. Natural Breeding vs. Artificial Insemination
ADVANTAGES:
DISADVANTAGES:
More efficient use of semen
Reduce transmission of diseases from stallion to mare
Reduce risk of breeding injuries in mare
Success of AI requires greater knowledge and skill
Increased cost
Greater risk of human injury during collections

59. Embryo Transfer, Why? Foals from older, injured, or sub fertile mares
Access to wider gene pool
Increase production and profit on genetically superior mare
Get embryo from mares who foal late in season
Foals from 2 year old mares
Foals form mares in competition

60. Embryo Transfer, why not?
Expensive
Need trained personell
Embryo recovery can be low
Lack of commercially available embryo
Lack of interest by many registries
Many breed organization do not accept
Harder to superovulate

61. Embryo Transfer Synchronization of donor and recipient mare
Embryo flushing
Embryo transfer procedure
First performed in 1972

62. PGF2 Lutalayse or Estrumate
Shorten the interval between estrous periods
Treatment of a maintained corpus luteum
After foal heat
Estrous synchronization with prostaglandins

63. Embryo Transfer Ultrasound or palpation for follicular development
Prepare donor mare
Induce ovulation
Flush 7 to 9 days after ovulation
Embryos collected in filter cup
Viewed
Transferred within 12 to 24 hours

64. Insert catheter with cuff, inflate cuff anddraw back for tight seal, gravity flow with flushing media infused and immediately drained into receptal with filter, usually done at least twice, recovered fluid searched for embryo, embryo measure and given quality score, usually transferred with 1 hr or frozen

65. Recipient Mare Good health and BCS Easy to handle
Similar in body size to donor
4-10 years old
Sound breeding condition
Responsive to teaser
Regular cycling
cheap