Equine - Mare Reproductive System

Cervix

Third seal that divides uterus and vagina

Uterus

Fallopian Tubes (Oviducts)

Highly convoluted tubes that connect the uterine horn to ovary. Fertilization occurs closer to uterine horn

Vagina

Muscular tube between vulva and cervix, foaling can cause bruises and tears in this area

Vulva

Opening to genital tract, forms a seal that protects from infection and air

Ovaries

Bean shaped, contain ova (eggs) and produce hormones, are hard in winter and softer in breeding season

Clitoris

Exposed during “winking” when in heat, sometimes swabbed before breeding (bacteria causes venereal disease like contagious equine metritis)

Caslick’s Procedure

Suturing with small opening for urinating and breeding

Vulva Tear

Problems from this are issues during foaling and itching. May require surgery

Hymen

Thin membrane in the vagina of maiden mares, acts as another seal

Endometrium

Inner layer of the uterus, forms the placenta during prenancy

Endometritis

Inflammation of the endometrium, failure to clear contaminants, major cause of decreased fertility, uterine lavage

Follicle

Fills with fluid. During ovulation, ruptures and releases ovum.

Corpus hemorrhagicum

Follicle collapses and bleeds after ovulation

Corpus luteum

Blood vessels and fibroblasts enter, progesterone secreted

Corpus albicans

Follicle stage after ovulation is scar tissue, non-functional

March through september

When is the natural breeding season?

1-2 years

What is the age of first ovulation (puberty)?

3 weeks

Length of complete estrous cycle?

3-7 days

Length of estrus (heat)

14-18 days

Length of diestrus?

“WInking”, frequent urination, squatting, pointing hind end towards stallion

Signs of estrus

Kicking, squealing, swishing tail

Signs of diestrus

Rectal Palpation

Vet puts hand in rectum and feels internal structures. Can diagnose pregnancy, check follicle size

Ultrasound

Probe inserted into rectum to see internal structures, also used to check for pregnancy

Vaginal Speculum

Opening of vagina is held open by a stainless steel instrument and the vagina and cerviz are visualized

Hormonal Assays

Blood is examined for the presence of normal hormones circulating at the appropriate times

Endoscopy

A fiber-optic tube is inserted into the vagina for examination

Uterine Culture and Cytology

Scrapings from cervix and uterus examined under the microscope

Uterine Biopsy

Tissue samples taken from uterus examined for abnormalities