Non-pregnant reproductive tract 3: Comparative topography of the Reproductive Tract and Associated Clinical Procedrues

What structures suspend the reproductive tract from the body wall?

Broad Ligament:

• Suspends tract from body wall

• Left and right sheets of fibrous tissue

What supportive structures support the following structures?

• Ovary

• Uterine Tube

• Uterus and Cervix

• Mesovarium - Supports ovary

• Mesosalpinx - Supports uterine tube

• Fold of mesovarium

• Forms the ovarian bursa

• Mesometrium- Supports uterus and cervix

The reproductive tract is continuous with ______ or ________ which functions to do what?

serosa, perimetrium

• Blood vessels, lymph vessels and nerves

How does the mesosalphinx appear in cows/sows, mares and bitches?

Cow / sow:

• shallow & open

• implications during rectal palpation

Mare:

• infundibulum attached at ovulation fossa

Bitch:

• Fat filled & encases ovary

• slit like opening

• Fimbriae of infundibulum visible

• Bursa & ovary removed at OVH

Describe the blood supply to the female reproductive tract.

1. Ovarian Artery:

2. Uterine artery

3. Vaginal artery

What structures does the ovarian artery supply?

• Direct from aorta = high pressure!

• Ovarian Branch: supplying ovary

• Uterine Branch: Supplying the uterus, uterine tubes, uterine horns

What structures does the uterine artery supply?

• Branch of internal or external iliac artery

• Supplies uterus

• Anastamoses (Connects) with uterine branch of ovarian artery

• Forms arterial arcade

• Or arches through the Mesometrium or broad ligament

What is notable about the uterine artery in cows and bitches?

Cows:

• Increased number of vessels in areas of carnucles

• 'Fremitus' in pregnant cows

• Uterine artery on either side of the uterus

• Fremitus is a buzzing or vibrating sensation felt in the uterine artery of a pregnant cow

Bitch:

• Is a branch of the vaginal artery

• The uterine artery is not separate

What structures does the vaginal artery supply?

• Branch of internal or external iliac artery

• Supplies caudal tract

How does venous drainage work in the female reproductive tract?

venous drainage mirrors arterial supply

How does the venous drainage function in the sow and cow’s reproductive tracts?

• Counter-current mechanism

• Ovarian artery & uterine vein very convoluted

• Extensive contact between vessels

  • Allowing easier hormone transfer between arteries and veins

• Prostaglandin transfer

How does the venous drainage function in the mare’s reproductive tracts?

• Ovarian branch of ovarian artery

• Peripheral vascular zone

• Spread over surface of ovary

• No counter- current mechanism

• Prostaglandin delivery via systemic circulation

What lymphatic drainage does the female reproductive tract have?

• Ovaries and cranial tract - aortic and medial iliac nodes

• Caudal tract - medial iliac and pelvic nodes

How is the female reproductive tract innervated?

• Sympathetic fibres follow arterial blood vessels

• Parasympathetic fibres from pelvic nerves via pelvic plexus

Describe the intra-abdominal topography of the bitch’s reproductive tract, describing the ovaries, uterine horns and uterine body / cervix / cranial vagina.

• Ovaries :

• located caudal to ipsilateral kidney

• Right ovary further cranial than left, right kidney also further

• Uterine horns:

• Dorsal to intestines

• Pass to left and right of descending colon (Which runs between them)

• Uterine body, cervix & cranial vagina:

• between colon (Dorsal) and bladder (Ventral)

Describe the topography of the three ligaments contained in the mesovarium in the bitch.

Mesovarium contains:

• Suspensory ligament

• Well developed in bitch

• Attaches ovary to body wall near last rib

• Ovaries move little even during pregnancy

• Broken down during OVH

• Proper ligament

• between ovary and uterine horn

• Round ligament:

• Embryological remnant - does not serve any function

• Fold of mesometrium

• Runs from tip of uterine horn (Proper ligament)

• Passes through inguinal canal

• Forms the Vaginal process

Describe the topography of the ligaments contained in the mesovarium in the mare.

• No suspensory ligament

• Ovaries don't migrate far

• Associated with kidneys

• R ovary cranial & dorsal to L

• Uterine horns suspended from ovaries

• Body - horn junctions ventrally located

Describe the topography of the ligaments contained in the mesovarium in the sow.

• Ovaries descended

• Ovaries and horns very mobile

• Long mesovarium and mesometrium

• Giving mobile reproductive tract to accomodate for large litter sizes

Describe the topography of the ligaments contained in the mesovarium in the cow.

• No suspensory ligament

• Ovaries migrate caudally during development

• Located lateral to uterus body / cervix

• Uterine horns coiled

• Like 'rams horns'

What serosa covers a majority of the female reproductive tract?

peritoneum

What do we call the areas where the peritoneum folds in on itself at the most caudal region of the animal?

peritoneal pouches

What are the four peritoneal pouches formed by infoldings of the peritoneum?

• Para-rectal fossa

• Genito-rectal pouch

• Vesico-genital pouch

• Pubo-vesicle pouch

What is the clinical significance of peritoneal pouches?

- Vaginal trauma

• Especially around parturition, a foot could rupture into abdominal cavity through one of these pouches, leading to infection

- Surgical access to ovaries from cranial vagina in large animals

What regions of the female digestive tract are extra-abdominal?

Caudal vagina:

• Retroperitoneal (outwith the abdominal cavity)

• Located within pelvic cavity

• Found between rectum and urethra

Vestibule and vulva:

• Extra-pelvic (Caudal to pelvis)

Describe the level of vestibules in cows, bitches and mares.

• Vestibule same level as vagina in cows - Easy to pass vaginoscope

• Bitch & mare:

• Vestibule vertical & vagina horizontal

  • Angle between them

    • Must redirect vaginoscope

What is the normal vulval conformation in a mare? What can happen to the normal mare vulval conformation in aged and emaciated horses?

• Entire vulval cleft should be ventral to level of pelvic floor / ischium

• Age / poor condition body condition

• Slippage of vulva dorsal to ischium, everything pulled inwards

• Airtight seal lost at vulvar cleft

  • Can lead to vaginal irritation, infection and reduced fertility

• Corrected using Caslick's operation

Why do we perform clinical examinations of the reproductive tracts?

• Pre- breeding examination

• Make sure everything is healthy before breeding

• Determine optimum time for Al

• Investigation of infertility

• Identification of endometritis / pyometra

How or what structures do we look at when performing a clinical examination of the caudal components of the reproductive tract?

• Caudal components of tract:

• Vulva

• Vestibule

• Vagina

• External os of cervix

• All species:

• Vaginoscope

• Manual palpation

• Swabs

How or what structures do we look at when performing a clinical examination of the cranial components of the reproductive tract?

• Cranial components of tract:

• Cervix

• Uterine body & horns

• Ovary

Rectal approach:

• Cow & mare:

• Manual palpation

• Ultrasound examination

• Sheep & other species:

• Rectal ultrasound performed using an adapter

Vaginal approach:

• Uterine biopsy in mare

• Follicular aspiration in cows

Bitch + Other Small Animals

• Rectal approach not possible

• Transabdominal ultrasound:

Describe the topography of the reproductive tract in a bitch and how it would be viewed on the ultrasound.

• Ovary located caudo-ventral to kidney

• Uterine body located

• Dorsal to bladder

• acts as acoustic window

• Ventral to colon

• Uterine wall appears uniform & lumen normally empty

What is pyometra?

• A distended pus-filled uterus, usually due to bacterial infection

• If cervix closed - no discharge

  • If open you may see discharge

How does pyometra look on ultrasound and radiographs?

Ultrasound :

• Black / anechoic material in lumen + friable tissue

Radiography:

• Cannot distinguish from early pregnancy

At what time is sterilization/spaying best performed?

anoestrus

Outline the steps of a ovariohysterectomy in a bitch.

• Ventral midline incision

• Caudal to umbilicus

• Locate first ovary

• Break down suspensory ligament

• Ligate ovarian artery

• Repeat for second ovary

• Break down broad ligament

• Ligate uterine arteries on either side of tract

• Fix to cervix

• Ligate cervix

• Same procedure for pyometra

Outline the steps of a ovariohysterectomy in a queen.

Spaying:

• Flank approach

• Incision 2 finger breadths cranial to wing of ilium

• Tract more mobile than dog

• Long suspensory & broad ligaments

• Ovarian bursa less fat filled than dog so ovaries more visible

• Ligate tract as far caudally as possible