Ovariectomy in the Mare

Question 1

(T/F) Since the broad ligament in a Mare is so short, pyometra is really rare in horses

Answer 1

True

Question 2

What is the most common reason for an ovariectomy to be performed on a mare?

Answer 2

Behavioral issues - either due to hormone-producing granulosa cell tumors or estrus-induced

Question 3

What is the most common hormone we use to alter estrus in horses?

Answer 3

Regu-mate (synthetic prostaglandin analog)

Question 4

A mare is diagnosed with a granulosa cell tumor of 30cm diameter from her left ovary. The owners would like to use her as a breeding mare. What is the best and safest choice for ovariectomy in this case?

Answer 4

Unilateral ovariectomy with laparoscopic ablation of the ovarian pedicle followed by tumor removal via ventral midline

Question 5

The approaches to taking out an ovary are either:

Answer 5

Open or Laparoscopically

Question 6

What are the open approaches to taking out an ovary?

Answer 6

• Vagina or Transvaginally through Colpotomy
• Through a flank Laparotomy
• Through a ventral midline
• Through oblique paramedian celiotomy

Question 7

What approach to taking out an ovary is the most common and safest to do on a horse?

Answer 7

Flank Laparoscopic removal of the ovary

Question 8

• Transvaginal approach
• Blind access to pedicles
• Pedicle crushed with a chain of ecrasure

Answer 8

Colpotomy

Question 9

Which is the most inexpensive, and best for spaying commercial/jump mares?

What can be some post-op complications?

Answer 9

• Colpotomy
• Hemorrhage
• Evisceration- vaginal incisions not closed
• Fecalectomy

Question 10

What are some complications of Laparoscopic Ovariectomy?

Answer 10

• Hemorrhage
• Incisional infections
• Post-op colic
• Can only remove normal-sized ovaries to mildly enlarged GCT’s

Question 11

Ventral midline celiotomy may be needed for tumors ______ cm diameter

Answer 11

> 20

Question 12

• The incision is ventral to the ovary
• Only 1 muscle to divide (rectus abdominus)

Answer 12

Ventral oblique Paramedian

Question 13

A uterine mass in a mare is determined to be leiomyoma on histopathology. What procedure is indicated and for what purpose?

Answer 13

Partial hysterectomy; leiomyomas interfere with uterine clearance and removal promote fertility

Question 14

• Uncommonly done
• Performed usually because of pyometra
• RARE in equine
• Cervix is usually fibrosed closed or partly open

Answer 14

Total Hysterectomy