Spaying rabbits and rats (Proceedings)
The procedure is generally very similar to a cat spay.
Spaying rabbits
Indications:
o Intact females have a high rate of uterine adenocarcinoma
• as high as 80% by age 3 years and older
• very high incidence of systemic metastasis (mainly lung and liver)
o Intact females are impossible to keep together due to constant fighting
o High reproductive rate
• Females can conceive within 24 hours post partum
Anatomy:
o The vaginal body is very long and more flaccid than in other species
o The vagina fills with urine during micturition
o Two cervices (bicornute cervix or cervix duplex) are present as normal anatomy
o The ovarian vessels are very well developed
o The bladder receives a branch from the uterine artery
o The uterine horns and the uterine blood vessels are often encased in large amounts of fat, especially in older females
o The large intestine, especially the cecum, is in close proximity to the surgery site
Preparation:
o All forms of stress should be avoided prior to surgery
• House rabbit in a quiet ward
• Avoid barking dogs
• Try not to house a ferret directly next to a rabbit
• Avoid olfactory or direct visual contact between the rabbit patient and prey species
o In older intact do perform radiographs and/or an ultrasound exam prior to surgery to check for subclinical uterine neoplasia or metastasis
o Ideally a CBC and a chemistry panel should be run prior to anesthesia
o Ensure doe is optimally hydrated
• Maintenance fluids are approximately 120 ml/kg/day
Procedure:
o Generally very similar to a cat spay
o Approach by ventral midline incision
o Make a 1-2 inch incision between umbilicus and pubis
• Make incision closer to umbilicus as ovarian ligaments are not 'stretchable'
o Cervices will be visible immediately in the incision
o Do NOT use spay hooks of any kind
o Avoid manipulation of GI tract at all costs.
o Follow uterine horn cranially to ovary
o Ovary is extremely small in relation to uterine horn, and yellow
• Left ovary is close to kidney
o Identify ovarian artery and ligate immediately
• Hemoclips will speed procedure up
o Bluntly dissect along uterine horn
• Radiocauthery can be used on smaller uterine vessels
o Repeat procedure on other side
o In young animals transection of uterine horn can be made cranial to cervix
• Will leave cervix behind and may provide an additional barrier against bacterial contamination from vagina
o In older animals remove cervices completely
o Transection is performed in vagina (ovario-vagino-hysterectomy)
• Reduces the chance of a subclinical uterine cancer in remnant tissue
o Close incision in a 3 layer fashion
• Use an intradermal suture pattern
Follow-up:
o make sure animal is eating, urinating and defecating
Possible complications:
o Intestinal adhesions
• Fibrin clots
o Ligation of a ureter
o Leakage of urine from vaginal stump
• If cervix is completely removed
o Uterine cancer in the residual tissue
• If cervices are not removed
Spaying rats
Indications:
o Intact females have a high incidence of mammary cancer (adenoma/adenocarcinoma)
• as high as 66% by about 2 years of age (21 months)
• Spayed rats have a significantly lower rate of mammary cancer.
• If mammary cancer develops it usually has a low incidence of systemic metastasis (e.g. lung and liver)
o High reproductive rate
• Note: Intact female hamsters normally have a vaginal discharge
• Often mistaken for pyometra
Anatomy:
o The ovaries are located caudal to the kidneys in a large fat pad
o The uterine horn wraps around the ovary
o The ovarian vessels are not well developed
o The ovarian ligament is very long and the ovary is easily exteriorized
Preparations:
o Evaluate patient thoroughly for sub-clinical forms of respiratory disease or heart disease in older animals (over 2 years old)
o Ideally a minimal screen (hematocrit, total solids, blood glucose and blood urea nitrogen) should be run prior to anesthesia
o Make sure animal is optimally hydrated
• Maintenance is approximately 100 ml/kg/day
Procedure:
Ventral approach :
o Very similar to cat spay
o Approach by ventral midline incision
o Make a 1 inch incision between umbilicus and pubis
o The cervix will be immediately visible in the incision
o Follow uterine horn cranially to ovary
o Identify vessels in mesovarium and ligate
• Hemoclips will speed procedure up, otherwise use 5-0 Maxon or PDS
o Bluntly dissect along uterine horn
• Radiocauthery can be used on smaller uterine vessels
o Repeat procedure on other side
o In all animals transection of uterine horn can be made cranial to cervix
• Will leave cervix behind and may provide an additional barrier against bacterial contamination from vagina
o Close in a 2 or 3 layer fashion
• Use an intradermal suture pattern
• Apply lidocain to suture site, this will decrease frequency of selfmutilation.
Dorsal approach:
o Developed in lab animal medicine where ovariectomy is a common procedure
o Ovaries and part of the uterine structures can be accessed dorsally
o A dorsal approach offers a number of advantages to the ventral approach
• Less invasive
• Less painful
• Smaller incision
• Less likely to see post-surgical incision complications due to self-mutilation or contamination with soiled bedding material
o Make a half-inch skin incision on midline, directly over the spinal column, between the last rib and pelvis.
o The skin incision can then be moved to the left or right side about 1 cm lateral to the spinal processes to access the body wall
o Move the skin incision laterally to one side and bluntly dissect through the body wall.
o A large fat deposit is usually seen when dissecting through the body wall and the ovary sits within this fatty tissue.
o Exteriorize the ovary and the uterine horn and place a hemoclip around the uterine horn prior to excising it
o The body wall can be closed with a 5-0 Maxon or PDS or can be left open
o Repeat the procedure on opposite site
o Close skin with an intradermal suture pattern
Follow-up:
o make sure animal is eating, urinating, and defecating
o recheck suture site frequently
o keep separate from other cage mates, as they sometimes 'groom' suture out
Common complications:
o suture removal by animal
o inadequate pain management often responsible for self mutilation.
Resource:
Capello, V. Surgical Techniques for Neutering the Female Pet Rabbit. ExoticDVM 7.5 page 15
Johnson-Delaney, C. Ovariohysterectomy in a Rat. ExoticDVM 4.4 page 17
