rodent soft tissue surgery

Question 1

by what age should rats be spayed to prevent mammary & pituitary tumors

Answer 1

7 months (in lab rats)

Question 2

downside to ovariectomies for rats?

Answer 2

predisposition to osteopenia

Question 3

behavioral benefit of spaying?

Answer 3

decreased anxiety if spayed at 3 months (not true if spayed @ 6 months though)

Question 4

What percentage of guinea pigs with uterine disease also had rete ovariian cysts?

Answer 4

18 out of 19. but it wasn’t follicular cysts and the relationship isn’t clear. nonetheless, pink book recc adult ovariectomies be done as a full OVH.

Question 5

all rodents have a single uterus: t/f

Answer 5

all rodents have a duplex uterus, with either one or two cervixes.

Question 6

which rodents have one cervix?

Answer 6

GP & hamster

Question 7

which rodents have 2 cervices?

Answer 7

chinchilla, rat, mouse

Question 8

during a guinea pig or other rodent dystocia, how do you encourage the uterus to return blood to circulation before removal? (e.g. huge uterus/anemic sow)

Answer 8

Rather than the standard en bloc, you do a C section, take out the pup and allow the uterus to involute first. Oxytocin IV, IM or directly into a uterine artery, will speed the involution. not 2 separate surgeries, just one slightly slower one.

Question 9

what rodent species are more likely to develop testicular tumors?

Answer 9

Rats commonly develop Leydig cell tumors

Prostatic and testicular tumors reported in gerbils

Question 10

which approach for neutering rodents puts the skin incision in contact with substrate?

Answer 10

inguinal approach. honestly, this one is weird.

Question 11

how long can viable sperm remain in teh ductus deferens after neuter?

Answer 11

6-8 weeks!

Question 12

Mammary tumors in guinea pigs:

Answer 12

Both males and female; in males the malignant are more common; do metastasize but not commonly. Locally the malignant ones can be quite invasive.

Question 13

Mammary tumors in chinch and degu:

Answer 13

Not really reported

Question 14

Mammary tumors in mice:

Answer 14

Nearly always malignant, associated with a mouse mammary tumor virus. Mass removal and/or ovariectomy do not prolong survival.

Question 15

Is spaying adult rats (once they have developed mammary tumors) protective against further?

Answer 15

Unlikely

Question 16

Mammary tumors in hamsters and gerbils:

Answer 16

Rare in both species; in hamsters usually benign, in gerbils usually malignant. They have nowhere near as much mammary tissue as a rat. (no one does)

Question 17

ventilating rats during thoracotomy

Answer 17

Tight fitting face mask with direct visualization of the lung inflation. They survived surprisingly well. Another option would be a temporary tracheostomy (for IPPV?)

Question 18

Normal fluid production from a thoracostomy tube?

Answer 18

1-2 ml/kg/d