Chapter 109: Ovaries and Uterus

Question 1

Where do the ovarian arteries arise from the aorta?

Answer 1

Caudal to the renal arteries and cranial to the deep circumflex iliac arteries.

Question 2

Where do the ovarian veins drain into?

Answer 2

• Right ovarian vein drains into the caudal vena cava
• Left ovarian vein drains into the renal vein

Question 3

What are the layers of the uterus?

Answer 3

• Serosa
• Muscularis
• Mucosa (endometrium)

Endometrium is the thickest layer

Question 4

What are the 4 phases of the estrus cycle?

Answer 4

Proestrus (Follicles growing, everything prepping, estrogen rising)
Estrus (sexually receptive / peak estrogen, ends at ovulation)
Diestrus (starts at ovulation - corpus luteum and progesterone dominate)
Anestrus (resting)

Question 5

How can parturition be predicted in a dog?

Answer 5

• 64-66 days after LH peak
• Preovulatory progesterone rise to 1.5ng/ml - 65 +/- 3d
• Skeletons detectable by d42 (20-21d to parturition), pelvises by day 57
• Progesterone drop to 2-3ng/ml 18-30hr
• Body temp drops 10-14hr after progesterone drop, parturition imminent

Question 6

List the three stages of parturition:

Answer 6

• Stage 1: Externally non-visible uterine contractions, behavioral changes. Lasts up to 24hr.
• Stage 2: Expulsion of a fetus
• Stage 3: Expulsion of placenta

Stage 2 and 3 alternate and last up to 36hr in dogs. Active straining should not exceed 30 mins without expulsion of a puppy and there should not be more than ~4 hr between each puppy

Question 7

How does pregnancy and parturition differ in cats?

Answer 7

• Placenta secretes progesterone too (not just ovaries
• Most cats deliver all within ~6hr, but in less than 1% of litters, parturition may be interrupted for up to 48hr
  -Skeleton can be seen one week earlier than in dogs
  -Average 66 days

Question 8

What % of intact bitches are reported to get pyometra?

Answer 8

24%

Question 9

List the indications for a C-section:

Answer 9

> 4 hours between puppies
- Contractions for 30 min
- Lochia without fetal delivery
- Obstructed birth canal
- Abnormal fetal presentation
- Lack of Ferguson reflex (oxytocin)
- Fetal HR 150-180 or less
- Absent fetal movements or presence of bowel motion
- Failed medical management of primary uterine inertia (30-40% successful)

Question 10

What are the most common uterine tumors in dogs and cats?

Answer 10

Dogs:
- 90% benign leiomyomas **

Cats:
- Most commonly malignant adenocarcinoma
- More likely to have mets, prognosis guarded

Question 11

How is the estrous cycle different in cats and dogs?

Answer 11

Cats are seasonally polyestrous
- Proestrus is much shorter and is not externally visible (feline vulva is not responsive to estrogen)
- Diestrus/formation of corpus lutea requires induction of ovulation, in non-pregnant cats the corpus will remain functional for 37 days.

Dogs have a seasonal cycle
- They ovulate spontaneously and enter diestrus without need for stimulation
- Corpus/progesterone dominance seen for 60-100 days in non pregnant bitches

Question 12

Which ovary is sometimes bigger?

What is normal for cat ovary?
Dog?

Answer 12

Left is sometimes larger

Cat: 8-9mm
Dog:15 x7 x 5

Question 13

What structure in the ovary keeps oocytes from getting in to abdomen?

Answer 13

The ovarian bursa / bordered by fimbriae of the infundibulum.