Page 971 - Small Animal Internal Medicine, 6th Edition

CHAPTER 54 The Practice of Theriogenology 943

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FIG 54.17
Norwegian rigid transcervical catheters.
FIG 54.14
Image showing the appropriate length of vaginoscope
required to visualize the canine cervix for transcervical
insemination.
0

1

FOLLICLE 2

3

4
L OVARY

FIG 54.18
Normal sagittal canine left ovary in the follicular phase of
FIG 54.15 the estrous cycle. The developing follicles (arrow) will
Endoscopic vaginoscope Karl Storz Hopkins Telescope with increase in size over time to the point of ovulation.
protective external sheath, 30-degree telescope, 3.5-mm
width, 3 ports, and 29-cm working length.
Ultrasonography can be used to identify ovulation in the
bitch, but early attempts were discouraging. The small size
of the ovaries and their similarity to close structures make
them difficult to visualize. Recent improvements in scanhead
technology and operator expertise have made ovarian ultra-
sound more effective. During proestrus, multiple anechoic
follicular cystic structures can be identified, enlarging with
time (up to 1.0 cm in diameter). These structures ultimately
have distinct thin walls and anechoic fluid centers with
distal enhancement (Fig. 54.18). The surface of the ovary
may become irregular or lumpy. The anechoic fluid-filled
follicles acutely become hypoechoic to hyperechoic corpora
hemorrhagica at the time of ovulation, progressing over
several days to a thicker walled corpora lutea (Fig. 54.19).
The ovarian follicles do not collapse in the bitch and queen.
During diestrus the ovaries may be lobular; the corpora lutea
are obvious hypoechoic structures of variable size. Results
show a close correlation to ovulation as predicted by LH
FIG 54.16
Endoscopic vaginoscope Karl Storz Uretero-renoscope with and progesterone testing. The main drawback is that imaging
telescope and instrument sheath combined into one 8F to must be performed 2 to 3 times daily when ovulation is
13.5F unit with 3 ports and 34-cm working length. anticipated.