Page 976 - Small Animal Internal Medicine, 6th Edition

948 PART VIII Reproductive System Disorders

through the channel of the scope, through the cervical os, unnecessary. This technique has a moderate learning curve.
and then into the uterine lumen (Figs. 54.24, 54.25, 54.26). Once practiced enough to gain expertise, it is highly reward-
VetBooks.ir Visualization of the cervix requires manipulation of vaginal ing and often can be performed in a matter of minutes.
Transcervical catheterization for intrauterine insemination
folds and scope, and catheterization of the cervix takes
is best accomplished with the estrual bitch standing on a
expertise and requires practice. Sedation is usually
nonskid surface under light restraint and with gentle support
of the abdomen to inhibit sitting. The scopes were developed
to be used in the standing bitch. The operator should work
from a sitting position, with the arms raised to the level of
the vulva to minimize muscle fatigue. An adjustable exami-
nation table and chair can facilitate operator comfort. Par-
ticipation of the breeder client for restraint and observation
is generally rewarding (Video 54.3). Concerns surrounding
potential introduction of vaginal flora into the uterine lumen
using transcervical insemination have not been realized thus
FIG 54.24 far and are unlikely, given recent knowledge that normal
Working end of the vaginoscope, showing the catheter tip vaginal flora can be found in the uterus during proestrus and
adjacent to the telescope. estrus. Certainly vaginal flora is introduced into the uterine
lumen with natural breedings; the uterus has an inherent
ability to normalize its flora after estrus. Maintenance of the
equipment is minimal; 10 minutes’ soaking of the immers-
ible parts in dilute (1:1000) chlorhexiderm solution and
thorough rinsing with distilled water is optimal. Stronger
disinfectants raise concerns because of their spermicidal
potential. As with all reproductive procedures, the success is
greatly influenced by the timing of ovulation in the bitch and
the quality of the semen from the male. An increased number
of inseminations (not limited by anesthesia and invasive
surgery) may improve conception and is now feasible with
this equipment and technique.

ESTROUS CYCLE OF THE QUEEN

Puberty in the queen usually occurs at 9 to 10 months
FIG 54.25 of age but may occur as early as 4 months or as late as
Placement of the vaginoscope in the vaginal lumen to 2 years. Because queens are seasonal breeders, the season
visualize the cervix.
in which the kitten was born influences the age at which
puberty occurs. Cyclicity is dependent on the photoperiod,
with queens requiring 12 hours or more of light to main-
tain normal cyclicity. Cyclicity and folliculogenesis stop
abruptly in queens exposed to less than 8 hours of light but
resume an average of 16 days after returning to a 14-hour
photoperiod. Seasonality is more pronounced in queens
exposed to natural lighting, especially at higher latitudes.
Long-haired breeds tend to be more seasonal than short-
haired breeds. The phases of the feline estrous cycle are
proestrus, estrus, interestrus, diestrus or pseudopregnancy,
and anestrus.
Proestrus precedes estrus and lasts 1 to 2 days but is rec-
ognized in fewer than 20% of queens. During proestrus, the
female is attractive to but not willing to accept the male. The
queen may rub against objects, vocalize, and assume a lor-
dosis; she will place her front quarters on the ground, elevate
FIG 54.26
Transcervical insemination. Semen being transferred into the her hindquarters, and lift her tail to one side. When the
uterine lumen via a polypropylene catheter under dorsal caudal area is stroked, she will tread with her hind
endoscopic guidance. legs.