Page 976 - Small Animal Internal Medicine, 6th Edition
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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.
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