Page 975 - Small Animal Internal Medicine, 6th Edition

CHAPTER 54 The Practice of Theriogenology 947

million per ejaculate. Higher numbers of morphologically an invasive procedure (laparotomy or laparoscopy) in the
normal sperm can be associated with the breeding season in bitch. In addition to its invasiveness, laparotomy requires
VetBooks.ir cats. In general, felids are frequently affected by teratosper- general anesthesia, which many clinicians and clients find
objectionable for an elective procedure such as artificial
mia, with normal toms having ~40% abnormal spermatozoa.
This is thought to be a result of decreased genetic variation
canine uterus has been used infrequently, especially in the
(Pukazhenthi et al., 2006). insemination (Fig. 54.23). Laparoscopic approach to the
practice setting, because of its relative invasiveness (multiple
incisions, insufflation) and because it requires special equip-
FRESH, FRESH CHILLED, AND FROZEN ment, expertise, and anesthesia. In some countries, elective
ARTIFICIAL INSEMINATIONS (AI) surgeries such as these are not considered ethical.
Transcervical insemination is becoming more common,
VAGINAL AI with techniques developed in Scandinavia and New Zealand.
With the bitch standing and comfortably restrained, using The Norwegian catheter is a 20- to 50-cm steel catheter with
digital guidance or a pediatric proctoscope, an insemination a 0.5- to 1-mm tip with a protecting nylon sheath, and is used
pipette is passed dorsal to the urethral papilla and as far into with a 6- to 20-mL syringe. Transcervical catheterization is
the vaginal vault as it will comfortably go. Vaginal insemina- accomplished by passage of the Norwegian catheter through
tions are best accomplished using a clean mare uterine infu- the vagina and blindly into the cervix by palpation and
sion pipette, which is rigid and allows placement of the manipulation of the cervix through the abdominal wall. This
semen near the cervix in the cranial vagina. Care must be technique requires training and expertise. Perforation of the
taken to not contaminate the semen with water, disinfectant uterus or vagina could occur, and introduction of vaginal
chemicals, or spermicidal lubricants. A 5F to 10F polypro- flora into the abdomen is possible. Good success rates have
pylene urinary catheter can also be used. Nonlatex syringes been reported using this technique.
are advised when handling semen. Transcervical insemination with fiberoptic visualization
Maneuvering the pipette over and under vaginal mucosal of the caudal cervical os permitting catheterization is optimal.
folds usually must be done. Once the pipette is in place, the After visualization, a polypropylene catheter is passed
bitch’s hindquarters are elevated onto an assistant’s lap in a
wheelbarrow position. The bitch’s abdomen should not be
compressed; the assistant should restrain the bitch by firmly
holding her hocks in a comfortable position. The syringe of
semen is then attached to the pipette, elevated, and slowly
infused. If the semen will not infuse, back the pipette out
slightly. A small amount of air in the syringe will empty the
pipette contents into the vagina. It is not necessary to con-
tinue elevating the bitch’s hindquarters after insemination as
this does not impact conception or litter size; walking the
bitch for 10 minutes without allowing her to sit or urinate is
optimal.

INTRAUTERINE AI
Cryopreservation and subsequent thawing diminish semen
quality and longevity post-thaw, necessitating special insem-
ination technology. Frozen thawed semen has to be placed
close to the site of fertilization (fallopian tubes) for accept-
able conception rates; intrauterine insemination is highly
recommended. The process and resultant quality of canine
cryopreservation have improved with time; insemination
techniques remained challenging until transcervical endo-
scopic intrauterine access was developed. Data supporting
the benefit of intrauterine deposition of frozen thawed semen
exists (40%-90% conception rates). We extrapolate that
better conception rates will occur with intrauterine insemi-
nation of chilled, extended, or otherwise compromised (sub-
fertile) semen as well.
The normal anatomy of the vagina and cervix in the bitch
hampered transcervical access to the canine uterus until FIG 54.23
rigid cystourethroscopes were developed and adapted for Surgical insemination: injection of semen into the uterine
vaginoscopy. Historically, intrauterine insemination required horn.