Dr. van der Ende

Boxjoy Kennels

Services Provided

Ovulation Timing

Semen Evaluation

TCI

Infertility in the Bitch

Infertility in the Stud
Dog

Fresh Chilled and
Frozen Semen

Ovulation Timing

---

Female Dog’s  Hormonal Cycle

Bitches will only accept a male  for breeding during the  Estrous cycle. The word Estrous by definition refers to this behaviour in the dog. We can monitor the estrous cycle to determine the ideal day of breeding via its outwards signs, e.g.   vaginal discharge and swelling of the vulva, flagging behaviour of the bitch and the stud dogs willingness to breed.

It is when these natural  occurrences don’t correspond to what is happening physiologically or when we use compromised semen i.e. frozen or fresh chilled  or poor quality live semen that we must rely on  vaginal cytology, vaginoscopy,  and progesterone levels.

During the early stage of the estrous cycle, (pro-estrous, ) estrogen levels rise.  The outward effect of estrogen is seen as firm swelling of the vulva and a bloody vaginal discharge.  Vaginoscopy will show a smooth ballooning of the vaginal lining.  Vaginal cytology will show rounded epithelial cells with relatively large nuclei , white blood cells (wbc's) and red blood cells (rbc) and bacteria.

Vaginoscopy:  Estrogenic phase

 

to produce a litter . This can only be accomplished if healthy sperm in adequate numbers are in the right place at the right time and that there is an adequate number of healthy eggs being produced which can implant into a healthy uterus.

As the estrogen level peaks it stimulates the release of Lutenizing Hormone which corresponds to a rise in the level of progesterone.  We now see a sudden decline in estrogen levels resulting  outwardly in the softening of the swollen vulva and a more watery bloody discharge. Vaginal cytology, although still exhibiting wbc’s, rbc’s and bacteria will show a change in the epithelial cells which are now larger and with sharp edges and very small or no nuclei.

Vaginoscopy shows the start of flattening of the previously balloon like vaginal folds and  of crenulation (wrinkling)  As the cycle progresses vaginoscopy shows progressively more crenulation seen as a significant wrinkling of the vaginal mucosa and squaring.