Tuire Tamminen DVM, Dip. ECAR

Animal Hospital Veter, Tampere, Finland

ARS, Animal Reproduction Science, University of Helsinki, Finland

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Vaginal problems in the bitch

The causes of vaginal disorders depend substantially on the age and the hormonal state of the bitch. Typical symptoms of vaginal problems are vulvar discharge and licking of vulva. Discharge may be mucous, purulent, bloody, or a mixture of these. Vaginal smear gives an overview of oestrogen production, inflammation, and bleeding. Tumour cells may also be noticed. Abnormal structures and masses may be identified by vaginal or rectal palpation. Vaginoscopy, with othoscope or endoscope, gives further information of these abnormal structures and masses, but also visualizes whether the vaginal mucous membrane is intact or has changes like irritation or blisters. In some cases, imaging with CT is necessary for proper surgical intervention, as ultrasound examination may be insufficient and challenging in the pelvic area. Most common vaginal problem, vaginitis, may be frustrating to treat. It is important to clarify the reason for the vaginitis to aim the treatment correctly. Antimicrobial treatment is not recommended unless the case is severe and not resolving with other treatments. At first, vaginal flushing with saline relieves the irritation until the underlying cause can be determined, and a decision of treatment made.

 

Ovarian abnormalities in the bitch

Disturbances in ovarian function usually lead to abnormal oestrous cycle. The interval of oestrus may be shortened or prolonged, dioestrus may be shortened, or oestrus may be prolonged. Vaginal smear, blood progesterone determination, and especially ultrasound examination of ovaries should be performed. Commonly occurring ovarian tumours are adenocarcinoma, adenoma, granulosa cell tumour, and teratoma. With early surgical removal (OHE) and no detectable metastasis, the prognosis is good. Ovarian cystic structures may be hormonally active or inactive. Medical treatment of ovarian cyst in bitches is challenging, and surgical removal of a cyst is suggested. Hormonally inactive cysts which do not cause any symptoms or pain, may not need treatment and can be followed. Insufficient progesterone secretion may lead to shortened dioestrus, and thus also oestrous interval is often shortened. In pregnant bitches an abortion may follow. In such case, further investigations are necessary to clarify the reason for luteal failure. Anovulation may be due to insufficient oestrogen, GnRH or LH secretion, or failure of the ovary to respond to LH peak. Quite often after anovulation a normal oestrus with ovulation follows. If an ovulatory oestrus follows an anovulatory oestrus in 1-2 months, the phenomenon is known as split heat.

 

Uterus as a reproductive organ

Uterus is a dynamic organ with demanding roles in storing and transporting of semen, accepting the embryos attaching to the endometrium, maintaining the pregnancy by closing the cervix and preventing myometrial contractions, and then changing from the quietness to active labour by opening the cervix and allowing the myometrial contractions for the parturition to proceed. At the same time the uterus is fighting against inflammation and infection, and it takes part in hormonal regulation of reproductive organs. For example, the ultrasound examination of uterus should be assessed in relation to the current hormonal state of the bitch. Subclinical endometritis is a common finding in bitches with history of infertility or recurrent abortions. Treatment options depend on the case, hormonal balance and other findings in uterus. Fibrotic and cystic changes worsen the prognosis for fertility. Endometrial inflammation may increase prostaglandin secretion and cause regression of corpora lutea which may lead to failure of pregnancy. Apart from pyometra, bacterial infection as a reason for infertility is unclear.

 

Dystocia in the bitch

Before and during parturition complex events like changes in hormone secretion, oxytocin receptor expression, neurohormonal activity, behaviour, and interaction between the dam and the offspring occur. The structure and the size of the pelvic cavity of the dam, sufficient ripening of the cervix, adequate ability of the uterus to contract to expel the puppies through the birth canal, and the duration of the parturition are key factors to successful parturition. Size, number, conformation, and vitality of the puppies affects to the survival of the litter. Uterine contractions reduce the placental blood flow causing decrease in oxygen supply to the foetus. Therefore, adequate progression of the parturition is necessary. Dystocia occurs in bitches from 5% to 16 %, but in certain breeds, occurrence is remarkably higher. A caesarean section is performed approximately in 60% of bitches with dystocia. Dystocia increases the risk of puppy mortality. The most common maternal cause for dystocia is primary uterine inertia, which can be complete or partial. In complete primary uterine inertia, the uterus fails to initiate parturition due to absence of uterine contractions and thus no puppies are born. In partial primary uterine inertia, the bitch may have weak uterine contractions or contractions that cease without any obvious reason (such as obstruction) before all puppies are born. Secondary uterine inertia is caused by prolonged parturition due to obstruction in the birth canal. Sometimes it is challenging to estimate whether the progress of parturition is normal or abnormal. Some bitches have minor changes in behaviour when parturition is not progressing, and the litter is already lost. Others act like having dystocia even when the parturition is proceeding well. To recognise a parturition where the vitality of the puppies is at a risk an advanced monitoring of parturition is necessary. One option is tocographic (tocodynamometry) follow up of uterine contractions which may reduce puppy mortality by faster diagnostics.

 

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