Uterine Rupture in Cattle: Incidence, Etiology, Symptoms, Diagnosis & Treatment

Uterine rupture in cows is a serious veterinary obstetric emergency, typically associated with dystocia, fetal emphysema, and uterine torsion.

Uterine Rupture is observed occasionally in late pregnancy or during parturition and may be the cause or a result of dystocia.

Incidence

Uterine rupture has been observed in 1–3% of dystocia cases in cattle. It occurs most frequently in the 2- to 3-year-old age group and more often in beef cattle than in dairy cattle.

Etiology and Pathogenesis

The uterine wall may rupture before parturition, a condition sometimes erroneously called spontaneous rupture. However, this term is misleading, as uterine rupture does not occur without a predisposing weakening of the uterine wall, which, when combined with abnormal fetal movement and uterine motility, may lead to rupture.

Uterine rupture may also result from a traumatic accident in late pregnancy. A large proportion of preparturient and parturient ruptures is associated with uterine torsion when ischemic necrosis of the uterine wall, caused by the occlusion of blood vessels, is followed by excessive movements of the stressed fetus or external trauma.

Uterine rupture has also been diagnosed in association with a large fetus, fetal emphysema, malformations and hydrallantois. Occasionally, extensive adhesions between the uterus and other pelvic and abdominal organs may cause uterine rupture during parturition. These adhesions are the sequeale of a previous laparotomy, caesarean operation or rupture.

The rupture is frequently large enough for the fetus to become partly or totally displaced into the abdominal cavity. The earlier fetal displacement occurs before parturition the greater are the chances of the fetus perishing and becoming encapsulated like a foreign body in the omentum.

In the majority of cases the rupture is found running longitudinally in the greater curvature of the pregnant horn. Less frequently the rupture is in the body of the uterus and sometimes involves the cervix.

Apart from the above mentioned causes, rupture may result from a faulty obstetrical technique. The most frequently is caused by excessive traction applied to the fetus in the presence of an incompletely dilated cervix, retropulsion at the time of a maternal expulsive effort, or simply incorrect or careless use of fetotomy instruments.

Once the rupture has occurred, the fetus can neither be propelled nor correct alignment maintained within the posterior birth canal because of ineffective uterine contractions. Consequently, reflex abdominal straining is not initiated or ceases if it has commenced.

Depending on the condition of the fetus, a varying degree of peritonitis develops. Irritation of the peritoneum is less when the fetus alive and the placenta functional. Even in the absence of bacterial contamination, severe peritonitis rapidly develops when the fetus is dead and together with the fetal membranes, undergoes autolysis.

True extra uterine pregnancy, when the fertilized ovum does not enter the uterus but acquires nutritive relations with tissues other than endometrium (Fallopian tube, ovary, peritoneum), have not been reported in catte.

Clinical Signs

These vary according to the time and duration of rupture. If rupture has taken place during the explusive stage of labor, straining may have been observed and in dystocia suspected or even diagnosed for some other reason.

Straining ceases immediately once rupture occurs, irrespective of the extent of extra uterine displacement of the fetus. The animal becomes dull and anorexia and ruminal stasis set in. The cow prefers to remain in a recumbent position and may grunt.

On vaginal examination, fetal parts may be palpated within the birth canal. Occasionally it may be possible to locate the uterine tear and even diagnose extrauterine displacement of the fetus.

The fetus may be inaccessible when torsion of the uterus or incomplete dilatation of the cervix is present. If the rupture is of less than 24 hours duration the edges are irregular, soft and friable and some hemorrhage may be evident by the presence of freshly coagulated blod. In long standing cases the edges become smooth and indurated.

Prolapsed loops of maternal small intestine may be found in the uterus when the fetus does not block the wound.

Rectal examination may be helpful in confirming a diagnosis of extrauterine displacement of the fetus. However, on many occasions a correct diagnosis is reached only after vaginal delivery of the fetus or laparotomy has been attempted.

Laparotomy also reveals the degree of peritonitis and hemorrhage present.

Prognosis

The overall maternal death rate ranges from 27-44%. The death rate is higher when extra uterine displacement of the fetus necessitates a laparotomy, and lower when the fetus has remained inside the uterus and vaginal delivery is achieved without difficulty.

Provided that endometritis does not ensue, conception will be possible. However, massive adhesions may develop and possible lead to ineffective labor or uterine rupture at the next parturition.

Treatment

Vaginal delivery is attempted when the fetus is easily accessible. If, after a reasonable effort, this cannot be done and uterine rupture is suspected a laparotomy is performed. When the fetus is partly displaced into the abdomen and uterus tightly contracted and tear must be enlarged to permit delivery.

Repair of the uterine defect is completed after debridement of its edges. Exteriorization of the partly involuted uterus for repair may be difficult.

Spasmolytic drugs are of limited help. Oxytocin is recommended to restore myometrial tone after the completion of surgery. Basically the procedure is similar to a caesarean operation.

If vaginal delivery is successful, the uterine tear can be repaired per vainam as per the following procedure. The anterior end of the laceration is located and both lips of it grasped with one hand in an attempt to approximate the edges.

The needle (No. 2, curved), with approximately 1 m of catgut (No. 2) attached, is introduced with the other hand. The needle is inserted through both lips of the laceration just beyond the fingers which hold the edges.

The suture is then tied and carried on as in inverted, continuous blanket suture until the posterior end of the laceration is reached. A knot is then tied and excess catgut removed.

Parental, intrauterine and intro peritoneal treatment with broad spectrum antibiotic or chemotherapeutic preparations is essential.

Supportive electrolyte therapy to combat shock is recommended during the operation and corticosteroids during convalescence.