Incomplete cervical dilation occurs very occasionally in heifers but the true incidence is difficult to determine because in most situations the onset of first stage labour has not been noted.
It is probable that some dystocia cases are classified as incomplete cervical dilation but merely represent over-zealous interference during early first stage labour. Typically, the opening is only 5-10 cm in diameter which may just allow passage of one hand.
Fig 1: Some dystocia cases are classified as incomplete cervical dilation but may represent over-zealous interference.
Manual pressure applied for 10 to 15 minutes may gradually dilate the cervix in some cases but such cases may well represent those heifers disturbed during early first stage labour. In some cases the vulva may also fail to dilate properly because there has been no pressure from the water bag and veterinary attention is necessary. Natural dilation is achieved by pressure from an intact water bag being pressed through the cervix into the vagina by contractions of the uterus. For this reason it is unwise to manually rupture the waterbag until full dilation is complete.
Too early/frequent human interference may delay normal progression of first stage labour especially in heifers. Farmers should be encouraged to leave cattle undisturbed for four hours after the appearance of a mucus string or allanto-chorion at the vulva, especially in heifers. However, frequent bouts of powerful abdominal contractions occurring more frequently than every five minutes or so must be investigated.
Dystocia caused by an oversized calf in normal anterior longitudinal presentation is common in beef cattle. The calf's muzzle and forefeet are presented at the cow's vulva.
Reasonable traction should deliver the calf when two people pulling can extend both front legs such that the fetlock joints protrude one hand's breadth beyond the vulva within 10 minutes' traction. Such movement of the calf's forelegs represents extension of both elbow joints into the cow's pelvis. Veterinary attention is necessary if greater traction is applied without obvious progress and the elbows are not extended easily.
Fig 2: The fetlock joints protrude more than one hand's breadth beyond the vulva - this calf will be delivered safely.
Tears in the vaginal wall during delivery of the calf may be sufficient to allow the protrusion of submucosal fat or extend to cause rupture of the uterine artery with life-threatening consequences.
Haemorrhage from a major artery in the vagina must be identified immediately after the calf has been delivered and veterinary attention sought urgently.
Hip lock often arises when excessive and inappropriate traction has been applied to an oversized calf in anterior longitudinal presentation. The cow quickly becomes exhausted with the calf protruding to the back of the rib cage but firmly lodged as the hips enter the cow's pelvis.
Fig 4: Excessive and inappropriate traction has been applied to this oversized calf in anterior presentation resulting in hip lock.
Further traction whilst attempting to rotate the calf or roll the cow is rarely successful and risks obturator/sciatic nerve damage of the cow. Immediate veterinary attention is essential.
The calf's forequarters are removed and the remaining vertebral column and pelvis are divided using embryotomy wire. The split hindquarters can be pushed apart and easily removed.
Fig 5: The calf's forequarters are removed using embryotomy wire then the remaining vertebral column and pelvis are divided.
Veterinary expertise is essential where there are doubts whether the oversized calf can be safely delivered.
Leg back is a common malposture in cattle obstetrics. The calf's head and one foreleg are presented at the vulva.
Fig 6: Leg back is a common malposture.
Correction of this malposture is best achieved after extradural injection by a veterinary surgeon to prevent forceful straining. After five minutes the calf's head and protruding foreleg are well lubricated and slowly repelled until the calf's poll is level with the pelvic inlet. By first grasping the calf's forearm then the mid metacarpal region, the elbow and carpal joints of the retained leg are fully flexed which brings the foot towards the pelvic inlet. With the fetlock joint fully flexed, and the foot cupped in your hand to protect the uterus, the foot is drawn forward into the pelvic canal extending the fetlock joint. Traction on the distal limb extends the elbow joint and the foot appears at the vulva where a calving rope is applied above the fetlock joint. Click for video simulation
The cow should now be haltered and tethered low down to a post in the calving box. Steady traction of two people pulling on the calving ropes applied to both legs will generally result in the heifer/cow assuming lateral recumbency which aids delivery of the calf.
The calf's umbilicus should be immediately fully immersed in strong veterinary iodine and repeated 2 and 4 hours later. Three litres of colostrum are administered by orogastric tube to ensure adequate antibody transfer because the calf will be unable to suck as a result of its swollen tongue.
Lateral deviation of the head is a common calving problem; the calf is often dead. Both fore feet are presented in the maternal pelvis (and possibly at the vulva).
The head back is often mistaken for a calf in posterior presentation (coming backwards) because you can feel two legs but no head. Note than the hooves face down not up and you are able to feel the carpal joints (knees) not the hocks or calf's tail.
Correction of the malposture is not easy especially when the calf is dead and veterinary attendance is often necessary. After extradural anaesthesia, the calf's forelegs and neck are carefully repelled as far as possible. A finger can be placed into the calf's mouth or an eye socket in an attempt to pull the head around into the pelvic inlet. Click for video simulation Alternatively, a leg rope placed around the calf's lower jaw. Once corrected, a head rope is placed behind the calf's poll and through its mouth to assist alignment into the pelvic inlet. Click for video simulation The calf is then delivered by traction as described above.
Recognition that second stage labour has not progressed and timely intervention.
Posterior presentation is a common cause of dystocia in cattle. Typically, the calf pelvic limbs protrude from the cow's vulva about one hand's breadth short of the hock joints.
Two strong people pulling on calving ropes should be able to extend both hocks more than one hand's breadth beyond the cow's vulva (calf's hindquarters now fully within the pelvic inlet) within 10 minutes. Further traction will deliver the calf safely. Other guidelines include whether your hand can be extended over the calf's tail head and underneath both stifle joints when the calf is drawn into the pelvic inlet.
Fig 7: Only moderate traction should be necessary to extend both hocks of the calf more than one hand's breadth beyond the cow's vulva.
Multiple rib fractures. Rupture of the liver.
Prolonged delivery resulting in compression of umbilical vessels causing lack of oxygen.
The calf's pelvis is firmly lodged at the entrance to the maternal pelvis with both hindlegs extended alongside the body.
Cattle show typical signs of first stage labour when they appear restless and isolate themselves wherever possible but abdominal straining is not seen because the foetus does not engage within the maternal pelvis.
Fig 8: Cattle with a breech presentation show initial signs of first stage labour but then appear restless with the tail raised.
The waterbag may rupture but remnants of the foetal membrane may not appear at the vulva. The calf's tail is readily palpable on vaginal examination. In some cases the calving problem is not noted until the calf/calves die and the cow develops severe toxaemia.
An extradural injection is given by a veterinary surgeon to block the cow's forceful abdominal contractions. The calf's tail head is slowly repelled beyond the level of the cow's pelvic inlet as far as your reach allows. Commencing distally, one calf's foot is cupped in your hand and the fetlock joint fully flexed. As the hind foot is drawn toward the maternal pelvis, the hock and stifle joints are fully flexed. Correction now involves extending each hip joint in turn while the distal limb joints (stifle, hock and fetlock joints) remain fully flexed. Further gentle repulsion of the calf may be necessary at this stage. In this manner a breech presentation is converted to a posterior presentation. Click for video simulation
Premature rupture of the umbilical vessels if the umbilicus has become hooked around one hind leg while correcting the hip flexion.
Uterine rupture during repulsion of the calf or correction of the hip flexion causing fatal peritonitis.
There are many possible combinations of heads and legs when two calves are presented simultaneously. It is necessary to identify which leg corresponds to which head by tracing the leg to the shoulder region, and then to the neck and head. Once both legs and head have been correctly identified and roped, the other calf is gently repelled as traction is applied to the first. Only slight/moderate traction should be necessary to deliver a twin calf in this situation; if little progress is being made it is essential to check that you have selected the correct anatomy. It is important to differentiate simultaneous presentation of two calves from foetal abnormalities.
Regular supervision of calving cows. Examine those cattle suspected of first stage labour exceeding six hours.
In most cases, any malpresentation of the calf will be more easily corrected with the cow in the standing position as this allows the calf to be repelled. Once the presentation is correct, delivery is best achieved with the cow in full lateral recumbency as, in that position, the pelvis is at its maximum diameter.
Immediately after the calf has been delivered and the airways cleared, the cow must be examined for:
Uterine rupture occurs during assisted delivery most commonly with the calf presented in breech presentation but also with lateral deviation of the calf's head.
If the condition is not recognised immediately the cow may appear to be normal for several hours after delivery. She then becomes increasingly dull and depressed with a painful expression, no appetite and little milk production. As peritonitis develops over several days, the abdomen becomes increasingly distended which contrasts with the cow's much reduced appetite.
Fig 11: As peritonitis develops over several days, the abdomen becomes increasingly distended which contrasts with the cow's much reduced appetite.
Treatment of diffuse peritonitis involving small intestine is invariably hopeless and cow must be euthanased for welfare reasons when this diagnosis is confirmed.
Haemorrhage from a major uterine artery may result from excessive traction in over-conditioned heifers and is apparent once the pressure has been removed with delivery of the calf. Haemorrhage from a major artery in the vagina must be identified immediately the calf has been delivered and veterinary attention urgently requested.
Monitor dry cow and heifer body condition scores regularly especially during the summer months. An episiotomy should be carefully considered in overfat heifers. Avoid excessive traction by electing to perform a caesarean operation.
Uterine torsion is relatively common in cattle. It is often associated with an oversized foetus. Uterine torsion, from 180 to 720°, prevents entry of the foetus/fluids into the twisted vaginal lumen such that the animal shows no sign to indicate the end of first stage labour. Failure of the cervix to dilate fully is a common consequence.
The cow may isolate herself from others in the group and show signs of first stage labour including slackening of the sacro-iliac ligaments but the foetal membranes (allanto-chorion) do not appear at the vulva. The vulva and tail head are slack which contrasts with the constricted (tight) vaginal lumen which is typically dry lacking mucus. As your hand passes into the vagina there is a distinct twist (corkscrew effect) with can be either clockwise or anti-clockwise. With a torsion less than 360° it may be possible to reach the cervix which is dilated with foetal extremities distally. In those cases where the torsion is more than 360°, or when the calf cannot be reached a caesarean operation is the best way of ensuring the delivery of a live calf and an undamaged dam.
If left unattended for several days, the cow becomes sick due to death of the calf and development of a septic metritis.
A uterine torsion can be identified by the tight vagina with an obvious "corkscrew" feel. Veterinary attention is necessary to correct the twisted uterus.
Uterine inertia is not uncommon in dairy cows and older beef cows with clinical hypocalcaemia (milk fever). Parturition does not progress beyond the end of first stage labour. Vaginal examination reveals the cervix to be fully dilated with the foetal membranes intact. Often the calf is already dead. There may be other signs of hypocalcaemia including recumbency and inability to rise, and free gas bloat.
Fig 12: Uterine inertia is not uncommon in dairy cows and older beef cows with clinical hypocalcaemia (milk fever).
Fig 13: Parturition does not progress beyond the end of first stage labour.
400 mls of 40% calcium borogluconate injected intravenously. If the calf is alive, it is usual to leave the cow for up to two hours to allow parturition to progress naturally.
Hypocalcaemia is discussed further in the bulletin on metabolic diseases.
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