Principles of decision making and surgical management of dystocia Flashcards
Look at this dystocia decision tree?
What are the guidelines for extraction for anterior presentation?
- Standing animal: apply traction of 1 strong person, and you palpate the greater tubercles of the humerus of the calf; if this is positioned less than 10cm cranial of the pelvic entry, you can extract the calf
- If legs are crossed over or the plantar side of feet are pointing towards each other (width of the calf is large and elbows and shoulders are pressed and rotated in the pelvic cavity) care must be taken, particularly when delivering heavy muscled beef calves.
- If you can pull the head of the calf into the pelvis (using a head rope or manually with calving chains on it legs pulling slightly towards the udder), you can deliver the calf with traction and patience. Space for your hand between the calf’s head and the ventral side of the sacrum further confirms the change of being able to deliver this calf per vaginam.
- In a recumbent animal the process is similar except the measurement between point of shoulder (greater tubercle) and pelvic entry is 5 cm or less; as recumbency changes (improves) the position of the pelvis, helping the cow to move the fetus further towards the pelvic entry.
What are the guidelines for extraction for posterior presentation?
Posterior presentation:
- Better assessed in recumbent animal
- Confirm the pelvis of the calf is at a 90 degree angle with the pelvis dam (see images in previous session)
- Pull towards the tail of dam with 2 persons’ strength
- If you can visualise tarsi outside the vulva you can extract the calf per vaginam (seeing to tarsi outside the vulva indicates that the greater trochanters are in the pelvic cavity). Remember that soft tissue birth canal often needs manual dilation before extracting the calf as this has not happened optimally in a posterior presented calf.
- Consider the position of the umbilical cord in these posterior presentations; once you pulled the calf up into the pelvic canal, the umbilical cord get compressed between the calf and the pelvic entry earlier in the delivery process than when presented in anterior position, which means you need to progress sufficiently fast to get the calf out and breathing. This is different in anterior position where you can ‘use’ the calf to stretch the soft tissue of the birth canal slowly, as the umbilical cord will remain intact longer.
When the calf is flexed at the shoulder, it will not be able to pass. You can identify this by the position of its nose, which is too far forward. Describe briefly using keywords, what are you going to do when you’re in this situation?
Apply lubricant into the pelvic canal and push the calf back into the pelvic cavity by pushing on it head and legs; once it is pushed back sufficiently pull on its legs using calving chains one by one to resolve the issue.
Once the head of the calf passed the vulva it is important to start rotating the calf as indicated in the image. You can do this easily when 2 people are pulling by swapping over the calving chains and rotate the calf in that way. When using a calving jack this is more difficult to achieve. Why is this rotation so important when dealing with large calves?
By rotating you optimize the space available in the pelvic cavity.
If the calf is not rotated well a ‘hiplock’ situation may occur where the greater trochanters of the calf are stuck within the pelvic cavity of the dam and it is not possible to pull the calf any further or repel the calf back into the pelvic cavity.
The image below depicts the situation we are aiming to achieve.
What is proper chain placement on calves?
Using the below approach, it gives you the best of both worlds; the chain won’t slip off and it is unlikely to put that much pressure on the metacarpus to cause a fracture.
The below the fetlock placement is preferred by some vets, as, when placed correctly (with the connecting link on top of the leg) it is the most favorable line of force (‘krachtlijn’, see image below) and limits the chance of overstretching or fracturing the metacarpus.
Some vets prefer chains over calving ropes; they may last longer and are easier to disinfect on farm. Some vets consider ropes are less damaging to the calf. Using whatever suitable equipment available on the farm has the advantage of a reduced risk of vets transmitting diseases via equipment they use on different farms, so you may need to be flexible in what you use.
Perhaps the most important message is to consider how hard you are pulling and if you’re technique is correct, as many vets in practice would apply different methods successfully. However, it is worth considering these different approaches and thinking about the pros and cons of each approach as you may decide on different approaches in different situations. Metacarpal fractures are not uncommon unfortunately and therefore knowing how to optimize the chances for a safe natural delivery is important.
Have a look at this video and describe what could have been done to improve the chance of delivery of this calf. https://youtu.be/RODHK8eUTWA
Rotation of the calf and the use of lubricant would have enabled delivery of this calf
It is recommended when extracting a calf to position the cow in lateral recumbency. Have a look at the image below, think about practicalities of delivering a calf and describe briefly three reasons why vaginal delivery in the cow is best attempted in lateral recumbency.
1= it enlarges the vertical diameter during abdominal press
2= the cow is in a better position to optimise her abdominal contractions
3= when pulling on the calf you can better control the direction of pull, particularly in a posterior presentation when the direction of pull should be towards the tail to optimize position of the calf’s greater trochanters inside the pelvic cavity of the dam (see image below)
When you have successfully managed your dystocia case (be it by extraction or caesarean or fetotomy) you need to consider management options with regards to aftercare and recommendations to the owner.
List 4 items of aftercare and/or recommendations you would consider in the case of a bovine dystocia (let’s assume it was a difficult delivery of a live calf after you corrected a malpresentation).
A few areas need to be considered here:
Pain relief: NSAIDs, such as meloxicam or ketoprofen (dependent on the situation you could provide analgesia before intervention)
Energy source: Propylene glycol, as the cow has likely not eaten much in the last 24 hours
Check each quarter for mastitis (do a CMT if in doubt)
Advice the farmer that foetal membranes should pass within 24 hours, if not it is important to monitor the health of the cow and call you back if she deteriorates. Retained placentas are common in dairy cattle, but a much more serious situation in equine, you will learn more about these differences later on.
Antibiotics: when the calving procedure was performed in a clean environment, using clean procedures, no damage was done to the soft tissue of the birth canal, and the patient was in reasonable health, antibiotics may not be indicated. If concerns for infection exist a 3-day course of a penicillin based antibiotic is recommended.
Oxytocin for uterine contractions: Debatable how useful this is, if the farmer can bring her to suckle the calf or bring her in for milking the same day (if she is walking confident enough) her natural oxytocin release will be more effective then one dose given by you (consider the short half life of oxytocin). Getting her milking/suckling soon is important to reduce the risk of mastitis, and at the same time oxytocin release in the first 24 h after calving will help to detach the placenta.
Recheck advice: to give you a call (for a revisit) if the cow is not well the next day (not eating, high temp)
Supportive therapy: soft bedding, good feed, stress free environment (leave in separate pen until eating well)
Discuss calving aids?
The ‘Vink’ calving aid (with frame to be placed on the hips) is better compared to the conventional calving aid as it give the opportunity to change the direction of pull. Using a pulley system (pulley block), as indicated in the right, gives you even more flexibility in direction of pull, however, you need to be in an environment that allows placing one end of the pulley in the right location (in a field you can use the tow bar of your car). The pulley has the added benefit of being able to release pressure on the ropes, so you pull along with the cows’ natural abdominal contractions, which is far less likely going to create soft tissue damage. This soft tissue damage is a high risk when a calving aid is put in the hands of people who do not know the normal calving process of the cow and who may exert to much force. This will likely achieve the aim of delivering the calf, but may severely damage the cow in the process. In the right hands calving aids are a very useful aid, however when sufficient manpower is available it is recommended to deliver the calf without these aids.
Compare tractive forces?
If convinced the fetus is dead, the calving guidelines direct towards partial or total fetotomy
The use of this technique is common in some places and less common in others, and may depend on training and experience of the vet involved. A fetotomy should be considered when the birth canal is sufficiently open to deliver parts of the fetus. A fetotomy is preferred over a?
Caesarean in those cases where contamination of the abdominal cavity is likely to lead to peritonitis if performing a caesarean. A fetotomy is less invasive for the dam and more cost effective.
Common indications for a partial fetotomy are:
deviation of the head (also seen in foals as ‘wryneck’, where the neck is drawn to one side by a rigid contraction), carpal, hip or hock flexion (where repositioning is proven impossible without uterine damage due to limited space), fetal pathologies such as a schistosoma reflexus, or a ‘hiplock’ situation as discussed in the previous session. In indication for a total fetotomy would be fetomaternal oversize, in the practical class you will go over the specific cuts needed for that.
There are 2 intrauterine methods to remove parts of a fetus; a percutaneous or subcutaneous technique.
Using the percutaneous technique you remove parts of the fetus by sawing them off using cheesewire. In percutaneous fetotomy you only cut the skin and remove parts of the fetus manually.
Which method is indicated in the 3 images below?
subcutaneous fetotomy
Look at some calving equipment?
Have a look at the image below; when removing the distal limb of a dead fetus with a flexed hock, why do we place the head of the fetotome below the tarsus?
It leave a stump proximal to which you can place a calving chain to facilitate extraction
Look at these fetotomy procedures?
