Genetic selection of lower birth weights and easy calving bulls means that calving problems because of fetal oversize are becoming rarer.
However, there are still common problems that are worth reviewing to help producers recognize and assist these deliveries and save more calves.
Fetal malpresentations are the most common calving difficulty that we see today in veterinary practice.
Producers can often correct this themselves by gently repelling the body and head back to give enough room to bring the leg around. This places the calf in the normal position to be pulled.
A cow can occasionally deliver a calf with one foot back depending on the size of its pelvic opening compared to the size of the calf. Always try to assist a backward calving.
Five to six percent of pregnancies are twins in some herds, and they pose a much greater risk of malpresentation because of the eight legs and two heads. The various combinations in which these body parts can be presented can really be a puzzle to sort out.
The most common combination is one backward (usually the first one) and one forward with both often trying to come together.
In this situation, the first thing to remember is that the top calf must be the one to come out first.
Secondly, follow the leg back to the body and make sure you are pulling on two legs from the same calf.
Producers can do one of two things to determine between back and front legs:
- When following the legs back, finding the neck and head means it’s the front legs and finding the tail means it’s the back legs.
- If you can’t reach that far, check the first two joints. If they bend the same way, it’s the front legs, and if they bend the opposite way, it’s the back legs.
Four front legs need to be sorted out if both calves are coming forward.
A cow that had twins in the previous year or two should be watched extra close because they often repeat.
My rule of thumb for any of these malpresentations is to call the veterinarian if no progress has been made after 20 minutes because the vaginal vault will be drying out.
You are generally behind with malpresentations because the uterine contractions may be de-layed or the water bag or feet won’t show the way they do with normal calvings. As a result, there is an increased percentage of stillborn calves.
Complete breech births, where the calf is presented tail first into the birth chamber, are the most common malpresentation. It takes skill and experience to bring the back legs around without damaging the cow’s uterus.
This form of malpresentation is more common with twin births.
The cow often delays pushing when just the butt end is presented.
It’s not clear whether this is be-cause nothing is presented into the pelvis, but I do know that more than half of these are stillborn.
The cow will often look uneasy and start making a bed but won’t get down to the act of calving. The entire placenta is often presented when the calf is delivered.
The navel cord may be wrapped around the legs, and veterinarians must be careful to not rip it during delivery.
Torsion of the uterus is rare, but it is important for the producer to recognize it right away and call for help.
You will get the impression during your vaginal exam that your hand and arm are going through a corkscrew with apparent tight tissue crossing your path. When you do reach the calf, it may appear upside down and the opening is not uniform like a partially dilated cervix.
A few options are available:
- The calf may be able to be rolled by an experienced veterinarian.
- The cow is rolled and the calf held.
- A caesarean is performed.
Veterinarians generally become involved with fetal monsters, fetal hydrops (excessive fluid in the calf’s abdomen), schistosomas reflexus (an inside out calf) and many other rare conditions such as two headed calves.
The calves are usually non-viable and are delivered by C-section or a fetotomy, in which the veterinarian will cut the fetus apart using obstetrical wire and an instrument called a fetotome. These are all undesirable options, but the life of the cow is spared.
Veterinarians also see cases where something is wrong with a cow’s pelvis. The tail head and spine may have dropped down, making the pelvic opening very small, or there may be a mass or other obstruction in the pelvis.
The solution is a C-section, even though the calf is normal sized. These cows are culled out in subsequent years.
Another problem is that our heifers are maturing early and the older calves are being bred at only a few months of age. These animals commonly have calving problems because of small pelvic openings.
Pulling bulls and pregnancy checking yearling heifers can eliminate these unwanted pregnancies in young heifers.
Roy Lewis works as a technical services veterinarian part time with Merck Animal Health in Alberta.