Proper pulling technique ensures safety, health of calves and cows
Cody Creelman, a veterinarian at Veterinary Ag Health Services in Airdrie, Alberta, says some calves are injured at birth by pulling too soon, too forcefully or by improper pulling methods.
He explains that forcing a calf before the birth canal is ready can cause a ruptured cervix or torn vagina and vulva.
The design of the cervix and the hormones that affect the cow’s body during labor program the cervix to open more fully as the calf’s head presses intermittently on it with each uterine contraction. A hard, steady pull on a calf can actually delay this process.
Creelman says, “If we do have to start pulling a calf before the cervix is fully dilated, go slow and easy, pulling only when the cow is straining.”
Detriment of slow birth
Ranchers can begin to pull once the calf is in proper position and the cervix is more fully dilated. There’s no point in waiting, however, if a calf is taking too long to come through the birth canal. At that point, the calf is subjected to a lot of pressure from uterine contractions and the constricted area of the birth canal, explains Creelman.
Each time the cow strains, abdominal contractions add to the pressure, constricting the blood vessels to the uterus, resulting in diminished oxygen supply to the calf. If this goes on a long time, the calf may be born weak or dead, he adds.
The calf’s head and tongue may be swollen due to pressure of being in the birth canal too long, explains Creelman, adding that, if the calf is born in cold weather, it won’t be able to shiver to keep himself warm if he is short on oxygen.
“A calf that spends minimal time in the birth canal will be livelier and stronger, able to get up quickly and find the udder,” he comments.
Preparing to pull
Most ranchers know they should use a double half-hitch when placing chains on the calf’s legs for pulling, with one loop mid-cannon and the other below the fetlock joint, but some people don’t understand where the chain should be between those two points, Creelman says.
“It should be on top of the leg, in the 12 o’clock position if the calf is coming normally,” says Creelman.
This applies most of the force and stress at proper angle along the strongest part of the leg bone.
“This is much better than having it underneath or to one side of the leg. Having the chain on top of the leg provides the most leverage when doing a forced extraction but is also safest for the calf, to prevent injury to the leg,” he says.
“Even if we can only get one loop around the leg when first applying chains while the legs are still inside the cow and we don’t have much room to work. After the legs come into the birth canal, we have more room to reposition the chains before putting a lot of force on the calf. Always have the double half-hitch before using a calf jack,” he says.
Make sure the calf’s elbows are through the pelvis before applying much force because they may hang up and make extraction difficult or impossible.
“Pull on each leg individually until the elbow comes through. We can often feel or hear a pop as the elbow comes through and the leg is finally straight. Then you can put equal pressure on both legs as you pull the calf,” he says.
Head position is something else to keep track of. Make sure the head is actually starting through the birth canal and not turning off to one side.
“When using a calf jack, always be aware the amount of force we can apply is far greater than what can be applied by human strength,” Creelman emphasizes. “A calf jack can easily apply as much force as four strong men, which is too much and can cause a lot of damage to the cow and calf if not appropriately applied.”
He continues, “We never want to hear the horror stories of hooking a quad or tractor to those chains. If that much force is required, we need a different kind of intervention, such as a Caesarean section or a fetotomy, which involves cutting the calf into pieces to bring out, if the calf is already dead.”
Timing is also important, since ranchers need to know when intervention should occur.
“When the cow is in second stage labor, with forced abdominal contractions, the general rule of thumb is, if she is not progressing within an hour, intervention or assistance is needed,” Creelman says, adding ranchers may have to check to see if the calf is coming normally or identify the problem and correct it.
“Don’t let it go too long. It’s also important to know when to request help from a veterinarian,” he says. “Our standard rule of thumb is, if we are unable to make progress with intervention within 20 minutes, it may require a different intervention.”
He also notes ranchers shouldn’t wait too long to make a decision and call a veterinarian, especially if it may take a while for them to get to the ranch.
Creelman comments, “The best success comes with early intervention rather than waiting too long.”
Oversize calves are the most common cause of dystocia, according to Creelman.
“One rule of thumb I use to determine if the calf is too large to come out is if the legs are crossing,” he says. “This usually means the calf is wide in the shoulders and may be too wide to come through.”
“Also, if ranchers are having trouble with the head going back or off to the side and not coming into the birth canal, this may mean the calf is too large,” says Creelman.
If the head starts to enter the birth canal but is too large, it stops there, and ranchers will be unable to put their fingers over the forehead.
“When in doubt, have a veterinarian come – and possibly do a Caesarean – and end up with a live calf,” Creelman says.
Heather Smith Thomas is a correspondent for the Wyoming Livestock Roundup. Send comments on this article to firstname.lastname@example.org.