Most calves can be pulled by hand after correcting any abnormal position, but occasionally a mechanical calf puller (“calf jack”) is needed. It is important to determine whether the calf can be safely pulled, or should be delivered by C-section.
Mark Alley, (NCSU College of Veterinary Medicine) says a calf jack is an excellent tool when used appropriately, but if used incorrectly it can cause a lot of damage. Most experts say you should not apply more force than what two strong men can do pulling by hand. When working by yourself, however, you may need more pulling strength and the calf jack is helpful.
Proper ways to pull a calf
Never apply a steady maximum pull. It’s best to pull only when the cow strains, and rest (or stop cranking the calf jack) while she rests. One study showed a calf jack can give a couple of thousands pounds of pull, whereas two men can give about 400 pounds of pull.
Chain placement is crucial so you don’t break the calf’s legs. The mechanical puller puts enough force on the leg to pull joints apart or fracture bones. Put one loop above the fetlock joint and a second loop (half hitch) below it, for two points of pull, spreading the pressure so it doesn’t all come in one place — or blood flow may be completely cut off. Give the cervix time to dilate, if it’s not completely dilated when you start pulling the calf. Pull slowly and gradually, using lots of lubricant.
Alley says one measure to predict ease of birth is if you can get the calf’s head and front legs into the pelvis without traction and get your hand between the calf’s forehead and the cow. If the calf’s head is hitting the cow’s pelvis, it should be delivered by C-section.
“If the forelegs are crossed, this usually means it’s a big calf and the shoulders are wedged in the cow’s pelvis,” says Alley. “You might or might not be able to pull it. Delivering calves is one of the most challenging things to teach people.” It’s an art and a science, and experience helps, because each case will be different.
“If you talk with experts who have delivered lots of calves, the reason they are experts is that they’ve made mistakes and have learned what not to do,” he says.
The most important thing — learn to know when to call for help. “If you’ve worked on a dystocia for 30 minutes and haven’t made progress, it’s time to re-evaluate,” he says. “Fetotomies and C-sections are options. A common mistake people make with a calf jack is trying to pull calves that cannot be delivered vaginally. The calf is too big. The other mistake is working too quickly. This may result in vaginal or uterine lacerations in the cow or injuries to the calf.”
How to use a calf jack
There are several ideas about how best to use a calf puller. Some veterinarians advise keeping the rod straight out from the back of the cow, in line with her spine and never moving it downward. Others recommend using it as a lever as well as a pulley, after the calf’s head emerges from the vulva. After the slack is taken out of the chain, the puller is slowly moved toward the cow’s feet, working with the cow as she strains. Then it’s moved back up while taking up all slack gained with this leverage action. This process is repeated several times, then the winch or ratchet is utilized to bring the calf out, taking care to go slowly and ratcheting only when the cow is actively straining.
“I prefer the cow to be flat on her side before using the puller,” says Alley. It’s easier to use, and easier for the cow to help you because she can strain more effectively. Gravity is against you when she’s standing; the heavy uterus and calf are resting on the abdominal floor; the calf must come up and over the pelvic brim.
It only takes a moment to lay a cow down if someone can help you. Put chains on the calf’s feet, then put the rope on the cow’s body, using a double half hitch. One person pulls on the rope and the other person pulls on the chains. This stimulates the cow to strain, and she wants to lie down. The key is pulling on the chains at the same time you pull on the rope. Once the cow is down, lay her flat on her side before positioning the calf jack.
“If you try to pull a calf with the cow standing, you don’t have much control on how you can handle the calf jack,” says Alley. “Once she’s down, I align the base (butt plate) of the calf jack just below the cow’s vulva. The chains or straps around the calf’s legs can then be hooked to the chain of the calf jack.
“I prefer a calf jack that can put alternating pressures on the legs, bringing them forward one at a time, walking the shoulders through the pelvis — like you would when pulling by hand,” he says.
He applies pressure on the jack, timing it with the cow’s contractions. When the calf’s head comes through the vulva, he may clear mucus from the calf’s nostrils. If you get in a hurry after the head comes through, you can end up tearing the cow. Small amounts of pressure can be applied after the head comes out — take your time.
As soon as the head is out, he starts pushing down a little with the end of the calf jack, toward the cow’s feet. “I try to deliver that calf in an arc, as he would come during a natural birth,’ he says. Don’t pull downward on the calf too much, too soon or you may injure its ribcage. Mimic nature in the way the calf curves over the pelvic brim and then comes head downward toward the cow’s hind feet as his ribcage passes through the birth canal.
Pulling straight out puts unnatural pressure on the calf’s spine because of the way the cow’s pelvis tilts. “We often see spinal fractures with a straight pull,” says Alley. “You may have a live calf, but he’s paralyzed.”
The calf’s hips tend to catch on the cow’s pelvis if it’s pulled straight out. If you start to pull the calf downward this raises the hips to come through the wider upper part of the pelvis. The cow’s pelvis is an oval in which the vertical diameter is greater than the horizontal diameter. On a big calf you should rotate it so the hips can come through at a diagonal, which gives more room. Rotate the calf as its shoulders come through the pelvis, so the widest part of the calf’s hips line up with the widest vertical diameter of the cow’s pelvis.
“Once the last rib of the calf has cleared the vulva, we assess its size, and whether we need to rotate the hips,” says Alley. It doesn’t matter if this takes a few minutes because the calf can start breathing; his ribcage is free of the birth canal and can expand. Additional lubrication used at this point can ease delivery.
“The pressure is off the ribs, but there’s pressure on the umbilicus, so the calf must start breathing,” Alley says. If you’ve taken time to clear calf airways, or let fluids come out of the nose as the ribcage is compressed going through the birth canal, it can start to breathe. This happens naturally as a calf is born, but can be hindered if you keep steady, unrelenting pressure with the calf jack.
One mistake some people make is letting the calf hang there (if the cow is standing), or hanging a calf upside down after delivery, thinking this will help fluid drain from the airways. If the calf is having a hard time breathing, this is counterproductive. Weight of his abdomen presses against the diaphragm and it’s hard for it to take a breath. †