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In most cases of dystocia, the calf can be pulled by hand. There are some instances, however, when a mechanical calf puller is needed during calving.
How to use a calf puller
Alley says he prefers the cow to be flat on her side before using a calf jack. It makes controlling the instrument easier for the handler, and the cow can strain more effectively. “Gravity is against you when she’s standing because the heavy uterus and calf are resting on the abdominal floor; the calf must come up and over the pelvic brim,” he says.
“Once she’s down, I align the base (butt plate) of the calf jack just below the cow’s vulva,” he says. 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 explains.
Alley times his efforts with the cow’s contractions. When the calf’s head comes through the vulva, he may halt for a moment to clear mucus from the calf’s nostrils. “Small amounts of pressure can be applied after the head comes out, but take your time,” he advises.
In the midst of calving? You might enjoy this calving blog from BEEF Daily blogger Amanda Radke.
“As soon as I get the head out, I start pushing down a little with the end of the calf jack, toward where the cow’s feet are. I try to deliver the calf in an arc, as it would come during a natural birth,” Alley says. But he cautions against pulling downward on the calf too much too soon, as the calf’s ribcage could be injured.
“If you continue to pull straight out, you put an unnatural pressure on the calf’s spine because of the way the cow’s pelvis tilts. This can paralyze a calf,” Alley says.
In addition, a birthing calf’s hips tend to catch on the cow’s pelvis if pulled straight out. Pulling downward raises the calf’s hips to pass through the wider upper part of the cow’s pelvis, which is oval-shaped – the vertical diameter is greater than the horizontal diameter.
“We rotate the calf as his shoulders come through the pelvis, so the widest part of the calf’s hips line up with the widest diameter of the cow’s pelvis,” he explains.
Once the last rib of the calf has cleared the vulva, Alley stops to assess the calf’s size to decide whether its hips need to be rotated. At this point, the calf can begin breathing, as its ribcage is free to expand. He also adds additional lubrication to promote easier delivery.
“If you’ve taken time to clear his airways, or to let fluids come out of his nose as the ribcage is compressed going through the birth canal, he 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,” Alley says.
One common mistake 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 its airways. If he’s having a hard time breathing, this is counterproductive, Alley says. The weight of his abdominal contents presses against his diaphragm and it’s hard for him to take a breath.