Dr. Harry Momont, University of Wisconsin-Madison – Calving 101: Everyone Gets Out Alive
When it comes to calving, the biggest question is when to intervene, according to Dr. Harry Momont, DVM, with the University of Wisconsin-Madison School of Veterinary Medicine. How to intervene runs a close second.
When to intervene?
Momont suggested a structured approach when it comes to deciding whether to stand on the sidelines or dive in to assist. His basic guideline is to give the cow enough time on her own. For heifers, that means waiting two to three hours and, for adult cows, one hour to an hour and a half. During this window of time, the cow should transition from the subtle, early signs of stage one labor into stage two of labor, meaning that the feet are through the vulva.
“If progress is not being made, assume something is wrong,” Momont advised.
Observation alone may validate that assumption if there is a bad odor coming from the cow or excessive bleeding, or a worker may need to reach into the cow to assess the situation.
How to intervene?
If assistance is needed, obstetrical chains are Momont’s tool of choice. Chains are easier to clean than a nylon strap and much more durable than baler twine. When attached properly, they should provide two points of traction: one above the dewclaw and one below it. This should only be done if the feet have emerged, not if they are still inside of the cow. Momont cautioned against the use of calf jacks because of the potential for trauma to both the calf and cow.
Maternity pen workers may not always be able to handle this job on their own, requiring the help of a professional veterinarian. If the calf is too large for the cow to deliver with pulling assistance, a cesarean is an option, though a relatively expensive one.
Momont has a rule of thumb for determining whether or not a calf is just too big for a normal birth. If two people pulling on a chain can get both of the forelimbs out with enough space for one handwidth above the fetlock joint, that indicates that the calf can get its chest through the cow’s pelvis. The calf may have to be rotated in order for its hips to pass through.
Deep-bellied cows carrying big calves are prone to uterine torsion (twisted uterus). In fact, 20 percent of dystocia cases in adult cows are attributed to this cause. Manual detorsion involves rocking the calf back and forth inside of the cow, but a trained professional may use a detorsion rod or roll the cow to right her uterus.
In some cases, a vet may perform a fetotome, in which the calf is deemed too large for delivery and specifically designed tools are used to dissemble and extract it in order to save the cow.
A veterinarian can provide proper training on timing and methods of calving interventions.
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