At calving time, we would prefer to have every cow and heifer calve on their own and deliver a live calf.
We try to ensure this by wisely selecting bulls in terms of birth weights and EPDs for calving ease, by ensuring a top-notch heifer management and selection program, and by providing good nutrition and a clean, well-managed calving environment.
However, despite our best preventive strategies we will still see some calving difficulties even in well-managed herds.
Dr. Jennifer Pearson from the University of Calgary’s Faculty of Veterinary Medicine published a paper on calving difficulties, or dystocia, based on results from the Western Canadian Cow-Calf Surveillance Network.
In the 2016 calving year, the herds in the study reported an average herd-level incidence of assisted calvings of 4.9 percent. When that was broken down by age groups, 13.5 percent of heifers were assisted and 3.2 percent of cows were assisted.
The stillbirth rate was 2.1 percent (3.3 percent in heifers and 1.9 percent in cows). There was definitely a trend that showed that later-calving herds, which were defined as those calving after March, were less likely to have assisted calvings, and had lower treatments of calves for disease and lower calf mortality.
We know there is a strong link between calves that require assistance at calving and the likelihood that they will require treatment or experience disease or death, and so some of this effect could probably be directly attributed to the lower dystocia rate in these herds.
We don’t want to interfere with a normal calving and create problems that might result in additional issues such as poor mothering, but we do need to intervene promptly in those calving cases that do require some assistance.
In many ways, this is one of the most important decisions a producer makes around calving time: when should you intervene and assist the calving cow?
At the recent Western Canadian Association of Bovine Practitioners conference, Dr. Mark Hilton gave a presentation on this issue.
I thought his advice was easy to remember: “progress every hour.”
We often try to tailor this advice and make it more complicated as we talk about the different stages of calving, and how heifers tend to take longer to calve than cows, but I think his motto of progress every hour is easy to remember and implement. That just means that if you notice a heifer with the water bag out and you check her in an hour and she hasn’t progressed, then you probably need to intervene.
If she has moved further along in the calving process, you can probably leave her alone and recheck her within the next hour.
Intervention usually requires restraining the cow and doing a vaginal exam to assess the problem. Before doing a vaginal exam, you should always clean the exterior of the vaginal area with warm soapy water and use rectal sleeves and lubricant while doing the exam.
Let’s assume we have a forward-facing calf in a normal position with its head resting on its front legs. Hilton recommended the routine practice of manual dilation before trying to manually pull any calves.
This involves putting obstetrical sleeves on both arms and placing both arms in the vaginal canal together. Clasping your hands together, you can move your elbows out laterally. Continue this action for one to two minutes and you may see that the calf’s legs are now able to protrude slightly farther than when you started, as the vaginal tissues relax and dilate.
If you can’t sort out the calf’s position within 30 minutes you should call your veterinarian for assistance.
When pulling a calf, you should only exert the force of about two people pulling. Calving jacks can exert a tremendous amount of force and so caution must be used to ensure that you don’t injure the calf or cow by putting too much tension on the chains.
Hilton is a big proponent of having cows lie down when delivering a calf. However, that may have to be a subject of a future article.
He also emphasized that when the calf is halfway out in a normal calving, the cow often takes a break. Many of you will have witnessed that quite commonly.
He suggested that when you get to this stage of pulling a calf that is coming in the forward position, it is important not to rush. The calf should be breathing and as the cow rests, the hips will begin to enter the pelvis of the cow. That waiting period allows the calf to slightly rotate in the pelvis, making it easier for the cow to deliver. The cow’s pelvis is at its widest vertically and the calf is widest across the hips. If you rush, the hips can become jammed or hip-locked.
Obviously, if the calf is coming backward with the rear legs first, we have to make sure the calf is delivered quickly because the calf will start trying to breath and inhale fetal fluids. As a result, this resting period does not apply in those situations.
Calving season is a stressful and exciting time of year, but hopefully these simple tips can help make some of those intervention decisions simpler.
John Campbell is a professor in the department of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.