Calving season is one of the busiest times of year for a cow-calf producer. It’s a high-stakes time, where you realize the results of work and decisions made all year—bull selection, heifer selection, nutrition planning, and vaccination choices. It all comes down to this: the live calf on the ground.
Seventy percent of beef calves that die between birth and weaning are either born dead or die within 24 hours of birth. Studies document that difficult births cause 60 to 70 percent of these calf losses. Additionally, calves born after a prolonged delivery are nearly two and one-half to six times more likely to become ill in the immediate postnatal period than calves born without difficulty. To minimize the negative impact of prolonged deliveries, timely and proper intervention must occur for the life and health of the calf and the reproductive health of the heifer or cow.
So what causes prolonged or difficult calving? In beef cattle, the single most common cause is an oversized fetus relative to the dam’s size. This is most often appreciated in heifers, but is seen in mature cows as well.
The second most common cause is incorrect positioning of the calf. This may include the head or a leg being turned back, the calf being backwards or in another position, which makes passage through the birth canal impossible.
Other more rare causes include the presence of twins, anatomic abnormalities of the calf, or a uterine torsion or twist, where the exit from the uterus is blocked by a tight twist. Rapid detection and correction of these abnormalities in cattle is necessary when normal delivery does not occur.
In order to know how to determine if a cow or heifer needs assistance in delivering calf, an understanding of the normal calving process is required.
The first stage of labor is a preparatory phase, where uterine contractions begin and the fetus moves into position. During this time, the dam may separate herself from the herd or begin to act uncomfortable. For heifers, this stage may last 12 to 48 hours, while in cows, three to eight hours is more typical. The “water bag” breaking marks the end of this first stage.
In stage two labor, the dam moves into full labor, with active abdominal pressing in order to expel the fetus. In heifers, this may last one to four hours and in cows, 30 minutes to one hour.
Once the calf is out, the third stage of labor begins. Here continued uterine contractions expel the placenta, which takes six to 12 hours.
What should be done during each stage of labor to help ensure early identification of problems?
Cattle are masters at hiding problems. Detecting the first stage of labor in some animals can be difficult, but when a heifer or cow stands off from the herd around the anticipated time of calving, move her to an area where she can be monitored closely for evidence of the water bag breaking or active labor. If this preparatory phase is prolonged, it may indicate that labor cannot be normally initiated and the cow or heifer should be evaluated.
Common causes of cattle not entering the second stage include a breech presentation of the calf or a uterine torsion. More commonly, delays in the progression of labor occur during the second phase. As stated above, stage two labor should never last more than four hours. Most animals deliver their calf within two hours. In general, if the calf is not delivered within two hours after the water bag breaks and the onset of active pushing, intervention is needed.
A skilled individual should thoroughly clean the vulva. With clean hands and arms, perform a vaginal exam to determine whether or not the cervix is fully dilated and the position and relative size of the calf. Only after verifying the position of the calf is correct and the size of the calf is small enough to be delivered, may you provide assistance by means of manual traction or use of a calf puller.
Great care should be used in placing chains or straps on the calf’s limbs and in applying pressure to a calf in the delivery attempt. Excessive force can cause severe damage to the calf’s limbs or the cow. For those with little experience in successful calf delivery, a veterinarian should be called two hours after the onset of labor for determination of the most appropriate next step.
Once the calf is delivered, the cow should be monitored for passage of the placental membranes. If passage does not occur in 12 hours, the cow should be closely monitored for general attitude and appetite. Failure to pass the membranes can set up a uterine infection that can cause serious illness or reduction in subsequent fertility. If at any time the cow becomes ill or the membranes are retained longer than three days, even in a healthy-acting cow, your veterinarian should be called as infection of the uterus may occur and prevent future reproductive success.
Delaying intervention during calving difficulty can mean loss of the calf and sometimes the cow or heifer. Close and regular monitoring of cows and heifers during the calving season allows for early recognition of problems and provides an opportunity to intervene when the likelihood of success is significantly greater.