It's likely that most readers of BEEF have watched a heifer or cow in labor and wondered if they should jump in or let her go a while longer. Let's look at the subject of when there should be an internal examination for calving progress.
The vast majority of calving problems occur in heifers. Most are due to the calf being too big for the heifer.
It's well documented that dystocia contributes to increased calf death loss, decreased growth of the calf and increased time for the heifer or cow to breed back. A common rule of thumb is that every 10 minutes of delay in calving assistance could add a day to the time required for that female to breed back.
The first stage of labor starts with uterine contractions that may be as far as 15 minutes apart and last for only a few seconds. They gradually increase to longer, stronger and more frequent contractions until they occur about one to two minutes apart.
During the first stage, the dilation of the cervix is due to pressure from the water bag. You may notice signs of “colicy” behavior such as kicking at the stomach and arching of the back. The duration of the first stage is extremely variable.
The second stage begins when the calf's feet enter the birth canal. It's typically a very short time before the water bag or feet are visible. Abdominal contractions will now be apparent, and the water bag will break.
Pressure from the calf's legs (and eventually the head in a head-first presentation) causes release of the hormone oxytocin. This hormone stimulates powerful uterine contractions at the rate of two to four contractions every five minutes, with each contraction lasting 1-1½ minutes. This stage ends with the calf being born and may take as few as 15 minutes.
We expect the second stage to take two hours at the very most in a normal delivery. Some recent studies indicate that cows and heifers take an average of approximately ½ hour and 1 hour, respectively.
The third stage of labor begins immediately after birth and finishes with expulsion of the fetal membranes (afterbirth), also referred to as “cleaning.” Normally completed within a couple of hours, it may take up to 24 in some cases.
If the afterbirth hasn't expelled by 24 hours and the cow is visibly sick (off feed, gaunt, temperature over 104°F), examination is indicated. If the cow hasn't cleaned and is feeling fine, she will eventually expel the placenta and no intervention is needed.
When To Help?
In the first stage, we can easily do more harm than good. If contractions appear mild, allow time for the cervix to dilate and the calf to enter the birth canal. Forcing the issue in the first stage can lead to a torn cervix or birth canal.
During the second stage, if you observe the water bag or feet visible for one hour in a heifer, or a half-hour in a cow, with no externally visible progress, it's reasonable to check progress internally.
Producers that use the “progress every hour” rule for heifers nearly always have more live calves to sell than those who wait longer. Newer studies with cows indicate that the rule should be “progress every half hour” for mature cows.
A heifer or cow with straining characteristics of the second stage (contractions over one minute in duration, significant abdominal effort, laying down), but with no externally visible water bag or feet, should absolutely be checked if there is no progress. The calf could be in a breech position (rear end first with feet back), or the cervix may not be dilating properly.
We suggest working with your veterinarian to determine what you're comfortable doing and the proper procedures for making an internal check of progress. Minimum equipment for making internal checks includes clean water, soap, a soft brush, disposable plastic sleeves and twine or rope to keep the tail out of the way.
Hygiene is very important for both you and the animal. During cleaning, pouring water from the bucket onto the brush and/or area to be cleaned will keep the water clean as opposed to repeatedly dipping the dirty brush into the bucket.
The goal is not a sterile environment but just absence of visible organic matter. The plastic sleeve should be put on the last thing before making the internal check.
We can't over-emphasize the need for training in the proper methods for assisting a cow or heifer in calving. Inappropriate traction or internal manipulation of the calf may lead to death of the dam and/or the calf. And always remember your own safety by providing for proper restraint before starting to work.
Mike Apley, DVM, PhD, is an assistant professor of beef production medicine at Iowa State University in Ames. W. Mark Hilton, DVM, is a professor of beef production medicine at Purdue University in West Lafayette, IN.