Dealing with Dystocia in Dairy Cows.

 By Heather Smith Thomas.

 Many dairies have several thousand cows or more, with many calves born each day.  Most of these dairies have employees whose only job is working at the maternity barn.  They become very good at what they do, and can manage most calving problems without professional assistance.

Thiago Vilar Silva, DVM, MSc, PhD (College of Veterinary Medicine, North Carolina State University) says that even though most cows give birth without problems, all calving cows and heifers should be closely monitored in case they need assistance to deliver the calf.

Dairy workers who deal with calving can usually pull a calf or reposition one that has a leg turned back or head turned back, but some difficult situations, such as a breech, or torsion of the uterus may require professional assistance. “Dairies usually have some employees who are trained to do C-sections or other more invasive procedures when necessary.  In a beef herd it is more common to call someone else—like a veterinarian—to do a C-section, but in a dairy it is fairly common to have someone who is able to do this,” says Silva.

“A C-section is the last of the resorts, after they’ve tried other methods to deliver the calf.  This is due to many reasons--the need for antibiotic and anti-inflammatory as a consequence of surgery, the risk of post-surgery complications, milk withdrawal, labor cost, and impact on the future performance of the cow,” he explains.

In some situations involving a difficult dystocia, especially if it is associated with a dead calf, an alternative method would be fetotomy (cutting the calf apart to get it out vaginally).  Dystocia increases the chance of culling, and cows that had more invasive procedures like C-section have even higher changes of being culled.  They will probably be kept only if they have superior genetics.

If a cow has a serious problem at calving, there is greater chance that she will have more days open before she can become pregnant again, which increases the chance of culling.  “This is especially true if she has any post-partum problem. Cows that had dystocia have higher risk to develop uterine diseases such as metritis and endometritis, which will increase the calving interval. Incidence of uterine diseases in dairy cows can range between 10 to 40%, whereas in a beef herd it would be 1 or 2%,” says Silva.

In dairy cows there are more post-partum problems like subclinical hypocalcemia that predispose them to metritis and other diseases.  In a dairy cow, you need to deal with any problems early on, to try to prevent bigger problems. On a large dairy there might only be one employee for every 120 to 150 cows, or more.  “They have a lot to do, and can’t afford to spend time treating one cow,” he explains.

For reproductive work and monitoring calving cows, most dairies have well-trained employees.  “They usually have someone from the big companies like Zoetis or Select Sires training them, with update sessions every month, looking at what can be done in various situations, what kinds of approaches might be better, etc.  If someone is being hired, the new employee usually works for a while with someone else who has more experience,” says Silva.

Some dairies may have IVF embryo calves being born.  “Due to the medium used in some IVF laboratories, calves can grow too much in the uterus and this can be a predisposing factor for dystocia,” he says.

“The percentage of dystocia in a dairy is still low in comparison with calving overall, maybe only 2 to 4%, but in a large dairy, such as 5000 cows or more, this means you might have a number of dystocia cases to work on, nearly every day.”  

Dr. Adrian Barragan, DVM MS, PhD, assistant clinical professor, Extension Veterinarian, Penn State University, teaches farm employees and managers in a personnel training program, as well as undergraduate students about best management practices in assisting difficult calving.  “There are some differences in beef and dairy calving practices, but the physiology is the same.  The three main things we talk about regarding best management practices are the why, the when, and the how,” says Barragan.

“Why is this a difficult calving?  The most common cause of dystocia, for dairy or beef, in cows that have already had at least one calf is malpresentation.  Most common cause in heifers is mismatch of maternal/fetal size (calf too large to be easily born).  The why also includes consequences of not assisting a dystocia properly or in a timely manner,” he explains.
First stage of the birth process is uterine contractions and dilation of the cervix. “I emphasize importance of not assisting too soon, or there’s more risk of trauma to the birth canal.  It’s also important to not be late in giving assistance because the calf may be dead by that time,” he says.

Thus it’s crucial to know when the cow actually started early labor and to monitor her progress.  “The main difference between beef and dairy is frequency of observation of the prepartum (pregnant, soon-to-calve) cows.  Most beef herds are in a large pen or pasture, with animals widely scattered.”  Someone might check them several times a day or a few times during the night, but there’s no one there fulltime watching them.

Ideally all prepartum cows should be checked every hour, to know when they start labor, and monitor progress to know whether they need assistance.  “In a dairy, checking the maternity pen once an hour is not a problem because there are enough people there to do it,” says Barragan.

“Employees should look for imminent signs of parturition in cows that are about to start stage two (active labor).  If the water bag was broken earlier and we didn’t see it, we’ll see the tips of the calf’s toes emerge.”  The cow is now straining (abdominal muscles pushing) in addition to uterine contractions.

The start of active labor (water breaking, abdominal straining) is when the clock starts and you need to keep track of how long it takes before the calf is born.  “From that point on, you should monitor the cow more closely, at least every 15 minutes, and expect some progress every 15 to 20 minutes.  If on the previous check I saw the water bag, on the next check I want to see the tip of the toes.  If I see the tip of the toes, within 15 to 20 minutes I want to see more of the legs and perhaps the nose,” he says.

It may take a bit more time—especially on a first-calf heifer—to get the head out after the nose is showing, since the vulva must stretch as the head comes through.  “One of the most common mistakes, especially in dairy facilities, is that the cow is assisted too soon.  The person is right there and wants to get the job done and go on to the next job, so he/she pulls the calf.  The calf usually doesn’t have any problems due to being hurried a bit.  The cow is more compromised by pulling the calf too soon, due to additional trauma to the birth canal.”  The tissues were not yet stretched enough.

“Trauma to the birth canal may increase the odds of retained placenta and metritis due to likelihood of bacterial infection.  Even if the calf is coming slowly, the cow may not need assistance; you just need to wait a little longer.  I tell people to wait 15 to 20 minutes, and if you don’t see any progress, wait another 15 or 20, and if in total there’s 30 to 40 minutes with no progress (nothing showing yet at the vulva), you need to check the cow,” says Barragan.

“You put her in the headlock and clean the perineal area—from the base of the tail to base of the udder.  When you reach into the cow, you need to assess two things—dilation of the cow, and calf presentation.  You may discover the calf is well presented and the cow is pushing and she is or isn’t dilated enough.  If she needs more time, you can let her out and let her keep working at it,” he says.

But if nothing is happening after 70 minutes, you need to help deliver the calf.  Based on research done in 2011, in which dairy cows were timed during normal and difficult births, the recommendation is to assist cows if after 70 minutes from the appearance of the amniotic sac at the vulva there is no progress.  The placenta may start to detach from the uterus; oxygen supply to the calf is compromised or halted, and pressure on the calf from being in the birth canal so long takes a toll.  Performance and future fertility of the cow will also be affected if she is in labor too long.

Twins can also be a problem, and dairy cattle have higher incidence of twins than beef cows, possibly because of the high metabolism of the dairy cow to produce more milk.  There is faster clearance of reproductive hormones such as progesterone, which may lead to multiple ovulations, and higher chance of twins.

Twins are more prevalent in multiparous cows than in first-calf heifers, and with twins there is more risk for dystocia.  “I encourage producers to identify and manage twin pregnancies by terminating the pregnancy early on,” Barragan says.  With ultrasound, pregnancy (and twins) can be detected within the first few weeks of gestation.  If twins are found, they can be terminated and the cow rebred fairly quickly If a cow does go full term with twins, they are often born without problems but there is always more risk for complications and malpresentation than with a single calf.  One may be backward, or the legs of both may be entering the birth canal at once, etc.

Silva instructs dairy workers to check for twins whenever a cow needs help with delivery.  “After the calf is born, they should always check to see if there is another calf.  Sometimes they are so busy, with a lot of things on their mind, and forget to check. Then a few days later when something goes wrong with the cow and she is palpated, there is a rotting calf inside her,” says Silva.

A simple backward calf (hind legs extended into the birth canal) is normal and the calf can be born, but usually not alive because its oxygen supply is compromised sooner; the umbilical cord is pinched by the pelvic bone, or breaks as the calf comes through—while the head is still inside the cow, and the calf cannot breathe.  What is considered abnormal (the calf cannot be born) would be a deviated leg or head, or a breech calf with hind legs forward--not entering the birth canal—anything that prevents the calf from making it through the birth canal.

The backward calf needs assistance to be born alive, pulling him out quickly after the hips have come through the pelvis and the cord is being pinched off.  “The mistake many people make is pulling those calves out too quickly—as soon as they see that it’s a backward position,” says Barragan.  A backward calf is not streamlined and it takes time for the cervix to dilate enough for the hips to come through.  If you start pulling too soon, there is more chance of injury to the birth canal.

“If you see that a calf is malpresented (only one leg, both legs but no head, etc.) you should not wait to assist,” he says. The farther the cow pushes it out, the harder it will be to correct the problem since the calf must be pushed back into the uterus where there is room to maneuver the head or legs.  It cannot come out until you correct the problem; it will be jammed tighter into the birth canal.

“Another situation would be when no one observed the start of labor and you don’t know how long the cow has been working at it.  It may be normal presentation—you see the legs and head—but the head is swollen.”  This means the birth is taking too long; the calf has had too much pressure, too long, with impaired circulation.  The nose and tongue may be swollen and blue.  You must assist immediately.

First clean her up and pull the tail out of your way, use obstetrical glove/sleeves, and lots of lubrication before entering the cow to assess the position of the calf.  “Always apply lubrication; it will make your job easier and the cow’s job easier,” he says.
“Assess the calf’s presentation and the birth canal dilation.  Next, correct any malpresentation.  Each situation may be a little different.  The main thing is to push the calf back in, to gain space to manipulate the calf.  I encourage people to use chains rather than ropes, because it’s easier to clean and disinfect chains between uses, and a chain doesn’t cut off limb circulation as much or create abrasions like a rope might do,” says Barragan.

“Place chains on the legs before you push the calf back to reposition, because when you start to pull, everything that was in normal presentation may shift around and is no longer normal.”  You thought you had that leg, and then it goes back, but if you already have a chain on it you can keep it from getting out of position.  Put a chain on, push the calf back in, and then start correcting the malpresented limb.  

Place chains properly (double half hitch with one loop above the fetlock joint and one below) to spread the pressure (putting the force in two places instead of one) and reduce risk of injury to the joint and the risk of fracture.  

“When pulling the calf, pull one leg at a time, to work the shoulders through the birth canal one at a time.  The widest part of the calf as it comes through in forward presentation will be the shoulders, and if we pull one leg at a time that width is narrower and the calf can come through easier,” he explains.

“Often people pull on both legs, which makes it harder for the calf to come through, and also make the mistake of pulling straight back, the whole time.  It’s ok to pull straight back until the shoulders are out, and once they are out, we can pull both legs at the same time, and start pulling downward at a 45 degree angle.” The calf has to come up out of the uterus and over the pelvic brim and then down, so it is best to follow that natural arc of the calf as it would normally come out.  This also raises the calf’s hips as they come through the cow’s pelvis, to where the pelvis is widest, with the most room for the calf’s hips to come through (less likely to become hiplocked).

Pull when the cow is pushing.  Rest when she rests.  She needs time to stretch and dilate fully, and you are more apt to injure her if you are pulling when she’s not pushing.  “You can help her dilate by putting your hands between the calf and the birth canal, to stretch it, and also keep putting in more lubrication,” he says.

It also helps, especially with a heifer (tight vulva and vaginal rings), if you place your fingers between the calf’s head and the vulva and pull/stretch the vulva as the calf’s forehead is trying to come through.

“One of the dairy farms I worked with had an ingenious method for adding lubrication while pulling a calf.  They had a hose connected to a hand pump/tub pump on a 10-gallon bucket of mineral oil.  Before they start assisting the birth, they insert a clean hose into the birth canal and give about 5 pumps--putting 2 or 3 liters of lubrication in there.  If they needed more as they are assisting the calf, they put in more oil,” he says.

Once the water bag breaks, and then the amnion sac, the natural lubrication for the calf is diminished and you need to add more.  “With your hands you might be able to put lubricant in the first 12 inches, but you can’t reach farther than that.  With a hose-pump lubrication system, you can put lubrication much farther into the birth canal.”

The next thing to consider is whether you can get the calf out or need professional assistance or a C-section or fetotomy.  “All too often, people keep trying, until it’s too late to do a C-section, or the calf is already dead.  If there is no progress within 15 to 20 minutes of effort, you need to reassess your technique,” he says.

“Assess whether the calf is still alive; even if there is no jerking or resistance by the calf when manipulating the legs, you might get a response by pinching between the toes, if the calf is still alive.  If it’ dead, it might be easier on the cow just to perform a fetotomy (cut up the dead calf to bring it out),” says Barragan.

“If the calf is alive and you are trying to pull it or reposition it but have made no progress in 30 to 40 minutes, call for help—either your supervisor or the veterinarian—someone who can provide professional assistance,” he says.