Calving: Delivering Backward Calves

by Heather Smith Thomas of Salmon, ID

Most calves are born head first, front feet extended. But a few are positioned backward (posterior presentation) and may not survive the birth process unless you are there to help. The number of backward calves in a herd during a calving season can vary from year to year, and all the factors influencing this presentation are not yet fully understood. While the fetus is growing in the uterus it is quite active and can change positions, especially while still relatively small. The position of a fetus when a cow is pregnancy-checked is not necessarily the position it will be in at the end of gestation when the birth process begins.

For instance, one fall (after a calving season with 5 backward deliveries in our herd of 170 cows), we asked our vet (Dr. Robert Cope) to check which way each calf was lying when he preg-tested the cows. He said at that stage of pregnancy (5 to 6 months) many calves are positioned backward, but shift to proper position before birth. We took note of the dozen that were backward at that time. Indeed, none of those calves were born backward, but three others were (calves that were not backward during the pregnancy test).

A number of factors may influence whether a calf ends up in a posterior or anterior (frontward) presentation at birth, but the most influential factor is heredity, according to Dr. Duane Mickelsen (bovine reproductive specialist at Washington State University, Pullman, Washington). He cites the work of an English veterinarian, Dr. G.H. Arthur, who found that almost all fetuses are carried backward and upside down during the first 6 to 6.5 months’ gestation and then rotate to anterior position, with only 5 percent or less remaining in posterior position. But this average 5 percent figure may increase when certain bulls are used.

Dr. Mickelsen says several ranchers he’s worked with have had much higher instances of backward calves some years, and began to suspect the sires had something to do with it. Certain bulls sired more backward-birth calves. When those sires were no longer used, incidences of backward births dropped back to more normal numbers.

More studies need to be done to confirm this but Dr. Mickelsen has heard and read of many similar situations – enough to suspect that heredity plays a major role. It may be that calves sired by some bulls grow too large by that stage of gestation when the fetus is rotating. If the calf doesn’t change to frontward position by the time he’s 6 to 6.5 months along, he gets too big and can’t turn over in the uterus. Dr. Mickelsen says size in itself does not mean a calf will be backward, since many huge calves are properly positioned, but there may be a correlation between fetal growth stages (which might be influenced by heredity) and whether the fetus shifts its position by the time it is 6 to 6.5 months along. He says, “If a rancher has a sudden increase in backward calves over what has been the usual herd average, suspect heredity. Take a look at the bull being used.” The incidence will usually drop again if the rancher changes bulls.

Dealing With Backward Births – Years ago our veterinarian told us a person is lucky to save one out of 10 backward calves. This is true when cows are not being checked frequently. But with closer observation – and assistance given at the proper time – you can beat those odds. In the 1960’s when our cows calved on pasture in late spring, we averaged a 4 percent birth loss. We’d find the newborn calf dead, and never know exactly what happened. But since 1969 we’ve been calving in winter, putting cows into pens or barns to calve, and we are there for every birth. As a result, our birth losses dropped dramatically, to less than 1 percent per year, with most years no birth losses at all.

During the past 38 years we’ve had a total of 56 backward and breech calves, an average of less than 2 per year (we usually have at least one, and some years as many as 5). We’ve lost only 4 of them. One died because we didn’t check inside the cow soon enough; the calf was breech (no legs entering the birth canal, presented rump first) so the cow was not straining yet. But the placenta was already detached and the calf was dead. The other three losses occurred during the birth process – big calves that were too difficult to deliver fast enough or were fatally injured during the delivery (broken rib punctured the lungs). But most posterior or breech presentations can be safely delivered.

A backward birth is an emergency. If hind legs don’t enter the birth canal or if the calf is in breech position (rump first, legs forward in sitting position), the calf cannot be born. The legs must be brought into the birth canal before the birth can continue. Even if the legs do enter the canal, birth is generally so slow and difficult the calf suffocates when the umbilical cord breaks or pinches off, since head and shoulders are still inside the cow. If a posterior or breech presentation is recognized early, however, there’s a better chance for saving the calf – by helping the cow and speeding the birth process, pulling the calf.

The backward calf is at a disadvantage; it’s not streamlined for coming through the birth canal in that direction. The hips are difficult to pass through the cow’s pelvis, and the ribcage tends to catch on the way through. Even the lay of the hair is wrong for streamlined movement through the narrow opening.

The umbilical cord may be pinched off or broken during birth, making it urgent the calf be delivered immediately. Occasionally the cord may be caught over a hind leg – stretched and broken before the calf is halfway out. This occurs if a hind leg passes under the cord as the legs straighten and enter the birth canal.

During early labor the calf moves a lot, and if he extends his hind legs and they enter the birth canal, he can usually be born successfully with human assistance. But he will need help. In all the backward calves we’ve had, there was only one born alive without being pulled. It was a small, streamlined calf (out of a roomy cow and by a bull that sired small calves). My husband and I arrived on the scene as the cow was laboring, with the calf halfway out as we approached.

We immediately saw the calf was backward, and rushed to grab onto it. But our running up to her startled the cow and she jumped to her feet, and the calf fell on out as she got up. The calf had been moving fairly well through the birth canal and he had not yet suffocated. Perhaps her jumping up was fortunate. If she had lain there for a few more minutes, he would have suffocated.

But most backward calves do not survive birth unless you pull them out and hasten the process. And if a calf doesn’t get its legs extended to enter the birth canal, it cannot be born at all, until you bring those hind legs into the canal. If this proves impossible, the calf will have to be delivered by C-section.

If the calf is breech (legs not entering birth canal), the cow is a long time in early labor and may not start straining at all. Abdominal contractions (second stage labor) do not begin until some part of the calf enters the birth canal, stimulating her to strain. If she does start to strain on a breech calf, she is jamming hocks or hips into the birth canal, but he can’t come through.

If a cow is in early labor a long time or doesn’t progress to hard straining when you think she should, check her. Usually a delay means the calf is positioned wrong and cannot come through the birth canal. The problem must be corrected before the cow is in labor too long and the calf dead. If help is given soon enough, legs can be brought into the birth canal and a live calf delivered.

If it is a “normal” posterior presentation (legs entering the birth canal) the feet often protrude from the vulva and you can tell they are hind feet; heels and dewclaws are up rather than down. Bottoms of the hoofs are pointing up. But before you assume the calf is backward, check. Occasionally a frontward calf will be upside down or sideways with legs twisted— when feet first appear they are pointed upward. Always be sure which part of the calf is presented before you start to pull. If they are front feet instead of hinds, be sure the head is there and not turned back, and rotate the calf into more proper position before you assist the birth. Don’t just assume the calf is backward and start pulling.

When helping a backward calf, go gently until his hips are free and ribcage safely through the cow’s pelvis. Once hips are clear of the vulva, hurry him on out. If you rush at first, you may injure the cow and kill the calf. It’s not uncommon for a calf’s ribcage to be crushed if you pull too forcefully too soon.

If the calf is large, you can’t deliver him fast enough without a mechanical calf puller or the help of several people. A puller can put a lot of traction on a calf, and care must be taken not to pull too fast, especially at first when you are easing the hips through. When using a puller with a winch/cable, stop for a moment and reposition the chains (from the lower legs, to above the calf’s hocks) after the hocks appear. This will give you more room (more length of cable) to winch. If the calf is long-legged, you may run out of cable about the time you need to be pulling fastest. There’s nothing more frustrating than getting a big calf almost out, then losing him because you run out of puller cable and don’t have the strength to get him on out by hand. To pull large backward calves, routinely switch your chains from above the ankle joints to above the hocks, to give yourself more leeway.

In breech presentation where you must bring the legs into the birth canal, it’s easier to manipulate the legs if the cow is standing rather than lying; you can more easily get both arms into the birth canal. The calf must be pushed back into the uterus as far as possible. Hold him forward with one hand and grasp a leg with the other, bending the hock and lifting it upward, rotating it as you lift. Draw the foot backward in an arc, keeping hock joint flexed tightly and calf pushed as far forward as possible. Lift the foot over the cow’s pelvis and cup your hand around it so it won’t tear the uterus. Do the same with the other leg. Once both are in the birth canal, you can attach chains and pull the calf.

After the calf is out, get the fluid out of his air passages and start him breathing. He may be alive but still in danger because air passages are full of fluid and he’s short of oxygen from extended time in the birth canal or because the umbilical cord pinched off or broke early in the delivery.

Some backward calves will seem dead at birth, limp and blue, eyes glassy. But a quick feel of the chest (behind the front leg, left side) will reveal a heartbeat. These calves can be saved if air passages can be cleared quickly and you can get them breathing. Stimulate him to cough by sticking a clean piece of straw up one nostril. If he’s unconscious and blue and won’t cough, close his mouth and cover one nostril with your hand, and blow gently into the other. Giving a calf artificial respiration can keep him alive and put enough oxygen into his system to revive him. We’ve saved several calves this way that seemed dead at birth and would not start breathing. Blow in a full breath (until you see the chest rise) then let the air come back out on its own. Keep breathing for the calf until he is able to begin breathing for himself.