Twins and Statistics


Natually Raised Farm Products - Rockwood, Tennessee

Cattle twins and mortality rates

I have read much about the twinning rate in cattle on many beef farming websites, but there hasn't been much about the rate with dairy breeds other than it is believed that the rate is more frequent than with beef breeds. I've also read many postings from farmers regarding the same, and they all argue that the twining rate is much higher than most studies show. I've talked to my neighbors, all beef breed farmers, and who have all experienced twinning, but they don't know a rate because they've never tracked that information. We track everything, hence the reason for this article.

Fraternal verses Identical - Fraternal *twins occur when the dam emits more than one egg during her cycle, and then both (or more) eggs are fertilized during breeding. If the female emits more than one egg, it is almost surely to be fertilized due to the volume of sperm deposited by the male. Identical twins occur when the embryo splits after fertilization. Twining can only occur on the maternal side, meaning that the sire does not contribute to the twining process other than fertilization.

This is opposite sex determination which is a factor of the bull alone. Of the 60 total chromosomes in cattle, two are sex, similar to other mammals. One of these is contributed by the female in the egg which is always an X (female) chromosome. During the breeding process, the male introduces the other which can be either X (female), or Y (male). XX will produce female offspring, and XY will produce male.

Twin rate in cattle

Our twin rate is 9.52% to date, with none recurring from the same dam and/or sire yet. So far we have had 100.00% heifer twins, 0.00% bull twins, and 0.00% mixed bull and heifer twins. Mixed twins commonly have reproductive problems due to hormone exchanges caused by the sharing of amniotic fluid. Apparently the problem occurs more with the female twin, a condition known as Freemartinism. The common published rate of these reproduction problems is 90% (mixed twins only). That is a rate we are yet to determine, but we will be working on it.

Our neighbor, an Angus cattle farmer, has told us that they have a particular cow that frequently births twins. So frequently in fact, that they always look for the twin. Relative to breed, our twin ocurrence has been from different breeds as well, but all dairy. We have some registered cattle, some of various breeds, and some cross breeds. We have had twins from all groups. This ratio is documented over our 6 year history of cattle breeding to date. For what it is worth, our breeding to this point has been natural, but that doesn't make much difference in the likelyhood of twins anyway.***

Birthing difficulty

This is another topic of much debate where few, if any, published and documented historical facts exist.

We know that bull calves tend to be noticeably larger than heifer calves, and twins are noticeably smaller than calves from a single birth. The latter is normal and expected since the size of the mothers womb is the greatest contributing factor determining fetal size. If there are two or more calves sharing that same space, then they are likely to be proportionately smaller. Consequently birthing is less likely to be difficult with twins. We also know that bull calves grow at a significantly faster rate once born (about 16-20% faster), so it may be safe to assume that is also the reason bull calves tend to be larger at birth.

Difficulty in birthing where the calf is correctly positioned is a problem of proportion as to the size of the exit chamber better known as the birth canal and vagina, verses the size of the fetus. The size of the womb has absolutely nothing to do with the size of the exit chamber. Bulls are often blamed for "throwing large or small calves", when the determination of size is more a factor of the dam rather than the sire.

I have also read that abnormal birthing positions such as breech are more likely with twins than in normal singular births. This has not held true on our farm. To date our abnormal birthing positions non-twin is 4.76%, and in twins 0.00%.

Just for information purposes, our DOA birth rate is 8.70% excluding losses from other causes. Our losses from other causes rate is 10.34% excluding DOA births. Causes of our other losses has been Pneumonia at 6.90%, and Predation at 3.45%. Causes of our DOA births has been abnormal fetal position at 4.76%, and premature at 4.76%. Our overall loss rate, a number that really hurts us, is 16.13%. We think this is terrible, but when we talk to our neighbors and hear their loss rate, it alleviates the pain a little. For example, one of our neighbors lost three cattle in one night due to drownings from a storm surge in a wide creek that rose from the normal ankle depth to more than twelve feet in a matter of hours. They also experience many more coyote related losses than we do.**

These loss rates are high in my mind, but the only way to get them down is to learn the language of cow. Then they can tell you when they have pains, upset stomachs, when labor begins, or when coyotes have been frequenting the pasture. Maybe train them to run to the door and knock when a problem arrises. Since none of that is going to happen, farmers have to check their livestock on a daily basis, and try to recognize and treat issues or abnormalities as they see them; as early as possible. Pneumonia has been our biggest cause of losses, and the only way to lower these numbers is catching the sickness earlier on. This is something we are working on along with better treatment methods. Predation has been our second biggest cause of other losses, and we are working on that as well by eliminating the coyote threat.

At what age can cattle breed?

Here is another case where we believed much of what we had read, and it proved to be wrong! When cattle can breed, and when you should breed them, are two entirely different factors. When we started breeding cattle, we simply let the calves run with the herd. For bull calves, this wasn't a problem because we usually slaughtered them at about six-months of age, and most of them had already been casterated anyway. With heifers, we were going to keep them to increase our herd size. This wasn't a problem until one day we were out in the pasture to load our bull which we had sold, when we witnessed him breeding one of our heifers that was only 100 days old. He just hiked up his right rear leg and slipped her a little gift, which she eagerly stood for. We were worried about the outcome of that event, but exactly 274 days later, at just over a year old, she gave birth without problem to a healthy but very small 35 pound heifer calf. That little heifer calf bred to a different bull when she was 127 days old. She also gave birth 274 days later to yet another heifer calf without problem.

The afore mentioned second event was the second generation of young breeding which we noticed resulted in a significant decrease in the size of the cow once full grown. We were witnessing the down breeding in cattle size. We sold those cattle, and decided not to let heifers run with the rest of the herd to prevent this down breeding in the future.

Most bulls can begin breeding at about eight months old. I think maybe if they could figure out what it's all about, they might be able to do something a little earlier. Up to eight months, it's all instinct motivating them to practice until they accidently reach one once, then everything kind of clicks so-to-speak.

Bulls will not hurt calves. In fact, calves instinctively know that the bull will look after them. Except when they are hungry, they will hang with the bull more than their mother. Often, when the cattle move about the pasture, the bull will gently nudge calves along if they aren't moving fast enough to suit him, but he won't hurt them.

Two bulls in the same pasture with a herd of cows is dangerous as they will fight a lot. They will not tolerate each other, and they will violently fight in an attempt to establish which one is dominant. One of them will lose and will likely be injured as a result. There is no case where two or more bulls should be in the same pasture with a herd of cows. All bulls are dangerous, it's just a matter of when. They will become mean to humans, no matter how much you might think they are a pet. You can never trust a bull no matter how docile he seems. He will hurt you sooner or later.

Some farmers have the idea that they need a bull for each fifty cows or so, or to prevent inbreeding. In the first case, one bull can easily service many more than fifty cows if ran with the herd. They don't all cycle at the same time, not by a long shot. An exception is if the bull is kept seperate from the cows to ensure seasonal birthing. Some farmers believe that calves will only be healthy if born during preferred times of the year, but this is yet another wives tale. We've had calves born all seasons, including during an ice storm, and they've all done well. With regard to inbreeding, one bull don't know if it's his turn or not, and he sure don't care. The only way to prevent inbreeding is to keep the cows and bulls seperate entirely, and then control which is with whom. There is a much better alternative to keeping bulls, that is artificial insemination, where you can control everything about the breeding without any risk at all.

Maturity in cattle: Cattle reach full height at about two years old, and full weight at about three years old. They will maintain a stable size if bred when they are about two years old. Prior to that, we believe that a decrease in size is likely to occur.

The language of cow - They all mooo right? Cattle make different sounds for different things. I was looking for words to describe these sounds, and I found nothing that does any justice whatsoever. I guess it's time to invent some new words, but Webster is only open to nonsensical crap like the greatest new word of 2018 originating on Twitter, "adulting". Cattle are basically quiet animals, they don't sit around all day and gossip, or sends moronic tweets to other cattle. When they make sounds, they have purpose. A farmer recognizes most of the sounds that cattle make. They have a distress call, which other than frequency is like the sound they make when they want your attention such as for feed. They have a sound they make to send their calves into hiding, and another to call them out of hiding. None of these sounds are like any of the generic descriptions I found in the dictionary, but farmer's know them, and they know them well.

Predation Losses - Most predation losses in the south will be coyote related. In the north it could be coyote or wolf. We have an advantage over most farmers in that we live in very close proximity to our cattle. So close in fact, that we don't have a lawn. In the summer it's hay field, and in the winter it's pasture. We can see 80% of where our cattle will be from October through March when coyote predation is the most dangerous. This is no accident; we changed the way we pasture our cattle due to the coyote problem. We can check on our cattle any time of the day or night from the warmth of our house through our custom gunport windows. Other farmers have to make their rounds checking on their cattle in the day time, and in the cold. These farmers would have no idea whether or not they had a twin birth during the night if a predator killed one of the twins. No, they wouldn't find any indication because predators don't leave any. We know this; we've studied it. They will take the entire carcass to a different location from where they killed it and devour it in it's entirety (a young calf). They can, we have video of them dragging an entire adult deer carcass. Of course they can't drag a full grown cow, so they will revisit that carcass until it's gone, often dragging it away piece by piece.

Some will argue that coyotes are lone hunters but they would be wrong. Though coyotes will hunt alone, they will often roam in male and female pairs. In winter when food is more scarce, they will hunt in groups of three or more, often led by a dominant male. The dominant male will be hard to kill because he is older, more cautious, and wary. He'll let the less experienced younger ones, male or female, take the greater risk.

There are other predators, such as bobcats and lions (aka panthers or cougars). They kill differently, and it is easy to tell the difference. Cats make neck kills on the spine or throat; usually quick deaths for the prey. Dogs kill brutally by eating or biting on the nose and flanks causing a slow death from blood loss or shock. We have not seen any evidence of cat kills though we do have the occasional cat on our game cameras.

Domestic dogs are as much a killer of livestock and wildlife as any other predator. Irresponsible "pet" owners let them run fee, and they pack up and kill. When we see dogs chasing animals, we shoot them on sight.

* For the purpose of this article, twins means two or more.

** Okay, some are going to catch that the percentages don't necessarily add up. That's because the number of birthings we've had, and the total number of cattle we've had, are not the same due to outside cattle purchases. The rate for DOA births is calculated from the total number of farm births, and the losses from other causes is calculated from the total number of live cattle we've had on the farm. The overall loss rate is calculated from the total number of live cattle we've had plus the number of DOA births we've had. The percentages are correct. Also, these rates are always current due to automatic updating when we have changes.

*** Using frozen semen does reduce the number of live sperm in a given volume, so there could be a lessor chance of multiple egg fertilization using artificial insemination.

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