Well… Maybe, maybe not.
When it comes to the question of whether or not twin cows are sterile, there isn’t a simple, clear cut answer. At least, not without some testing.
Considering we’ve had several bouts (Batches? Sets?) of twins in our Brown Swiss cattle herd lately, I figured it was high-time to talk about TWINS.
Even if you have no desire whatsoever to ever own a cow, you might find this info interesting, regardless.
So What’s the Deal with Bovine Twins?
My long-time readers will remember that our herd matriarch, Oakley, had a lovely set of heifer twins back in 2015.
It was a welcome surprise– a heifer is always a welcome outcome, so two is even better.
We dubbed them Opal and Mabel and ended up breeding them via artificial insemination when they reached breeding age. They both easily became pregnant with zero fertility issues.
They were due to calve around the same time, so when I headed down to the barn one evening after supper to check on them, there was a bit of confusion when I found Mabel standing in a pen with not one, but TWO freshly born babies.
Did they both calve simultaneously? I checked Opal and confirmed that wasn’t the case.
There was only one explanation– TWINS, again.
(Twins are hereditary, so I suppose it shouldn’t have been a huge surprise– but honestly, it didn’t really cross my mind at the time…)
But this time, instead of two heifers (females), we had a mixed set: one boy and one girl.
Thanks to my time spent working at a local vet clinic pre-kids and pre-homestead, I knew that meant it was likely we had a freemartin heifer.
What is a Freemartin Heifer?
For my science-prone readers, here’s the official definition according to The Cattle Site
Freemartinism is recognized as one of the most severe forms of sexual abnormality among cattle. This condition causes infertility in the female cattle born twin to a male. When a heifer twin shares the uterus with a bull fetus, they also share the placental membranes connecting the fetuses with the dam.This causes exchange of blood and antigens carrying characteristics that are unique to each heifers and bulls. When these antigens mix, they affect each other in a way that causes each to develop with some characteristics of the other sex. Although the male twin in this case is only affected by reduced fertility, in over ninety percent of the cases, the female twin is completely infertile.
For us non-sciency folk, basically it means things get mixed up between the bull and heifer fetuses in utero and cause the heifer’s reproductive organs to develop abnormally.
It also means in these instances, the heifer calf will be sterile.
Now, not all sets of bull/heifer twins will result in a freemartin, however it is the case 92% of the time. So our odds weren’t great.
We decided to just keep the twins until they were a bit older and then we would likely just sell the heifer at the sale barn as if she was a steer. It was a fabulous plan until…
The Great Mix Up
Ever tell yourself that you’ll remember what you put in the plastic container as you jam it into the freezer, and then 2 months later, you find yourself staring at a frozen chunk of food with ZERO recollection of ever even making it.
Apparently this syndrome also applies to cattle.
We had another Brown Swiss heifer calf born the same time as our set of boy/girl twins. This other heifer was larger in size and lighter colored and seemed different enough at first…
I told myself I didn’t need to tag her, as SURELY I’d remember which heifer was the single, and which one was the twin.
BWAHAHAHAHA. HA. HA.
You know what happened next, right?
There was I was, staring at two perfectly identical heifer calves with zero idea of which was which.
Brilliant, Jill. Brilliant.
Initially we considered drawing some blood and testing for freemartinism that way. It’s only $25 and seems fairly reliable.
Sometimes a freemartin heifer will have some external characteristics such an abnormal appearance under her tail, or more masculine characteristics. However, the most sure way to tell what you have is to palpate her to see if her ovaries are developed properly.
Considering Christian just graduated from cattle artificial insemination school this spring (yes, it’s a very real thing), we decided to skip the test and check the old-fashioned way.
You know, the method that requires a long, blue sleeve…
And the good news? You get to come along for the whole process in one of our latest Youtube videos!
Other Cattle Posts You’ll Find Helpful:
- How to Draw Blood from Cattle
- Keeping a Family Milk Cow: Your Questions Answered
- How to Stop Your Milk Cow from Kicking
- Signs Your Cow is Close to Calving
Liz (Eight Acres) says
Thanks for explaining this!
Laurelynne Wice says
Wow! I grew up on a dairy farm and had no idea! Now I have to think waaaay back as to what happened to our set of boy/girl calves. Their names were Robert E Lee and Isabelle. I do remember Isabelle had a calf but then she disappeared from our barn. Robert was kept for a couple more years and then sold. We started using AI regular at that time. Thanks for this post!
Missy Burke says
Love the information. Thanks
Thanks for the explanation . I always knew this but we had set of twins jersey born last night and was wanting the reason for this . Also …we got big milk cow trying to nurse and did not know about the wiener …now I got two answers. God bless!! And awesome about the doTerra diamond!!! Deb