Although to some people the word “Twinning” make evoke the thought of baseball in Minnesota, twinning in beef cattle is when a cow gives birth to twin baby calves. This is a natural phenomenon that occurs occasionally, although with certain sires it can happen more frequently than the average.
My first experience with twinning came as a teenager on my family’s ranch. During a blizzard in March with -50 F windchill, one of our cows did not come up to the bunk to eat. We assumed that she must be calving, so out to the pasture we went to find her. In her bovine logic, she picked the coldest spot on the entire ranch. She calved in a valley that opened up towards the cold northwest wind, right next to the frozen stock dam. I reached her just after she pushed out the second calf. The first one lay on the ground shivering.
I pulled my coat off and covered the first one and Dad did the same with the second. We took them back to the house and dried them off, then turned them back out with the cow in the barn. Both of them lived and grew up fine and healthy. It was a lot of fun to check cows all summer and see both calves running around their mom together.
Although cows have twins on their own, they do need help calving more frequently than cows that give birth to a single calf. This is due to the two calves competing for the same opening. If a leg from one and a head from another are in the birthing canal, they need to be sorted out so they can come through one at a time.
Twinning in cattle also creates another interesting phenomenon, the Freemartin heifer. In the womb, cattle have a diffuse placenta which is shared between the twins. This causes some of the hormones produced by one twin to influence the other. If one twin is male and the other female, this hormone sharing causes the female’s reproductive tract to not fully develop. She will be infertile and have a slightly abnormal looking vagina. However, the abnormalities are not painful and have no effect on urination or any other bodily function, so she will live a perfectly normal life. A heifer with this condition is called a “freemartin”.
After the twins are born, the mother will often take both twins as her own. Sometimes a cow might only accept one calf, or the rancher might only let her have one calf because she doesn’t have enough milk to feed two. The other calf is bottle fed or grafted onto another cow that lost her calf to raise to weaning.
Twins are a bit of a mixed bag, they are great because you get two calves from one cow, but they usually require more work on the part of the rancher during birthing and the first few weeks of life. Because it is a natural occurrence, ranchers just deal with it as it comes up. The part I like is that twins are quite photogenic for this blog!