Hornless cows have become a common sight today, which could lead many to think that cows or bulls do not grow horns naturally. However, this is an erroneous assumption—cows grow horns unless they are bred as polled, dehorned, or disbudded as calves. This raises another key question: Do cow horns grow continuously?
The horns grow continuously throughout the cow’s life. This happens because cow horns are permanent, not seasonal. In addition, the hollow bone that makes up the core of the horn is the only bone in cows that grows perpetually.
It’s important to understand how cow horns grow to fathom why they grow continuously. I’ll discuss both issues in this article, as well as address the question of whether cow horns can grow back when broken or cut off. First, though, let’s have a quick definition of horns.
What Are Horns?
Horns are the hard growths that appear in pairs on the heads of cattle. They have a bone texture at the core and are covered with keratin on the outside. Keratin is the fibrous protein that’s also the primary material making up hooves, nails, hair, feathers, claws, and the external layer of the skin in vertebrates.
Horns are different from antlers in wildlife, for example. They are continuous and not branched. In cattle, horns can vary in shape and size depending on breed and sex. Bulls tend to have longer and larger horns and breeds like the Longhorn cow have longer horns than the commonly known dairy breeds.
Read More: How Quickly Do Deer Grow Antlers
Why Do Cows Have Horns?
As a dairy hoof trimmer, I’ve dealt with my fair share of horned cows. Horns often catch ropes in the chute and can turn a routine trimming into a frustrating ordeal, especially if you’re dealing with a particularly grumpy cow. It got me wondering—why exactly do cows have horns in the first place? Some reasons are pretty obvious, while others might surprise you.
Here are some practical reasons cows develop horns:
- Temperature Control: Horns help cattle regulate their body temperature. Blood vessels inside the horns release heat, which keeps the animal cool in hot environments.
- Defence: Horns are natural defence tools, protecting cattle from predators and allowing them to defend themselves and their young from threats.
- Foraging and Digging: Horns assist cattle in foraging behaviour, helping them dig or uncover roots and plants in search of food.
- Dominance and Communication: Horns play a crucial role in herd hierarchy and social interactions, allowing cattle to assert dominance and communicate clearly.
Needless to say, the dairy cow (or a pet cow) is a domestic animal, making some of these natural horn benefits irrelevant or even problematic. Horned cows in a dairy barn can cause unnecessary trouble, including damage to facilities or even injuring themselves and other cows. I still clearly remember cows getting their horns stuck in the feed bunk, turning a simple feeding into a stressful situation for everyone involved.
Do Cows Have Horns?
Both male (bulls) and female (cows) cattle can have horns. Whether or not cattle develop horns depends mostly on their genetics, not their gender. Many breeds of cattle are naturally horned, meaning both males and females can grow horns. However, farmers often prefer hornless cattle for safety reasons. Through selective breeding, some cattle breeds are naturally polled (hornless), while others are commonly dehorned at a young age to prevent injuries among animals and handlers.
Do All Cows Have Horns?
Not all cows have horns. While horn growth is common in many cattle breeds, selective breeding practices have produced certain breeds that naturally do not develop horns (known as polled breeds). This reduces the need for dehorning and minimizes the risk of injuries on farms.
Below are examples of breeds categorized by their horn characteristics:
Some Breeds of Cows Naturally Have Horns
Due to their genetic makeup, several cattle breeds naturally grow horns. These breeds typically maintain their horns unless farmers actively remove them for safety or practical reasons.
Examples include:
- Texas Longhorn
- Scottish Highland
- Holstein (if not selectively bred for polling)
Some Breeds of Cows Are Naturally Polled (Hornless)
Other breeds of cattle have been selectively bred over time to be naturally hornless or “polled.” These breeds do not require dehorning and are often preferred in farming practices for their safety advantages.
Examples include:
- Angus
- Polled Hereford
- Red Poll
Dehorning and Disbudding of Cattle
In commercial farming, calves from breeds that naturally develop horns often undergo procedures known as dehorning or disbudding. These processes involve removing or preventing horn growth when calves are very young, which helps maintain farm safety by reducing the risk of injury among cattle and handlers.
Do Cow Horns Grow Continuously?
Yes, they do. The hollow bone of the horn is the only bone that grows during a cow’s entire life, meaning that the horns grow continuously.
Unlike animals that have antlers and shed them seasonally, cows never shed their horn bone and sheath. Their horns never stop growing, even though horn growth slows down as the cows get older.
For example, Texas Longhorn cows grow their horns their entire life, but they gain most of their horn length by the time they are six or seven years old. After that, horn growth significantly slows down. I’ve explained how long it takes for cow horns to grow in another article.
What Length Do Cow Horns Reach?
There’s no standard length for cow horns—it depends on the breed and the family line. In general, dairy breeds have relatively shorter horns than beef breeds.
Cow horn size can be measured in different ways.
- Tip to tip. Place the end of the measuring tape on the tip of one horn and extend it to the tip of the other horn.
- Total horn. The total length of each horn.
- Base circumference. The length at the base of each horn.
- Composite size. The sum of tip-to-tip length, the total for both horns, and the base circumference of both horns.
A study at Kansas State University that measured horn growth among Brahman and Longman heifers during a feedlot period of 194 days recorded notable differences in horn growth:
Cow horn length can also be affected by wear or damage. Sometimes, damage to a cow’s horn leads to its irreversible loss.
How Do Cow Horns Grow?
Like all other cow body parts, horns begin growing during gestation, the period between conception and birth. Studies by the Davies Livestock Research Centre compared horned and polled cow fetuses and found that the horn bud in cows is already formed by day 58 of gestation. At this stage, the horn buds look like depressed skin. The bud is also denser than the surrounding tissues, having six to eight layers as opposed to one or two layers in adjacent tissues.
By the fifth month of gestation, cow fetuses have a small protrusion on the skull. This protrusion is what’s considered the horn bud at birth. Usually, the horn bud is a tiny, dark, and hairless patch covered by a rosette of hair.
Several weeks after birth, the horn bud develops further and grows upwards. By then, it is a sheath that connects to the skin (not the skull) and can be held and moved with the fingers.
By the time the calf is two to three months old, the forehead bone develops and grows into the horn sheath. Initially, the bone is a skeleton of cartilage, but later becomes solid and attaches to the skull.
At 12 months, the frontal sinus, which lies under the skull around the horn bud, connects to the surrounding portion of the horn. As the cow grows, the sinuses spread to the core of the horn, creating the hollow part of the horn. This hollow bone will keep growing even when the cow fully matures.
Conclusion
Unless they are intentionally bred as polled, dehorned, or disbudded as calves, cows will naturally develop horns. Horn development commences during gestation and continues throughout the cow’s life, which explains why cow horns grow continuously.
The length of a cow’s horn is primarily determined by its breed and family genes. If damaged due to an accident or a dehorning procedure, the horns remain so for the rest of the cow’s life: They won’t grow back.
Frequently Asked Questions
Do Cow Horns Grow Back?
Cow horns can grow back if the dehorning process isn’t done correctly. If the horn growth cells are not fully removed or damaged, horns can partially regrow. Proper dehorning techniques usually ensure horns do not return, emphasizing the importance of performing this process carefully.
Do Cows Shed Their Horns?
No, cows do not shed their horns. Horns are permanent structures made of keratin—the same material found in human fingernails. Unlike antlers, which deer shed annually, horns continue to grow throughout a cow’s life and are not naturally replaced.
