When allowed to grow, animal horns consist of a keratin shell – the same ingredient found in hair and fingernails – covering a central core of living bone. They grow on ruminants of both sexes, appearing as buds on the top or sides of the animals’ skulls soon after birth and, depending on the species, grow in either curved shapes or perpendicular from skulls.
On wild animals, they perform a variety of functions, ranging from defense and asserting dominance in herds to being part of mating rituals. For example, deer rub trees with their antlers during the mating season to mark their territories and then later, spar with other males as competition for females to breed.
When allowed to grow on domesticated animals, similar behavior can result in injury to both humans and animals alike. To eliminate this risk, most farmers dehorn their livestock as soon as it is practical – The younger the better.
Responsible farmers dehorn their livestock while they are still very young. For some species, this means doing it as soon after birth as is practical. Producers understand it is a painful procedure and requires the farmer or veterinarian to anesthetize the animals to minimize that pain.
“Younger animals recover faster,” said Mary Smith, a veterinarian and professor of ambulatory and production medicine at Cornell University. “The older the animal is, the larger its horn button is and the more pain you cause when removing it.”
A good rule of thumb is to dehorn dairy cattle before 2 months of age. Beef calves, because they often have to be caught first, can be dehorned as late as 4 months old, which is before the horn button grows to more than an inch in diameter. The term used to describe goat dehorning is disbudding.
“Because they develop much faster than cattle, they should be disbudded much younger, within days of birth,” Smith said.
Polled animals represent an alternative to dehorning beef cattle, as opposed to dairy cattle or goats.
“Polled goats have been tied to fertility problems,” she said. “It’s difficult to find polled dairy bulls with good milk production in their backgrounds, though less so more recently.”
There are a number of tools farmers can use to dehorn their livestock, ranging from caustic paste to electric and gas-powered tools, to gougers, cutters and saws. In kind of a strange twist, the more primitive tools require greater skill to use, while the more modern ones are simpler to manage, though they require a much lighter touch.
Caustic paste can be a useful tool for dairy species but less so for beef cattle.
“It can be okay,” said Mike Baker, a Cornell University Extension beef specialist, “but you have to be careful with it.”
Using it on dairy cows or even dairy goats is much less of a problem than beef cattle because milking young stock are separated from their mothers relatively quickly.
“Beef cattle are different because the calves continue to nurse and run the risk of transferring the paste from their heads to their mothers’ udders and injuring them,” he noted.
Still, there’s some research suggesting caustic paste is one of the most painless ways to dehorn livestock. For more information, read the studies posted on dehorning.com, the website of livestock medication manufacturer, H.W. Naylor Company of Morris, New York.
Electric dehorners have gotten pretty good, especially the battery-operated ones, Baker said. “They can be used on calves as soon as the calf is born,” he said. “You can feel the horn buds on horned Hereford calves at birth.”
Crossbred cattle can be a different story, however. “Horn buds on crossbred cattle sometimes don’t show up until three to four months of age,” Baker noted.
There is a whole suite of manual dehorning tools called keystone or guillotine dehorners. Many look like antique or medieval devices. They have two handles that move a blade downward against a plate or another blade to slice through the base of the horn.
A similar tool is the Barnes dehorner, sometimes called a “scoop” or “gouge” dehorner. It looks like a nutcracker except it is manipulated with both hands. These tools require considerably more skill to use than their more modern counterparts.
“There is a great potential for bleeding when using this kind of dehorner. You have to remove the blood vessels and you get cavities where the horns were. Flies become a real concern,” Baker said.
Smith agrees. She won’t dehorn older cattle where the surgery makes an opening into the sinus after April 15 and resumes in October or November because of the season’s flies.
Once horns get 3 inches long, things get messy and risks to livestock are greater, to say nothing of the pain. Tools like saws, especially wire saws, when used properly and fast enough will cauterize the wound, but blood and open wounds are the order of the day.
“I’d just as soon call a veterinarian in to cut them at that point,” Baker said. “It’s the price you pay for not doing things correctly.”
Dehorning beef calves can be a challenge because they spend the first few months of their lives on pasture. That is why it is a good idea to dehorn them inside, either in a building or a corral, where they can be restrained with a halter or in a livestock chute.
Optimally, dairy calves should be dehorned within 2 to 4 weeks of age.
“Bull calves should be dehorned more quickly than heifers because their horn buds grow faster,” Smith said.
Smith manually restrains calves by straddling them and immobilizing them with her legs. Her first task is to administer a local anesthetic to control the pain of horn bud removal.
She uses 3 to 4 cubic centimeters of lidocaine, administered subcutaneously into a nerve located on either side of the animal’s head. The two injection sites are located directly beneath bony ridges located between the eye and the horn buds on either side of the calf’s head.
Then she clips the hair around the horn bud. With the hair gone, she won’t have to deal with hair getting into the wound and the smell of it burning. Secondly, it makes the horn bud clearly visible on the animal’s heads.
Next, she takes the iron, centers it on the bud and presses down firmly once the dehorner has been heated to its maximum temperature.
“The idea is to burn the skin thoroughly without damaging the bone in the skull underneath,” Smith said. “That can be to cut through to the bone or to burn long enough to kill the full thickness of the skin.”
Burning too deeply can lead to infections in the bone underneath and even tetanus, which can eventually kill the animals. She then removes the burned horn bud again to prevent infection.
With the horn bud removed, Smith then administers a painkiller. The goal is to provide calves with pain relief equivalent to taking ibuprofen at four-hour intervals over the next few days. She prefers a single dose of meloxicam. Not approved for use with food animals, it requires a veterinarian-client relationship to secure a prescription.
Dehorning older animals involves considerable risk. Because horns have to be cut off, they will take weeks to heal, Smith says. Additionally, because the operation involves much older tissue, stronger drugs are required to control the pain. Smith recommends the use of a tranquilizer, xylazine.
“Tetanus is a possible, though rare, risk,” she said. “If hay gets into the sockets, it will cause infections. Cattle can bleed to death, too.”
Older animals require constant monitoring throughout the healing process to assure none of these things happen.
Working with goats
Goats mature much faster than cattle do, which requires dehorning to take place within days of their being born. Similar to calves, males develop faster than females.
“Males should be disbudded within three days of birth and females within five to seven days,” Smith said. “A 6-week-old goat will have the horns of a 5-month-old heifer.”
Tetanus is a much greater concern with goats. Mothers should get a vaccine booster three to four weeks prior to kidding. In the absence of boosters to the mother, kids should be given a dose of tetanus antitoxin at the time of disbudding.
Instead of the two injections required for calves, goats need four injections, two on either side of the head. The first is administered in the same location required for calves, underneath the bony ridge located between their eyes and the horn bud. The second should be injected under the skin immediately above the orbit of their eyes.
Again, Smith uses lidocaine for pain control and meloxicam for pain relief, both prescribed by the farm veternarian.
“I use 1 cubic centimeter per 10 pounds of body weight but dilute with sterile water to have a higher volume for each of the four injections. Because lidocaine is acidic and stings when administered, I buffer it with bicarb.”
Newborn goats don’t have the same sinus cavity between their horns and brains that cattle do.
“You are dehorning right on top of the brain, making it much riskier,” she said. Get the iron as hot as it will get, clip the hair around the site and burn only the skin.
“A better iron is a hotter one,” Smith said. “Take out the center of the bud to reduce the chance of the horn growing back and put an icepack on the kids’ heads immediately afterward.”
Males especially should be watched for horn regrowth. Called scurs, they can be trimmed back with hoof trimmers if caught early enough.
Cover Photo by malerapaso/istockphoto.com