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Dehorn cattle for more profits: Part two – Methods

By Neil Anderson – Lead Veterinarian – Disease Prevention, Ruminants/OMAFRA (Ontario Ministery of Agriculture and Food)

Last month we discussed the reasons for dehorning and in this second part of the short series we take a look at different methods of dehorning.

Polled bulls

Horned or polled cows mated to a naturally polled bull (Angus) will give birth to polled calves. However, some non-naturally polled bulls carry the gene for horns and will not breed true for the polled trait.

Advantages and disadvantages

  • welfare friendly
  • availability of genetics for a specific beef or dairy breed
  • selection for genetically polled is a trend for exotic breeds
  • sensitive issue for breeders of horned Cattle

Chemical dehorning

Caustic chemicals will prevent the growth of horns when properly applied to the horn buds of new-born (less than three weeks of age) calves. The chemical destroys the horn-producing cells around the horn bud. The chemicals are available as sticks or pastes (Figure 1). To protect yourself, wear gloves when applying the chemicals. To protect the calf, avoid application near its eyes. Do not use caustics in rainy weather.

Technique

  • Administer sedation, analgesia and local anaesthetic.
  • Expose the horn bud by pushing the hair back (Figure 2).
  • Apply the caustic to the horn button. Use a wooden applicator. Apply a thin layer.
  • Re-position the hair over the paste and horn bud to cover the horn bud.
  • Although the package insert may instruct operators to clip hair at the horn bud, experienced operators have shown that not clipping hair is preferable, because the hair keeps the caustic in place, reduces the risk of irritation to the cows udder and flanks and reduces irritation to other facial skin of the calf.
  • Protect the calf and the cow from accidental caustic burns. One method is to place a patch of duct tape over each horn bud. The duct tape usually falls off in a few days. Keep dairy calves in individual pens.
  • In some countries, the technique is only permitted in calves younger than eight days of age.

Advantages and disadvantages

  • performed at a young age with less stress than some other techniques
  • bloodless
  • use in any season
  • painful without anaesthesia
  • avoid contact with eyes; operator should wear gloves
  • do not use in rainy weather not permitted in some countries
  • horns or scurs follow improper technique
  • requires pain control

Hot iron dehorning

Hot iron dehorners are available in versions heated by a furnace or fire, 12-volt battery, 220-volt electricity, power packs such as Buddex™ or LP gas (Figure 3). The head of the iron is a hollow circle and it fits over the horn bud. Proper application of the hot iron will destroy the horn-producing skin at the base of the horn. This technique works well for calves up to 12 weeks old. There are several sizes of dehorning irons. The proper size is one where the burner makes a complete ring around the base of the horn. For electric irons, use a short extension cord as voltage drops with a long cord, limiting the amount of heat generated by the dehorner.

Technique

  • Administer sedation, analgesia and local anaesthetic.
  • Preheat the dehorning iron to a red colour. Both electric and gas irons work best when they are “red” hot.
  • Wear gloves to protect your hands.
  • Hold the calf’s ear out of the way to keep it from being burned.
  • Place the tip of the burner over the horn and apply slight pressure. When the burning hair begins to smoke, slowly rotate the dehorner by twisting your wrist.
  • Continue the application of heat for 10 to 15 seconds. Do not leave the dehorner in place for much longer, especially with young calves. Heat can be transferred through the thin bones of the skull and damage the calf’s brain.
  • Dehorning is complete when there is a copper-coloured ring all the way around the base of the horn.
  • The horn bud or button will slough off in 4 to 6 weeks.

Advantages and disadvantages

  • bloodless
  • can be used at any time of the year
  • young calves up to 12 weeks of age
  • unreliable when done incorrectly,leads to scurs (partial horn growth)
  • requires expertise – pain control andtechnique

Dehorning spoon or tube

Dehorning spoons or tubes providea quick and efficient technique forremoving horn buds in calves younger than eight weeks of age (Figure 4).With this method, a sharpened metal tube cuts through and removes the horn-producing skin at the base of the horn bud. Use the proper size tube to remove the horn plus about 1/8 inch of skin around the entire horn bud.

Technique

  • Administer sedation, analgesia and local anaesthetic.
  • Select the correct size tube (4 sizes available) to fit over the horn bud, and cover about 3 mm of skin around the horn base.
  • Place the cutting edge straight down over the horn.
  • Apply pressure to the tube; push and twist the tube until the skin has been cut through.
  • Cut under the horn bud and remove it, using a scooping motion.
  • Apply an antiseptic to the wound. Some bleeding may occur.
  • Clean and disinfect the cutting edge of the tube between calves.

Advantages and disadvantages

  • not bloodless
  • useful for young calves
  • risk of infection because of open wounds
  • avoid use during fly season
  • unreliable when done incorrectly, leads to scurs
  • requires expertise – pain control, technique, control of bleeding

Scoop, gouge or Barnes-type dehorner

Scoop dehorners are used for calves ranging in age from two to four months with horns up to four inches long. Some operators claim better dehorning with a rectangular-shaped scoop because it removes an even ring of skin around and with the horn bud. When used properly, it does not go too deep, but the dehorner can open the frontal sinus when used at the top end of the age and horn-size range. The blades must be kept sharp for best results.

Technique

  • Administer sedation, analgesia and local anaesthetic.
  • Close the handles together.
  • Place the jaws of the dehorner over the horn bud. The objective is to completely remove a ring of skin surrounding the horn base. Therefore, adjust the opening as needed
  • Press the gouge gently against the head. Maintain the pressure and quickly spread the handles apart to bring the blades together to remove skin and the horn bud.
  • Control bleeding by pulling the artery with forceps or using a hot iron to cauterise the artery.
  • Clean and disinfect the jaws of the gouge between calves.

Advantages and disadvantages

  • fast – takes a few seconds to perform
  • useful after the horn bud attaches to the skull
  • not bloodless
  • risk of infection because of open wounds
  • opens the frontal sinus in older calves
  • avoid use during fly season
  • unreliable when done incorrectly, leads to scurs
  • requires expertise – anaesthesia, sedation, analgesia and technique
  • requires control of bleeding – pulling arteries or cautery

Aftercare

Dehorning and disbudding are surgical procedures. Calves require observation and aftercare following the surgery.

  • Observe closely for bleeding for 30 to 60 minutes after dehorning.
  • When bleeding is present, cauterise with a hot iron to stop the bleeding.
  • Wounds usually heal well with no treatment.
  • A fly repellent and a wound dressing are often recommended.
  • For 10 to 14 days after dehorning, look for signs of infection and treat as needed.
  • Get professional help for calves showing severe pain or infection.

Disinfection of equipment

Diseases can be spread from animal to animal on dehorning equipment contaminated with blood. Enzootic bovine leucosis virus and the wart virus are two examples. It is essential to disinfect the tube and Barnes-type dehorners after each calf is dehorned.

Technique

  • Rinse blood off with cold water after each calf is dehorned.
  • Place the equipment into an antiseptic after the calf is dehorned.
  • Change the antiseptic solution frequently to maintain its potency.
  • Prepare a disinfectant solution by adding 110 g of creosol to 4,5 ℓ of water.
  • Store the equipment only after cleaning and disinfecting.

The heat from electric dehorners effectively disinfects them between calves. Hot-iron dehorners occasionally require cleaning with a wire brush.

Visit http://www.omafra.gov.on.ca/english/livestock/dairy/facts/09-003.htm for more information.

Figure 1: Dehorning paste is a caustic chemical applied to horn buds to destroy horn-producing cells.
Figure 1: Dehorning paste is a caustic chemical applied to horn buds to destroy horn-producing cells.
Figure 2: The circle at the base of the ear shows the location of the horn bud in a young calf. The horn bud is readily visible after pushing back the hair. Reposition the hair over the paste and bud after applying the dehorning paste
Figure 2: The circle at the base of the ear shows the location of the horn bud in a young calf. The horn
bud is readily visible after pushing back the hair. Reposition the hair over the paste and bud after applying
the dehorning paste.
Figure 3: An electric hot-iron dehorner will destroy the hornproducing skin at the base of the horn bud.
Figure 3: An electric hot-iron dehorner will destroy the hornproducing
skin at the base of the horn bud.
Figure 4: A dehorning spoon or tube is used to remove the horn bud plus the horn-producing skin at the base of the bud.
Figure 4: A dehorning spoon or tube is used to remove the horn bud plus the horn-producing skin at the base
of the bud.
Figure 5: A Barnes-type dehorner scoops the horn and horn-producing skin surrounding the horn base.
Figure 5: A Barnes-type dehorner scoops the horn and horn-producing skin surrounding the horn base.

Figure 6: With young calves, the Barnes-type dehorner removes horn-producing skin but does not cut into the frontal sinus as shown by the arced line. In older calves with the horn attached to the skull, the dehorner cuts into the frontal sinus.
Figure 6: With young calves, the Barnes-type dehorner removes
horn-producing skin but does not
cut into the frontal sinus as shown
by the arced line. In older calves
with the horn attached to the skull,
the dehorner cuts into the frontal
sinus.

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