Dehorning and disbudding

Question 1

What tags should a calf have and what should they denote?

Answer 1

Question 2

Where should the management tag (plastic) and secondary tag (metal) be placed?

Answer 2

The tag should be placed between the two cartilage ribs which run the length of the ear, in its middle third

Metal tags should be placed on the proximal boarder of the ear in its middle third

Question 3

What problems can occur with tagging?

Answer 3

Infection

• Infection and abscesses can develop at the tagging site

Treatment

• If present, lance abscess (unusual)
• Clean with antibacterial washes e.g. Chlorhexidine
• Apply topical antibiotics e.g. Oxytetracycline spray
• In bad cases (hot, swollen, painful ear +/- pyrexia) administer broad spectrum antibiotics (e.g. long acting penicillin)
• In severe cases it may be necessary to remove the tag

Trauma

• Tags can become caught on objects in the environment and torn out causing haemorrhage

Treatment

• Clean with anti-bacterials
• Clamp or tie off vessels or
• Compression e.g. bandage
• Surgical repair is possible for aesthetic purposes e.g. show cattle, but rarely performed

Question 4

Why do bulls have nose rings?

Answer 4

All adult bulls should be rung to aid safe handling. Whilst it can be performed at any age, it is best done when animals are between 6 and 12 months

Question 5

How does a copper bull nose ring stay in place?

Answer 5

After fitting the ring, the screw is used to hold the ring together. It can be tightened by hand or with pliers and then the screw “handle” is broken off to permanently fix the ring in place.

Question 6

What is the protocol for fitting a nose ring?

Answer 6

Restraint

• In a crush or suitable stanchion
  
  • Halter +/- nose tongues
  • Light sedation with xylazine / detomidine may be necessary for fractious animals
  • Alternatively, heavy sedation with xylazine / detomidine (inducing recumbency) in a well bedded straw box

Anaesthesia

• Whilst local infiltration of the septum with procaine is theoretically possible, practically it is very difficult to administer

Technique

• The ring is placed through the soft tissue of the nasal septum in front of the cartilage. It must not be placed through the cartilage itself
• Four methods:
  
  • A “nose punch” is used to cut out a circular punch of tissue
  • The sharp end of the ring is driven through the septum by hand
  • The sharp end of the ring is driven through the septum using a applicator designed specifically for the job
  • A scalpel blade (size 11) is used to cut a slit through which the ring is passed
• Which every method is used prepare carefully and ensure everyone is aware of their respective roles, prior to commencing the procedure

Question 7

What is this and what is it used for?

Answer 7

Rings can be fitted through a hole created by a “Nose Punch” which cuts a small punch of skin out from between the nostrils in front of the cartilage which divides them.

Question 8

What is this and what is this used for?

Answer 8

• Rings can be fitted using a “Bull Ring Applicator”. One end of the ring is “sharp” and can simply be driven through the skin dividing the nostril either by hand or more simply using an applicator.
• After application, the septum must be allowed to heal before the ring is used to restrain the animal
• Occasionally animals can tear the ring from the nose. Whilst repair is theoretically possible, in most cases the nose should be allowed to heal by secondary intention

Question 9

What is the legislation surroinding disbudding cattle?

Answer 9

Under The Protection of Animals (Anaesthetics) Act 1954, as amended, it is an offence to disbud calves or dehorn any cattle without the use of an anaesthetic other than when chemical cauterisation is used. Chemical cauterisation may only be used during the first week of life.

Question 10

Discuss the sue of NSAID’s when disbudding?

Answer 10

• The use of local anaesthetic during disbudding is a legal requirement*
• There is increasing evidence that NSAIDs are beneficial in reducing the chronic pain associated with the procedure
• There use is becoming more widespread, however the provision of preoperative analgesia should always be considered and recommended to the client, so they can make an informed choice as to whether it is used

*Except if caustic paste is used within the first week of life

Question 11

Dicuss dehorning cattle?

Answer 11

• Background
• Dehorning is a major procedure and should not be considered “routine”
• Clients must be advised to disbud when animals are young rather than dehorn them as yearlings or adults
• From the Welfare Codes
  
  • “Ideally a veterinary surgeon should do it, and only if it is necessary for the herd’s welfare. It should not be a routine procedure”
• Avoid summer months when flies (and the risk of fly strike) are prevalent

Question 12

How should cattle be restrained for dehorning?

Answer 12

• Good quality crush
• Halter +/- bulldogs
• Secure to side to crush to minimise movement of the head as far as possible
• Light sedation with xylazine / detomidine may occasionally be necessary for fractious animals
• Alternatively, heavy sedation with xylazine / detomidine inducing recumbency, in a well bedded straw box (much less common)Very fractious animals
• If a good quality crush is not available

Question 13

How should anaesthesia and analgesia be provided for dehorning?

Answer 13

Cornual nerve block

Basic method as per calves:

• Palpate temporal ridge (runs from lateral canthus to the horn)
• Mark point half way between lateral canthus and horn with thumb. Direct needle under the ridge
• ~19 / 20 gauge, 1” needle; depth of needle insertion ~1-3cm
• Always withdraw prior to injection, 5-10mls procaine each side, then massage.

Subcutaneous branches of second cervical nerve

• Can provide substantial innervation to the caudal aspect of the horn in some adults
• Subcutaneous local infiltration with procaine

Allow time for anaesthesia (at least 10 mins)

Anaesthesia can be checked by pricking around the horn base with a needle

NSAIDs

• The provision of preoperative analgesia should always be considered and recommended to the client
• Do not administer without client consent because of the cost

Question 14

Outlie the methods of dehorning?

Answer 14

Remove horn close to / flush with the scull

Four methods available, choice will depend on the size of the horns, availability of equipment and operator preference

Scoop / gouge dehorners

• E.g. “Barnes” dehorners. Good for smaller horns

Shears / guillotines

• Quick. Require considerable strength to operate
• Anecdotally, can “fracture” the frontal bone in large animals

Embryotomy wire

• Slow. Require less strength but greater stamina. Better haemostasis

Bone saw

• Relatively quick. Effective in the hands of a skilled operator

Question 15

What are these?

Answer 15

Scoop / Gouge Dehorners

Barnes dehorners can be used to remove small to medium / large horns quickly, however they are a little cumbersome and require some strength to operate. They can be purchased in a variety of different sizes.

Question 16

What are these?

Answer 16

Shears / Guillotines

Heavy duty dehorning shears can be used to remove small to very large horns quickly and cleanly, however they are cumbersome and require long arms, plenty of room and considerable strength to operate.

Question 17

Discuss haemostasis when performing dishorning?

Answer 17

• Significant haemorrhage occurs if horns are large (3-4 arteries).
• Haemorrhage is significantly less if a wire is used (heat and dust generated limit bleeding)

Haemostasis methods

• Grasp and pull or twist the artery slowly with haemostats causing them to break below the bone line where they clot
• Can be difficult or impossible to grasp in some cases. In this case matches can be driven into the arterial canal and broken off.
• Work around the wound circumferentially with a hot iron
• Will not stop large arteries, blood rapidly cools iron
• Apply a tourniquet around the base of the horns and the poll with baler twine or bands e.g. section of inner tube
  
  • Must be removed after a few days

Question 18

Outline dehornig aftercare?

Answer 18

• Many clinicians will treat the wound with oxytetracyline spray
• Ideally animals should be returned to a clean environment
• Advise the client that animals must be regularly checked during the first 24 hours to ensure any haemorrhage has stopped
• Rule of thumb is that if individual drops of blood can be identified and counted its usually not a problem i.e. very fast drops – slow run should be dealt with
• Stress should be minimised following the procedure e.g. no group changes or change of environment
• In large horns the frontal sinus extends into the horn and is therefore left open following dehorning. Animals should be fed off the floor and not from a rack to prevent foreign material falling into the sinus

Question 19

What are problems and complications of dehorning?

Answer 19

• Haemorrhage. Animals may bleed to death or close to death in extreme cases
• Infection at the surgical site
  
  • Rarely a significant problem
  • Manage as any superficial infection (clean and topical ABs. Systemic ABs in severe cases)
• Sinusitis
  
  • Foreign material may gain entry to the sinus especially if animals are fed from racks
  • Can be severe in some cases requiring systemic treatment and potentially trephination of the sinus
• Fly strike
  
  • Avoid dehorning during the fly season

Question 20

What is cosmetic dehorning?

Answer 20

• Very unusual, but possible in show or pedigree animals
• General anaesthesia or heavy sedation and local anaesthesia
• Aseptic preparation and procedure
• Clip and clean
• Incise and reflect skin around horns
• Dehorn and close skin with sutures to achieve primary healing
• See surgery text books