Cornual nerve block

• This is a common local anesthetic block used in cattle practice to provide analgesia for disbudding and dehorning Disbudding and dehorning.
• Disbudding and dehorning is not an innocuous procedure and has been shown that cattle undergoing these procedures eat and ruminate less in the 48 hours following surgery than those that do not have the surgery.
• Use of a local anesthetic Local anesthetic for disbudding and dehorning has been demonstrated to have a number of benefits including reducing the cortisol response to surgery and this was not seen when Xylazine Xylazine alone was used.
• A combination of local blockade and an NSAID Anti-inflammatory drugs: overview provided even more effective and longer-lasting analgesia beyond the 203 hours seen with local anesthetic usage alone.

• The horn corium and the skin around its base receive their sensory input from a branch of the trigeminal nerve (zygomaticotemporal branch). The nerve emerges from the orbit and ascends behind the lateral ridge of the frontal bone. The lateral ridge can be easily palpated and in the upper third of the ridge, the nerve is relatively superficial in the top third of the ridge as it is only covered by skin and thin frontalis muscle.

Uses

• Usually used for disbudding or dehorning Disbudding and dehorning.

Advantages

• Provides good analgesia in calves, although the administration of NSAIDs currently improves the longevity of this analgesia and is now strongly recommended in the recent position statement from the BCVA and BVA (2017).

Disadvantages

• Need knowledge of the neuroanatomy of the region.
• Some animals may have variations to normal nerve distribution resulting in failure of complete neural blockade.
• In some animals it may also be necessary to block the cornual branch of the infratrochlear nerve and also the frontal nerve.
• If the block is performed at too great a depth, the nerve may not be desensitized and the block will fail.
• This technique alone may not be sufficient for dehorning older animals and additional ring blocks around the horn may be required. An adaptation to the block can prevent the need to perform a ring block for dehorning in adult cattle.
• Can lead to Hematoma Hematoma formation.

Alternative techniques

• Ring block Ring block of local anesthetic around the base of the horn.
• Infratrochlear nerve block [Infratrochlear nerve block].