Goat Disbudding and Dehorning PDF

Goat disbudding and dehorning Karin Mueller MVSc DCHP DECBHM MRCVS Dehorning section first published in the GVS Journal (2010, 26: 9-14). Reprinted with kind permission of the Goat Veterinary Society Disbudding Ideally performed in 2-4 day-old kids, and no older than 7 days. If kids are presented af...

Goat disbudding and dehorning Karin Mueller MVSc DCHP DECBHM MRCVS Dehorning section first published in the GVS Journal (2010, 26: 9-14). Reprinted with kind permission of the Goat Veterinary Society Disbudding Ideally performed in 2-4 day-old kids, and no older than 7 days. If kids are presented after this window, wait until they are several weeks old, when the horn can be removed with a wire, followed by cauterisation. Anaesthesia options: 1. Local infiltration of 1% lidocaine (1ml per site) around cornual branch of lacrimal nerve (as in calf) plus cornual branch of infratrochlear nerve dorso-medial to eye, close to orbit. Just as in the calf, a small proportion of animals also has a caudal nerve supply, therefore consider a third administration point along the caudal border of the horn bud. Note: Toxic dose of lidocaine is 6 mg/ kg bodyweight, i.e. 3 ml of 1% solution for a goat kid of 5 kg BW. 2. Inhalation anaesthesia using halothane / isofluorane & oxygen mixture. Note: Oxygen supports combustion, i.e. do not bring ignited disbudding iron into close proximity without shutting off anaesthetic machine. 3. Injection anaesthesia: in theory, alfaxalone (Alfaxan, Jurox UK Ltd.) is an effective choice, at a dose rate of 2 – 3 mg/kg BW (equal to 1 – 2 ml per kid). However, it is not licensed and the prescription cascade cannot be applied as no withholding period exists in any species. Avoid xylazine: neonates do not compensate for its cardiovascular effects well. The disbudding iron’s diameter must be large enough to encompass the entire horn bud. Note that a standard calf iron is usually too small. Ensure the iron is very hot. Apply the iron two to three times for 3-4 seconds at a time with even pressure until the horn growing tissue destroyed. Common complications:  Tissue not removed, with re-growth  Death under anaesthesia (especially xylazine)  Meningo-encephalitis as a result of prolonged iron application. Kids have a much thinner skull than calves and care must be taken not to overheat the meninges and brain. Clinical signs typical of encephalitis develop after 2-3 days, usually followed by death. Cosmetic dehorning Dehorning of an adult goat should not be taken on lightly. It is a very invasive procedure, resulting in opening of the sinuses, with relatively long wound healing. However, undue aggression in a horned goat against other goats or humans, or fracture of the horn may require dehorning. For an in-growing horn, I prefer to regularly (e.g. every 6-12 months) cut a few centimetres off the horntip with embryotomy wire, rather than fully dehorn the animal. GA is recommended, because the procedure will lead to bleeding into the sinuses, potentially causing stress to the animal (smell, obstruction of nasal passages). A regional block should still be applied: both the cornual branch of the infratrochlear nerve (just below the lateral edge of the frontal bone halfway between the eye and the hornbase, as in calves) and the lacrimal nerve (just caudal to the supraorbital process, halfway between the lateral canthus and the caudal horn) need to be blocked (see Matthews, 1999). After the usual surgical preparation, a figure-of-eight incision is made at a distance of one centimetre around both hornbases (i.e. circular around each base with an incision connecting the two circles at the poll), and the skin undermined for a few centimetres along the entire incision. The horns are sawed off flush with the skull. A hacksaw gives best control of the cutting angle. To facilitate its placement, the bulk of the horn may have to be removed with an embryotomy wire. The incision is closed with interrupted horizontal mattress sutures, using a 3.5 to 4 metric nonabsorbable suture material (e.g. Prolene). Better closure may be achieved by making a relieve incision caudal to each hornbase, but full apposition may not be achieved. A tight figure-of-eight bandage is placed around the head either side of the ears with a non-stick wound dressing (e.g. melolin), with a section cut out around the eyes. The bandage is replaced after 2 to 3, and then seven, days. Occasionally, a fourth bandage is required. Sutures are removed after 12 to 14 days. References Matthews, J. (1999) Diseases of the Goat: Anaesthesia, 2nd Ed., Blackwell Publishing