L Block

The L block is still the most common form of local anesthesia in small ruminants and is performed in the same manner as in cattle, except the needle should be 18- to 20-gauge (ga) × 1 to inches long.

Paravertebral Block

The paravertebral block is also used in small ruminants, but the needle should be an 18- to 20-ga × -inch to 3-inch spinal needle. A trocar is not needed for the procedure. In goats and sheep, the recommended volume of lidocaine is 2 to 5 ml per site. When the distal paravertebral approach is performed, a 20- to 22-ga × 1-inch needle is used in small ruminants, with 2 to 4 ml of lidocaine administered.

Cornual Nerve Block

Goats have a dual nerve supply to each horn; therefore, two sites must be blocked.

The cornual branch from the lacrimal nerve is blocked just behind the caudal ridge of the supraorbital process, at a depth of approximately 1 to 1.5 cm. A 22- to 23-ga × 1-inch needle is used, and local anesthetic (0.5–1 ml for kids, 2–4 ml for adults) is deposited.

The cornual branch of the infratrochlear nerve is blocked at the dorsomedial margin of the orbit, at a depth of approximately 0.5 cm. A 22- to 25-ga needle is used, and local anesthetic is deposited (0.5 ml for kids, 1–3 ml for adults) (Fig. 16-1).

Sheep are rarely dehorned. The nerve supply is only from the cornual branch of the lacrimal nerve; it is blocked using the same protocol as for blocking the cornual branch of the lacrimal nerve in goats.

Intravenous Regional Analgesia (Bier Block)

When intravenous regional analgesia is performed on small ruminants, a 22- to 25-ga needle should be used, and up to 10 ml of anesthetic should be used.

Caudal Epidural Analgesia

Small ruminants require an 18- to 21-ga × 1- to -inch needle for caudal epidural administration. Because of sensitivity to local anesthetics, the dose should not exceed 0.5 to 1 ml of 2% solution per 50 kg body weight in sheep and goats.

Inhalant Gases

In animals weighing less than 150 lb, facemask induction is possible. Adult sheep and goats may resist facemask induction unless they are sick or sedated. Oxygen (3–5 L/min) is given for 1 to 2 minutes before the anesthetic gas is introduced. Recommended gas concentrations are halothane 3% to 4%, isoflurane 3%, and sevoflurane 4% to 6%. Intubation is performed as soon as depth of anesthesia allows. A long-blade laryngoscope is useful for calves and small ruminants (Fig. 16-2). As with other species, appropriate size of endotracheal tube is estimated by palpation of tracheal diameter through the skin of the neck and usually is 10 to 12 mm in adults. Other commonly used drugs include diazepam and ketamine combinations and propofol in small ruminants.

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