Distal paravertebral nerve block in goats undergoing reproductive laparoscopy: Are 1% and 2% lidocaine hydrochloride equally effective?

•2% Lidocaine hydrochloride (LH) is the most popular local anesthetic.•LH has the historical reputation of being toxic in goats.•Distal Paravertebral Nerve Block (DPNB) requires comparatively larger volume of LH.•Use of 1% LH was therefore compared with 2% in goats undergoing reproductive laparoscopy.•Satisfactory flank analgesia developed after DPBN using both 2% and 1% LH. A blinded, randomized, prospective experimental study was planned to compare the use of 1% and 2% lidocaine hydrochloride (LH) for distal paravertebral nerve block (DPNB) in Bakerwal goats undergoing reproductive laparoscopy. The goats (n = 13) were randomly allotted to two treatments: Treatment I (n = 7) and Treatment II (n = 6) and injected 15.0 mL of either 1% or 2% LH. Nociceptive stimuli during pre- and postoperative periods comprised of superficial and deep pinpricks. The reaction of the animals to the surgical intervention and alterations in their behaviour were recorded intraoperatively. The time to inject the anesthetic (5.4 ± 1.6 and 4.9 ± 0.9 min), onset time (2.6 ± 1.6 and 2.3 ± 1.4 min), the incision length (5.0 ± 1.4 cm and 4.7 ± 1.7 cm) and the sensory blockade duration (121 ± 18 and 123 ± 17 min) in Treatment I and Treatment II goats respectively showed no significant difference. In Treatment I goats the anesthetic dose (5.2 ± 1.1 mg kg -1) injected was significantly less than Treatment II (9.8 ± 0.8 mg kg -1) but their laparoscopy time (73 ± 25 min) was significantly more than Treatment II (56 ± 4 min) animals. The satisfactory sensory blockade lasted for similar period; Treatment I (121 ± 18 min) and Treatment II (123 ± 17 min). The physiological parameters fluctuated most of the times within the normal range. Signs of toxicity, acute pain or distress were not recorded in any of the animals. From this study it is concluded that satisfactory sensory blockade develops after DPNB using either 2% or 1% LH in goats. However, further trials involving higher number of healthy and ailing animals and evaluation of other nerve blocks are needed before advocating the routine use of 1% preparation in the caprine clinical practice.