Grad Student Competition
From Fast Acting to Long Lasting: Comparing Cornual Nerve Blocks in Goat Kids
| Date/Time: |
8/28/2026
08:00
|
| Author: |
Erica Schmidt |
| Clinic: |
University of Minnesota CVM |
| City, State, ZIP: |
St Paul, MN 55102 |
Erica Schmidt, BS
1
;
Alonso Guedes, DVM, MS, PhD, DACVAA
2
;
Beth Ventura, MS, PhD
3
;
Gerard Cramer, DVM, DVSc
1
;
Whitney Knauer, VMD, PhD
1
;
1Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, USA
2Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, USA
3Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, USA
Introduction:
Local anesthetic nerve blocks are a common method for pain relief during cautery disbudding. While lidocaine is the standard, fast-acting, and cost-effective choice for dairy calves, its use in goat kids is limited. In goat kids, lidocaine offers a short duration of action, a narrow safety margin, and is challenging to administer effectively. Although longer-acting anesthetics have demonstrated extended analgesic effects in other species, their efficacy has not yet been assessed in goat kids. This study's objective was to describe the latency and duration of desensitization for buffered lidocaine (BL), bupivacaine (BUP), and bupivacaine liposome injectable suspension (BLIS) for a cornual nerve block in goat kids.
Materials and methods:
Twenty-four healthy kids (5 ± 2 d old) were randomly assigned into one of three treatment groups: BL (9:1 2% lidocaine to 8.4% sodium bicarbonate; 18mg/mL), BUP (bupivacaine HCl 0.5%; 5mg/mL), or BLIS (Nocita®; 13.3 mg/mL) (n = 8 per group). One horn bud was randomly assigned per kid to receive treatment. Horn bud (right or left) and kid sex were balanced between treatment groups. Each bud received 1 mL of local anesthetic, split equally between the cornual branches of the infratrochlear and lacrimal nerves. A nerve stimulator (SunStimTM Pro) with a ball electrode attachment was used to assess baseline sensitivity prior to treatment, as well as at predefined intervals to assess latency (2.5, 5, 6, 7, 8, 9, 10, 12.5, 15 min) and duration (BL and BUP every 0.25 h; BLIS at 0.5, 1, 2, 4, 6, 8, 24, 48, 72 h). Latency to and duration of desensitization were determined from behavioral responses scored using a predefined ethogram. Latency was defined as the first Grade 0 response (no reaction), and duration as the time from onset to return of a Grade 2 response (escape, head shake, head withdrawal, and/or vocalization.
Results:
All three treatments produced a complete cornual nerve block. Latency to achieve desensitization was similar across treatments and all had blocked by 8 min(BL: 5-6 min, BUP: 5-7 min, BLIS: 5-8 min). The duration of desensitization varied among treatments. BLIS had the longest duration, lasting between 8 and 72 h, although the number of desensitized kids decreased over time (n = 8 at 6 h; n = 5 at 8 h; n = 1 between 24–72 h). In contrast, BUP lasted 1.75 to 3.5 h (n = 8 at 1 h; n = 6 at 1.75 h; n = 4 at 2.25 h; n = 2 at 3.25 h), and BL had the shortest period of desensitization, lasting 1 to 2.25 h (n = 6 at 1 h; n = 1 at 1.75 h).
Significance:
Our findings suggest that local anesthetic injection should take place at least 8-10 minutes prior to a painful procedure to account for latency to full onset. All three local anesthetics tested appeared to offer full desensitization during the period at which kids would be subjected to the procedure of cautery disbudding. However, BLIS demonstrated the longest duration of desensitization, suggesting its potential to provide hours of post-operative protection against the pain from disbudding, though further research is needed to assess its efficacy during and after cautery disbudding.
