ABOMASOTOMY TECHNIQUE FOR THE EXTRACTION OF Haemonchus contortus IN LIVE GOATS

Abstract

Background: Goats are increasingly being used as surgical models in animal experiments. Some ruminant parasitological studies require collecting adult nematodes directly from the abomasum of donor animals. A methodology to collect those adult worms in vivo could avoid the unnecessary sacrifice of donor animals. Objective: To describe an abomasotomy technique to obtain adult Haemonchus contortus from live goats and evaluate the immediate post-surgical recovery time. Methodology: Nine worm-free adult goats were infected with 6000 H. contortus L3. The monospecific infection was confirmed on day 28 post-infection. The anesthetic procedure included fentanyl (10 μg * kg BW-1 load dose (LD) and 10 μg * kg BW-1 hour in constant-rate-infusion (CRI), lidocaine (2 mg * kg LD-1 and 50 μg * kg BW-1 minute CRI), ketamine (1.5 mg * kg-1 and 50 μg * kg BW-1 min CRI) and propofol (4 mg * kg LD-1 and 0.4 mg * kg BW-1 min CRI). The surgical protocol consisted of eight “surgical time-points”. Purposeful animal movement in response to surgical stimulation, or any changes in the autonomic response (> 20% from baseline values of HR and arterial blood pressure (SAP, MAP, and DAP)) were used as criteria to identify trans-surgical nociception. Post-surgical pain was evaluated once daily with the wound healing evaluation. Results: The surgical protocol lasted 1 h, allowing the recovery of adult H. contortus from live goats. The anesthetic protocol successfully controlled trans-surgical pain, with only two animals crossing the HR threshold (>20%) from T2 to T6. Post-surgical recovery (“time to extubation” and “time to standing”) was achieved before 1 h, while animals consumed water after only 4 h post-surgery. Goats did not require rescue analgesia, and suture withdrawal was achieved 7 days post-surgery without complications. Impications: The abomasotomy technique here described can be used for parasitological studies in small ruminants when the collection of nematodes is required from live animals. Conclusions: The anesthetic and surgical protocol here described is a viable and rapid alternative for the collection of nematodes from the abomasum of live goats with minimal pain and rapid postsurgical recovery.

Keywords

• cabras
• abomasotomía
• recuperación de parásitos
• protocolo quirúrgico
• anestesia.