Activity of ivermectin against natural infections by abomasal nematodes in lambs in controlled tests: evaluation of equine and bovine injectable formulations administered intraorally.

The research investigates the application and effectiveness of two versions of ivermectin, an injectable medication meant for horses and cattle, given orally to lambs to treat natural infections by abomasal nematodes. The findings show a high rate of parasite removal, ranging from 98% to 100%, without causing toxicity in the treated lambs.

Objective and Methodology

• The researchers aimed to test the effectiveness of two injectable formulations of ivermectin, designed for horses and cattle, administered orally to lambs at a dose of 200 micrograms/kg of body weight, against naturally occurring infections by abomasal nematodes.
• Two controlled tests were conducted. The first test (A) included 17 lambs treated with the horse formulation and 16 lambs without treatment. The second test (B) also included a control group of 12 lambs without treatment and 14 lambs that received the cattle ivermectin formulation. Hence, the sample sizes were different to account for potential discrepancies.

Findings and Analysis

• In test A, where the horse formulation of ivermectin was used, only mature nematodes were found in the lambs, indicating that the treatment was successful in removing immature parasites. The removal rates of the mature parasites ranged from 98% to 100% for all nematode species discovered, including Haemonchus contortus, Ostertagia circumcincta male, O trifurcata male, Ostertagia spp female, and Trichostrongylus axei.
• In test B, where the cattle ivermectin formulation was used, both immature and mature nematodes were found. Removal rates ranged from 99% to 100% for all nematode species, similar to test A.
• The researchers found no evidence of toxicosis in the treated lambs, indicating the safety and tolerability of the ivermectin dosage in this context.

Implications and Conclusion

• The results of the study demonstrate the effectiveness and safety of using injectable ivermectin formulations, originally intended for horses and cattle, as an oral medication in lambs to treat abomasal nematode infections.
• With removal rates of parasites ranging from 98% to 100%, the treatment could be seen as an effective solution in combating these types of infections.
• This study could provide new avenues to treatment options in veterinary medicine, and suggests the potential for exploring the use of medicines across different animal species, with due caution for variances in species response.