# Anthelmintic control failure and associated risk factors reported by farmers in communal sheep farming, Oliver Tambo District, Eastern Cape, South Africa

## TL;DR

This study explores why anthelmintic treatments for sheep parasites are failing in South African communal farms and identifies risk factors reported by farmers.

## Contribution

The study identifies specific risk factors for anthelmintic control failure in communal sheep farming in South Africa.

## Key findings

- 62% of farmers reported anthelmintic control failure.
- Use of 5- or 10-mL syringes and lack of weight estimation were linked to treatment failure.
- Commonly used drugs included Valbantel, Maxicare, and Prodose Orange.

## Abstract

Helminth control on communal farms of South Africa, primarily relies on anthelmintic drugs, administered by farmers without veterinary supervision. This study investigated risk factors associated with farmer‐reported anthelmintic control failure on communal sheep farms in Oliver Tambo District of the Eastern Cape of South Africa.

A semi‐structured questionnaire capturing farm characteristics, helminth control practices and treatment failure was administered to 107 farmers between January and August 2024.

Most of the farmers encountered were older males (56%) aged over 65 years. Helminth eggs were identified in sheep faecal samples, revealing four genera: Haemonchus spp. (100%), Strongyloides spp. (67%), Moniezia spp. (61%) and Trichuris spp. (17%). A total of 15 anthelmintic drug brands were recorded. The most commonly used compounds (46%) were Valbantel, Maxicare and Prodose Orange, all co‐formulations of benzimidazoles and salicyanilides. Anthelmintic control failure was reported by 62% of farmers. The predominant sheep crossbreed raised on the farm (Dorper‒Merino), the use of 5‐ or 10‐mL syringes for anthelmintic drug administration, and the absence of sheep weight estimation were statistically associated with farmer‐reported anthelmintic control failure.

These findings underscore the need for improved helminth management strategies to enhance the effectiveness of anthelmintic treatments in communal farming systems.