Experimental and field studies with thiophanate in pigs.

Thiophanate, administered at a dosage of 50 mg per kg to artifically infected pigs, removed 96 to 99 per cent of adult Oesophagostomum spp, Hyostrongylus rubidus and Trichuris suis. Activity was also high against larval stages of these nematodes, except for 26-day-old T suis. Thiophanate also showed ovicidal and larvicidal activity against H rubidus and Oesophagostomum spp. At 50 mg per kg thiophanate administered alone was inactive against Ascaris suum and Metastrongylus apri, the former species also being refractory at 200 mg per kg. Field trials confirmed these efficacy results in naturally infected animals. Pellet formulations providing mean dosages of 63 mg thiophanate per kg for adult pigs and 75 mg thiophanate per kg with 83 mg piperazine base per kg for growing pigs were highly effective in reducing the faecal output of Oesophagostomum spp, H rubidus and T suis eggs. In growing pigs, A suum was controlled by the thiophanate/piperazine product. No palatability or tolerance problems were observed when thiophanate or thiophanate/piperazine mixtures were administered at recommended dosage or multiples thereof in experimental or field studies.