Prophylaxis of trichostrongylid infection afforded by low-dose phenothiazine given in two successive years to first-season calves on a common area of pasture.

Abstract

Reduced trichostrongylid infection on herbage and in calves was obtained when first-season calves, grazing a common area of pasture, received low-dosage phenothiazine (PTZ) in two successive years. The average daily dose of PTZ was 7.0 or 10.3 mg kg-1 in the first year and, in the second, between 5.0 and 7.0 mg kg-1. The effect on herbage infection was attributed mainly to ovicidal action. Treatment increased weight gain by 22 and 50 to 60 per cent in the respective seasons. The results suggested a cumulative effect produced by treating calves of successive years. Two calves developed PTZ-induced photosensitivity (corneal opacity) in the first season, and two calves in the second season but in the latter, severe bronchopneumonia was believed to be a predisposing factor. To avoid photosensitivity and still maintain adequate drug activity, the daily intake of PTZ should probably be restricted to around 6 mg kg-1.

• Authors: C J Somers, N E Downey, J O'Shea
• Journal: Research in veterinary science (Res Vet Sci) Vol. 43 Issue 2 Pg. 143-9 (Sep 1987) ISSN: 0034-5288 [Print] England
• PMID: 3685627 (Publication Type: Journal Article)

Chemical References

• Phenothiazines
• phenothiazine

Topics

• Administration, Oral
• Animals
• Body Weight
• Cattle
• Cattle Diseases (parasitology, prevention & control)
• Feces (parasitology)
• Phenothiazines (administration & dosage, adverse effects, therapeutic use)
• Photosensitivity Disorders (chemically induced, veterinary)
• Trichostrongyloidiasis (veterinary)
• Trichostrongylosis (prevention & control, veterinary)