Effect of strategic gastrointestinal nematode control on faecal egg count in traditional West African cattle

This paper reports on the effect of strategic anthelmintic treatments and o ther determinants on faecal egg counts (FEC) of Trichostrongyles in N'Dama cattle of a west African village. Initially, 527 animals from 13 private N' Dama cattle herds were monitored in a longitudinal study from October 1989 to December 1994. Each herd was stratified by age and animals were sequenti ally allocated to two groups with similar age distributions. One group rece ived a single anthelmintic treatment of fenbendazole (7.5 mg/kg BW), in Oct ober 1989 (n = 250), whereas the other group remained untreated (n = 277) t hroughout the study. In the next rainy season (June to October), the treate d animals were treated twice tin July and September). The same treatment sc hedule was used in the subsequent rainy seasons until December 1994. Biannu al anthelmintic treatments decreased the level of FEC between 31% (late dry season) and 57% (rainy season), when compared to untreated controls. The h ighest levels of FEC were found during the rainy season from June to Octobe r. FEC levels decreased until 4 years of age, after which they remained on a constant low level. The variability of returns to anthelmintic treatments between herds did not seem to be influenced by FEC at the herd level. The financial evaluation of anthelmintic interventions cannot be predicted from FEC and must necessarily rely on the direct monitoring of livestock produc tivity parameters.