Effects of three benzimidazole anthelmintics on the ruminal fermentation ability of sheep.

The effects of albendazole, fenbendazole and oxfendazole on the fermentation ability of the rumen were assessed in 12 Dorset sheep, using as parameters volatile fatty acid concentration, percentage digestibility of cellulose in vitro and pH. Although the digestibility of cellulose was affected only at high concentrations, volatile fatty acid concentrations were markedly reduced after treatment. Correlation coefficient analysis revealed a significant correlation between digestibility of cellulose and volatile fatty acids, as well as between volatile fatty acids and pH. Despite an evident decrease in volatile fatty acids and digestibility of cellulose, it is suggested that this does not outweigh the advantages derived from the use of these benzimidazoles.