The effect of short-term consumption of a forage containing condensed tannins on gastro-intestinal nematode parasite infections in grazing wether goats

Abstract

The effect of grazing a forage containing condensed tannins (CT), sericea lespedeza (SL, Lespedeza cuneata, 46g extractable CT/kg DM), on the total fecal egg production of gastrointestinal nematodes (GIN) and egg hatch percentage was compared with a control forage low in CT (rye/crabgrass (RC), 6g extractable CT/kg DM) using Spanish wether goats (47.0kg BW). A crossover experimental design was utilized with groups of five and six animals. Each group grazed one forage species in the first 15 day period and then were switched so they grazed the other forage species during the second 15 day period. The mean fecal egg count (FEC) and total fecal egg output (TFEO) were reduced (2500 versus 710 eggs/g, P<0.0001 and 173 versus 45×104 eggs per day, P<0.01) in goats grazing SL compared with RC. The percentage of eggs developing to L-3 larvae was reduced from 99 to 58.2% (P<0.01) by grazing SL. It is concluded that grazing SL, a CT containing forage, reduced fecal egg production from GIN, reduced hatch and development of larvae and consequently, would reduced pasture contamination by infective larvae, thereby mitigating the need for anthelmintics to control GIN.