Wattle tannins as control strategy for gastrointestinal nematodes in sheep

摘要

Nematode resistance to anthelmintic drugs is affecting small ruminant production in South Africa. This study evaluated the effect of wattle tannins as an alternative nematode control drench. Two experiments (Exp) were conducted to determine the effect of tannin concentration (Exp 1) and frequency of dosing (Exp 2) on nematode parasites. In each experiment gender, egg count (egg per gram, EPG) and initial live weight aided in blocking sheep into groups, within which they were randomly allocated to and drenched with different tannin treatments. In experiment one, 24 sheep (16 females and 8 males, aged 8-9 months) were placed into four treatment: 0, 0.8, 1.6 and 2.4 g tannin/kg BW; they were drenched for three consecutive days in a study that lasted for 21 days. In Experiment 2, 26 sheep (11 males and 15 females aged 9 to 18 months) were placed into three treatments of 9, 9, and 8 sheep each. These treatments were drenched with 1.6 g tannins/kg BW/day for one day, two or three days for the three treatments, respectively. For the two experiments, EPG were counted and L3 larvae cultured and counted in individual feacal samples. In Exp one, for all tannin treatments, EPG decreased (P<0.05) over time and EPG consistently decreased with increasing tannin level, while efficacy increased (P<0.05) with tannin level.? Dosing with 1.6 and 2.4g tannin /kg BW for 3 consecutive days had similar effects on the EPG. Dosing frequency showed that 1.6g tannin /kg BW for 3 consecutive days was enough to reduce EPG and reduce the degree of pasture contamination.?Keywords: Wattle tannin, GI nematodes, L3 larvae, sheep.