Effect of Acacia molissima tannin extract on the control of gastrointestinal parasites in sheep

This study investigates the anthelmintic effect of condensed tannin extracts (CTE) from Acacia molissima on lambs naturally infected with Haemonchus contortus and Trichostrongylus colubriformis. Twenty Santa Inês sheep were divided into four groups and allocated to four paddocks with five animals each in a 60-day trial. Two groups were drenched with CTE (1.6 g/kg LW) for two consecutive days at the beginning of the trial and 30 days later and two groups were maintained undrenched (control) throughout the trial. The animals were weighed every 14 days; blood was collected once a week and faecal egg counts (FEC) were measured twice a week. Twenty-eight days after the final CTE administration, all lambs were slaughtered and worm burden counts were determined. Mean body weight changes were not different among treatments. Globular volume for the drenched group was higher or showed tendency to be higher than the undrenched group at days 14 (P=0.043), 21 (P=0.074), 28 (P=0.026), 42 (P=0.007) and 48 (P=0.089). No differences were observed in haemoglobin values between treatments. The CTE drenching was associated with a reduction in FEC (P=0.003) and worm burden in the abomasum (P<0.003), but not in the small intestine. The results confirm the anthelmintic effects of CTE on gastrointestinal nematodes in lambs and demonstrate the potential use of CTE as an alternative endoparasite control in livestock.