Implications of tannin containing plants for productivity and health in small ruminant animals: A review

Infection with parasitic nematodes is a serious threat to health and production of small ruminant worldwide. It causes reduction in feed intake, weight gain and eventually death of the host. The primary control method of the nematode infection relied on frequent use of anthelmintic drugs. Unfortunately, this control strategy is no longer effective due to widespread anthelmintic resistance, which necessitates search for novel approaches to control nematodes. Condensed tannin (CT) containing forages have been used as anthelmintic to control parasitic nematodes for years. This paper reviews available information about effects of CT on productivity and health of small ruminants infected with parasitic nematodes. Many of temperate and tropical forages are nutraceutical plants (possess both nutritional and health benefits). Consumption of CT containing forages reduced negative impacts of gastrointestinal parasitism in sheep and goat by regulating establishment of worm as shown in reduced worm burdens, fecal egg count (FEC) and worm fecundity. Parasitized sheep and goats fed forages containing CT had high feed intake and body weight gain, probably due to increase in protein and amino acids supply. Condensed tannins containing feeds result in lighter meat color and tend to improve antioxidant activity. Therefore, the use of CT containing forages to control parasitic nematodes and improve production of small ruminants is one the alternatives to anthelmintic drugs.