The role of bioactive tannins in the postpartum energy retention and productive performance of goats browsed in a natural rangeland

The role of bioactive tannins in browse in the postpartum performance of goats grazed under natural range conditions was studied using 40 yearling Mubende goats (20 +/- 0.32 kg). In a completely randomized design, goats of one group (n = 20) received a daily drench of 50 g per goat of polyethylene glycol (PEG) of molecular weight 4000 given as a condensed tannin (CT) deactivator, and goats of the other group (n = 20) acted as the control (no PEG). Mean birth weights, live weight gains, abortion and twinning rates, litter size and tissue energy retention were measured. The PEG drench resulted in lower postpartum weight gains and tissue energy retention (p < 0.05). Postpartum weekly weight loss per doe was 0.65 kg in the PEG group and 0.46 kg in the control group, while tissue energy loss was 17.7 MJ per goat in the PEG group and 10.23 MJ per goat in the control group in the first 8 weeks. Net weight gain was observed in the control group at the 11th week but was delayed in the PEG group (15th week). The PEG group had lower birth weights and higher kids mortalities (p<0.05). Selective feeding in the Ankole rangeland exposes goats to beneficial concentrations of dietary CT with apparent cumulative effects leading to improved postpartum performance of does and kids.