Comparison of polyethylene glycol and wood ash extract on feeding value and economic efficiency of mixes of high-tannin feed sources in growing Ethiopian Bonga lambs.

Dietary inclusion of tannin-deactivating agents such as polyethylene glycol (PEG) and wood ash can enhance the feeding value of tannin-containing feeds. To evaluate this, 24 intact male Bonga lambs were divided into three blocks of eight animals per block based on their initial body weight in randomized complete block design with three treatments, 30 days adaptation and 10 days of data collection. The dietary treatments consisted of T1 (= hay 40% + concentrate 5% + Albizia gummifera 30% + Rhus glutinosa 10% + Syzygium guineense 15%), T2 (= T1 + wood ash), and T3 (=T1 + PEG6000). Animals were individually fed at 50 g DM/kg BW and had free access to clean drinking water and mineralized salt licks. Nutrient intake, digestibility, nutrient conversion ratio, and live body weight gains were determined. The condensed tannin concentration in tannin-rich trees and shrubs (TRTS) mix was 140 g DM/kg, respectively. The highest improvement in nutrient intake and apparent digestibility was recorded in T3 compared to other treatments (P < 0.01). The total return (TR) Ethiopian birr/currency (ETB)/sheep was 478 ETB, 554 ETB, and 569.6 ETB for T1, T2, and T3, respectively. Accordingly, the addition of PEG and wood as a tannin-binder improved digestion and performance in sheep, but with the highest effect size was recorded for PEG.