Evaluation of nutrient utilization and economic feaseability of bonga sheep and kaffa goat breeds supplemented with mixes of tannin rich tree leaves with or without polyethylene glycol

Abstract

The study was conducted to evaluate the effects of dietary inclusion of leaves of the condensed tannin-rich trees(Albizia schimperiana (AS)and Ficus ovata (FO)) in grass-based hay with or without polyethylene glycol (PEG (4000 & 6000)) on nutrient intake and digestibility, weight change, feed conversion and economic efficiency of 8 intact male Bonga sheep and 8 kaffa goats( 12+0.46 months old, weighing initially 22.2+2.9 kg and 23.1+1.5kg (mean +SE) respectively). Experimental animals randomly assigned to 4 dietary treatment groups sequentially in separate periods. The experiment was arranged with four treatments in a 4 × 4 randomized crossover design. A 15-day adaptation and 7-day data collection conducted for each treatment. The dietary treatments consisted of grass based hay alone (=T4, control); AS (36%) +FO (9%) +control diet (55%)=T3; T3+PEG6000 (=T2); T3 +PEG4000 (=T1). Animals were individually fed at 50g DM/kg live weight and had free access to clean drinking water and mineralized salt licks. Nutrient intake and Apparent digestibility coefficients were determined for dry matter (DM), crude protein (CP), crude fat (EE) acid detergent fiber (ADF) and neutral detergent fiber (NDF). Partial budget analysis was conducted after the end of each period. Condensed tannin contents of AS and FO were 110 and 191 g/kg DM, respectively. Nutrient intake was higher (P<0.001) in goats than sheep. Sheep and goats in the control treatment lost BW (2.2 & 2.1 g/day), while in T2 supplemention they gained 37g/day & 41g/dayBW , respectively (p<0.001). The feed DM intake of sheep ranges (625- 960 g/d), goats (631-976 g/d) where as apparent digestibility of sheep (46-65 %), goats(48- 67%) while FCR goats were significantly higher (P<0.01 ) than sheep. The improvement in nutrient intake, digestibility, weight gain, feed conversion rate and profitability after PEG supplementation emphasizes the negative effect of CTs on feed utilization. Feeding local grass hay would be inadequate as the sole source of nutrients for Bonga sheep and Kffa goats. For each Ethiopian birr invested on test browse feeds with T2, farmers would have to obtain additional 2.3211 0.42 and 1.7038 0.63 ETB from Kaffa goat and Bonga sheep respectively .The control treatment resulted in a negative return while high level of tannin source supplementation with PEG6000 (T2) resulted in the best return (2.32 ETB/Kaffa goat & 1.7ETB/Bonga sheep). 36% AS + 9% FO + PEG6000 supplementation could maintain the optimum utilization of the grass based hays for sheep and goats. The overall improvement in nutrient utilization, weight gain and feed conversion was more pronounced for goats with or without PEG suggested that goats could be able to utilize tannin rich diets. Bonga sheep could only be efficiently use mixes of tannin rich diets either as maintenance or production ration with the presence of tannin binding agents such as PEG.In general Bonga sheep and Kaffa goats would need to be appropriately supplemented to achieve profitable production.