Effect of Graded Substitution of Barley Grain with Raisin Waste in Diet Contained Low Quality Forage on Growth Performance, Blood Metabolites and Nutrient Digestibility of Growing Ram Lamb

Raisin waste (RW) is produced during grapevine processing after harvest for raisin production. The aim of current study was to substitute the barley grain with RW in diet containing cereal straw as the only forage source in growing ram lambs feeding. Ground barley was substituted with RW at the rate of 9and 18% of diet (dry matter (DM) basis) in iso-nitrogesnous and iso-energetic diets. Twelve growing ram lames (first body weight of 26±2 kg) used in 3 × 3 replicated Latin square with three experimental periods. At each period of experiment, 6 pens of lambs (each 2 lambs placed in each pen) were randomly assigned to 3 treatments (2 pens for each treatment). Raisin waste contained (% DM) 78.4 DM, 5.4 ash, 3.7 crude protein (CP), 10.6 ether extract, 18.5 acid detergent fiber (ADF), 1.4 total tannin, 2.2 total phenol and 0.8 non-tannin phenolic. Dietary substitution of ground barley with RW did not influence lamb final body weight (32.9, 32.2 and 32.1 kg respectively for three treatments), average daily gain, feed intake (1060.1, 960.2 and 920.3 g respectively) and apparent total tract nutrient digestibility including DM, organic matter, CP and ADF (P 0.05). Blood glucose, red blood cells and white blood cells count were similar among treatments (P 0.05). Blood urea decreased in lambs fed with diets contained RW (P 0.05). Blood total protein and triglycerides increased mostly at the level of 9% of substitution in lambs (P 0.05) compared with other level of substitution. In conclusion, in diets contained cereal straw as the only forage source, up to 18% of ground barley could be replaced by RW without detrimental effects on growth performance, nutrient digestibility and blood measures in growing ram lambs.