Effects of replacing barley grain with triticale-based dried distillers’ grains with solubles on nutrient digestibility, lamb growth performance and carcass traits

Abstract

The objective of this research was to determine the effects of increasing proportions of triticale-based dried distillers’ grains with solubles (TDDGS) in the diet on nutrient digestibility, growth and carcass traits of lambs. The control diet contained 72.5% barley grain, 10.0% beet pulp, 9.0% sunflower hulls, 3.0% alfalfa meal and 5.5% mixed supplement, which contained molasses, calcium carbonate, minerals and vitamins. Treatment diets contained TDDGS in place of barley grain at 20, 40 or 60% of diet dry matter (DM). In a growth study, 60 weaned lambs stratified by live weight (26.6 ± 3.6 kg) were fed one of the four diets to slaughter weight. Additionally, a digestibility study using these diets in a replicated 4 × 4 Latin square design was conducted using 12 ram lambs. Increasing dietary allocation of TDDGS in the diet did not affect (P > 0.12) DM intake, average daily gain or feed efficiency (feed:gain). At slaughter, cold carcass weight and grade rule scores responded quadratically (P = 0.04) to increasing TDDGS in the diets. Feeding TDDGS did not affect other carcass traits (P > 0.22). Total saturated fatty acids and monounsaturated fatty acids in subcutaneous fat were unaffected by TDDGS, whereas polyunsaturated fatty acids increased linearly (P = 0.03). Concentration of t10, c12-conjugated linoleic acid (CLA) in carcass fat increased linearly (P = 0.02) with increasing TDDGS, but there was no effect (P ≥ 0.20) on concentrations of c9, t11-CLA or t11-18:1. In the digestibility study, DM intake increased linearly (P < 0.01) with increasing TDDGS in the diet, whereas digestibility of DM, crude protein and fat responded quadratically (P < 0.01). Starch digestibility decreased and ADF digestibility increased linearly (P < 0.01), but there was no treatment effect on NDF digestibility (P > 0.29). Total nitrogen, total phosphorus and soluble phosphorus excretion increased (P < 0.01) with increasing TDDGS. In conclusion, TDDGS can be fed in place of barley grain at levels up to 60% in diets for lambs without adverse affects on growth performance or carcass traits, but this practice will lead to an increase in N and P excretion into the environment.Key words: Lamb, digestibility, triticale distillers grains, performance, carcass characteristics