Replacing cottonseed meal and sorghum grain with corn dried distillers' grains with solubles in lamb feedlot diets: carcass, trained sensory panel, and volatile aroma compounds traits

In a randomized design study, lambs were individually fed with ad libitum access to 70.9% concentrate diets for 56 d in individual pens. The positive control diet (CNTL) contained cottonseed meal (CSM), sorghum grain, and cottonseed hulls, but no dried distillers' grains with solubles (DDGS). Four treatment diets were similar to CNTL but did not contain CSM. Corn DDGS replaced 0% (0DDGS), 33% (33DDGS), 66% (66DDGS), or 100% (100DDGS) of the sorghum grain in the treatment diets. At 48-h postmortem, the longissimus muscle (LM) was removed from the carcass, cut into chops, frozen, thawed, cooked, and evaluated by a trained sensory panel. Lambs fed CNTL were compared with 0DDGS using contrasts and linear and quadratic effects were evaluated among the four DDGS diets. Lambs fed CNTL had greater (P ≤ 0.03) hot carcass weight (HCW) and LM area than lambs fed 0DDGS. As DDGS incrementally replaced sorghum grain, marbling linearly decreased (P = 0.03), LM area tended to linearly increase (P = 0.06), and skeletal maturity tended to linearly decrease (P = 0.06). As DDGS incrementally replaced sorghum grain, flavor attributes quadratically increased to 33DDGS then decreased (brown, roasted, umami; P ≤ 0.03), quadratically decreased to 33DDGS then increased (metallic; P = 0.004), or linearly decreased (lamb flavor identity; P = 0.03). Volatile aroma compounds 2-(hexyloxy)-ethanol decreased and 2,3-octanedione and methyl pyrazine increased quadratically with an increase in DDGS (P < 0.05). Additionally, 2-heptenal, heptanal, and 2-pentyl furan increased linearly, while 2-butanone decreased linearly as DDGS increased in the diet (P < 0.05). Results indicate that carcass and sensory characteristics and volatile aroma compounds are not negatively affected, in fact brown, roasted, and umami flavors are enhanced, when 33% DDGS replaces CSM and sorghum grain in Dorper lamb feedlot diets.

278 Replacing cottonseed meal and sorghum grain with corn dried distillers grains with solubles in lamb feedlot diets: volatile compounds from cooked lamb chops

Dorper ram lambs (n = 46) were fed diets replacing cottonseed meal (CSM) and sorghum grain with dried distillers grains with solubles (DDGS). Lambs were fed with ad libitum access to 70.9% concentrate diets for 61 d in individual pens. The positive control diet (CNTL) contained CSM, sorghum grain, and other concentrates, but no DDGS. The four treatment diets were similar to CNTL, but did not contain CSM. Corn DDGS replaced 0%, 33%, 66% or 100% of the sorghum grain in the treatment diets. Lambs fed CNTL were contrasted to those fed 0% DDGS and linear and quadratic effects were evaluated within the four treatment diets. At 48-h postmortem, the longissimus muscle was removed from the carcass, frozen, thawed, cooked, and volatiles were collected using SPME/GC/MS. One volatile, 3-methyl,1-butanol was greater (P = 0.03) in CNTL, while 0DDGS had effectively no volatile present. For linear effects, 1-heptanol (fruity aroma) and 2-pentyl furan (caramel aroma) tended to increase linearly (P = 0.06 and 0.05, respectively), while 2-butanone tended to decrease linearly (P = 0.06; fruity-green aroma) in chops as DDGS increased in the diet. Additionally, 2-heptanone (P = 0.02; banana aroma) and heptanol (P = 0.03; woody aroma) both increased linearly in chops as DDGS increased in the diet. In the quadratic effects, decanoic acid (ethyl ester; grape aroma) tended to decrease quadratically (P = 0.07), while 2-butanone, methyl pyrazine (meaty, roasted aroma), and 2-ethyl-5-methyl pyrazine (coffee, nutty aroma) tended to increase quadratically (P = 0.05, 0.09, and 0.08, respectively) in chops with an increase in DDGS. The volatiles 2,5-dimethyl pyrazine (musty, cocoa aroma) and 2,3-octanedione (warmed-over aroma) both increased quadratically (P &lt; 0.05) in chops as DDGS increased in the diet. Except for 2,3-octanedione, volatile aroma compounds were enhanced when DDGS replaced CSM and sorghum grain in lamb feedlot diets.

275 Replacing cottonseed meal and sorghum grain with corn dried distillers grains with solubles in lamb feedlot diets: carcass characteristics and sensory panel traits

Carcass and sensory panel traits were evaluated in Dorper ram lambs (n = 46) fed feedlot diets where cottonseed meal (CSM) and sorghum grain were replaced with dried distillers grains with solubles (DDGS). In a randomized design study, lambs were individually fed ad libitum 70.9% concentrate diets for 61 d in individual pens. The positive control diet (CNTL) contained CSM, sorghum grain, and other concentrates, but no DDGS. Four treatment diets were similar to CNTL, but did not contain CSM. Corn DDGS replaced 0% (0DDGS), 33% (33DDGS), 66% (66DDGS) or 100% (100DDGS) of the sorghum grain in the treatment diets. Lambs fed CNTL were contrasted to those fed 0DDGS and linear and quadratic effects were evaluated within the four treatment diets. At 48-h postmortem, the longissimus thoracis was removed from the carcass, frozen, thawed, cooked, and evaluated by a trained sensory panel. Lambs fed CNTL had greater (P ≤ 0.03) hot carcass weight (HCW) and ribeye area (REA) than lambs fed 0DDGS. As DDGS incrementally replaced sorghum grain, HCW and flank fat quadratically increased (P ≤ .05), marbling linearly decreased (P = 0.03), ribeye area tended to linearly increase (P = 0.06), and skeletal maturity tended to linearly decrease (P = 0.06). No differences in sensory characteristics were observed (P ≥ 0.06) between lambs fed CNTL or 0DDGS. As DDGS incrementally replaced sorghum grain, juiciness linearly increased (P = 0.03), cook loss quadratically increased (P = 0.05), lamb flavor identity tended to quadratically increase (P = 0.09) and certain flavor attributes quadratically increased (brown, roasted, umami; P ≤ 0.03), quadratically decreased (metallic; P = 0.004), or linearly increased (bloody; P = 0.003). Results indicated that carcass and sensory characteristics are not negatively affected (some are enhanced) when DDGS replaces CSM and sorghum grain in Dorper lamb feedlot diets.