Browsing by Subject "Beef"
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Item Dietary influence on lipid composition and oxidation of fresh and processed meat products(2013-12) Compart, Kaitlyn MargaretTwo experiments were conducted to evaluate the effects of diet on fresh and processed meat quality in beef. In experiment 1, steers and heifers (n = 48) were assigned randomly to one of four treatment groups and fed individually. Treatments were as follows: steam-flaked corn diet with no modified distillers grains with solubles (MDGS) or glycerin (CON); CON with 35% MDGS (MDGS); CON with 10% glycerin (GLY); and CON with 35% MDGS and 10% glycerin (MDGS/GLY). When cattle reached a mean weight of 590 kg, they were humanely harvested at a commercial abattoir. Strip loins and shoulder clods were removed from the right side of each carcass. Treatment had no effect any specific fatty acid (P > 0.05), vacuum purge loss (P = 0.75), cooking loss (P = 0.40), Warner-Bratzler shear force values (P = 0.94), strip steak L*, a*, or b* values (P > 0.05) or ground beef L*, a*, or b* values (P > 0.05). CON and MDGS had higher values for consumer overall liking and texture liking of strip steaks (P < 0.05). Treatment did not affect flavor liking (P < 0.05). In experiment 2, shoulder clods and inside rounds from 24 forage-finished steers were ground in groups, divided into five 35 kg batches, and assigned randomly to one of five antioxidant treatments: control (CON); ground wild rice (WR); rosemary extract (ROSE); cherry seed powder (CHERRY); rosemary and pomegranate extract blend (X). Each antioxidant was added at 1% and mixed into a batch for 1 minute. Batches were formed into patties and objective and subject color scores, sensory evaluation, and TBARS were measured. L* and b* did not differ between treatment (P = 0.49 and 0.66, respectively), however inclusion of CHERRY did increase a* values (P = 0.01). Texture liking was decreased with X compared to the WR and CHERRY (P = 0.006. Toughness was decreased with WR (P = 0.03) as compared to X and juiciness increased with the addition of CHERRY (P = 0.003). Overall liking, flavor liking, and off flavor were unaffected by treatment (P = 0.09, 0.07, and 0.06, respectively). TBARS values were lower with the addition of ROSE, CHERRY, and X on d0 than CON (P = 0.0005). WR was also lower on d7 than CON (P <0.0001).Item Effect of cereal grains on the formation of heterocyclic aromatic amines in fried beef patties(2012-08) Kyllo, Rachel RenaeThe effect of incorporating flours representing different anatomical parts of the grain of corn, wild rice, and oat as well as corn bran extract into beef patties on the formation of heterocyclic aromatic amines (HAAs) during grilling was investigated. Beef burgers containing 5 or 10% dry cereal solids or cereal extract adsorbed to a cellulose carrier were grilled for 7 minutes per side on an electric grill. The HAA content of the cooked material was assessed using an optimized solid-phase extraction method, reversed-phase HPLC separation, and UV and fluorescence detection. 9H-Pyrido[3,4-b]indole (norharman), 1-methyl-9H-pyrido[3,4-b]indole (harman), 9H-pyrido[2,3-b]indol-2-amine (A-alpha-C), 1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridin-2-amine (PhIP), and 3,8-dimethyl-3H-imidazo[4,5-f]quinoxalin-2-amine (MeIQx) were detected in all burgers. Norharman and harman formation were significantly increased in fried beef patties grilled with wild rice hulls, wild rice flour, and oat hulls. Other treatments also tended to increase beta-carboline (harman and norharman) and PhIP levels relative to plain beef patties. Due to the analytical set-up it was not possible to obtain a full set of reliable data about the effect of cereal materials on the formation of MeIQx, but some materials may be able to reduce the formation of this HAA. It is concluded that the addition of whole cereal materials in beef patties is not an effective way to reduce the formation of beta-carbolines and PhIP during grilling. Definite conclusions about the effect of cereal materials on the formation of MeIQx and structurally related HAAs cannot be drawn from this study.Item Effect of manipulation of growth and fermentation patterns on nutrient availability and performance of feedlot cattle(2019-08) Larson, HaleyAlteration of ruminal environment by nutritional strategy presents opportunities for manipulating beef cattle growth. Changing fermentation patterns by altering feed type can impact both the composition and rate of gain in beef cattle. Three experiments were conducted to examine the effect of manipulation of growth and fermentation patterns on nutrient availability and performance of feedlot cattle. Experiment 1 studied the impact of ruminal environment on the passage of omega-3 fatty acids through the rumen of grass-fed verses grain-fed cattle. Omasal samples were collected from steers fed either fresh green chop, a high grain diet supplemented with flaxseed oil, or a high grain diet supplemented with corn oil. Regardless of diet, fatty acids with the greatest number of unsaturated bonds found in the highest abundance were transformed preferentially. Despite no differences (P = 0.88) in omega-3 transformation across treatments, grain-fed cattle with a flaxseed oil supplement demonstrated the greatest (P < 0.01) g of omega-3 fatty acid flow escaping biohydrogenation due to an increase in intake of dietary omega-3 fatty acids. Experiment 2 evaluated how utilization of bio-fuel coproducts impacts rumen environment and fatty acid profile at end point of fermentation. Omasal samples were collected from steers fed a steam flaked corn (SFC) basal diet with a portion of corn replaced by distillers grains (DGS) (40%), crude glycerin (GLY) (10%) or both. Total unsaturated fatty acids concentration in digesta were not different (P = 0.43) for the main effect of GLY, which indicates GLY is an effective alternative to corn when provided at the dietary concentrations evaluated in this study. The decrease (P < 0.01) in unsaturated fatty acids in digesta for main effect of DGS may be beneficial for shelf life stability of meat. Experiment 3 used a meta-analysis approach to examine how nutritional strategy and performance during a post-weaning growing phase can be used to predict finishing performance and carcass characteristics. When examining feedlot and carcass performance attributes by growing strategy factors, like ADGgrowing, DOFgrowing, and initial BWfinishing, interacted to create the most optimal compensatory gain response. Optimal combinations of DOFgrowing and initial BWgrowing differed between performance characteristics (Table 4.6) but as an average across dressing percent, LMA, Final BWfinishing, and HCW it was identified that maximized performance occurred when cattle began the growing phase around 240 kg.Item Effects of feeding cattle calcium hydroxide treated corn stover during backgrounding on carcass characteristics and beef quality(2016-07) Fehrman, ChristinaSixty-seven purebred Angus steers (initial mean BW 197 kg.) were used to evaluate the effects of calcium hydroxide treated corn stover in backgrounding diets and a common finishing phase. Steers were randomly assigned to 1 of 4 dietary treatments: untreated corn stover (CON), corn stover treated with 50% DM water (H2O); 50% DM, water and calcium hydroxide treated corn stover (Ca(OH)2); grazing on a turnip cover crop (CC) for 29 days before adapted to ad libitum alfalfa haylage diet fed in feed bunks for remaining 20 d of backgrounding. Steers were fed individually using a Calan system for 49 days. All diets were formulated on a dry matter (DM) basis to contain 30% corn stover, 15% alfalfa haylage, 25% dried distillers grains with solubles, 25% dry rolled corn, and 5% supplement containing monensin. Upon completion of dietary treatments, steers were fed a common feedlot diet for 240 days. Steers were then harvested at a commercial abattoir, and carcass characteristics were recorded 48 hours postmortem. Strip loins and shoulder clods (IMPS #180 and #114) from the right side of the carcass were collected. All primals were transported to the University of Minnesota Meat Laboratory for further evaluation. Strip loins were fabricated into 2.54 cm steaks at 96 hours postmortem. Strip loin steaks were used to evaluate vacuum purge, cook loss, and Warner-Bratzler shear force (WBSF), color scores, as well as consumer acceptability. Shoulder clods were processed to ground beef for evaluation of subjective and objective color scores as well as Thiobarbituric Acid Reactive Substances (TBARS). Portions of ground beef were then processed into bologna to be evaluated for objective and subjective color as well as consumer acceptability. Dietary treatment had no effect on carcass characteristics including hot carcass weight (HCW) (P = 0.694), ribeye area (REA) (P = 0.259), 12th rib backfat (P = 0.780), marbling score (P = 0.845), USDA Yield Grade (P = 0.890), and USDA Quality Grade (P = 0.877). Although purge loss (P = 0.884) and cook loss (P = 0.149) were not affected by treatment, WBSF values were lower for CC than CON (1.6 v 2.23kg respectively; P = 0.001). Lean color scores for fresh steaks were affected by dietary treatment (P = .004). On day 5, CC (5.34) was less bright cherry red than CON (5.66; P = .017) and H2O (5.76; P = .001). On day 7, CC (4.92) was less bright cherry red than CON (5.22; P = .032) and H2O (5.29; P = .007). Overall desirability scores for fresh steaks differed (P = .011) among dietary treatments with H2O being more desirable than CC on day 5 (5.35 v 4.93; P = .023) and Ca(OH)2 was more desirable than CC on day 6 (5.36 v 4.98; P = .047). Discoloration scores for fresh steaks varied among treatments (P = .003). On day 5, CC (10.02) was more discolored than H2O (10.30; P = .019) and Ca(OH)2 (10.32; P = .016). On day 6, steaks from CC were more discolored than H2O steaks (9.27 v 9.57; P = .013). Day 7 fresh steak discoloration scores shows that CC (9.13) was more discolored than CON (9.42; P = .027), H2O (9.5; P = .003), and Ca(OH)2 (9.42; P = .024). Yellowness (b*) color values for ground beef varied among treatments (P = .025). Ground beef lean color as assed by a trained panel was affected by dietary treatment (P < .001). On day 0, H2O (6.77) was less bright cherry red than CON (7.06; P = .022) and Ca(OH)2 (7.13 P = .006). On day 1, CON (6.91) was more bright cherry red than H2O (6.51; P = .012) and CC (6.52; P = .017). On day 2, CON (6.12) was more bright cherry red than H2O (5.7; P = .006) and CC (5.7; P = .007). On day 3, CON (5.32) was brighter than CC (4.72; P < .001) and Ca(OH)2 (4.98; P = .029), and H2O was brighter than CC (5.1 v 4.72; P = .005). On day 4, CC (3.47) was less bright red than H2O (3.90; P < .001) and CON (3.84; P = .006). Desirability scores were affected by dietary treatment (P < .001). On Day 0, H2O (7.16) ground beef samples were less desirable than CON (7.39; P = .032) and Ca(OH)2 (7.44; P = .016). On day 1, CON (7.21 was more desirable than H2O (6.74; P = .005) and CC (6.77; P = .009). On day 2, CON (6.32) was more desirable than H2O (5.80; P < .001) and CC (5.68; P < .001), and CC was less desirable than Ca(OH)2 (5.68 v 6.04; P = .031). On day 3, CON (5.36) was more desirable than H2O (4.93; P = .004), CC (4.54; P < .001) and Ca(OH)2 (4.71; P < .001); H2O was more desirable than CC (4.93 vs 4.54; P = .006). On day 4, CC (3.00) was less desirable than CON (3.46; P = .001) and H2O (3.44; P = .016). On day 5, Ca(OH)2 (2.14) was less desirable than CON (2.44; P = .039) and H2O (2.43; P = .016). Discoloration scores for ground beef was affected by dietary treatment (P < .001). On day 2, H2O was more discolored than Ca(OH)2 (8.55 v 9.29; P = .039). On day 3, CON (8.83) was less discolored than H2O (8.09; P = .028), CC (7.39; P < .001) and Ca(OH)2 (7.59; P < .001); H2O was less discolored than CC (8.09 v 7.39; P = .028). On day 4, H2O was less discolored than CC (6.3 v 5.68; P = .034). In regards to steak sensory, no differences were found in flavor liking (P = 0.102), juiciness (P = 0.375), or off-flavor (P = 0.313). Differences were found in overall liking (P = 0.008) with CC being more liked than CON (P = 0.013) and Ca(OH)2 (P = 0.019). Texture liking was affected by dietary treatment (P < 0.001), with CC higher than CON (P < 0.001), H2O (P = 0.021), and Ca(OH)2 (P < 0.001). Toughness scores were also affected by dietary treatment (P < 0.001) with CC having the lowest values compared to CON (P < 0.001), H2O (P = 0.015), and Ca(OH)2 (P < 0.001). For bologna sensory, no differences among dietary treatments were found for overall liking (P = 0.610), flavor liking (P = 0.707), texture liking (P = 0.828), juiciness (P = 0.371), and off-flavor (P = 0.716). A difference in toughness was found (P = 0.011) with H2O being more tough than Ca(OH)2 (P = 0.008). It was concluded that the use of calcium hydroxide treatment of corn stover in backgrounding diets of beef calves does not affect carcass characteristics or moisture loss, but does affect fresh and further processed beef characteristics. Although there were differences found among dietary treatments for meat characteristics, these differences do not appear to be large enough from a practical stand point to make a recommendation against the feeding of alkali-treated corn stover during calf backgrounding.Item Effects of human actions on four ecological systems, with a focus on trophic relationships(2013-12) Kosmala, Margaret CandaceThere are, perhaps, no parts of earth remaining that haven't been impacted by human actions, either purposefully or unintentionally. Agriculture and livestock grazing occupy much of earth's arable land, oceans are overfished, greenhouse gas emissions are changing the climate, and human transportation has facilitated unintentional invasions of organisms. In order to become better stewards of Earth's biota, we must better understand how our actions - both direct and indirect - affect ecosystems and species. I examine four ecological systems and the direct and indirect effects of human change on them, with a focus on trophic (eating) relationships. First, I analyze the environmental impact of beef production, especially in the U.S., which has the most industrialized system in the world. Next, I present the results of an experiment testing the effects of plant diversity on the biological control of an agricultural pest species. An invasive species, the soybean aphid, has become a major pest of soybean in the U.S. in the past fifteen years, and efforts to control the aphid with natural enemies could reduce the need for pesticides. Third, I analyze a twenty-year seed addition experiment to investigate the long-term dynamics of plant communities. The results highlight the importance of dispersal limitation combined with local competition and movement of species over time. Finally, I describe a model that captures the dynamics of an emerging wildlife disease: bovine tuberculosis in lions in Kruger National Park, South Africa. The modeling results reveal the most likely long-term effects of the disease in this lion population and efficacy of intervention approaches.Item Effects of the combination of protein and fiber in whole foods on satiety, blood glucose response and food intake in humans(2014-06) Bonnema, AngelaThe obesity epidemic continues worldwide and is considered a major health concern. A shift back to consumption of whole foods may be an important part of the solution in the current rising obesity trend. Both protein and fiber have satiating properties, but few studies have examined whether their impact on different biological mechanisms work additively to more strongly enhance the overall satiety potential of a meal. In the first study, the objective was to determine the effects of a high protein meal (beef) compared to a moderate protein, high fiber meal (beans) on subjective appetite and energy intake at a subsequent meal. We hypothesized that a moderate protein, high fiber meal containing beans would be as satiating as a high protein meal containing beef. Twenty-eight adults, 14 men and 14 women participated in this randomized, controlled study in which subjects consumed two test lunches including a "meatloaf" made from either beef or beans. The primary outcome was to observe satiety ratings using visual analogue scales to assess hunger, satiety, fullness, and prospective food intake. Secondary outcomes included: food intake at the subsequent meal offered in the form of snacks, gastrointestinal tolerance, and palatability of the meals. No difference between the beef and bean was observed for appetite ratings over 3 hours, food intake at the subsequent meal, or sum of GI score. Gas and bloating were reported more often after the bean meal than the beef meal. The conclusion to this first study was that a beef-based meal with high protein and a bean-based meal with moderate protein and high fiber produced similar satiety, while the bean-based meal resulting in higher, yet moderate, gas and bloating.In the second study, we examined the effect of egg alone and in combination with whole grains compared to a refined ready-to-eat cereal on satiety and food intake in human subjects. We hypothesized that breakfast meals containing eggs, both high protein with white toast and moderate protein with whole grain toast containing fiber, would result in increased satiety ratings compared to an isocaloric standard refined cereal breakfast. Forty-eight adults, 24 men and 24 women, participated in this randomized, cross-over study. We designed whole food diets, controlled for macronutrients. The primary outcome was to observe satiety ratings using visual analogue scales to assess hunger, satiety, fullness, and prospective food intake. Secondary outcomes included: post-prandial blood glucose response, food intake at the subsequent meal offered in the form of an ad libitum pizza lunch, gastrointestinal tolerance, and palatability of the meals. No difference was observed between the cereal and egg + whole grain toast breakfasts for AUC for all satiety ratings however the egg + white bread breakfast was significantly improved for all 4 satiety ratings. Lunch intake was significantly reduced in both egg breakfasts compared to the cereal breakfast. No difference was observed for the sum GI score between the egg + white toast, egg + whole grain toast and cereal breakfasts, however gas and bloating was significantly higher for the egg + white toast breakfast compared to the cereal meal. Food intake at the subsequent meal was reduced for both egg breakfasts compared to the cereal breakfast. The results from these studies support the hypothesis that protein and fiber contained within whole foods results in greater satiety than refined carbohydrate foods. Protein, with and without fiber, produced the greatest satiety outcomes suggesting that the incorporation of high protein foods into the diet, specifically for breakfast, may result in greater feelings of satiety that could lead to decreased food intake and weight loss over time.Item Impact of using reduced-fat distillers grains in beef feedlot diets on carcass and meat quality(2014-11) Johnston, Justin EdwardPurebred Jersey steers (n=12) and Limousin X Jersey Crossbred steers (n=24) were blocked by breed. Nineteen purebred Jersey steers (initial BW 455 ± 49 kg) and 29 Jersey-Limousin crossbred steers were individually fed in Calan gates for 93 d. Four dietary treatments were evaluated in this experiment. A dry rolled corn-based diet served as the control treatment. Distillers grains treatments consisted of feeding reduced-fat distillers dried grains dietary inclusion at 20% with corn oil, to represent full fat distillers grains, reduced-fat distillers dried grains dietary inclusion at 20%, or reduced-fat distillers dried grains dietary inclusion at 47% of dietary DM. This study found the following results, Jersey X Limousin Crossbred steers had greater REA and HCW but no differences in the carcass or meat quality attributes evaluated. Feeding reduced-fat distillers grains in replacement of dry-rolled corn did not substantially affect the carcass or meat quality attributes evaluated.