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Browsing by Author "Engle, Terry E., advisor"

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    ItemOpen Access
    Can DNA marker technology improve feedlot growth promotion management decisions to ultimately improve the consumer's beef eating experience?
    (Colorado State University. Libraries, 2011) Thompson, Katelyn M., author; Wagner, John J., advisor; Engle, Terry E., advisor; Pritchett, James, committee member
    Three hundred and sixty crossbred yearling steers that were sorted from an initial group of 1,100 steers were used to evaluate the effectiveness of sorting feedlot cattle into tenderness and marbling outcome groups based on DNA marker technology and to determine if interactions related to end-product quality and palatability existed between predicted outcome group and growth promotion management strategy. Treatment factors included in the study were tenderness genotype (low versus high), marbling genotype (low versus high), and growth promotion strategy {moderate (Revalor-IS d 1 and d 70) versus aggressive (Revalor-XS d 1 and Zilpaterol supplementation)}. Interactions between tenderness and marbling genotypes and between tenderness genotype and growth promotion treatment were not significant (P > 0.10) for all feedlot performance variables. Steers sorted into the high tenderness (HT) genotype were 5.9 kg heavier at the start of the study (P < 0.05), 11.8 kg heavier at harvest (P < 0.01), and achieved greater DMI (P < 0.05) from d 1 - harvest (9.80 versus 9.38 kg•hd-1•d-1) as compared with the low tenderness (LT) steers. Warner-Bratzler shear force (WBSF) was 0.33 kg lower (more tender) for the HT longissimus steaks as compared with the LT steaks. Steers sorted into the high marbling (HM) genotype were 9.1 kg heavier at the start of the study (P < 0.001), 20.9 kg heavier at harvest (P < 0.0001), and ADG (P < 0.01, 1.56 versus 1.47 kg•hd-1•d-1) and DMI were greater (P < 0.05, 9.80 versus 9.39 kg•hd-1•d-1) as compared with the low marbling (LM) genotype from d 1 - harvest. High marbling genotype carcasses were 12.7 lb heavier (P < 0.05); had greater fat depth (P < 0.06); adjusted fat depth (P < 0.08); higher measured (P < 0.06), adjusted (P < 0.08), and camera adjusted (P < 0.10) PYG; and greater average yield grade (P < 0.09), marbling score (P < 0.05), and camera marbling score (P < 0.05) as compared with the LM genotype. There were no differences (P > 0.60) in WBSF associated with predicted marbling genotype. From d 107 - harvest, steers subjected to the aggressive growth promotion program (AGP) had greater ADG (P < 0.01) and superior (P < 0.001) FG, GF, and NE recovery as compared with steers subjected to the moderate program (MGP). Steers subjected to AGP were 8.2 kg heavier (P < 0.06) at harvest and had 12.2 kg heavier (P < 0.05) HCW and greater (P < 0.01) dressing percentages than steers subjected to MGP. From d 1 - harvest, ADG (P < 0.05), FG (P < 0.01), GF (P < 0.01, and recovered NEm and NEg (P < 0.05) were improved for AGP as compared with MGP steers. Camera adjusted PYG (P < 0.07), calculated yield grade (P < 0.05), and camera yield grade (P < 0.05) were lower and grader LM area (P < 0.01) and camera LM area (P < 01) were greater for AGP as compared with MGP carcasses. Marbling score and the distribution of USDA quality grades were not affected by growth promotion strategy. Aggressive strategy steaks had increased (P < 0.01) WBSF as compared with MGP steaks. Interactions between marbling genotype and growth promotion strategy suggest that steers categorized as HM genotypes did not respond to Zilpaterol to the same degree as LM genotypes. Three-way interactions for USDA yield grade distribution indicated that for HT - LM and the LT - HM steers, AGP had limited impact on the percentage USDA yield grade 3 carcasses but reduced the percentage USDA yield grade 4 carcasses as compared with MGP. Yearling steers can successfully be sorted into marbling or tenderness outcome groups based on DNA marker technology. Tenderness can be improved by using MGP as compared with AGP; however, growth promotion strategy did not impact marbling or USDA quality grade distribution and few interactions related to end-product quality and no interactions for WBSF existed between predicted outcome group and growth promotion management strategy indicating that the degree that end product quality is impacted by growth promotion strategy is largely independent of marbling and tenderness genotype.
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    ItemOpen Access
    Copper, zinc, and manganese in beef cattle production: effects of supplementation and source on reproduction, mineral status, feedlot performance, immunity, and carcass characteristics
    (Colorado State University. Libraries, 2004) Ahola, Jason K., author; Engle, Terry E., advisor; Burns, Patrick D., advisor; Seidel, George E., committee member; Whittier, Jack C., committee member; Field, Thomas G., committee member
    Over a two-year period, crossbred mature beef cows ( n = 178, Year 1; n = 148, Year 2) and young females (n = 43 nulliparous heifers, Year 1; n = 37 primiparous cows, Year 2) grazing in eastern Colorado were used to evaluate the effects of Cu, Zn, and Mn supplementation and source on reproduction, mineral status, immunity, and cow and calf performance. Cow treatments included: 1) control (no supplemental Cu, Zn, or Mn); 2) organic (50% organic and 50% inorganic Cu, Zn, and Mn); and 3) inorganic (100% inorganic CuSO4, ZnSO4, and MnSO4) trace minerals. Heifer treatments included: 1) organic, or 2) inorganic trace minerals. Free-choice mineral feeders were used to provide current NRC-recommended concentrations of Cu, Zn, and Mn from 54 and 82 d (Year 1, heifers and cows, respectively) and 81 d (Year 2) prior to the average calving date of the herd through 110 and 119 d (Year 1, cows and heifers, respectively) and 135 d (Year 2) post-calving. Terminal steer and heifer calves from each year's calf crop were maintained on their appropriate pasture trace mineral treatments and had exclusive access to mineral treatments via creep feeders from approximately 95 d of age until weaning. After weaning, calves were grown and finished in a feedlot on the same pre-weaning trace mineral treatments. Performance, immune response, mortality, morbidity, mineral status, carcass traits, and longissimus dorsi fatty acid profiles were evaluated. In the grazing portion of the experiment, results indicate that trace mineral supplementation in cows and source in cows and heifers affected trace mineral status. Reproductive results were variable in heifers; however, in cows trace mineral supplementation improved pregnancy rate to AI compared to cows not supplemented with Cu, Zn, or Mn for more than 1 yr. Calf performance was greater in non-supplemented control calves vs. supplemented calves in both years, while source also affected calf performance but not consistently in both years. Trace mineral source did not affect calf performance in young grazing females. During the feedlot phase in Year 1, gain to feed ratio was greater in Inorganic vs. Organic calves in both the growing and finishing phases and greater in non-supplemented control calves vs. supplemented calves only during the finishing phase; however, gain to feed ratios were not affected by either supplementation or source in Year 2. Liver Cu and Mn concentrations were affected by supplementation, however immune response, morbidity, carcass traits, and longissimus dorsi fatty acid profiles were not different across treatments. Based on the reduced reproductive performance in non-supplemented cows, as well as literature indicating that Cu affects luteinizing hormone (LH) release, the effect of Cu status, supplementation and source on pituitary responsiveness to gonadotropin releasing hormone (GnRH) were evaluated using 12 multiparous, non-pregnant, non-suckling, ovariectomized Angus cows. After receiving 5 mg Mo/kg diet and 0.3% S during a 216-d Cu depletion phase, nine cows were considered Cu deficient (liver Cu concentrations < 30 mg Cu/kg) and were stratified based on age, BW, BCS, and liver Cu concentration and randomly assigned to treatments. Treatments included: 1) control (deficient Cu status; no supplemental Cu), 2) organic (adequate Cu status; 100% organic Cu, 10 mg Cu/kg diet), and 3) inorganic (adequate Cu status; 100% inorganic CuSO4 , 10 mg Cu/kg diet). By d 77 of the 159-d repletion phase all supplemented cows had adequate liver Cu, and liver Cu concentrations were greater in supplemented cows vs. non-supplemented controls, and this was maintained throughout the repletion phase. Beginning on d 99, cows were catheterized every fifth day and blood samples were collected at 15 min. intervals for 1 h prior to, and 4 h after, GnRH administration at low (0, 3, and 9 ug; experiment one) and high doses (0, 27, and 81 ug; experiment two) and analyzed for LH concentration. Copper status, supplementation, and source had no effect on pituitary sensitivity to GnRH (based on basal, peak, and total LH released at varying GnRH doses) or pituitary stores of LH.
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    ItemOpen Access
    Effect of zinc source and dose and chromium supplementation on performance and carcass characteristics of feedlot cattle
    (Colorado State University. Libraries, 2018) Budde, Ashley Marie, author; Engle, Terry E., advisor; Wagner, John J., advisor; Myrick, Christopher A., committee member
    Four-hundred cross-bred steers were utilized in a randomized complete block design to investigate the effect of supplemental Zn source and concentration and Cr supplementation on performance and carcass characteristics of feedlot steers fed a steam-flaked corn-based finishing diet. Steers were blocked by initial BW with in cattle source and randomly assigned within block to 1 of 5 treatments (10 steers/pen; n = 8 pens per treatment). Prior to the initiation of the experiment, trace mineral supplement sources were analyzed for Zn and Cr. Zinc and Cr concentrations of the Zn sources were used to balance all dietary treatments to obtain correct Zn and Cr experimental doses. Treatments consisted of: 1) 90 mg Zn/kg DM from ZnSO4 and 0.25 mg Cr/kg DM from Cr propionate (90ZS+Cr); 2) 30 mg Zn/kg DM from Zn hydroxychloride and 0.25 mg Cr/kg DM from Cr propionate (30ZH+Cr); 3) 90 mg Zn/kg DM from Zn hydroxychloride and 0.25 mg Cr/kg DM from Cr propionate (90ZH+Cr); 4) 60 mg Zn/kg DM from ZnSO4 and 30 mg Zn/kg DM from Zn methionine (90ZSM); and 5) 90 mg Zn/kg DM from Zn hydroxychloride (90ZH). Steers were individually weighed on d-2 and on two consecutive days at the end of the experiment. Initial liver biopsies were obtained from all steers during processing. Equal numbers of pen replicates per treatment were transported to a commercial abattoir on d 162, 176, and 211 and slaughtered; individual carcass data and final liver samples were collected. Total finishing dietary Zn and Cr concentrations were 118.4, 58.2, 114.2, 123.0, and 108.2 mg Zn/kg DM and 0.711,0. 647, 0.731, 0.767 and 0.521 mg Cr/kg DM, for treatments 1 to 5, respectively. There were no treatment main effects for any response variables measured. However, treatment was a significant source of variation for certain response variables when single degree of contrasts (unprotected F-test) were performed. Steers receiving 90ZH+Cr had greater final BW (P ≤ 0.04) and ADG (P ≤ 0.03) when compared to steers receiving 90ZH. Additionally, hot carcass weight was 8.5 kg greater (P ≤ 0.03) for 90ZH+Cr compared to 90ZH supplemented steers. Steers receiving 90ZH+Cr had greater longissimus muscle area when compared to steers receiving 90ZSM. Dry matter intake, G:F, final liver Zn concentrations, and all other carcass parameters (dressing percentage, marbling score, yield grade, subcutaneous adipose tissue depth, and KPH) were similar across treatments. These data indicate, that under the conditions of this experiment, Zn source and concentration had no impact on live performance, liver mineral Zn concentrations, and carcass characteristics. Supplemental Cr in diets containing 90 mg of supplemental Zn/kg DM may improve final BW, ADG, and hot carcass weights.
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    ItemOpen Access
    Effects of Aspergillus oryzae α-amylase supplementation on rumen volatile fatty acid profile and relative abundance of mRNA associated with nutrient transporters in ruminal and duodenal tissue on beef steers
    (Colorado State University. Libraries, 2014) Gordon, Britney N., author; Engle, Terry E., advisor; Wagner, John J., advisor; Pritchett, James G., committee member
    The objective of this study was to investigate the impact of Aspergillus oryzae α-amylase (AAM) supplementation on rumen volatile fatty acid (VFA) profile and relative abundance of mRNA associated with nutrient absorption in ruminal and duodenal tissue from beef steers. Nine crossbred beef steers (BW 622 ± 50 kg), fitted with rumen and duodenal fistulas were used in this experiment. Steers were housed in individual stations and fed a high concentrate finishing diet (74.6% corn on a DM basis) twice daily for 8 d. Treatments included 1) CON (5 g corn meal; n=5) and 2) AAM (5g 750 fungal α-amylase units/g; n=4). Dietary treatment supplements were manufactured prior to each feeding by mixing 3 g of α-amylase or corn meal into 150 g of dried distiller's grains (DDG) for the AM feeding and 2 grams of α-amylase or corn meal into 100 g of DDG for the PM feeding. Supplements were applied as a top dress for every feeding and thoroughly mixed by hand. On d 5, rumen fluid samples were obtained every 4 h for 24 h and analyzed for VFA. On d 9, rumen papillae and duodenal mucosal tissue samples were collected. Total tissue RNA was extracted for real-time PCR analysis. Sodium/potassium ATPase pump α1, glucose transporter 2 and 5, putative anion transporter, isoform1, sodium/hydrogen antiporter isoforms1, 2 and 3, 3-hydroxy 3-methylglutaryl coenzyme A synthase isoform2, down regulated in adenoma, monocarboxylate co-transporter isoform1, and glyceraldehyde-3-phosphate dehydrogenase mRNA were tested. Relative expression (fold change) of mRNA in ruminal and duodenal tissues were analyzed using PROC GLM and VFA distribution was analyzed using PROC MIXED as a randomized block design with repeated measures. No treatment differences were detected for any of the genes analyzed in ruminal or duodenal tissue. Concentrations of VFA and the acetate to propionate ratio were similar across treatments. However, the acetate:propionate ratio and molar percentages of butyrate were numerically greater in AAM steers compared to controls. Under the conditions of this experiment, AAM supplementation had no impact on relative expression (fold change) of mRNA associated with nutrient absorption and minimal impacts on molar proportions of VFA.
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    Effects of copper source and concentration on copper status and immune function in growing and finishing steers
    (Colorado State University. Libraries, 2002) Dorton, Kristy L., author; Engle, Terry E., advisor; Hamar, Dwayne W., committee member; Siciliano, Paul D., committee member
    Forty-eight, individually fed, purebred Angus steers (approximately 7 months of age, 218 + 9.1 kg) were used to determine the effects of copper (Cu) source and concentration on performance, Cu status, and immune function. Steers were stratified by weight and initial liver Cu concentration and randomly assigned to one of five treatments. Treatments consisted of: 1) control (no supplemental Cu), 2) 10 mg Cu/kg DM from Cu sulfate (CuS04), 3) 10 mg Cu/kg DM from a Cu-amino acid complex (Availa Cu), 4) 20 mg Cu/kg DM from CuS04, and 5) 20 mg Cu/kg DM from Availa Cu. Steers were housed in individual pens and fed an alfalfa-com based growing diet for 56 d then were fed a high concentrate diet for 144 d. On d 56 of the growing phase and d 112 of the finishing phase, liver Cu concentrations were higher (P < 0.01) in Cu supplemented steers. Steers receiving 20 mg Cu/kg DM had higher (P < 0.01) liver Cu concentrations than steers receiving 10 mg Cu/kg DM. On d 112 of the finishing phase, steers receiving 20 mg Cu/kg DM from Availa Cu had higher (P < 0.01) liver copper concentrations than steers supplemented 20 mg Cu/kg DM from CuS04. In the growing phase, steers supplemented with 20 mg Cu/kg DM had greater (P < 0.04) plasma Cu concentrations than steers supplemented with 10 mg Cu/kg DM. In the growing and finishing phases, plasma Cu concentrations were higher (P < 0.03) in steers supplemented with 20 mg Cu/kg DM from Availa Cu than steers receiving 20 mg Cu/kg DM from CuS04. Cell mediated immune response to phytohemagglutinin was higher (P < 0.01) in steers supplemented with 20 mg Cu/kg DM than 10 mg Cu/kg DM treatments. Total immunoglobulin (lg) and immunoglobulin G (IgG) concentrations specific to pig red blood cells (PRBC) were greater (P < 0.01) in steers supplemented with 10 mg Cu/kg DM from CuS04 than 10 mg Cu/kg DM from Availa Cu. During the finishing phase, IgG concentrations specific to PRBC were higher (P < 0.03) and antibody titers specific to ovalbumin (OVA) were lower (P < 0.05) in control steers relative to Cu supplemented steers. Steers receiving 20 mg Cu/kg DM had higher antibody titers specific to OVA (P < 0.02) than 10 mg Cu/kg DM steers. Steers receiving 20 mg Cu/kg DM from Availa Cu had higher (P < 0.01) antibody titers specific to OVA than steers supplemented with 20 mg Cu/kg DM from CuS04 . These results indicate that Cu source and concentration may have an effect on the immune system. Furthermore, it appears that the immune response to an antigen varies depending on the type of antigen administered as well as the concentration and source of Cu supplemented.
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    Effects of endocrine modifiers on growth, carcass characteristics, and blood and tissue metabolites of finishing beef cattle
    (Colorado State University. Libraries, 2008) Bryant, Anthony C., author; Engle, Terry E., advisor
    The effects of vitamin A and the interaction of steroids and beta-adrenergic agonists on growth and carcass performance, tissue metabolite profiles, and lipogenic enzyme activity were evaluated in beef cattle. In 1 experiment steers were fed 1 of 5 supplemental levels of vitamin A (0, 1,103, 2,205, 4,410, or 8,820 IU/kg DM). Final BW, G:F, ADG, HCW, LM area, marbling, and quality grade distribution did not differ among treatments. Except for d 56, no correlations between marbling score and tissue retinol concentrations or vitamin A intake were found. A negative correlation between liver retinol and α-tocopherol was observed, which may have potential health implications. Results suggest that vitamin A supplementation up to twice the NRC-suggested concentration has little effect on performance, marbling, or lipogenic enzyme activity in yearling steers and further suggest that 2,205 IU supplemental vitamin A/kg of DM is adequate for growing/finishing beef steers.
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    Effects of trace mineral supplementation, trace mineral source, growth implants, and induced morbidity on performance, trace mineral status, immune function, carcass characteristics, and lipid metabolism in steers
    (Colorado State University. Libraries, 2005) Dorton, Kristy L., author; Engle, Terry E., advisor; Johnson, Celina R., committee member; Hamar, Dwayne W., committee member; Siciliano, Paul, committee member
    Steers were utilized to determine the effects of trace mineral (TM) supplementation and source, growth implants, and morbidity on performance, TM status, immune function, carcass characteristics, and lipid metabolism. In experiment 1, steers were backgrounded at their respective ranches for 30 d post weaning on one of the following treatments: 1) control (no supplemental TM), 2) inorganic TM, and 3) iso-amounts of organic TM. After the 30 d backgrounding period, steers were transported to the feedlot where half of the steers per treatment were implanted and the remaining half were not implanted. In experiment 2, the first group of steers was inoculated intranasally with IBRV four months prior to weaning. The second group was inoculated with IBRV on arrival to the feedlot and the third group was not inoculated with IBRV. Once at the feedlot, calves were sorted to treatments, which consisted of 1) organic TM and 2) iso-amounts of inorganic TM. During the backgrounding phase of experiment 1, calves supplemented with organic TM had a greater ADG and a lower incidence of morbidity than calves supplemented with inorganic TM. Steers supplemented with organic TM had greater concentration of total IgM during the growing phase and greater concentrations of antibody titer specific to ovalbumin than steers supplemented with inorganic TM. Steers that were implanted had a greater ADFI, REA, HCW, dressing percentage, and acetyl CoA carboxylase activity, and a lower KPH than non-implanted steers. In experiment 2, liver Mn and Zn concentrations were decreased in IBRV steers, whereas, Cu concentrations were unaffected. Inoculated steers had lower oleic acid (18:1 n-9) and monounsaturated fatty acids. Steers that were inoculated with IBRV prior to arrival at the feedlot had lower concentrations of myristic acid (14:0) and linoleic acid (18:2 n-6). Key Words: Steers, trace minerals, growth implants, induced morbidity, performance, immunity, carcass characteristics, lipid metabolism.
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    Examining in vitro and in vivo characteristics of Intellibond and sulfate forms of copper, zinc, and manganese
    (Colorado State University. Libraries, 2015) Caldera, Emmanuel, author; Engle, Terry E., advisor; Wagner, John J., committee member; Archibeque, Shawn L., committee member; Rollin, Bernard, committee member
    Trace minerals have long been identified as essential components in the diets of domestic livestock species. The mechanisms underlying Cu, Zn, and Mn absorption are complex, but research has demonstrated interesting opportunities to optimize the involvement of trace minerals in ruminant nutrition. To further our understanding of absorption and retention of modern forms of trace minerals 4 experiments were conducted to examine in vitro and in vivo characteristics of Intellibond (IB) and sulfate forms of copper (Cu), zinc (Zn), and manganese (Mn). In experiment 1, in vitro incubations were used to examine the effects of pH and mineral concentration and source (IB vs sulfate) on Cu, Zn, and Mn solubility. Solubility was measured at elemental concentrations ranging from 0.1 to 10.0 mg of product/ml (0.1, 1.0, and 10.0 mg/ml) at: 1) pH 5.5 (in McDougal's artificial saliva mixture 0.1 M NaHCO3-Na2HPO4KCl- MgSO4*7H2O-urea buffer) and 2) pH 2.0 (in McDougal's artificial saliva mixture 0.1 M NaHCO3-Na2HPO4KCl- MgSO4*7H2O-urea buffer). On average, the overall solubility of Cu, Zn, and Mn, from both trace mineral sources were similar at a pH 5.0 and 2.0. In Experiment 2 eight cross-bred steers were utilized to estimate the duodenal appearance of Cu, Zn, and Mn in steers post ruminal administration of IB and sulfate forms of Cu, Zn, and Mn in steers fed a corn silage and steam flaked corn-based diet. Treatments consisted of 1) 60 mg of Zn/kg DM from ZnSO4; 20 mg of Cu/kg DM from CuSO4; 40 mg of Mn/kg DM from MnSO4, and 2) 60 mg of Zn/kg DM from tetra-basic ZnCl; 20 mg of Cu/kg DM from tri-basic CuCl; 40 mg of Mn/kg DM from tri-basic MnCl. Individual trace mineral treatments were thoroughly mixed with 0.23 kg of ground corn and administered as a single dose via the rumen fistula. Rumen and duodenal samples were obtained at -4, -2, 0 h, pre dosing and at 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, and 42 h post dosing. Duodenal appearance of Cu, Mn, and Zn post ruminal administration of different trace mineral sources were similar across treatments. In experiment 3, eight cross-bred steers were utilized in a 19 d experiment to investigate the effects of trace mineral source on apparent absorption and retention of Cu, Zn, and Mn in steers fed a corn silage and steam flaked corn-based diet. Steers were blocked by BW and randomly assigned to one of the 2 treatments. Treatments consisted of: 1) 30 mg of Zn/kg DM from ZnSO4; 10 mg of Cu/kg DM from CuSO4; 20 mg of Mn/kg DM from MnSO4; and 2) 30 mg of Zn/kg DM from tetra-basic ZnCl; 10 mg of Cu/kg DM from tri-basic CuCl; 20 mg of Mn/kg DM from tri-basic MnCl. Total fecal and urine output was measured daily for all steers during the 5 d collection period. Dry matter disappearance, apparent absorption, and apparent retention of Cu, Zn, and Mn were similar across treatments. In experiment 4, four-hundred cross-bred steers (initial BW 335 ± 9.6 kg) were utilized to investigate the effects of supplemental Zn, Cu, and Mn concentration and source on performance and carcass characteristics of feedlot steers fed a high concentrate steam flaked corn-based finishing diet for 159 d and zilpaterol hydrochloride for the last 21 d prior to slaughter. Treatments consisted of: sulfate) 90 mg of Zn/kg DM from ZnSO4; 17.5 mg of Cu/kg DM from CuSO4; 48 mg of Mn/kg DM from MnSO4; IB-1) 30 mg of Zn/kg DM from Zn Hydroxychloride; 10 mg of Cu/kg DM from basic Cu chloride ; 20 mg of Mn/kg DM from Mn Hydroxychloride; IB-2) 45 mg of Zn/kg DM from Hydroxychloride; 12.5 mg of Cu/kg DM basic Cu chloride; 29.5 mg of Mn/kg DM from Mn Hydroxychloride; IB-3) 60 mg of Zn/kg DM from Zn Hydroxychloride; 15 mg of Cu/kg DM from basic Cu chloride; 39 mg of Mn/kg DM from Mn Hydroxychloride ; and IB-4) 90 mg of Zn/kg DM from Zn Hydroxychloride; 17.5 mg of Cu/kg DM from basic Cu chloride; 48 mg of Mn/kg DM from Mn Hydroxychloride. No differences were observed for final body weight (P > 0.42). Overall ADG, DMI, and feed efficiency were similar across treatments. Hot carcass weight, dressing percentage, yield grade, LMA, adjusted fat thickness, KPH, and marbling score were similar across treatments. Concentrations of Zn, Cu, and Mn in liver and blood samples collected on d 112 and at harvest were similar across treatments. Overall data collected from these 4 experiments indicate that under the conditions of these experiments, supplemental Zn, Cu, and Mn concentration and source had no impact on any of the response variables measured.
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    Influence of BOVAMINE DEFEND® Plus on growth performance, carcass characteristics, estimated dry matter digestibility, rumen fermentation characteristics, and immune function in finishing beef steers
    (Colorado State University. Libraries, 2024) Miller, Alexandra C., author; Engle, Terry E., advisor; Edwards-Callaway, Lily, committee member; Holt, Timothy, committee member
    One hundred and eighty crossbred beef steers (406.0 ± 2.2 kg) were used to determine the impact of a novel direct-fed microbial (DFM) on growth performance, carcass characteristics, rumen fermentation characteristics, and immune response in finishing beef cattle. Steers were blocked by body weight and randomly assigned, within block, to 1 of 2 treatments (3 replicates/treatment: 30 steers/replicate). Treatments included: 1) no DFM (control) and 2) DFM supplementation at 50 mg∙animal-1∙d-1 (BOVAMINE DEFEND® Plus). All steers were fed a high-concentrate finishing diet and individual feed intake was recorded daily via the GrowSafe® system. Body weights were collected every 28 d. On d 55, 10 steers per pen were injected with ovalbumin (OVA). Jugular blood samples were collected from each steer on d 0, 7, 14, and 21 post-injection. On d 112, the same steers were injected again with OVA and intramuscularly with a pig red blood cell solution. Jugular blood samples were collected from each steer on d 0, 7, 14, and 21 post-injection. On d 124 rumen fluid was collected from 3 steers per treatment and used to estimate in vitro rumen fermentation characteristics. Equal numbers of steers per treatment were transported to a commercial abattoir on d 145, 167, and 185 of the experiment, harvested, and carcass data collected. Initial body weight (BW) was similar across treatments. On d 28 and 55, steers receiving DFM had heavier BW (P < 0.01) compared to controls. Average daily gain was greater in DFM-supplemented steers from d 0 to 28 (P < 0.01) and d 0 to 55 (P < 0.01) of the experiment compared to controls. Overall dry matter intake was greater (P < 0.04) and overall feed efficiency was similar in DFM-supplemented steers compared to controls. Dressing percentage (P < 0.02) was greater in steers receiving DFM compared to controls. Antibody titers to injected antigens were similar across treatments. However, red blood cell superoxide dismutase activity was greater (P < 0.05) in DFM-supplemented steers compared to controls. In vitro molar proportions of isobutyric and butyric acid were greater (P < 0.01) and dry matter (DM) digestibility tended (P < 0.07) to be greater in rumen fluid obtained from steers supplemented with DFM. These data suggest that BOVAMINE DEFEND® Plus supplementation improves growth performance during the initial period of the finishing phase, increases overall dry matter intake and dressing percentage, and may impact antioxidant status in beef cattle.
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    Influence of trace mineral concentration and source on yearling feedlot steer performance, carcass characteristics, and trace mineral status
    (Colorado State University. Libraries, 2013) Berrett, Cari J., author; Engle, Terry E., advisor; Wagner, John J., committee member; Brummer, Joe E., committee member
    Effects of trace mineral (TM) concentration and source on yearling feedlot steer performance, carcass characteristics, and liver TM status, were determined utilizing 360 crossbred steers (initial BW=350 ± 4.0 kg). Steers were blocked by initial BW and randomly assigned to one of 4 treatments (10pens/treatment; 9 hd/pen). Treatments consisted of: 1) negative control (NC), no supplemental TM (basal diet contained 7.65 mg Cu/kg DM, 50.5 mg Zn/kg DM, 27.7 mg Mn/kg DM, and 0.12 mg Co/kg DM); 2) basal diet supplemented with 10 mg Cu/kg DM from CuSO4, 30 mg Zn/kg DM from ZnSO4, 20 mg Mn/kg DM from MnSO4, 0.50 mg I/kg DM from EDDI, 0.10 mg Se/kg DM from Na2O3Se, and 0.10 mg Co/kg DM from CoCO3 (NRC); 3) basal diet supplemented with inorganic forms of Cu, Zn, Mn, EDDI, Se and Co at consulting nutritionist recommendations (CNI, 20, 100, 50, 0.50, 0.20, and 0.20 mg of mineral/kg DM, respectively); and 4) basal diet supplemented with 66.6% inorganic and 33.4% organic Cu, Zn, Mn and Co, and inorganic forms of I and Se at iso-concentration to consulting nutritionist recommendations of treatment 3 (CNO). All steers were fed a high concentrate, steam-flaked, corn-based diet for 154 d. Steers were individually weighed on d -1, 0, 35, 121, 153, and 154. Continuous data were analyzed on a pen mean basis using a mixed model appropriate for a randomized block design (fixed effects = treatment and time; random effect = replicate). Categorical data were analyzed utilizing GLIMMIX (fixed effect = treatment; random effect = replicate). Initial and final BW, ADG, DMI, F:G and G:F ratios and calculated net energy recoveries were similar (P > 0.23) across treatments. Subcutaneous adipose tissue depth, HCW, KPH, yield grade, marbling score, and quality grade were similar across treatments (P > 0.17). Final liver Zn, Mn, Se, and Co concentrations were similar across treatments (P > 0.37). Under the conditions of this experiment, it appears that basal dietary concentrations of Cu, Zn, Mn, and Co were adequate for growth and performance of finishing yearling feedlot steers. For experiment 2, an in vitro analysis was utilized to determine "releasability" of trace minerals from the basal diets fed in experiment 1. Three tubes for each treatment ration as listed for experiment 1 were incubated for 0, 6, 12, and 24 h in a 3:1 ratio of modified McDougall (1984) buffer and rumen fluid taken from steers fed high a concentrate finishing diet. Dry matter disappearance percentage was similar across treatments (P > 0.49). Percent Cu released was significantly different (P > 0.02) for treatment where NC was less than Suppl, and percent Zn released was also significant (P > 0.0004) for treatment NC was also lower than Suppl. From the simulated conditions of the second experiment, it appears there are differences in the ration "releaseabilities" of Cu and Zn from the simulated abomasal and ruminal conditions from treatment diets.
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    Interaction of copper source, bile composition on microbial growth, and Cu protein homeostasis
    (Colorado State University. Libraries, 2011) Arnold, Mark Alan, author; Engle, Terry E., advisor; Wagner, John J., committee member; Van Metre, David C., committee member
    One hundred twenty weaned nursery pigs (6.12 ± 0.56 kg) were utilized in this experiment to determine the effects of Cu concentration and source on performance, bile components, Cu metabolism, and gastrointestinal microbial distribution in nursery pigs blocked by weight and gender and placed in pens containing 5 pigs of similar weight distribution per pen. Pigs were fed one of four dietary treatments for 21 or 22d. Treatments consisted of: 1) Control (5 mg of Cu/kg from CuSO 4); 2) 250 mg of Cu/kg from CuSO 4, (250-sulfate) 3) 75 mg of Cu/kg from Cu-MINTREX®Cu (75-Min; Novus International, Inc., St. Charles, MO), and 4) 75 mg of Cu/kg from CuSO4 (75-sulfate). On d 22 and 23, equal numbers of pigs per treatment were slaughtered. Post slaughter, blood, liver, intestinal tissue and contents, and bile samples were obtained. Body weights, ADG, and ADFI were similar across treatments (P > 0.20). Feed efficiency was greater (P < 0.05) for pigs receiving 250-sulfate compared to controls (0.53 vs. 0.43 ± 0.03, respectively), and pigs fed 75-Min (0.47 ± 0.03) or 75-sulfate (0.44 ± 0.03) were intermediate. Pigs receiving 250-sulfate had greater (P < 0.05) bile (7.05 vs. 2.06 ± 0.49; respectively) and liver (124.4 vs. 53.3. ± 24.6, respectively) Cu concentrations than controls. Bile components, intestinal bacterial populations, and small intestine gene expression profiles (Ctr-1, Atox-1, Cox-17, ATP7a, and ATP7b) associated with Cu absorption and homeostasis were similar across treatments (P > 0.20). Antimicrobial effects of bile (determined by measuring the diameter of the zone of inhibition; mm) tended (P < 0.20) to be higher for 250-sulfate and 75-Min treatments compared to controls. Data from this experiment indicated that Cu dose influenced pig performance, but dose or source did not influence measured bile components, intestinal bacterial populations, or intestinal gene expression profiles associated with Cu absorption.
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    Propionibacteriaium acidipropionici CP 88 dose alters in vivo and in vitro ruminal fermentation characteristics
    (Colorado State University. Libraries, 2024) Levenson, Jonah, author; Engle, Terry E., advisor; Wagner, John J., committee member; Torres-Henderson, Camille, committee member
    Twelve steers, fitted with rumen canulae were used in a 4 x 4 Latin square design to examine the impact of the direct fed microbial Propionibacteria acidipropionici (PA) on rumen fermentation characteristics. All steers were housed together in one pen equipped with GrowSafe feed intake monitoring stations and one Greenfeed system used to estimate in vivo methane production. Steers were fed a corn silage-based diet throughout the experiment. Treatments consisted of PA administered at: 1) 0.0; 2) 1.0 x 108; 3)1.0 x 109; and 4) 1.0 x 1010 CFU∙animal-1∙day-1. Treatments were administered directly into the rumen as a single bolus dose daily. On day 7 and 14 of each period, rumen fluid was collected from each steer 2 h post treatment administration for VFA analysis and for determining in vitro fermentation characteristics. Following a 14-d washout period, animal treatments were switched, and the experiment repeated. Data were analyzed as a 4 x 4 Latin square design. In vivo propionic acid molar proportions (25.4 vs 23.6±0.24 mM) and total VFA concentrations (125.2 vs 121.3±1.87 mM) were greater (P < 0.05) in steers receiving PA when compared to controls. In vitro DM disappearance (P < 0.05; 63.3% vs 59.2%±1.12) and total VFA (P < 0.05; 147.9 vs 145.2±1.76 mM) were greater and methane (ml/g DMD) lesser (P < 0.04; vs 13.1 vs 15.6±0.11) in fermentation vessels incubated with rumen fluid from animals receiving PA when compared to controls. Dry matter disappearance (P < 0.03) and propionic acid (P < 0.04) increased linearly as dose of PA increased. In vitro total VFA tended (P < 0.08) to increase linearly and methane production tended (P < 0.09) to decrease quadratically in response PA dose. In vivo methane production was similar across treatments. In conclusion, PA addition improved in vivo and in vitro rumen fermentation, gas production, and rumen microbial manipulation.
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    Selected factors that influence profitability of feedlot cattle
    (Colorado State University. Libraries, 2010) Tibbetts, Gary K., author; Whittier, Jack C., advisor; Engle, Terry E., advisor; Field, Thomas G., committee member; Mortimer, Robert George, committee member
    For the primary emphasis of this dissertation, twenty-three ranches were selected from ranch cooperators in a large scale Nebraska-based cattle system to establish baseline measurements for liver concentrations of trace minerals, disease titers, parasite load, percent morbidity and gain performance. Upon arrival at the feedlot blood, liver, and fecal samples were collected from approximately 10% of each ranch group. After all yr 1 cattle were harvested an 11 ranch subset of the original 23 ranches was selected based on ranch weaning practice for a second yr survey. In yr 2 all ranches shipped calves to the feedlot on the day of weaning and all fed a standardized free choice mineral containing organic trace mineral complexes (OTM) to cow calf pairs 45 d prior to weaning. Comparing yr 1 and 2 for the 1 ranches, percent 1st pulls decreased from yr 1 to yr 2. Carcass quality was decreased from yr 1 to yr 2. Liver Cu concentrations of calves at weaning increased from yr 1 to a yr 2 and Zn and Mn liver concentrations were similar across years. Across both years, higher liver Cu concentration was correlated with decreasing total pulls and increasing ADG and mortality tended to decrease as Cu concentration increased. Higher liver Mn concentrations tended to be correlated with lower total pulls. There was no correlation between liver Zn concentration and animal and health performance. In conclusion, allowing cow-calf pairs access to free-choice mineral containing OTM prior to weaning improved some aspects of feedlot health and performance. For a second paper feedlot performance records from the U.S. Meat Animal Research Center feedlot for 1993 through 2000, were analyzed to evaluate the impact of footrot on ADG and total days on feed. Records from the original pool of 36,755 bull, steer and heifer calves were sorted so that only steers that had a single footrot incidence and those with no other morbidities were included in the data set (7,100 steers). To roughly pattern these data to industry production practices, time of footrot insult during feeding was divided into three production periods; starting (0-60 d), growing (61-120 d) and finishing (121d - harvest). Records were evaluated to determine which limb was more likely to be affected with footrot. A total of 459 (6.5%) steers were treated for a single footrot incident. ADG for cattle experiencing a single footrot incident was decreased compared to non effected cattle. The production period of footrot onset impacted both ADG and total days on feed. Mean days on feed for the non-affected cattle was 262 d while mean days on feed for footrot affected cattle was 267 d (P<0.01). The impact of footrot on days on feed for the starting, growing and finishing periods was -9.9 d, +2.2 d and +14.3 d.
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    The effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers
    (Colorado State University. Libraries, 2011) Westover, Elin C., author; Wagner, John J., advisor; Engle, Terry E., advisor; Ham, Jay M., committee member
    Six hundred crossbred steers (BW, 329.7 ± 7.58 kg) were used to investigate the effect of CP withdrawal and the use of oscillating CP concentrations on feedlot performance, digestibility, carcass merit, and ammonia emissions from the pen surface of yearling steers. Steers were randomly assigned to one of the following treatments: HCP [Control, 13.5% CP, 3.5% CP equivalents (CPE)]); OCP (11.62% CP, 1.5% CPE fed Wednesday, Thursday, and Sunday and the HCP diet fed Monday, Tuesday, Friday, and Saturday); EICP (12.56% CP from d28 to slaughter, 2.53% CPE); ELCP (11.62% CP from d28 to slaughter, 1.55% CPE); LICP (HCP throughout with the ICP diet fed the last 27d); and LLCP (HCP throughout with the LCP diet fed the last 27d). Urea was used to modify dietary CP concentrations. Steers were housed in 9-steer pens (n=48) or 7-steer mass balance pens (n=24). Steers were weighed and ultrasound images and fecal grab samples were taken 3 or 4 times (depending upon replicate) throughout the trial. Feed samples, fecal grab samples, and mass balance pen surface samples were analyzed for DM, AIA, N, and P. Soil samples were obtained from the mass balance pens for treatments HCP, OCP, and ELCP and tested for total ammonia volatilization. Steers were harvested on d 149 or d 175 and camera carcass data was collected. Although initial BW differences between treatments were not significant (P > 0.18), initial BW was a significant (P < 0.10) source of variation describing interim and final BW and was therefore included in the data analysis as a covariate. There were no treatment differences for BW (P > 0.23) throughout the study. Average daily gain for each time period or for the entire study was not affected by treatment (P > 0.26). There was a difference (P < 0.05) in DMI between treatments from d 106 to slaughter (HCP > ELCP, LLCP, and LICP), and overall DMI tended (P < 0.11) to be affected by treatment (HCP > ELCP and LLCP). Treatment differences for G: F and net energy recovery were not significant (P > 0.30). There were no significant (P > 0.21) effects of dietary treatment on carcass merit. Treatment differences for DM digestibility calculated from DMI and fecal output as estimated by AIA, were not significant (P > 0.37) and averaged 85.7, 83.6, 84.2, and 83.0% for the HCP, OCP, EICP, and ELCP diets respectively. Treatment differences for CP digestibility, calculated from N intake and fecal N, were significant (P < 0.001) and averaged 83.3, 76.6, 78.8, and 74.3% for the HCP, OCP, EICP, and ELCP diets respectively (HCP > OCP, EICP, and ELCP). Nitrogen intake was significantly (P < 0.0001) affected by treatment and averaged 183, 172, 167, and 155 g per head daily for the HCP, OCP, EICP, and ELCP treatments respectively. Differences between treatments for amount of fecal N (P > 0.18) and calculated amount of retained N (P > 0.42) were not significant. Urinary N, calculated as N intake minus fecal and retained N, excretion was reduced (P < 0.0001) as N intake decreased with treatment averaging 128, 111, 108, and 94 g per steer daily for the HCP, OCP, EICP, and ELCP treatments, respectively. Retained N as a percentage of N intake increased (P < 0.0001) and calculated urinary N excretion decreased (P < 0.001) with decreasing N intake associated with treatment averaged 12.6, 13.6, 14.1, and 15.0% and 69.8, 64.6, 64.6, and 60.7% of N intake for the HCP, OCP, EICP, and ELCP treatments respectively. Cattle on the ELCP diet had significantly lower N loss than the HCP treatment (P < 0.02) and the OCP treatment (P < 0.10) for sampling from d 45 and d 92. Similar results were observed from samples taken on d 148; however there were no significant differences. Ammonia flux reduction of ELCP diet compared to HCP diet decrease from 40% to 21% with increasing days on feed. The average ammonia flux over the feed period for all treatments was 147.3 g/m2/d. There were no treatment differences (P > 0.36) for N, P, or N: P ratio found in samples from manure cleaned from the pen surface at the end of the study. Nitrogen to P ratios ranged from 2.13 to 2.23 and was lower than the fecal grab sample N: P ratio. These results indicate that ADG and carcass merit were similar for steers fed OCP and CP withdrawal diets as compared with the HCP control. Although DMI declined during the later stages of the finishing period, feed efficiency was not impacted by OCP or CP withdrawal diets. Reduced CP intake whether it was through the OCP or CP withdrawal diets was associated with less urinary N excretion and lower ammonia emissions from the pen surface.
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    The effect of feed additive program in steam-flaked corn diets containing wet distiller's grains on performance and carcass merit in yearling feedlot steers
    (Colorado State University. Libraries, 2011) Domby, Elizabeth Marie, author; Wagner, John J., advisor; Engle, Terry E., advisor; Van Metre, David C., committee member
    Crossbred yearling steers (432, BW = 329 ± 10.5 kg) were used in an unbalanced randomized block design to examine the effect of feed additives on performance and carcass merit. Treatment factors were arranged as a 2 x 2 factorial and included ionophore and antibiotic [Rumensin/Tylan (R/T) or Cattlyst/Aureomycin (C/A)] and dietary S (constant or variable). High S diets were fed on random days to the variable (VAR) treatment. Low S diets were fed to the VAR treatment on remaining days and to the constant (CON) treatment all days. From d 0 through 35, the high S diet was achieved by using a high S granular supplement; however, since S concentration in wet distillers grains (WDG) is associated with distillers solubles (DS) added to WDG and H2SO4 added to the DS, the high S diet was achieved from d 36 through 159 by using a DS based liquid supplement with 2.35% S while the low S diet was achieved using a 0.99% S DS based liquid supplement. Cause of cattle death for study steers was verified by necropsy. No interaction between S and additive treatments existed for feedlot performance; therefore, only main effects are presented. Most of the sulfur comparisons from this study will be addressed in another manuscript. Feedlot performance and carcass merit were similar for feed additive treatments. The S by feed additive interaction was significant (P < 0.05) for dressing percentage indicating that S treatment had no effect on dressing percentage if R/T was fed but when steers were fed C/A, dressing percentage was reduced by 0.72% (P < 0.02) if VAR diets were fed. The results of this study indicate that performance and carcass characteristics for cattle fed Cattlyst and Aureomycin are similar to performance and carcass characteristics for cattle fed Rumensin and Tylan.
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    The effects of olive meal supplementation on feedlot performance and longissimus muscle fatty acid composition of Wagyu steers and the impact of calcium dose and olive meal on in vitro rumen fermentation characteristics
    (Colorado State University. Libraries, 2022) Tangredi, Briana V., author; Engle, Terry E., advisor; Delmore, Robert J., committee member; Holt, Timothy N., committee member
    Two experiments were conducted to evaluate the effects of olive meal supplementation on feedlot performance of Wagyu steers and the impact of Ca dose and olive meal on in vitro rumen fermentation characteristics. Experiment 1: Eighty-three American Wagyu steers (725 ±10.7 kg) were used to evaluate the effects of olive meal supplementation on feedlot performance and carcass characteristics. The steers were blocked by BW. The heaviest 8 steers were stratified into two pens containing 3 or 4 steers per pen with similar pen BW. This was considered a paired weight block. This process was repeated until all steers were assigned to pens. Each pen contained 3 or 4 steers/pen with 11 replicates/treatment. Steers were blocked by initial body weight (BW) and randomly assigned within block to one of two treatments. Treatments consisted of: 1) Control (basal ration with no olive meal) + 1 kg of supplemental cracked corn per animal per day, or 2) Control diet + 1 kg of supplemental olive meal per animal per d ay. Steers were housed in feedlot pens (n=4 steers/pen; 11 replicates/treatment) and fed a traditional American Wagyu finishing diet (DM basis: 68.4% DM, 14.3% CP; 74.8% TDN, 1.16 Mcal/kg NEg, 5.3% crude fat). Diets were delivered to pens, once daily, in the morning in amounts to allow ad libitum access to feed over a 24 h period. Olive meal and cracked corn were top-dressed to the appropriate treatment pens immediately after delivery of the basal ration. Steers were individually weighed on d -1 and 0, and approximately every 28 d throughout the 177 d experiment. Equal numbers of steers per treatment were slaughtered throughout the experiment and carcass data were collected. Steers receiving olive meal had a lower final BW, ADG, DMI, and FE (P < 0.05) when compared to steers receiving the control diet. Longissimus muscle C18:1 tended to be greater (P < 0.06) in steers receiving olive meal when compared to controls. Under the conditions of this experiment, feeding olive meal at 1.0 kg/ animal /day reduced live animal performance and had minimal impacts on longissimus muscle fatty acid composition. Experiment 2: Rumen fluid from three beef steers (480 ± 10 kg) fitted with rumen canulae, was used to investigate the impact of Ca dose and olive meal on in vitro rumen fermentation characteristics. Steers were fed a high concentrate finishing diet for 21 d and rumen fluid was collected from each steer 2h post-feeding. A 2 x 4 factorial arrangement of treatments was used for this experiment. Factors included: 1) 0 or 5% olive meal and 2) Ca dose: 0, 0.02, 0.04, and 0.08% Ca from CaCl2. A McDougall's buffer-rumen fluid mixture (1:1; 30 mL 5 total volume) was added to conical tubes containing 0.5g of the ground basal diet with the appropriate treatments and incubated at 39°C for 0, 4, 8, and 12h (5 replicates per treatment per time point). After incubation, supernatant was removed for VFA analysis and the remaining digesta was dried to determine DM disappearance (DMD). There were no olive meal x Ca interactions for any response variables measured. At 4 and 8 h post incubation digestion tubes containing 0.04% Ca had greater (P < 0.001) DMD when compared to all other Ca doses. At 12 h post incubation, DMD was greater (P < 0.001) in digestion tubes containing 0.02% and 0.08% Ca compared to all iv other Ca doses. At 8 h post incubation, molar proportions of acetic acid were greater (P < 0.03) in digestion tubes containing olive meal compared to no olive meal and were greater (P < 0.001) in digestion tubes containing 0.08% Ca compared to all other Ca doses. At 12 h post incubation, iso-butyric acid (P < 0.01) and butyric acid (P < 0.02) were greater in digestion tubes containing 0.02% and 0.04% Ca compared to all other Ca doses. Butyric acid was lesser (P < 0.02) with olive meal inclusion at 12 h. Total VFA concentrations were similar across treatments. These data suggest that Ca and olive meal may impact in vitro fermentation. Dietary treatment was a significant (P < 0.05) source of variation for caproic (C6:0), capric (C10:0), linoleic (C18:2n-6), linolelaidic (C18:2n-6 trans), and docosahexaenoic (C22:6n-3) longissimus muscle fatty acids. Steers receiving the control diet had greater C6:0 (P < 0.02), C10:0 (P < 0.02), C18:2n-6 trans (0.02), and C22:6n-3 (P < 0.05) fatty acids when compared to cattle receiving olive meal. Steers receiving olive meal had greater C18:2n-6 (P < 0.04) when compared to controls. All other fatty acids identified were similar across treatment. Based on these data Ca addition at the concentration supplied in this experiment did not inhibit biohydrogenation of unsaturated fatty acids but did improve fermentation characteristics.
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    The influence of propionibacteria on in vivo rumen fermentation characteristics and in vitro lactic acid clearance rate in fistulated steers fed moderately high concentrate diets
    (Colorado State University. Libraries, 2022) Gifford, Ryan J., author; Engle, Terry E., advisor; Wagner, John J., committee member; Torres-Henderson, Camille, committee member
    The objective of this experiment was to determine the impact of a direct fed microbial (DFM) supplementation on rumen fermentation characteristics and in vitro lactic acid clearance. Fistulated steers (n = 6) were sorted into two groups of three steers, randomly assigned to one of two treatments, and fed a moderately high concentrate diet (14.9% CP, 1.17 Mcal/kg NEg, and 28.3% NDF) for 21 d prior to beginning the experiment. Treatments consisted of: 1) Control (No DFM; carrier only) or 2) DFM (0.225g∙animal-1∙day-1 of 4.45x 1010 CFU/g of Propionibacteria acidipropionici - CP88). Treatments were administered daily, directly into the rumen via the cannula as a single bolus dose at the time of feeding. Immediately after treatment administration, the rumen contents were thoroughly mixed by hand. Two hours post feeding, rumen pH was determined, and rumen contents were sampled and analyzed for short chain fatty acids (SCFA), daily. On d 7 and 14, rumen fluid was collected from all steers and subjected to an in vitro lactic acid clearance challenge. Lactic acid and SCFA concentrations were determined at 0, 3, 6 and 9 h post-incubation. After d 14, all cattle received the basal diet for 21 d. On d 22, treatment crossover was implemented, and the experiment repeated. Data were analyzed by a mixed effects completely randomized block design (Proc Mixed, SAS Inst. Carey, NC). There were no treatment x block, treatment x time, or treatment x block x time interactions for any in vivo or in vitro rumen variables measured. Propionic acid concentrations were greater (P < 0.05) and total SCFA tended (P < 0.06) to be greater in rumen fluid from steers receiving DFM compared to controls. Other in vivo rumen fermentation characteristics were similar. D- and total lactic acid concentrations but not L+ lactic acid concentrations were lesser (P < 0.05) at 3 h post incubation in vitro, for steers receiving DFM. D-, L+, and total lactic acids concentrations were similar between control and DFM treatments at 0, 6, and 9 h post incubation. In vitro molar proportions of propionic acid and total SCFA concentrations were greater (P < 0.05) and acetic acid molar proportions were lesser (P < 0.05) in steers receiving DFM. Collectively, under the conditions of this experiment, these data indicate that the DFM test article (P. acidipropionici - CP88) used in this experiment alters rumen fermentation characteristics in vivo, and in vitro, and lactic acid utilization in vitro.
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    Understanding the relationships between swine behavior, physiology and management to improve animal welfare, reduce in-transit losses and improve meat quality in swine
    (Colorado State University. Libraries, 2009) Edwards, Lily Nowell, author; Grandin, Temple, advisor; Engle, Terry E., advisor; Rollin, Bernard E., committee member; Anderson, David B., committee member
    The objective of these studies was to determine the relationship between pre-slaughter management, physiological measures, and meat quality using commercial swine marketing practices. Experiments 1 & 2 were conducted to determine the effects of distance moved at the farm, time of lairage in holding pens prior to slaughter and distance moved from lairage pens to the stunning area on blood lactate concentration ([LAC]), rectal temperature and meat quality. Both [LAC] and temperature changed during the marketing process (P< 0.0001). The highest [LAC]s were observed at loading and exsanguination. Longer distance resulted in higher [LAC] during loading (Exp. 2). Unexpectedly, longer rest resulted in higher [LAC]s at exsanguination (Exp 1 & 2) and at the end of lairage (Exp. 2). An increase in [LAC] during loading reduced glycolytic potential (Exp. 2) and had a positive impact on meat quality measures, i.e. decreased drip loss, increased 24 hr pH and trends for lower L* and higher visual muscle color score (Exp 1 &2). Specific measurements of pre-stun handling, jamming, rearing, vocalization, electric prod use, backing up, were found to be correlated with exsanguination [LAC] (P<0.05). Experiment 3 evaluated the persistence of blood changes in swine during the marketing process following alteration of dietary electrolyte balance (dEB). Experimental pigs were assigned to a Low (121 meq/kg) or High (375 meq/kg) dEB diet ad libitum for 3 days prior to slaughter. Prior to transport, animals were fasted in the barn for 10 h, then shipped to the plant, rested for 8 h and slaughtered. Blood was sampled four times, initial and final weights were obtained and meat quality parameters were measured. Increasing dEB had no adverse effects on growth performance, meat quality, carcass yield or incidence of pars esophageal ulcer scores. Exsanguination [LAC] was negatively correlated to 60 min pH (r = -0.32, P = 0.0004) and positively correlated (r = 0.21, P = 0.02) to drip loss. These results suggest that exsanguination [LAC] is predictive of the rate of early post-mortem metabolism. This study demonstrated that the effect of dEB on blood parameters was not maintained following a 10 h feed withdrawal (P > 0.22). Therefore, it is likely that the animal‟s ability to withstand any increased metabolic acid load associated with the stress of transport was lost following feed withdrawal. This research supports the use of LAC as a sensitive tool to determine changes in handling and management. These studies emphasized the impact that pre-slaughter management has on physiological parameters of swine throughout the entire marketing process.