Master of Science / Department of Clinical Sciences / Michael D. Apley / One hundred ninety four steers, bulls, and heifers weighing 182-318 kg were purchased at an Arkansas sale barn and shipped 12 hours to a northern Kansas feedlot. There was no previous history of treatment and the cattle had been delivered to the sale barn within the 24 hour period prior to the sale. The objectives of the study were to evaluate (1) bacterial pathogen isolates in different locations in the respiratory tract, (2) pathogen load in clinically ill and clinically normal calves, and (3) compare histological damage that may be a result of clinical disease. Fifteen calves were identified with signs of acute bovine respiratory disease (BRD) based on clinical score and a minimum rectal temperature of 40° C. An additional 5 calves with no clinical signs and rectal temperatures < 40° C were selected as controls. Cattle were humanely euthanized following recording of antemortem clinical observations. At postmortem, samples for microbiologic and histologic (hematoxylin and eosin stain) analysis were collected from grossly normal and/or consolidated tissue in each lung lobe. Samples were also collected from the tonsils and trachea. Quantification of the BRD pathogens per gram were determined for each positive site and then converted to total counts for each animal. Total colony forming units (CFU) of pathogens in the entire lung for cattle with identified pathogens ranged from 2x10[superscript]7 – 2x10[superscript]8 CFU for Pasturella multocida and 9x10[superscript]6 – 9x10[superscript]8 CFU for Mannheimmia haemolytica. Total visual estimated percent consolidation ranged from 0.0% to 45.0% of the total lung. Isolated pathogens from the upper and lower respiratory tract were compared and showed to have no significant agreement. Histology scores of 0-4 were assigned to the tissue samples and compared to the quantified BRD pathogens to test a possible association between the pathologic process and the total agents in that tissue sample. A significant difference in bacterial counts between histology scores of zero or 1 and a histology score of 4 was observed.

Doctor of Philosophy / Department of Animal Sciences and Industry / Jim L. Nelssen / Eleven-thousand one-hundred eighty-five pigs were used in 11 experiments to determine effects of birth-weight, feeder design, and dietary astaxanthin (AX) and ractopamine HCl (RAC) on growth, carcass, and pork quality characteristics of pigs. Also, data from 27 experiments were used in meta-analyses to improve prediction of pork fat iodine value (IV). In Exp. 1, increased birth-weight resulted in greater (quadratic, P < 0.05) pre-weaning survivability, ADG, final BW, and likelihood of achieving full-value market at 181-d of age. In Exp. 2, 3, 4, 6, 7, and 8, pigs using the wet-dry feeder (WD) had greater (P < 0.05) ADG, ADFI, and final BW than those using the conventional dry feeder (CD). Pigs using WD had poorer (P < 0.05) G:F in Exp. 3 and 4, and increased (P < 0.05) HCW and backfat depth in Exp. 3, 4, 6, and 7, compared to pigs fed using CD. In Exp. 5, pigs using WD from 19 to 38 kg had decreased (P < 0.02) ADFI and better G:F than pigs using CD. Increased feeder opening of WD increased (P < 0.05) ADG, ADFI, and final BW in Exp. 5, 6, and 7; as well as HCW and backfat depth in Exp. 6 and 7. Reducing WD opening at 28- and 56-d in Exp. 7 decreased (P < 0.05) ADG, ADFI, and backfat depth. Different openings of CD had little effect on performance in Exp. 5 and 6. In Exp. 8, changing water-source of WD to a separate location during late-finishing reduced (P < 0.05) overall ADG, ADFI, and final BW. Limited responses to AX were observed in Exp. 9, 10, and 11, but ADG, G:F, final BW, HCW, and fat-free lean were improved (P < 0.05) for pigs fed RAC in Exp. 10 and 11. Total color change during retail display of LM chops for gilts and pigs fed RAC was reduced (P < 0.05) in Exp. 10 and 11, indicating their color shelf-life improved. In the meta-analyses, models using dietary PUFA with ADG, BW, or backfat depth improved the fat IV prediction from R2 = 0.45 to R2 = 0.90.

Master of Science / Department of Animal Sciences and Industry / Michael D. Tokach / A total of 5,212 nursery pigs were used in 11 experiments to evaluate amino acids in nursery pig diets. Experiments 1 and 2 were conducted to determine whether the Lys level fed during one phase of the nursery influenced the response to Lys during subsequent phases. Experiment 1 tested a wide range of dietary Lys in 2 phases and reported that pigs fed high Lys during each period had increased growth performance; however, compensatory growth occurred for the pigs previously fed low Lys diets, resulting in no impact on overall ADG or final BW. Experiment 2 tested a narrow range of dietary Lys in 3 phases and found that marginally deficient diets can be fed in the early nursery phases without influencing final BW or the response to Lys levels in subsequent phases. Both experiments demonstrate that the low dietary Lys levels used in each can be fed in the early nursery phases with no negative impact on overall nursery growth rate provided that adequate levels are fed thereafter. Experiments 3 to 6 were conducted to determine the standardized ileal digestible (SID) Lys requirement of nursery pigs from 7- to 14-kg. Data from all experiments were combined and break-point and quadratic broken-line analysis was used to determine the estimated SID Lys requirement. The SID Lys requirement for optimal growth was at least 1.30% for ADG and 1.37% for G:F, or at least 3.86 and 4.19 g SID Lys/Mcal ME, respectively. Experiments 7 to 11 were conducted to evaluate the effect of replacing specialty protein sources with crystalline AA and AA requirements for 7- to 12-kg pigs. Experiment 7 demonstrated that crystalline AA can be used to replace fish meal in diets with no negative effects on growth performance. Experiment 8 demonstrated that L-Trp, L-Val, and a source of non-essential AA were needed in low-CP, AA-fortified nursery diets to achieve maximum growth performance, whereas the addition of L-Ile was not required. Experiment 9 indicated that feeding greater than 7.35% total Lys:CP decreased growth performance and Exp. 10 indicated that a SID Val:Lys ratio of 65% was sufficient for optimal growth of early nursery pigs. Implementing the results from the previous experiments, Exp. 11 determined that crystalline AA in nursery pigs diets can replace high amounts of fish meal, meat and bone meal, and poultry meal when balanced for minimum AA ratios and maximum Lys:CP with no negative effect on growth performance.

Master of Science / Food Science / Edgar Chambers IV / Palatability of pet foods is judged by the use of animals in colonies. Pet food manufacturers would like to understand how palatable a food is compared to another food. This generally is accomplished by a two pan test where a pet has the opportunity to freely choose between two foods. Preference is evaluated through the use of an intake ratio, the ratio of the amount of test food consumed divided by the total amount of the foods consumed. Although this is easy to do in laboratories, another option would be to do such studies with animals in more ‘real-life’ home environments. The purpose of this study was to develop, and test a method to capture feeding information from a study of canines in the home environment and analyze the results of the palatability tests. Individual dog owners were screened for information on the household and pets. Twenty-five dogs of different ages, breeds and sizes were selected to participate on the in-home panel. Seven different palatability tests were performed using the in-home panel with four of those tests being replicated; a total of 11 comparative tests. These dogs were tested using a proprietary computer-based technology that collected information about intake of each food for each individual dog for a duration of seven days for each of the 11 comparative studies. Data was analyzed and resulted in showing that differences between foods can be found. Statistical analyses compared initial day one data to subsequent day data collected during each study to determine whether a full seven day test was needed. In addition, comparisons were made to compare the impact of prior foods eaten to subsequent preferences of the dogs. Results of the in-home panel were the same on day one as for all seven days of testing. Also, previous exposure to a food did not alter subsequent preference for that food. Such data has implications for pet food manufacturers related to timing and cost of testing.

Master of Science / Department of Animal Sciences and Industry / Duane L. Davis / Culturing stem cells is usually done on tissue-culture treated plastic. Over time the cells change their gene expression and start to differentiate. Porcine umbilical cord (PUC) stem cells express the embryonic transcription factors Oct4, Nanog and Sox2 and changes in their expression may be useful for to evaluating culture-induced changes in the cells. We developed an extract of porcine Wharton’s jelly matrix (JMX) that may provide some characteristics of the stem cell niche located in the umbilical cord. Our extract used whole cords and enzyme digestion to simplify preparation of the product. We compare cells cultured on plastic to those grown on thin and thick gels of JMX in four experiments. In Exp 1a and b, growing PUCs on a thick JMX coating for 3(1a) or 4(1b) d increased the number of cells at the end of culture (P < 0.05) with minimal effects on gene expression. In Exp 2 we compared PUCs grown on thin and thick layered JMX with added collagen (+C) and to control cells. The JMX layers caused the cells to adopt a small, round shape and to form clumps or colonies during culture. No differences (P > 0.10) were seen between thin10 +C and control wells for viable and total cell counts but thick layered +C resulted in decreased numbers of viable cells compared to thin + C (P < 0.10) and control wells (P < 0.05). In a follow up experiment (Exp. 3) growing the PUCs mixed within, rather than plating on top of, a thick layer of JMX + C caused marked morphological changes with dense 3-dimensional structures formed. Exp 4 compared JMX allowed to gel for 10 (Thin10 +C) or 60 (Thin60 +C) min before the non-gelled fraction was removed. There were no effects on cell numbers at the end of culture (P > 0.10) but Sox2 expression was increased in Thin60 +C compared to controls on plastic (P < 0.05) and Thin10 +C (P < 0.10). In summary, JMX extracts change cell morphology and in some formats increased cell proliferation and may increase Sox2 expression. Further investigation is needed to fully understand the effects of JMX on PUCs.

Doctor of Philosophy / Department of Animal Science / Jim L. Nelssen and Michael D. Tokach / The optimum sampling method swine producers should use to estimate the mean and SD of pig BW within a barn was determined based upon both the time required to conduct and the precision and accuracy of each sampling method. Weighing 5 pigs from 15 pens was determined to be the optimal sampling method. This should require approximately 55 min to complete. Weighing 5 pigs from 15 pens had a CI range of 7.2 to 8.0 kg for estimating the mean BW and 5.6 kg for estimating SD. Next, a meta-analysis was conducted using data from existing literature to generate equations to predict finishing pig back, belly, and jowl fat iodine value. While numerous factors were evaluated, dietary essential fatty acids, dietary net energy content, and backfat thickness had the greatest influence on predicting iodine value of the 3 distinct fat depots. Lastly, 6 experiments were conducted to determine the effects of added Zn on growth performance, pork quality, plasma Zn, and ileal mucosal inflammation mRNA expression of finishing pigs fed diets containing ractopamine-HCl (RAC; Elanco Animal Health, Greenfield, IN). Additional Zn increased plasma Zn and reduced relative expression of IL-1β, but did not improve growth performance of pigs fed diets containing RAC in 5 of the experiments. However, in 1 of the experiments, adding Zn to diets containing RAC resulted in a trend for improved growth performance of pigs. Supplementing the RAC diets with dietary Zn decreased the percentage of type IIA fibers and tended to increase the percentage of type IIX fibers compared to pigs fed the RAC diet without added Zn. Ractopamine-HCl produced chops that were lighter and less red, but possessed reduced metmyoglobin reducing ability at the end of the display period. However, adding Zn to RAC diets increased metmyoglobin reducing ability levels at the end of the display period.

Master of Science / Department of Animal Sciences and Industry / J.S. Drouillard / A series of experiments were conducted in which wheat gluten film forming solutions were modified by various means to produce films that would improve resistance to ruminal degradation. There was an interaction between pH and temperature, whereby low pH (pH 3) and high temperature (75°C) of film forming solution resulted in films that had highest resistance to microbial degradation. Strategies that proved unsuccessful in improving resistance to ruminal degradation included use of the cross-linking enzyme, transglutaminase; induction of a Maillard reaction; and increasing the time of heating film forming solutions. Utilizing HCl versus acetic acid as the means to lower the pH of the film forming solution resulted in poor film formation, which can be attributed to glutenin‟s solubility in acetic acid. When acetic acid was replaced with 25% HCl, however, no compromise in film formation was observed and ruminal degradability was not affected. In order to develop an economical and effective means of encapsulating lysine for rumen bypass, wheat gluten and corn zein were evaluated as encapsulation materials. Coating soybean meal with either wheat gluten or zein resulted in superior protection against ruminal degradation when compared to unprotected soybean meal. Compared to wheat gluten, zein was observed to have greater resistance to ruminal degradation in vitro. Lysine was encapsulated by the spray dry method with wheat gluten or zein. Results from an in vitro ammonia release experiment were inconclusive with respect to effectiveness of the encapsulation process. Wheat gluten films were approximately 59% degraded in pepsin solution. Our results suggest that 72% of the wheat gluten film will bypass the rumen and 59% of the bypass fraction of the film will be degraded in the abomasum. Wheat gluten and zein are suitable candidates for development of encapsulated nutrients for ruminal protection.

Doctor of Philosophy / Department of Animal Sciences and Industry / John A. Unruh / Two experiments were conducted to evaluate the effects of exercise on feedlot cattle well-being, growth performance, and carcass characteristics (Experiments 1 and 2). Additionally, two experiments assessed the volatile compound profiles of beef in response to various postmortem processes (Experiments 3 and 4). Experiment 1 compared heifers (n=30) assigned to either a sedentary treatment or an exercise regimen 3 times/wk (20 min/d for the first 2 wk, 30 min/d for the next 2 wk, and 40 min/d for the final wk). Exercised heifers showed decreased blood insulin, daily gains, final body weights, and lower numerical yield grades in conjunction with decreased a* and b* color values of longissimus muscle lean. Experiment 2 exposed steers (n=419) to 1 of 4 treatments; not exercised (CON), or exercised 3 times/wk by animal handlers for 20-30 min for the first 10 wk (EARLY), the last 7 wk (LATE), or for the entire 116 d finishing period (ALL). EARLY treatment cattle exhibited a decrease in blood insulin while EARLY and ALL treatment cattle produced carcasses with decreased marbling scores in comparison to CON cattle. Experiment 3 assessed the volatile compounds generated by raw and cooked beef gluteus medius steaks (n=30) subjected to blade tenderization and aging times ranging from 5 to 61 d. Raw steaks aged longer than 19 d produced greater concentrations of heptanal, octanal, and nonanal than raw steaks aged 5 d, but cooked steaks showed no change in these compounds in response to aging. Additionally, blade tenderization reduced the concentrations of lipid oxidation and Maillard reaction products in cooked steaks. Experiment 4 investigated cross-sections, external, and internal locations of beef longissimus lumborum steaks (n=54) cooked to 63, 71, or 77 °C and aged for 5, 21, or 37 d. External locations generated aldehydes in greater amounts than internal locations while pyrazines are produced exclusively at external locations. Increases in degree of doneness increased all aldehydes, except nonanal, in steak cross-sections. Aldehydes, except hexanal and octanal, generated from external locations became similar to internal locations as aging times increased. Pyrazines from external locations were reduced by increased aging times.

Doctor of Philosophy / Department of Animal Sciences and Industry / Mike Tokach / In 11 experiments, 7,325 pigs were used to determine the effects of: 1) diet type and form on finishing pig growth performance and carcass fat iodine value (IV); 2) pellet quality and feeder adjustment on pig growth performance; 3) corn particle size and diet form on finishing pig growth performance and carcass characteristics; and 4) dietary acidification, diet complexity, and feed-grade antibiotics on nursery pig growth performance. Feeding diets with wheat middlings and dried distillers grains with solubles all the way until marketing decreased G:F and carcass yield, and worsened carcass fat IV. Withdrawing these ingredients 17 d prior to market restored carcass yield, but resulted in small improvements in IV. Pelleting diets improved growth performance; however, a novel finding is that pelleting diets fed to finishing pigs increased belly fat IV. Feeding nursery pigs from a wide feeder gap may improve ADG and ADFI, with no negative effects on G:F. For finishing pigs, reducing feeder gap reduced feed disappearance and improved G:F. In all experiments, feeding pelleted diets improved G:F, but the greatest improvements occurred when the percentage of fines was minimized. Grinding corn finer than 650 microns decreased ADFI and improved G:F for finishing pigs fed meal diets, but not for pigs fed pelleted diets. Pelleting diets improved ADG and G:F, but the greatest magnitude of G:F improvement to pellets occurred when pigs were fed diets containing the largest particle size corn. Thus, grinding corn finer than 650 microns improved feed efficiency for finishing pigs fed meal diets, but provided no additional benefit for pigs fed pelleted diets. When dietary supplementation of benzoic acid was evaluated, added benzoic acid in nursery pig diets did not influence growth performance in university conditions, whereas feeding complex diets or antimicrobials improved growth. In the commercial setting, acidifiers improved growth in one experiment but not the other. The varying response to acidifiers is likely influenced by health status, age, or starting weight of pigs.

Master of Science / Department of Animal Sciences and Industry / Dale A. Blasi / Drought conditions in the past have created a shortage of prairie hay and other grass hays that are used as roughage sources for receiving and growing beef diets. Historically, wheat straw and other cereal crop residue has been discounted as a feedstuff due to its low nutrient content. Chemical methods, including ammonia application, can improve the feeding value of cereal crop residue while constraining costs. While there are studies that show the efficacy of utilizing ammoniated wheat straw in beef cow and maintenance diets, limited data are available characterizing the feeding value of ammoniated wheat straw in receiving and growing diets. The objective of these two studies were to evaluate cattle growth and diet digestibility for receiving and growing diets containing either wheat straw (STRW), anhydrous ammonia treated wheat straw (AMMN), or a prairie hay and alfalfa blend (CONT) at 30% inclusion. Exp. 1 utilized 288 crossbred steers (271 kg) randomized to 8 pens per treatment and fed their respective test diets for 56 d and a common diet for 14 d to equalize gastrointestinal tract fill. No effect of straw ammoniation was observed on final bodyweight (BW), average daily gain (ADG), dry matter intake (DMI), or gain to feed (G:F) (P > 0.31). The 56-d BW, ADG, and G:F for CONT were significantly different from both STRW and AMMN (P < 0.001). Exp. 2 utilized 6 ruminally fistulated Holstein heifers (288 kg) in a replicated 3 × 3 Latin square design. There were no observed differences between AMMN and STRW in dry matter (DM), organic matter (OM), or ADF intake (P > 0.57) although CONT differed significantly from both straw treatments in DM, OM, and ADF intake (P < 0.05). Digestibility of DM, OM, and ADF were not different between AMMN and STRW (P > 0.43), where as CONT and STRW were different (P < 0.05). Anhydrous ammonia treatment of wheat straw had no effect on ruminal VFA concentration (P > 0.32). Ruminal pH was not affected by anhydrous ammonia application (P = 0.32), but STRW and CONT were different (P < 0.05). Fluid passage rate was not different among the three treatments (P = 0.33). Wheat straw is a suitable replacement for ammoniated wheat straw at 30% inclusion in receiving and growing diets that contain 40% of dietary DM as wet corn gluten feed. Further research is necessary to determine the effect of varying levels of wheat straw and ammoniated wheat straw in conjunction with wet corn gluten feed and other by-product feeds in receiving and growing diets in order to capitalize on performance and efficiency gains while constraining costs.