Doctor of Philosophy / Diagnostic Medicine/Pathobiology / Steven S. Dritz / The overall goal of this dissertation was to evaluate the effects of different amino acid (AA) levels on performance of pigs under commercial conditions. To reach this objective, a total of 12 experiments were conducted. For the sow research, 1,102 highly prolific sows were used to determine the effects of AA and energy intake during late gestation on piglet birth weight and reproductive performance of sows. Weight gain depended on the energy and AA intake levels while sows fed increased amount of energy had increased stillborn rate; however, there was no statistical differences due to energy intake in stillborn rate of gilts. The modest increase in individual piglet birth weight is due to energy rather than AA intake during late gestation. Pre-weaning mortality was reduced in piglets suckling from sows fed high AA diets during late gestation while subsequent reproductive performance was not affected. With recent advances in statistical computing capability, linear and non-linear mixed models were refined to estimate the AA ratio dose-response relationships. Then, 4 experiments using 2,420 wean-to-finish pigs were conducted to validate the methods for estimating the standardized ileal digestible (SID) AA to lysine (AA:Lys) ratio requirement. Subsequently, 7 experiments using 7,562 pigs were conducted to estimate the SID tryptophan (Trp) to Lys and Valine (Val) to Lys ratio requirements of wean-to-finish pigs. In 11- to 20-kg pigs, optimum SID Trp:Lys ranged from 16.6% for maximum mean G:F to 21.2% for ADG. In 30- to 125-kg pigs, optimum SID Trp:Lys ratio ranged from 16.9% for maximum mean G:F to 23.5% for ADG. However, 18% SID Trp:Lys captured 96 and 100% of the maximum mean ADG and G:F for finishing pigs, respectively. In 25- to 45-kg pigs, optimum SID Val:Lys ratio ranged from 72.3% for maximum mean G:F to 74.4% for ADG with 99% of the maximum mean ADG and G:F at approximately 69% and 65% SID Val:Lys ratio, respectively. In conclusion, optimum SID Trp:Lys and Val:Lys were consistently higher for ADG than G:F. This finding is critical for conducting economic evaluations and reference tables such as NRC (2012) should consider presenting requirement values for different response criteria.

Doctor of Philosophy / Department of Animal Sciences and Industry / Christopher D. Reinhardt / Two studies evaluated dry-rolled corn (DRC) manufacturing considerations in feedlot finishing diets. In study 1, feedlots (n = 35) participated in a survey to evaluate dry-rolled corn (DRC) processing practices, processed corn particle size distribution, and fecal starch content in finishing cattle. Average particle size of dry-processed corn, including DRC and hammermill-ground corn across all operations (n = 35) was 4,223 ± 1,265 µm with a range of 1,165 to 6,823 µm. Fecal starch content averaged 19.0 ± 6.5% with a range of 7.0 to 36.6%. Diet composition was evaluated for co-product [27.8 ± 13.4%] roughage concentration [8.9 ± 2.0%] and NDF concentration [19.3 ± 4.3%]. In study 2, cross-bred yearling steers (n = 360; initial BW = 395 ± 33.1 kg) were used to evaluate the effects of dry-rolled corn (DRC) particle size in diets containing 20% (DMB) wet distiller’s grains plus solubles (WDGS) on feedlot performance, carcass characteristics, and starch digestibility. Treatments were Coarse DRC (4,882 µm; COARSE), Medium DRC (3,760 µm; MEDIUM), Fine DRC (2,359 µm; FINE), and Steam-flaked corn (SFC, 0.35 kg/L). Final BW and ADG were not affected by treatment (P > 0.05). Dry matter intake was greater and G:F was lower (P < 0.05) for steers fed DRC vs. SFC. There was a linear decrease (P < 0.05) in DMI in the final 5 weeks on feed with decreasing DRC particle size. Fecal starch decreased (linear, P < 0.01) as DRC particle size decreased. In situ starch disappearance was lower for DRC vs SFC (P < 0.05) and increased linearly (P < 0.05) with decreasing particle size at 8 and 24-h. The final study evaluated steam-flaked corn (SFC) manufacturing practices implemented, equipment utilized, and methods used and parameters targeted to measure flake quality from commercial feedlots (n = 17). Significant variables contributing to the final multiple linear regression model using enzymatic starch availability (Enzymatic) as the dependent variable were: SFC Moisture, cooled flake density (CoolFD), throughput, roll diameter, steam cabinet temperature (Temperature), and temper time (Enzymatic = 19.4476 - (0.6927*SFCMoisture) - (2.1664*CoolFD) - (0.5060*Throughput) + (0.6281*Roll Diameter) + (0.4312*Temperature) – (0.1963*Temper Time; P < 0.15).

Master of Agribusiness / Department of Agricultural Economics / Ted Schroeder / Selection of a herd sire has always been of paramount importance given the initial financial investment and their contribution and effect on the genetic make-up of a beef herd. Data was collected from the nation’s longest consecutively run bull test conducted at the University Farm of Oklahoma Panhandle State University (OPSU). The Bull Test and Bull Sale data utilized were collected from 2008-2013. Performance data was collected over a 112 day test period with data collection occurring at 28 day intervals. The top seventy bulls from each year’s test were selected based upon a performance index of ½ ADG and ½ weight per day of age (WDA), and a semen quality and motility score of excellent and sold at auction. Angus bulls were the focus of the study as they represented the vast majority of individuals sold. Three hedonic pricing models were created to try to determine what attributes buyers at the OPSU bull test sale were placing emphasis on. The initial hedonic model contained production data that included BW, ADG, WDA, Julian age, final test weight ultrasound data, and a dummy variable for sale year. The second model utilized all production data and added genetic variables in the form of production EPDs (Calving Ease Direct (CED), BW, Weaning Weight and Yearling Weight) and maternal EPDs (Calving Ease Maternal, Maternal Milk). The third model included the variables from the first and second models with the inclusion of carcass EPDs (Marbling, Ribeye Area (REA) and FAT). Year was significant in all three models however there was less of an effect on price as more variables were included. In model one, the production facts that were of significance were: ADG (P<0.01), BW (P<0.01) and final test weight (P<0.01). In the second model, ADG, BW and final test weight retained their significance at the P<0.01 level. The only production EPD that was significant (P<0.05) was CED. In the third model, years, ADG and BW were still significant (P<0.01). Final test weight (P=0.70) and CED (P = 0.132) had substantial changes. The carcass EPD ribeye area had a P value of 0.057. Producers who are placing bulls on test can utilize the given information to assist with their selection. It cannot go unsaid that while single trait selection can be very detrimental; ADG was significant across all models. The study indicates that performance and growth are of utmost importance to buyers, followed by birth weight consideration.

Master of Science / Department of Grain Science and Industry / Greg Aldrich / Water soluble B-vitamins play an integral role in normal metabolic function in cats. For example, thiamine deficiency results in anorexia, neurological impairment, and, in severe cases, death in a few weeks’ time. However, little research has addressed how these vitamins are affected during cat food canning. Thiamine is the most susceptible to degradation during this process, with less known about how it affects the other B-vitamins. Therefore, our objectives were to determine the effects of modifying processing parameters on thiamine and other water-soluble B-vitamins in a model canned cat food. In a series of five experiments, various processing parameters were adjusted: including cook (retort) time, batter moisture and temperature, pH, protein source, and the addition of sulfites. Pressure (172368.93 Pa) and temperature (121 ̊C) within the retort remained the same for all treatments. As retort time increased, thiamine concentration decreased (P ≤ 0.05). No loss of B-vitamin concentration was noted for thiamine, riboflavin, cobalamin, and pantothenic acid as batter moisture increased. Likewise, as batter temperature increased, concentration of riboflavin, niacin, pyridoxine, folic acid, and pantothenic acid remained constant (P ˃ 0.10). When different types of thiamine were included for supplementation, thiamine mononitrate tended to have a greater retention of the vitamin than thiamine hydrochloride (P = 0.12). The protein sources selected for the experiment included chicken as a control, beef liver, chicken liver, pork liver, salmon, tuna, and whitefish. The salmon, tuna, and whitefish were grouped together for analysis. Beef liver, chicken liver, and pork liver were grouped together for analysis. The vitamin retention of each group was compared. When compared to chicken or liver, thiamine retention was greatest in diets containing fish (P≤ 0.05). In addition, riboflavin, niacin, and cobalamin retentions were greatest (P≤ 0.05) in diets containing liver. The addition of sulfites came from dehydrated potatoes added to thediets in exchange for rice. Thiamine tended to decrease in those diets with sulfite containing dehydrated potatoes (P= 0.07) compared to diets containing rice. Pyridoxine and pantothenic acid retention decreased in diets containing dehydrated potatoes (P≤ 0.05) compared to diets containing rice. The largest negative impact on thiamine retention was time in the retort; cobalamin, folic acid, and riboflavin were also negatively affected. Including sulfite-containing potatoes in the diet tended to decrease thiamine, pyridoxine, and pantothenic acid. It was expected that diets containing chicken would retain more thiamine than those formulated with fish and liver. However, diets containing fish retained more thiamine, pyridoxine, and pantothenic acid. Therefore, it appears that processing and diet composition can affect the B-vitamin content of canned cat foods and must be accounted for when producing commercial products.

Doctor of Philosophy / Department of Animal Sciences and Industry / K C Olson / The objective of this series of studies was to examine select factors that affect behavior of beef cattle grazing native-tallgrass rangelands. Mineral supplements with divergent palatability characteristics were delivered to beef cows grazing native tallgrass range during various seasons of the year in order to measure mineral intake, frequency of supplement use, and duration of supplement use. We concluded that molasses-based mineral supplements influenced the activities of grazing cows more strongly than salt-based mineral supplements. These influences extended to the amount of supplement consumed as well as to the frequency, duration, and timing of use. Diet selection preferences of experienced, multiparous beef cows and naïve, primiparous beef cows grazing dormant, native tallgrass pastures were examined also during a short-term winter grazing bout. Naïve, primiparous cows selected more forbs and fewer grasses than experienced, multiparous cows. Previous research indicated that preference for broadleaf plants generally increased with grazing experience; however, these conclusions were based on research with greater-quality forages than those evaluated in our study. The differences in diet selection patterns between experienced, multiparous cows and naïve, primiparous cows during a short-term winter grazing period could be indicative of differences in long-term foraging strategies. In addition, the botanical composition of diets grazed by lactating beef cows with suckling calves and non-pregnant, non-lactating beef cows grazing either burned or unburned native tallgrass prairie during summer were evaluated. There were no differences in botanical diet composition between lactating cows suckling calves and non-lactating cows. In contrast, total graminoid selection was greater on burned (74.2%) than unburned pastures (71.8%) and total forb selection was greater on unburned (28.2%) than burned pastures (25.8%). We interpreted these data to suggest that forage selection preferences of beef cows can be altered with spring burning of native tallgrass pastures. Effects of large, round hay bale feeding method on intake of smooth bromegrass hay and eating behavior by beef cows were examined on dormant tallgrass prairie pastures during winter. Three large, round hay bale-feeding systems were evaluated: bales fed in a ring feeder, bales unrolled on the ground, and bales chopped with a flail-type hay processor (20-cm particle length) and deposited on the ground. Hay intake, hay refusal, frequency of use, and duration of use were not influenced by hay-feeding method. Foraging behaviors of beef cows in our studies were influenced by supplement type, cow age, and prescribed burning of rangeland. Conversely, foraging behaviors of beef cows were not influenced by lactation or by hay-feeding method.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Christopher D. Reinhardt / The effects of supplementing forms of flaxseed on plasma and longissimus muscle (LM) fatty acid (FA) composition, finishing performance, and carcass characteristics were evaluated in five studies. In study 1, steers were fed diets with soy oil (SO), ground flaxseed (Flaxseed), or urea formaldehyde condensation polymer treated flaxseed (UFCP). In study 2, steers were fed diets with SO, linseed oil (LO), or a combination of flaxseed and field peas that was extruded (LinPro). Feeding flaxseed products increased (P < 0.01) α-linolenic acid (ALA), omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to cattle fed SO. Feeding LinPro increased (P < 0.01) ALA, omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to steers fed SO or LO. In studies 3 and 4, steers were fed diets with and without Flaxseed and implanted or not. Implanting improved (P ≤ 0.05) DMI, ADG, feed efficiency, HCW, and LM area compared to cattle not implanted. In study 4, cattle fed Flaxseed had increased (P < 0.01) ALA and omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to cattle fed SO. In study 5, heifers were fed diets with 0% or 5% linseed meal, and administered with or without exogenous hormones (NHTC). Administering exogenous hormones improved (P ≤ 0.02) DMI, ADG, G:F, and HCW compared to NHTC cattle. Omega-3 FA increased in LM when cattle were supplemented with flaxseed products. Cattle fed LinPro achieved the highest levels of ALA and omega-3 FA. Flaxseed products did not interact with implants as a natural growth promoter in finishing cattle.

Master of Science / Department of Animal Sciences and Industry / KC Olson / Condensed tannins (CT) in plants are phenolic compounds with relatively high binding affinities for proteins. In ruminants, dietary CT limit DM intake and digestibility, and ruminal protein degradation by forming CT-protein complexes. Effects of dietary CT, animal species, prior dietary CT exposure, and antimicrobial inclusion on 48-h rate and extent of digestion were measured in two in vitro experiments. Cattle, sheep, and goats (n = 3 / species) were used in a 2-period, randomized complete-block experiment with a 2 × 3 × 2 × 3 factorial arrangement of treatments. Factor 1 was substrate: tannin-free or high-CT. Factor 2 was source of ruminal fluid inoculum: cattle, sheep, or goat. Factor 3 was prior animal exposure to a high-CT diet: non-exposed or exposed. Factor 4 was inclusion of antimicrobials: no antimicrobial, penicillin + streptomycin to suppress bacterial activity, or cycloheximide to suppress fungal activity in the fermentation. Tannin-free or high-CT substrates were incubated in vitro using ruminal fluid from animals either not exposed (period 1) or exposed to dietary CT (period 2). Periods consisted of an adaptation to tannin-free (10 d) or high-CT diets (21 d) and a 15-d period of ruminal-fluid collection via stomach tube. The presence of CT or penicillin + streptomycin in in vitro fermentation reduced (P < 0.001) total gas pressure, DM disappearance, and total VFA, acetate, propionate, butyrate, valerate, and branched-chain VFA concentrations. We concluded that: 1) CT had negative effects on fermentation, 2) prior exposure to dietary CT attenuated some but not all negative effects, and 3) CT effects were similar to the effects of penicillin + streptomycin.

Master of Science / Department of Animal Sciences and Industry / Joel M. DeRouchey / A total of 6,858 pigs were used in 6 experiments to evaluate the effects of crude glycerol, dried distillers grains with solubles (DDGS), Ractopamine HCl (RAC), NutriDense corn, and feeder adjustment on growing and finishing pig performance. In Exp. 1, pigs were fed diets with 0, 2.5, or 5% crude glycerol with 0 or 20% DDGS. Adding DDGS increased ADFI and decreased G:F with no differences for pigs fed glycerol. Neither glycerol nor DDGS affected any carcass characteristics. Pigs fed DDGS had increased iodine value in carcass fat. In Exp. 2, pigs were fed diets with 0 or 5% glycerol with 0 or 7.5 ppm RAC. Feeding RAC increased ADG and G:F and decreased ADFI while glycerol tended to improve G:F. Ractopamine HCl improved carcass traits. Loin chop drip loss worsened when glycerol and RAC were added separately, however, drip loss decreased when the combination of both were fed. Glycerol did not affect loin characteristics. Neither RAC nor glycerol influenced iodine value of carcass fat. Exp. 3 and 4 were conducted to determine the 4th limiting amino acid in diets containing NutriDense corn. In Exp. 3, pigs fed the positive control and the diet with added Ile, Trp, and Val (in combination) had greater ADG. Pigs fed added Ile or Trp had greater ADG than pigs fed the negative control indicates these amino acids were co-4th limiting for 37 to 59 kg pigs. In Exp. 4, pigs fed the positive control, added Trp, or the combination of added Ile, Trp and Val had greater ADG then pigs fed the negative control or pigs fed either Ile or Val indicates these amino acids were co-4th limiting for 77 to 100 kg pigs. Exp. 5 and 6 evaluated feeder adjustment on growth performance of finishing pigs. In Exp. 5, reducing feeder opening decreased ADFI. In Exp. 6, pigs were fed at three feeder opening and either a corn-soybean meal or byproduct-based diet. Diet type did not affect pig performance. Widening feeder openings increased ADG and ADFI. Feeder setting tended to influence G:F with the best G:F at the intermediate opening.

Doctor of Philosophy / Department of Animal Sciences and Industry / Duane Davis / Umbilical cords matrix stem cells (UCs) have been characterized most thoroughly in humans (HUCs) and are considered to have great promise for regenerative medicine and cell-based therapy. Although UCs were first identified in pigs the description of porcine UCs (PUCs) is limited. Here we reported some standard mesenchymal stem cell characteristics for PUCs. Development of knowledge about PUCs is useful because the pig is a valuable biomedical model for humans and the species is an important human food source. PUCs were isolated from Wharton’s jelly using an explant technique. They attached on the plastic and showed fibroblast-like morphology. Immunophenotype analysis showed they are positive for CD44, CD90 and CD105 and negative for CD31, CD45 and SLA-DR. Under specific in vitro conditions, PUCs were differentiated to adipocytes, chondrocytes and osteocytes. The growth curve of PUCs exhibited a lag phase, log phase and doubling time of 24, 60 and 13.8 hour respectively. Engraftment potential of allogeneic PUCs administered orally and intraperitoneally (IP) was evaluated. Newborn, 1-day, 1-week, 2-week and 3-week old pigs were administered a dose of fluorescently labeled PUCs (1.1x107 cells/kg body weight) and their tissue incorporation were evaluated using confocal microscopy with confirmation by PCR to detect SRY gene, the Y-chromosome gene of male PUCs in female recipients. One week after PUCs administration, they were found mostly in the gastrointestinal tract and abdominal organs after either oral or intraperitoneal transplantation. The intestinal mucosa layer around the base of villi and intestinal crypts was the main location. PUCs were also detected in thoracic organs, muscle and bone marrow. Additionally, PKH26-labeled fibroblasts labeled were detected in recipient intestine 1 week after IP injection. Donor cells were not found in blood at one week post transplantation. When recipients were sacrificed at 6 h after IP injection PKH26-labeled PUCs were found mostly in omentum and diaphragm by PCR. It is likely these are the primary sites for donor cells in the peritoneal cavity to enter the circulation. Fluorescent in situ hybridization (FISH), using an SRY probe and PCR, demonstrated the PUCs isolated from recipient intestines by enzymatic digestion. Therefore, transplanted PUCs were recovered from the intestinal mucosa and were viable and able to proliferate in vitro.

Doctor of Philosophy / Department of Animal Sciences and Industry / Curtis Kastner / The U.S. agriculture industry is diverse and dynamic, plays a vital role in the nation’s economy, and serves as a critical component in providing the global food supply. Agriculture has and always will be susceptible to threats such as pests, disease, and weather, but it is also threatened by intentional acts of agroterrorism. One specific area of concern is foreign animal diseases (FAD) and the danger these diseases create for the U.S. livestock industry. Whether a disease outbreak is intentional or accidental, it could devastate animal agriculture and the food infrastructure and have a lasting impact on state, national, and global economies. One of the most economically devastating diseases that raise fear and anxiety in the livestock industry is foot and mouth disease (FMD). A number of administrative, regulatory, and legislative actions have been implemented at state and federal levels designed to protect the agriculture industry and to prevent, prepare for, and respond to an accidental or intentional introduction of an FAD. However, the consistency, clarity, and long-term commitment of these policy approaches remains in question. Effective policy decisions require a multidisciplinary approach that consider and balance science, economics, social factors, and political realities. A significant number of policy analysis tools exist and have been applied to animal emergency scenarios but few actually address the complexity of these policy dilemmas and provide information to policymakers in a format designed to help them make better decisions. Policy development needs to take a more multidisciplinary approach and better tools are needed to help decision makers determine the best policy choices. This dissertation analyzes three FAD policy dilemmas: mass euthanasia and depopulation, carcass disposal, and vaccination. Policy tools are developed to address the multidisciplinary nature of these issues while providing the information necessary to decision makers in a simple and useful format.