Master of Science / Department of Animal Sciences and Industry / Jim L. Nelssen / Eight experiments used 1,712 pigs to determine influences of dietary enzymes or specialty proteins on nursery pig performance. Experiments 1 and 2 evaluated the effects of fish meal, fermented soybean meal, or dried porcine solubles on performance. Experiment 1 showed pigs fed dried porcine solubles had improved (P = 0.01) ADG and G:F compared to pigs fed the control diet, and improved (P = 0.03) G:F compared to pigs fed the combination of fermented soybean meal and fish meal. Experiment 2 showed pigs fed increasing fermented soybean meal had improved (quadratic, P = 0.03) G:F. Experiments 3 and 4 evaluated the effects of commercial enzyme addition to diets containing dried distillers grains with solubles (DDGS) on performance. In experiment 3, neither DDGS nor enzyme addition influenced (P > 0.10) ADG and G:F. Experiment 4 found there were no (P > 0.32) enzyme × DDGS source interactions. Corn DDGS did not influence pig performance (P > 0.36). Sorghum DDGS reduced (P = 0.003) G:F, with no difference between sorghum DDGS sources. Adding enzymes to 30% DDGS diets did not improve (P > 0.57) performance. Experiments 5 and 6 evaluated the effects of fish meal (SMFM), spray-dried animal plasma (SDAP), or peptone on performance. In Experiment 5, different specialty proteins had similar (P > 0.10) ADG, ADFI, or G:F. Experiment 6 showed pigs fed 4% Peptone 2 during phase 1 and 2% Peptone 2 during phase 2 had improved (P < 0.05) ADG compared to pigs fed SMFM, and improved (P < 0.05) G:F compared to pigs fed all other diets. Experiments 7 and 8 developed an available P release curve for commercial phytase products. In both experiments, pigs fed increasing inorganic P had improved (linear, P < 0.01) G:F and percentage bone ash. Pigs fed increasing OptiPhos 2000-M, Phyzyme XP, or Ronozyme P had improved (P < 0.001) percentage bone ash. Available P release for up to 1,000 FTU/kg of Escherichia coli-derived phytases can be predicted by the equation (y = -0.000000125x[superscript]2 + 0.000236245x + 0.015482), where x is the phytase level in the diet.

Doctor of Philosophy / Department of Animal Sciences and Industry / James S. Drouillard / A series of studies were conducted to evaluate extrusion processing of finishing diets on growth performance, carcass characteristics, and meat quality attributes of feedlot cattle. Extruded diets were processed in a 24:1 (length/diameter) corotating, fully intermeshing twinscrew extruder (model BCTG-62, Bühler AG CH-9240, Uzwil, Switzerland). In Experiment 1, extrusion processing of corn based diets decreased dry matter intake (DMI) and improved gain efficiency (G:F) by 15% compared to heifers fed steam-flaked corn (SFC) diets. Carcass characteristics were not different between treatments. Steaks from heifers fed SFC diets were juicier and had a less pronounced off-flavor than steaks from heifers fed extruded diets. In Experiment 2, average daily gain (ADG), DMI, G:F, carcass characteristics, and meat quality attributes were not different between heifers fed SFC and extruded processed corn diets. In Experiment 3, we evaluated different degrees of extrusion processing by altering the level of process water added to the extruder. Mechanical energy inputs, die pressure, die temperature, and torque of drive motor decreased as the level of water added to the extruder increased from 4% to 12%. Water addition did not affect DMI or ADG of feedlot heifers. However, live body weight (BW) and G:F decreased as the level of process water increased. Gain efficiency (carcass-adjusted basis) was 3% greater for extruded corn diets processed with 4% water compared with SFC diets and was 6% poorer than SFC diets when processed with 12% water. Apparent total tract digestibility was not different, but IVDMD improved with increasing levels of water. Improvements in G:F when fed extruded feed was variable among the 3 studies. This may be due, in part to severe infestation by European Starlings during Experiment 1. Impact of feed depredation by starlings was therefore evaluated. Starlings consumed 86% of the SFC diet offered to them compared to, none of the extruded corn diets. In addition, starlings preferentially selected for the energy dense portion of the rations (steam-flaked corn). Therefore, it is plausible that a portion of the 15% improvement in G:F observed in Experiment 1 for heifers fed extruded corn diets can be attributed to differences in feed depredation by starlings. Finally, two studies were conducted to evaluate extrusion processing of sorghum-based diets. In the first experiment, DMI was greater and G:F was poorer for heifers fed extruded sorghum diets compared to heifers fed steam-flaked sorghum (SFS) diets. However, carcass characteristics and meat quality attributes were not different. In the second study, particle size of the ground sorghum added to the extruder was evaluated. Processing sorghum to a smaller particle size (581 μm) prior to extrusion processing decreased DMI, improved G:F, and increased apparent total tract digestibility compared with larger particle sizes (1,264 μm). However, heifers fed SFS diets were still more efficient that heifers fed extruded diets made with either particle size of sorghum. Overall, this research suggests that extruding complete diets into homogeneous pellets may improve G:F of cattle fed corn-based diets while reducing feed depredation of starlings. It is also clear from our results that G:F is improved to a greater extent to processing diets under high shear conditions (i.e., high mechanical energy inputs) than when processed under low shear conditions.

Master of Science / Department of Animal Sciences and Industry / Joe D. Hancock / Nine experiments were completed to evaluate the effects of feed manufacturing practices on milling characteristics of diets and growth performance and stomach morphology in pigs. In Exp. 1 and 2, reducing the particle size of sorghum from 800 to 400 μm improved (P < 0.04) efficiency of gain in finishing pigs by 5% but had negative effects on cost of milling and stomach morphology. In Exp. 3 and 4, finishing pigs fed diets with 10 mg/kg of ractopamine HCl, had improved (P < 0.05) ADG, G:F, HCW, dressing percentage, and percentage carcass lean. However, increasing mix time of the diet from 0 to 360 s did not affect (P > 0.06) the response of finishing pigs to ractopamine HCl. In Exp. 5 and 6, adding ground and cracked corn to a pelleted supplement for nursery pigs decreased (P < 0.01) growth performance compared to feeding a complete pellet. In Exp. 7, increasing the percentage of cracked corn in a diet for finishing pigs decreased development of stomach lesions but also had a generally negative effect on efficiency of gain. In Exp. 8, adding cracked corn to a pelleted supplement (as done for the nursery pigs) decreased milling costs and improved health of stomach tissue. But, G:F was decreased by 6% (P < 0.05) which will make this technology unattractive to swine producers. In our final experiment (Exp. 9), pigs fed pellets tended to have the greatest growth performance, pigs fed mash the worst, and pigs fed pellets for only part of the grow-finish phase fell in between. In conclusion, grinding sorghum-based diets for finishing pigs improved efficiency of growth but extensive mixing to maximize diet uniformity had no effect on growth performance or carcass measurements. Use of cracked corn in diets does decrease diet costs and improve stomach health in finishing pigs but feeding of complete pellets for the entire finishing period supports maximum rate and (or) efficiency of gain.

Master of Science / Department of Animal Sciences and Industry / Teresa L. Slough / Teresa L. Slough / There is increasing interest in the use of point-of-care glucometers to monitor glucose concentrations in horses with metabolic disorders. The first study reported herein compared equine glucose concentrations obtained by a handheld glucometer using whole blood or plasma, a YSI 2300 bench top glucose analyzer using whole blood or plasma, and a SEVEN continuous glucose monitoring (CGM) device that measured glucose in interstitial fluid to readings obtained by a standard laboratory glucose analyzer utilizing plasma. In addition, glucose concentrations obtained by the CGM were compared to those obtained by the handheld glucometer using whole blood or plasma. Post-prandial increases and decreases in glucose concentrations were detected utilizing all glucometers tested. When glucose measurements obtained with the CGM in interstitial fluid were compared to glucose measured using the handheld glucometer in plasma or whole blood, glucose measurements from plasma had better reproducibility. Although the CGM could be a useful instrument for collecting nearly continuous data for the researcher and clinician, there are technical difficulties related to the CGM that must first be overcome. The second study was designed to compare the effects of consuming a twice-daily meal of sweet feed (SF) to ad libitum access to a molasses-based block (BL) supplement on patterns of interstitial glucose concentrations in horses. A novelty effect of the BL was observed, in which horses consumed increased quantities in the first 12 h. Treatments had no effect on intake of forage in this study. The range and means of glucose values were similar between treatments, and significant glucose responses to treatments had lag times that were indirectly similar, even though molasses intake was greater for horses on BL. Variability between horses was noted in quantity of BL consumed as well as timing and magnitude of glucose responses. Based on the results of this experiment, there does not appear to be a clear advantage to either treatment, SF or BL, in attenuating post-prandial glucose increases or in minimizing glucose fluctuations in the horse.

Doctor of Philosophy / Department of Psychology / Jerome Frieman / The present experiment investigated whether dwarf hamsters (Phodopus campbelli) demonstrate temporal discounting. This was investigated by comparing the behavior of dwarf hamsters and Sprague-Dawley rats (Rattus norvegicus) in an adjusting delay procedure and applying the theory of behavioral economics to explain the resulting behavior. Dwarf hamsters demonstrated temporal discounting and tolerated longer delays than did the more impulsive rats. There was not a statistically significant difference between these species concerning indifference points. There was a statistically significant difference in the slopes of their discounting functions and the delay at which the end criterion was met. Neither species exhibited sex differences with respect to these measures nor with storage of food. There were a number of differences between the species. Rats started responding quickly, whereas dwarf hamsters waited significantly longer. When faced with increasing delays, rats increased the number of pellets earned while dwarf hamsters earned the same amount. Finally, rats lost weight throughout the experiment while dwarf hamsters gained weight. There were also a number of similarities. When faced with an increasing delay, both rats and dwarf hamsters increased the number of responses made, and increased the number of times they timed out on Larger Later trials. Some of these findings disagree with previous research and predictions of the behavioral economic theory of demand, creating a need for further research.

Master of Science / Department of Clinical Sciences / Luciana Bergamasco / As public concern for food animal welfare increases, the need for objective pain assessment and methods to alleviate pain associated with production practices such as castration gains attention. The aims of this study were (i) to evaluate the physiological response to pain induced by castration in calves and (ii) to elucidate age-related differences in pain response of calves subjected to different castration methods. Seventy six Holstein bull calves were blocked by age (≤ 6 weeks and ≥ 6 months) and randomly assigned to one of four treatment groups: control (n = 20), castration by banding (n = 18), cut and clamp surgical castration (n = 20), and cut and pull surgical castration (n = 18). Measurements included electroencephalogram, heart rate variability, infrared thermography, electrodermal activity, and concentrations of serum cortisol, and plasma substance P prior to, during, and following castration. Electroencephalogram recordings showed desynchronization for all treatments, consistent with increased arousal; yet the magnitude of desynchronization was greatest for 6-month-old calves castrated by cut and clamp. Additionally, older calves in the cut and pull group showed greater desynchronization than younger calves in the same group. Based on the heart rate variability analysis, 6-month-old calves in the control or cut and pull castration groups showed greater sympathetic tone than younger calves in the same treatment groups. Overall, younger calves showed lower electrodermal activity than older calves. Regardless of treatment, concentrations of cortisol and plasma substance P were greater in 6-month-old calves relative to their younger counterparts. In summary, neurohormonal and electroencephalographic stress responses of calves to castration were age-specific. Castration by cut and clamp showed the most pronounced stress response in 6-month-old calves.

Master of Science / Department of Animal Sciences and Industry / Joel DeRouchey / Thirteen experiments using a total of 7,589 nursery and finishing pigs were conducted to evaluate the effects of deoxynivalenol (DON), feed additives and processing conditions on nursery pig growth performance. In addition, feed withdrawal and diet blending were evaluated in finishing pigs. Experiment 1 tested 3 feed additives in DON-contaminated diets with only Defusion Plus improving performance. Experiment 2 evaluated Biofix in both low- and high-DON diets and showed no effects on growth. Experiments 3 and 4 further evaluated levels of Defusion and the effects of pelleting and supplemental nutrients in DON-contaminated diets. Defusion improved growth in low-DON diets, but had variable effects in high DON diets. Pelleting DON-contaminated diets resulted in comparable growth to pigs fed positive control diets in meal form. In Exp. 5 and 6, pilot studies evaluated DON-detoxification using sodium metabisulfite (SMB) with hydrothermal treatment in both an autoclave and a pellet mill. These conditions reduced analyzed DON by as much as 89 and 75% for the autoclave and pellet mill, respectively. In Exp. 7 and 8, pelleting DON-contaminated diets with SMB improved growth. Experiments 9 and 10 evaluated feed-withdrawal time on carcass composition and economic returns. These experiments showed that pre-slaughter fasting for up to 36 h prior can be used to avoid weight discounts in heavyweight pigs without negatively impacting carcass composition and maintaining overall revenue. However, these advantages come with a potential reduction in carcass weight and increased incidence of leaking ingesta, which can result in condemned heads. Experiments 11, 12, and 13 compared phase-feeding to blending diets using an automated feed delivery system. These studies showed that corn-supplement blending is not economical and feeding diets blended to a Lys curve results in lower feed costs compared to phase-feeding, but due to reductions in growth and carcass weight, these savings do not translate into higher income over feed cost. Finally, Exp. 13 showed that over- and under-budgeting situations do not significantly influence overall returns, but pigs fed under-budgeted diets performed more closely to those fed correctly estimated feed budgets.

Doctor of Philosophy / Department of Animal Sciences / Barry Bradford / The transition into lactation is a period of primary concern to dairy producers because of the tremendous incidence of health disorders observed during this time. Two common disorders that lead to decreases in production and retention within the herd include fatty liver disorder (FL) and ketosis. These two disorders have been commonly associated with negative energy balance, yet recently it has been hypothesized that inflammation is a contributor to the etiology of these disorders. Three individual projects were completed for this dissertation, all involving inflammation. The role of endogenous inflammation was determined by administration of sodium salicylate (SS) to cows for 7 d after parturition, and metabolites and production responses were evaluated. Overall it appears that SS induced hypoglycemic conditions and increased triglyceride accumulation in the liver (while administered), increased lipid mobilization and ketones (2 weeks after administration ended), and increased whole lactation milk production in older cows. A sensitive, specific sandwich ELISA for bovine tumor necrosis factor-[alpha] was developed, which provided the ability to measure “normal” circulating levels of this cytokine. The final study involved inducing inflammation by daily injections of the TNF[alpha] to the early lactation dairy cow. In this model, cows receiving TNF[alpha] had a reduction in dry matter intake, water intake, and decreases in milk production and milk components. Overall, it appears that inflammation is involved in the normal biology of the transition dairy cow and disrupting this can lead to interesting negative effects and some improvements of production; however, when inflammation is much greater it can lead to negative production effects.

Master of Science / Department of Animal Sciences and Industry / Timothy G. Rozell / Malnourished piglets that suffer from periweaning failure to thrive syndrome (PFTS) may show no signs of respiratory or enteric diseases but may have decreased feed intake and become debilitated after weaning. Euthanasia is a necessary component of swine production as it is sometimes the only option to alleviate suffering of piglets that are born with congenital defects or suffer from PFTS. Fifty-eight nursery-aged piglets were utilized in two experiments to evaluate blood parameter differences between healthy and unthrifty piglets and to compare euthanasia methods. Piglets were categorized into two health groups: healthy or unthrifty. During selection, blood was collected for analysis of blood parameters. Piglets were euthanized 24-32 hours after initial blood sampling and a second sample was collected for comparison. After euthanasia, piglets were necropsied for evaluation of euthanasia on pulmonary lesions. No significant difference in number of pulmonary lesions was found between health groups (P = 0.88). Healthy piglets had higher concentrations of glucose, ionized calcium and sodium, and greater pCO₂ than unthrifty piglets (P ≤ 0.05). Unthrifty piglets showed higher concentrations of hemoglobin and hematocrit (P = 0.0002) than healthy piglets. Piglets were assigned to one of two euthanasia methods to compare electrophysiological and behavioral parameters of hypobaric hypoxia and carbon dioxide gas. Two piglets at a time were euthanized for each method. One animal in the pair was fitted with electrocardiogram and electroencephalogram monitoring devices during euthanasia. Behavioral parameters were also recorded. The average treatment times were 27.4 ± 6.7 minutes for HH and 13.8 ± 5.1 minutes for CO2. Piglets euthanized via CO2 reached an isoelectric state faster than piglets euthanized via HH (P = 0.009). Behavioral observations revealed gasping in 100% of CO2 euthanized piglets during the first five minutes of treatment and only 28.6% of HH euthanized piglets during the same period. During HH, 57.1% of piglets became ataxic in the first five minutes while 76.9% of CO2¬ piglets became ataxic during the same period. Results of this trial indicate that HH may be a lower stress alternative to CO₂ as it causes fewer incidences of aversive behaviors in early stages of treatment.

Master of Science / Department of Animal Science and Industry / L.N. Edwards-Callaway / This thesis includes two studies that assessed pain responses to husbandry procedures in order develop mitigation tools. The objective of the first trial was to identify method-related differences in behavioral pain responses in calves of two ages (6 week and 6 months) subjected to castration: surgical cut (CP; n=18), surgical cut and emasculator (CC; n=20), rubber banding (BAND; n=18), or control manipulation of the scrotum (CONT; n=20). Behavior was evaluated pre- and post-castration to record foot stamps, tail flicks, kicks, elimination, in addition to standing and lying post-castration. For 6 week calves, the probability of kicking and eliminations was greater for surgical castrates and all castrated animals, respectively. The probability of kicking was greatest for all 6 month castrates while BAND and CONT had greater probability of elimination. Both age groups increased standing post-castration. Lying decreased in 6 week calves but was unchanged for 6 month calves. Six week calves displayed more tail flicks and tended to display less foot stamps than 6 month calves. Six week calves showed a decrease in tail flicks and foot stamps in response to castration while 6 month calves showed an increase in both behaviors. CP and CC, but not BAND, resulted in less tail flicks than CONT post castration. The second trial compared the effects of preemptive analgesics administered to calves subjected to dehorning with local anesthesia. Six month Holstein steers were randomly assigned to receive one of the following treatments (n= 8/group): meloxicam (1 mg/kg PO), gabapentin (15mg/kg PO), meloxicam (1 mg/kg) and gabapentin (15 mg/kg) PO, flunixin (2.2 mg/kg IV), or a placebo. Drug, cortisol, ex-vivo prostaglandin, haptoglobin, and substance P concentrations, ocular thermography, algometry, and average daily gain were evaluated. Analgesic-treated calves had lower plasma SP concentrations and improved ADG compared with controls. Flunixin calves had reduced cortisol and ex-vivo prostaglandin concentrations for 24h compared to controls. Meloxicam treated calves showed an increase in MNT at two horn bud sites compared with the other treatments. Overall, the results provide validation of responses to noxious stimuli that can be used to develop pain alleviation for livestock.