Doctor of Philosophy / Department of Animal Sciences and Industry / Michael D. Tokach / Five experiments were performed to determine the influence of creep feeding on individual consumption characteristics and growth performance of neonatal and weanling pigs. These evaluated the effects of lactation feed intake and creep feeding (n = 84 litters; Exp. 1), creep feeding duration (n = 54 litters; Exp. 2), creep feeder design and feed accessibility (n = 54 litters; Exp. 3), organoleptic properties of the creep feed (n = 50 litters; Exp. 4) and creep diet complexity (n = 96 litters; Exp. 5). In summary, creep feeding did not affect preweaning gains and weaning weights of pigs weaned at 3 weeks of age. Creep feeding for 18 d did not influence sow performance. However, creep feeding tended to improve litter weaning weights due to improved survivability. Creep feed consumption was related to piglet maturity rather than the induction of creep feeding. In both experimental and field conditions, pigs that consumed creep feed (eaters) had greater post-weaning feed intake and daily gains compared to non-eaters (pigs that did not consume creep feed) and non-creep fed pigs. This led to improvements in pig weight uniformity and reduction of the severity of post-weaning lag. These benefits were achieved regardless of weaning weight, the complexity of the creep diet, and the duration of creep feeding. The proportion of eaters of creep feed in whole litters can be manipulated. Longer duration of creep feeding increased the proportion of eaters. A rotary creep feeder with a hopper created the most eaters with the lowest creep feed disappearance. Creep diet complexity had the greatest effect in increasing the proportion of pigs consuming creep feed. On the other hand, low feed intake of lactating sows and adding feed flavors to the creep feed did not affect creep feed consumption and the proportion of pigs consuming creep feed. Therefore, creep feeding that focuses in encouraging more suckling piglets to eat is beneficial in producing weanling pigs that are better adapted to weaning, which improves post-weaning performance.

Master of Science / Department of Animal Sciences and Industry / Micheal J. Brouk / Supplemental phosphorus (P) in varying forms and sources: pellet (PELLET), meal (MEAL), liquid (LIQUID) and corn dried distiller’s grains with solubles (DDGS) were compared in twelve multiparous Holstein cows producing approximately 43 kg of milk (115 [plus minus] 55 DIM) in a 4x4 Latin square with 21d periods. PELLET and MEAL diets contained monocalcium phosphate with a wheat middlings carrier, and the LIQUID contained ammonium polyphosphate in a cane molasses base. The DDGS supplied an organic P source. Cows were blocked by parity, DIM and milk production and randomly assigned to treatments. Data were analyzed using the MIXED model procedure of SAS. Phosphorus intakes of 116, 116, 119 and 118 g/d were similar for PELLET, MEAL, LIQUID and DDGS diets, respectively. Cows consuming the LIQUID diet experienced greater sugar intakes (P<0.001). Fat intake was lower (P<0.001) for the PELLET, MEAL and LIQUID diets compared to the DDGS diet (1.14, 1.12, 1.07 and 1.36 kg/d, respectively). NEL intake was similar for all treatments (P=0.55). Milk yield differences (P=0.05) occurred with the DDGS diet yielding the most milk (34.6, 35.4, 34.1 and 36.5 kg/d). No differences resulted for either milk fat (P=0.26) or milk protein (P=0.33) percentages or for daily lactose production (P=0.22). Excretion of P in feces tended (P=0.07) to differ between treatments (67.4, 66.3, 57.5 and 60.0 g/d) resulting in a trend (P=0.10) for greater P retention in diets excreting less P. Secretion of P in milk did not differ (P=0.51) between treatments. Differences (P=0.04) occurred in P concentration between diets (0.47, 0.47, 0.49 and 0.47%), but the amount of P fed was not different (P=0.83). With similarities for DMI and P concentration in refusals (P=0.21) it may be deduced that sorting of the P supplement did not occur. These data show that supplemental P sources do not affect DMI or P intake, however P source resulted in slight differences in P utilization, but it was not related to sorting of the diet. Utilizing DDGS showed similar responses to inorganic P mineral supplements with favorable production yields making it an adequate substitute for mineral sources of P.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / A trial was conducted replacing portions of steam-flaked corn with either dry-rolled corn or dried distiller’s grains with solubles to evaluate effects on performance, carcass characteristics, carcass composition, meat color stability, and meat sensory attributes. Seven hundred crossbred yearling heifers (302 ± 65 kg initial BW) were used in a randomized complete block experiment with a 2 x 2 factorial arrangement of treatments. All diets contained steam-flaked corn (SFC), and factors consisted of the levels of dry-rolled corn (DRC; 0 or 25%) and dried corn distiller’s grains with solubles (DDGS; 0 or 25%). Results revealed no interactions between DRC and DDGS in terms of effects on feedlot performance, and only minor interactive effects were observed for carcass characteristics and meat quality attributes. Feedlot performance and carcass characteristics were not affected by the addition of DRC or DDGS (P > 0.05). Carcass composition and meat quality attributes were measured to determine if fat content of carcasses was altered by feeding DDGS. Diet had no significant effects, as carcasses from the four treatments contained similar amounts of separable portions of muscle, adipose, and bone; and similar percentages of protein, moisture, and ether extract. Compositions of both adipose and muscle tissue were evaluated to assess differences in fatty acid profile. Minimal effects were noted on the fatty acid profiles of the muscle and adipose tissue from cattle fed DDGS or DRC. Feeding cattle DDGS decreased alpha tocopherol (vitamin E) content of meat (P < 0.05). Meat quality attributes were largely unaffected by addition of DRC or DDGS to the diet, as retail color display life, lipid oxidation, sensory attributes, and heterocyclic amine concentrations were not different among treatments. Overall, DRC or DDGS can replace portions of SFC without negatively altering feedlot performance, carcass characteristics, meat composition, or meat quality attributes.

Master of Science / Department of Animal Sciences and Industry / J. Ernest Minton / It has been well documented that omega-3 PUFA (n-3 PUFA) can confer a wide variety of health benefits to humans and animals. The current study was designed to evaluate the ability of n-3 PUFA to modulate the innate immune response in two diverse breeds of horses. Ten Quarter Horse and 10 American Miniature Horse mares were assigned to either an n-3 PUFA supplemented or control diet (5 full-sized and 5 miniature mares/treatment) for 56 d. The treatment diet was designed to deliver 64.4 mg/kg BW combined eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) daily. Whole blood (20 mL) was collected via jugular veinipuncture into heparinized tubes on 0 d, 28 d, and 56 d. Serum PUFA analysis was conducted by gas chromatography. Peripheral blood mononuclear cell (PBMC) production of tumor necrosis factor-alpha (TNFalpha) in response to toll-like receptor (TLR) ligands lipopolysaccharide (LPS), flagellin, and lipoteichoic acid (LTA) was estimated using an equine-specific ELISA. Peripheral blood samples from d 56 were also analyzed for total and differential leukocyte counts and subjected to flow cytometric analysis. Body type did not affect basal or TLR stimulated TNFα production. Serum PUFA analysis revealed a decrease in linoleic acid (LA) and substantial increases in arachidonic acid (ARA), EPA, DHA, and docosapentaenoic acid (DPA) at both d 28 and 56 in horses fed n-3 PUFA (P less than 0.0001 for all). Dietary n-3 PUFA supplementation reduced (P less than 0.05) un-stimulated basal, but not TLR stimulated TNFalpha production by PBMC’s. Supplementation with n-3 PUFA did not affect total or differential leukocyte counts, nor selected cell surface markers. These results suggest that n-3 PUFA supplementation in the horse can modify circulating PUFA and alter the inflammatory response by reducing basal TNFalpha production. Furthermore, under conditions of the current study and considering the endpoints evaluated, the American Miniature Horse could potentially be used as a model for full-sized horse breeds.

Master of Science / Department of Animal Sciences and Industry / Joann M. Kouba / The objective of this study was to evaluate the reproductive effects of supplementing normally cycling mares with marine-derived omega-3 (n-3) fatty acids during the estrous cycle. Fifteen mares were assigned to a control diet (CONT, n=7) or a fish oil supplemented diet (FO, n=8) containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The FO mares received 18.48 g EPA/10.08 g DHA/mare/d. At the start of the trial, mares were synchronized using a progesterone and estradiol protocol. Following synchronization, mares were monitored with transrectal ultrasonography throughout the second estrous cycle. Ovarian activity, ovulation, and presence of a corpus luteum were noted. Mares were ultrasounded throughout the third estrous cycle until a 35 mm follicle was detected. Upon detection of the 35 mm follicle, hCG was administered. Within 16 hr, transvaginal ultrasound-guided follicular aspiration (TUGA) was performed on the preovulatory follicle, signifying the end of the trial. Follicular fluid was analyzed for fatty acid and hormone concentrations. Serum fatty acids were measured every 2 wk and serum hormone concentrations were analyzed during the second estrous cycle at 5 d to 1 d prior to ovulation, at ovulation, and 3 and 5 d post-ovulation. Samples were also collected prior to hCG administration and on aspiration day for hormone analysis. Serum estradiol-17β, progesterone, luteinizing hormone (LH), and insulin-like growth factor 1 (IGF-1) were measured. Fish oil supplementation increased (P < 0.01) arachidonic acid (ARA), EPA, docosapentaenoic acid (DPA), and DHA in mare serum and increased (P<0.01) EPA, DPA, and DHA in follicular fluid. No overall treatment effect was found on serum hormone concentrations during the second estrous cycle, but a decrease (P<0.05) in IGF-1 was noted in the FO group on aspiration day. Concentrations of IGF-1 were also lower (P<0.05) in follicular fluid in the FO group compared to controls. No other follicular fluid differences were observed. Supplementation resulted in a smaller diameter follicle (P<0.05, 38.0 ± 0.47 mm) on aspiration day than the CONT group (39.5 ± 0.5 mm). Dietary n-3 fatty acids modify mare serum and follicular fluid fatty acid profiles, with supplementation of EPA and DHA decreasing serum and follicular IGF-1 concentrations.

Master of Science / Department of Animal Sciences and Industry / Michael E. Dikeman / The longissimus lumborum (LL) muscle from 117 steers and the LL, gluteus medius (GM), and triceps brachii (TB) from 132 heifers were obtained to evaluate the effects of feeding zilpaterol hydrochloride (Zilmax®; ZH) (7.56g/907kg on a 100% DM basis) on tenderness. Both genders were blocked by initial weight into 6 blocks of 4 pens. Pens were assigned to treatments of either 0, 20, 30 or 40 d on ZH, with a 3 d withdrawal. One steak was removed from each muscle for proximate analysis and three 2.54 cm thick steaks were vacuum aged for either 7, 14 or 21 d. Steaks were cooked to 70 ˚C and six 1.27 cm diameter cores were removed for Warner-Bratzler shear force (WBSF) determinations. All muscles from steers and heifers fed 30 and 40 d with ZH, had higher (P < 0.05) WBSF compared with controls. The WBSF of steer LL and heifer TB from the 20 d treatment was higher (P < 0.05) than controls. There were no treatment by aging interactions (P > 0.05) for WBSF of steaks from steer LL, heifer LL or heifer TB, but there was a treatment by aging interaction (P < 0.05) for WBSF of steaks from heifer GM. There were no differences (P > 0.05) in percent intramuscular fat for any muscle due to treatment. When using percent intramuscular fat as a covariate, differences in WBSF of steer LL and heifer TB were not altered, but there were slight differences in heifer LL and GM WBSF due to treatment when compared with not using percent fat as a covariate. Percentages of steaks with WBSF ≥ 5 kg increased as days on ZH increased and decreased as days of aging increased. Warner-Bratzler shear force values among the three aging times for steer LL control, 20 and 40 d treatments; all heifer LL treatments, and heifer TB 20 d were all positively correlated (P < 0.01) with each other. Feeding ZH for 20 d generally increased WBSF values, but means were still acceptable. Feeding ZH for 40 d was very detrimental to tenderness.

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.

Doctor of Philosophy / Department of Animal Sciences and Industry / Barry J. Bradford / The transition period in dairy cows is characterized by dramatic increases in nutrient requirements for lactation and substantial metabolic stress. The disturbed metabolic balance, coupled with suppressed immune function, contributes to markedly elevated incidence of health disorders. Several lines of evidence suggest that increased inflammation is common during the transition period. Unlike the classical inflammation associated with acute infection, the postpartum inflammatory state is low-grade and often of metabolic origin. This metabolic inflammation plays a key role in numerous disorders; an improved understanding of inflammatory pathways in transition cows may improve our ability to predict and prevent disorders. To mimic metabolic inflammation, in Experiment 1, we administered low amounts of recombinant bovine tumor necrosis factor-α (rbTNFα), a pro-inflammatory cytokine, to early lactation cows, and evaluated whether rbTNFα affects milk production, metabolism, and health. We found that rbTNFα administration increased systemic inflammation, decreased feed intake and milk yield, and increased incidence of disorders. Conversely, preventing excessive inflammation has the potential to improve productivity and health of dairy cows. To identify nutritional strategies that could enhance metabolism and immunity, we evaluated the efficacy of several feed additives. In Experiment 2, we evaluated effects of chromium propionate, rumen-protected lysine and methionine, or both on metabolism and immunity in lactating dairy cows, and found that supplementation of these nutrients may enhance neutrophil function. In Experiment 3, we determined whether supplementation of yeast product to transition cows could enhance production, metabolism, and immunity, and found that yeast product modulated feeding behavior, metabolism, immunity, and uterine inflammation. Overall, a greater understanding of the role of metabolic inflammation in the transition period and the nutritional strategies that could modulate these signals may improve the production and health of dairy cows.