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.

My objectives were to determine if nutritional benefits occur when animals are offered foods with compounds -- alkaloids, saponins, and tannins - that are potentially complementary. I hypothesized that food intake and digestibility increase when lambs consume plants such as alfalfa ALF that contain saponins or birdsfoot trefoil (BFT) that contain tannins when the basal diet is endophyte-infected tall fescue (TF) or reed canarygrass (RCG) both of which contain alkaloids. I predicted that the nutritional status of lambs would be enhanced if basal diets of alkaloid-containing grasses were supplemented with ALF or BFT. Lambs fed a basal diet of either endophyte-infected TF or RCG ate more food and consequently digested more dry matter, energy and nitrogen when supplemented with ALF or BFT. Lambs ingested more dry matter and digested more nutrients when fed a basal diet of RCG than one of TF, and supplementing with ALF and BFT was more beneficial for lambs fed TF than for lambs fed RCG. Increased intake of digestible nutrients was due to greater intake when lambs were offered more than one food, not due to an increase in digestibility. In pen trials meant to complement the field trials, lambs were offered an alkaloid-containing (either gramine or 5-methoxy-N,N-dimethyltryptamine) total mixed ration and supplemented with a food that contained saponins or tannins. All rations were isocaloric (3.3Mcal/kg) and isonitrogenous (14% CP). Lambs fed a ration with either alkaloid and offered a food containing saponin digested approximately the same amount of dry matter, energy, nitrogen, and NDF as lambs not offered saponin. When lambs were fed a ration with either alkaloid and supplemented with food that contained tannins, tannin consumption adversely affected dry matter, energy, and NDF digestibility, but lambs offered food with tannins increased dry matter intake, and as a result, they digested the same amount of dry matter, energy, and NDF as lambs not offered the food with tannins. Lambs offered tannin digested and retained more nitrogen than lambs not offered tannin. These findings indicate a nutritional advantage for sheep eating mixtures as opposed to monocultures of foods with different profiles of secondary compounds and nutrients.

Doctor of Philosophy / Department of Animal Sciences and Industry / J. Ernest Minton / The three experiments described below offer support of immune function by the swine gastrointestinal epithelium. Experiment one evaluated mediators that regulate the movement of macrophages (macrophage migration inhibitory factor; MIF), neutrophils (interleukin 8; IL8), dendritic cells (CC chemokine ligand 20; CCL20) and epithelial remodeling (osteopontin; OPN) in pigs challenged with Salmonella enterica serovar Typhimurium (ST) or Choleraesuis (SC). The proximal ileum had greater IL8 expression than the distal ileum (P < 0.05), and ST increased CCL20 (P < 0.05). In vitro, MIF, IL8, CCL20 and OPN mRNA expression induced by lipopolysaccharide (LPS), ST or SC using pig jejunal epithelial cells (IPEC-J2) resulted in increased IL8 secretion, and increased IL8 and CCL20 mRNA by ST and SC (P < 0.05). Experiment two evaluated how Lactobacillus reuteri (LR) and Bacillus licheniformis (BL) differed from ST or SC in their ability to regulate, stimulate, or modify IL8, CCL20, and tumor necrosis factor α (TNFα) in IPEC-J2 cells. ST stimulated an increase in IL8 secretion, with increases in IL8 mRNA (P < 0.05). BL increased IL8 mRNA (P < 0.0001). CCL20 mRNA was upregulated by ST (P < 0.05) and BL (P < 0.05). Only ST increased TNFα mRNA (P < 0.05). Another objective evaluated whether pre-exposure of IPEC-J2 cells to LR or BL modified ST induced IL8 secretion. IL8 secretion was increased by ST (P < 0.0001), and reduced by LR (P < 0.05). Only the BL/ST co-treated wells blunted basolateral IL8 secretion (P < 0.0001). Experiment three characterized the swine CCL20 mRNA sequence and evaluated tissue expression. Cloning of CCL20 from the porcine jejunum predicted a 97 amino acid peptide. All healthy tissues expressed CCL20 mRNA. In animals challenged with Salmonella spp., SC increased spleen and liver CCL20 expression. The data demonstrate that invasive bacterial pathogens in the pig gastrointestinal tract trigger upregulation of selected proinflammatory mediators; Salmonella spp. elicited differing patterns of activation in vitro and in vivo; IPEC-J2 cells increased IL-8 secretion in response to ST and BL, but not LR, while ST stimulated secretion was inhibited basolaterally by BL pre-exposure; and numerous porcine tissues are prominent sources CCL20.

Master of Agribusiness / Department of Agricultural Economics / Ted C. Schroeder / Annual vaccination of the beef cow herd is a common management tool for most beef herd operations. However, no studies have established the minimal vaccination frequency needed to attain an acceptable herd production output with minimal financial inputs. The hypothesis of this study stated that the production output and profitability of the cow herd would not be decreased by vaccinating the cow herd at intervals of greater than one year. An animal's immune response to a vaccine or a direct challenge by a pathogen requires it to partition nutritional resources from other functioning biological systems within the body such as reproduction and lactation. According to the concept of diminishing returns, there is a point at which the cost of inputs (labor costs, vaccine costs and frequency of vaccination) does not result in corresponding levels of production output (measured by calf weaning weight, cow pregnancy rate and calf survivability). Thus, the objective of this thesis was to evaluate the effect of varying the interval of vaccination on cow reproductive productivity, calf productivity at weaning and herd profitability. It is important to note that this research study does not question the premises of vaccinating a cow herd or the effectiveness of the vaccines, but only investigates the time interval between vaccinations. This study consisted of approximately 1000 head of beef cattle divided between two ranch locations in south central South Dakota. Permanent and yearly production records were collected for each individual cow and calf for three production years 1998, 1999 and 2000. At each location cows were randomly assigned into four treatment groups:1) Group V0 – control or non-vaccinated, 2) Group V1 – vaccinated in 2000, 3) Group V2 – vaccinated in 1999 and 2000 and 4) Group V3 – vaccinated in 1998, 1999 and 2000. At the conclusion of this four year study, varying the interval of vaccinations did not decrease the production and the profitability of the treatment groups compared to the control group in the weaning weight and calf mortality models. However, in the pregnancy model conception rates were significantly reduced in 2 of the 3 treatment groups.

Master of Agribusiness / Department of Agricultural Economics / Michael D. Tokach / Lone Tree Farms, Inc. is a diversified agricultural enterprise located in Harrisonville, Missouri. Since operations began in 1962, the hog operation has been expanded to the present size of a 2500 sow farrow-to-wean operation. The results of the thesis research lead Lone Tree Farms believes that there are economic and efficiency reasons behind adding to the existing farrow-to-wean operation with a 2500 sow farrow-to-wean operation. The thesis confirms and reveals several points. First, the project takes between 9 months and a year to complete. Some of the inputs required are eight more personnel and an additional 90,000 bushel of feed grain per operating year. Approximately 3,000 gilts are utilized to stock the project and building costs of approximately $3.5 million dollars will be accrued. The total costs of developing the project will be approximately $4.25 to 4.5 million dollars before the first pig is sold (2007 US Dollars). Many risk factors affect the outcome of the project, including risk of high grain prices due to ethanol, labor needs, environmental issues, and manure utilization needs of the project. The spreadsheet model that was developed as part of this thesis reveals that low productivity of the sow herd is the greatest risk factor for the success of the project. Reducing pigs weaned per sow from 11.0 to 8.5 would lower projected return on equity from 32.7. to 7.6% and increase the cost to produce a weaned pig by $8.72/pig. A major change in both corn (over $2.50/bu) and soybean meal (over $200/ton) price would be required for feed cost to have a similar impact on the cost to produce a weaned pig. The start-up and initial production year pose the greatest challenges and risks. After that, production flows should reach more consistency and effectively lower the risk. The initial start-up capitalization of approximately 30% reduces exposure and liquidity risks. The timing of the project should be made when both input expenses and output prices (pig price) are able to be managed. Combined with good management which maximizes pigs/sow weaned, the project stands a very good chance of being considered successful.