Master of Science / Grain Science and Industry / Cassandra K. Jones / A total of 7 experiments were conducted to evaluate the effects of particle size and thermal processing on swine growth performance or to develop improved analytical methods for particle size prediction. First, 5 experiments utilized 596 nursery pigs to assess how corn particle size and pelleting affected nursery pig growth performance and feed preference. The improvements from reducing particle size were mixed among experiments, potentially because pigs preferred to consume more coarsely ground corn in both mash (P < 0.05; 79.3 vs. 20.7%) and pelleted diets (P < 0.05; 58.2 vs. 31.8%) diets. Pelleting diets led to a reduction in feed disappearance, which tended to improve feed efficiency in nursery pigs (P < 0.05; 0.61 vs. 0.64 for pigs fed mash vs. pelleted diets in Exp. 1). Next, a total of 270 finishing pigs were utilized to determine the effects of long-term conditioning or extrusion of low energy feedstuffs on finishing pig nutrient digestibility, growth performance and carcass characteristics. Treatments included the same basal diet processed as: 1) non-processed mash, 2) pelleted with 45 s conditioner retention time, 3) pelleted with 90 s conditioner retention time, or 4) extruded. Thermal processing, regardless of type, improved daily gain and feed efficiency (P < 0.05), but did not affect feed intake (P > 0.10). Extruded diets tended to improve feed efficiency compared to pelleted diets (P < 0.10). However, pigs fed thermally-processed diets had greater jowl iodine value compared to those fed mash diets (P < 0.05). Finally, 420 samples were used to determine the impact of top sieve size, grain type, technician, and flow agent on the ability of a 3-sieve analytical method to accurately predict the mean particle size determined by a standardized 12-sieve method. The experiment was a 3 × 2 × 2 × 3 factorial with 3 technicians, 2 sieve sizes (U.S. No. 12 vs. 16 sieve as the top sieve), 2 flow agent levels (0 vs. 0.5 g), and 3 grain types (corn, sorghum, or wheat). Linear regression was used to develop individual equations to predict the mean particle size for each of the 3-sieve methods compared to the standard 12-sieve method recognized as ASAE S319.4, and the GLIMMIX procedure of SAS was used to evaluate the impact of main effects and interactions on predication accuracy. All interactions were removed from the model due to insignificance (P > 0.10). Technician, screen size and flow agent did not affect (P > 0.10) the accuracy of the prediction equations. Grain was the only main effect of significance (P < 0.05), where the prediction equation overestimated the particle size of wheat by approximately 15 µm and underestimated the particle size of corn by approximately 12 µm. While statistically significant, these variations were deemed to be sufficiently accurate for the 3-sieve method, and that separate equations for each grain type were not warranted to retain the simplicity of the method. In summary, technician, sieve size, grain type, and the use of flow agent did not greatly affect the accuracy of the 3-sieve particle size analytical method, so the original method was concluded to be accurate and the preferred method.

Doctor of Philosophy / Animal Sciences and Industry / Joel M. DeRouchey / Eight experiments using a total of 2,964 finishing pigs and 2,947 feed, phytase, or premix samples were used to determine the effects of: 1) wheat source, particle size and feed form on finishing pig performance; 2) feed form feeding strategies; 3) fine generation from pellets during feed manufacturing and delivery, and 4) thermal stability and shelf life of phytase products. Exp. 1 and 2 evaluated wheat sources, particle size, and diet form for finishing pigs. Fine gound hard red winter wheat fed in meal form improved G:F and nutrient digestibility, whereas wheat ground from ~700 to 250 µ in pelleted diets did not influence growth or carcass traits. Feeding hard red winter wheat improved ADG and ADFI compared with feeding soft white winter wheat. In Exp. 3, pellet feeding regimens were used to evaluate finishing pig performance and stomach morphology. Feeding pelleted diets improved G:F but increased stomach ulceration and pig removals; however, rotating pellets and meal diets provided an intermediate G:F response with fewer stomach ulcers and pig removals. Experiments 4 to 6 investigated fines formation during pelleted feed manufacturing and delivery. Pellet quality worsened as pellets were transported through the feed mill post pelleting and during delivery. Unloading speed or feed line location had little effect on pellet quality. There were significant differences between the fines and pellet nutrient profiles as noted by the increased concentration of ADF, crude fiber, Ca, ether extract, and starch in the fines and decreased CP and P when compared to pellets. In Exp. 7 and 8, the thermal stability and shelf life of 4 commercial phytase products was determined. Increasing conditioning temperatures decreased phytase stability regardless of product. Phytase activity was affected by storage duration, temperature, product form, and phytase source. Pure products stored between 15 and 22˚C were the most stable and premixes were affected by longer storage times and higher temperatures.

Doctor of Philosophy / Department of Animal Sciences and Industry / Terry Houser / One experiment was conducted to determine the collagen and adipocyte characteristics in pork belly fat with different iodine values (IV) and if these factors contribute to belly firmness. An additional two experiments were conducted to create an objective method to score bacon distortion during cooking and to determine how IV and cooking method contribute to bacon distortion. Experiment 1 sorted pork bellies (n=72) into three IV categories: High 76.5 g/100g, Intermediate 70.5 g/100g, and Low 64.9 g/100g. Belly characteristics and firmness were measured before processing into bacon. After processing, 3 bacon slices were selected from the belly and analyzed for histochemistry and collagen analysis. No differences were observed between belly characteristics, while High IV bellies showed softer bellies. Adipocyte characteristics remained unchanged between IV groups. High IV bellies showed greater amounts of collagen. Experiment 2 cooked bacon slices (n=585) on three different appliances (griddle, microwave, and oven) and scored the resulting distortion using a subjective scale. Raw and cooked bacon characteristics were measured to determine which response variables contributing to distortion. Bacon slices were removed from 6 different locations within each belly sampled. Two distortion measurements were created to objectively describe distortion response (crest frequency and bacon distortion index. Subjective distortion scores, crest frequency, bacon distortion index, and raw and cooked bacon characteristics were shown to change between locations of the belly. Accuracy of predictive equations developed to predict distortion scores were low. Experiment 3 evaluated how IV interacts with cooking methodology to influence cooking characteristics, fat quality and distortion of bacon. Bacon slices (n=300) were organized into two IV categories, Low (61.52 to 65.54 g/100g) and High (78.83 to 85.34 g/100g) and cooked using three different appliances (oven, microwave, and griddle). Bacon from the Low IV group had the greatest amount of fat. Cooking bacon on a griddle showed the greatest distortion scores, while the oven produced bacon with the lowest distortion scores. Bacon with higher IV produced bacon with increased distortion scores. Bacon from the High IV group showed smaller cooked dimensions than the Low IV bacon. Neither cooking method nor IV level affected the cooked fatty acid composition.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Hops β-acid extract was fed to 80 heifers (389 ± 23.6 kg initial BW) to assess impact on feedlot performance and ruminal fermentation. Heifers were randomly assigned to individual pens and fed once daily for 147 d. Treatments were a control (no additive); 33 mg monensin (Elanco Animal Health, Greenfield, IN)/kg diet DM; and 10, 25, 50 mg β-acid extract of hops (DSM Nutritional Products, France)/kg diet DM. Ruminal fluid was collected on d 44 and 86 by rumenocentesis for analyses of VFA, lactate, and NH[subscript]3 concentrations. Cattle were harvested at a commercial abattoir on d 147. Hops β-acids decreased propionate (P = 0.01) concentrations and increased caproate (P = 0.05), A:P (P = 0.04), and ammonia concentrations (P = 0.03) compared to monensin. Growth performance of heifers fed β-acid or monensin was not different than that of heifers fed the control diet. Additionally, two in vitro studies were conducted to evaluate effects of hops β-acid extract on starch fermentation by mixed microbial populations from the bovine rumen. In trial 1, 2 treatments were assigned in triplicate to fermentation bottle, fitted with Ankom[superscript]RF1 Gas Production System modules (Ankom[superscript]RF Technology, Macedon, NY) using starch as substrate (Difco Soluble Starch; Dickinson and Company, Sparks, MD) and either 0 or 33 mg hops β-acid extract (10.99% active hops beadlet; DSM Nutritional Products, France)/kg substrate. Gas production was measured over 30 h. Terminal pH, IVDMD, and VFA and lactate were measured after 30 h of fermentation. Gas production increased in response to β-acid (P ≤ 0.05). Terminal pH, IVDMD, VFA, and lactate were unaffected by addition of β-acid extract (P ≤ 0.05). In trial 2, pH, VFA concentrations, and IVDMD were measured at 6-h intervals during a 30-h incubation period using 36 fermentation tubes. There was no effect of hops β-acid on in vitro fermentation (P > 0.05). In conclusion, under the conditions of these experiments, hops β- acid extracts hops had little impact on feedlot performance, though there are indications of an impact on ruminal fermentation.

Master of Science / Department of Animal Sciences and Industry / Teresa Douthit / Joann Kouba / Gonadotropin-releasing hormone (GnRH-I), as well as its receptor, GnRHR-I, once thought to be localized solely to the hypothalamus and anterior pituitary, have since been detected in the testis of numerous mammals. Another isoform of GnRH, GnRH-II, has been isolated from the testis of numerous mammals and binds a specific receptor, GnRHR-II. Our objective was to establish whether GnRH-I and GnRH-II, along with their specific receptors, are produced and present in the equine testis. Testicular tissue was collected from colts < 2 yr (n = 5) and stallions ≥ 2 yr (n = 10) of age during routine castrations. Total RNA extracted from testicular tissue was reverse transcribed and cDNA was subjected to conventional PCR using gene specific primers for GnRH-I, GnRHR-I, GnRH-II, and GnRHR-II. Protein was extracted and subjected to dot blot and Western blot using antibodies directed against GnRH-I, GnRH-II, GnRHR-I, or GnRHR-II. Transcripts for both ligands and receptors were detected in all testes. Product identity was confirmed by sequencing, which also clarified that unusual band sizes were the result of alternative splicing of GnRHR-II, and the retention of an intron in the GnRH-II mRNA was discovered. Prepro-GnRH-I and prepro-GnRH-II protein was detected in all stallion testes via dot blot technique. On Western blots, testicular samples from colts (n = 4) had 3-fold greater GnRHR-I levels compared to stallions (n = 7; P < 0.022). Conversely, there was a tendency for GnRHR-II protein to be greater in tissue collected from stallions compared to colts (P < 0.0756). Finally semen was collected from mature stallions (9 to 18 yr; n = 4) and purified using a discontinuous gradient. By utilizing immunocytochemistry, GnRHR-II was localized to the connecting piece of mature stallion spermatozoa. This is the first report identifying GnRH-I and -II and their receptors in the equine testis and GnRHR-II on mature stallion spermatozoa. These decapeptide hormones may act via autocrine and/or paracrine signaling to affect steroidogenesis and spermatogenesis in the stallion testis.

Doctor of Philosophy / Department of Animal Sciences and Industry / Twig T. Marston / The primary study investigated the use of ractopamine HCl and implants in cull beef cows. Thirty-two cull cows were used to determine the effects of feeding ractopamine HCl and/or implanting on feedlot performance and carcass composition. Cows were individually fed a high concentrate diet for 60 days. Carcass data were collected and carcasses were fabricated. Implanted cows had greater dressing percentages and tended to have heavier hot carcass weights than non-implanted cows. Cows that had been treated with implant and ractopamine HCl tended to be fatter than those not treated. Ractopamine HCl fed cows had more marbling than their contemporaries. The data also indicated that younger cows (< 6 years of age) had greater feedlot performance than the older cows. An experiment was conducted to determine if corn and grain sorghum dried distillers grains could be effective protein supplements for growing cattle. Crossbred heifers (n = 78) were individually fed 2.72 kg·head·-1d·-1 of supplements containing corn, soybean meal, and grain sorghum; or cracked corn and corn distillers grains with solubles; or cracked corn, sorghum distillers grains with solubles, and ground grain sorghum (all formulated to equal 20% CP). Heifers grazed native-grass and were fed smooth broom hay. A digestion trial was done during the last week of the trial. No differences were noted in weight gain or total diet digestibility, however, DMI was less for heifers receiving either distiller’s based supplement. Ninety-six pregnant, mature, spring-calving cows grazing native grass pasture were used to determine if early weaning calves reduced subsequent winter supplementation cost. Previous to the feeding trial, calves had been weaned at 115 or 212 d of age. Cows were fed either 1.4 kg·hd-1·d-1 or 1.27 kg·hd-1·d-1 of a common 45% CP supplement. Cows were supplemented for an average of 110 d of pregnancy. Earlyweaned cows were heavier and had greater body condition scores than contemporaries at the commencement of supplementation. At calving the early-weaned cows fed the lesser supplemental amount had similar body weight and body condition scores as later-weaned cows fed the greater amount of supplement, thus, the early weaning routine allowed a 30% savings of winter protein supplement.

Doctor of Philosophy / Department of Grain Science and Industry / Keith C. Behnke / A series of experiments were conducted evaluating the effects of marker selection and mix time on feed uniformity, feed uniformity on animal performance, and the addition of cracked corn to a concentrate pellet on broiler performance. Utilizing a common corn-soybean meal based poultry diet, as mix time increased, there was an overall decrease in % Coefficient of Variation (CV) observed, which was independent of which marker was used. Crude protein should be considered to be an inferior marker as several ingredients in the batch contribute some level of protein and overall decreased numerically less than 1% CV. Synthetic amino acids (methionine and lysine) prevailed as the most consistent markers reducing in magnitude by 60.32% and 55.97% (methionine and lysine, respectively). To evaluate the effects of feed uniformity on broiler performance, as determined by CV, methionine was added to a basal diet and mixed for 10, 20, 30, 40, or 120-s, with methionine being the only ingredient varying. During the starter period (d 0 to 16) ADG increased significantly (quadratic P<0.001) as well as F:G (quadratic P<0.001). However, in overall (d 0 to 41) growth performance only ADG improved (quadratic P<.001). Average daily feed intake appeared to be a contributing factor in growth performance for all stages of growth. Cracked corn was added to a concentrated pellet to evaluate growth performance on broilers and potential cost reductions at the feed manufacturing facility. A linear decrease was observed overall (0 to 41 d) for ADG, ADFI, and F:G (P<0.003, respectively). Gizzard weight and gizzard yield were significantly increased (P<0.043 and P<0.008, respectively) as cracked corn level increased.

Doctor of Philosophy / Department of Animal Sciences and Industry / Robert D. Goodband / Two experiments evaluated effects of glycerol on pellet mill production and pig performance. In Exp. 1, increasing glycerol increased (quadratic; P < 0.01) pellet durability index through 9% added glycerol. Adding glycerol decreased (linear; P > 0.01) production energy (kWh/t). In Exp. 2, pigs were fed one of seven diets with no added soy oil or glycerol (control); the control diet with 3 or 6% added soy oil, 3 or 6% added glycerol, and 6 or 12% additions of a 50:50 soy oil/glycerol blend in a 26-d growth assay. Adding glycerol improved (P < 0.01) pellet durability compared to soy oil and the soy oil/glycerol blend treatments. Pigs fed glycerol had increased (linear, P < 0.03) ADG. Adding soy oil, glycerol, or the soy oil/glycerol blend resulted in similar final BW. Two experiments evaluated the effects of glycerol as a replacement for lactose on pellet mill production and nursery pig performance. In Exp. 1, pigs were fed one of ten treatments that included 0, 3.6, or 7.2% lactose or 0, 3.6, or 7.2 % glycerol and fed in either meal or pelleted form. Pellet durability index increased (linear; P < 0.01) with added lactose and glycerol. Glycerol decreased (linear; P < 0.01) production energy (kWh/t). There was a tendency (P < 0.06) for an inclusion level × diet form (meal or pellet) interaction observed for ADG. Pigs fed the pelleted diets containing the 7.2% glycerol inclusion had decreased ADG compared to all other treatments. In Exp. 2, pigs were fed one of fourteen diets that included 0, 3.6, 7.2, or 10.8% lactose or 0, 3.6, 7.2, or 10.8 % glycerol and fed in either meal or pelleted form. There was no effect (P < 0.27) of diet form, inclusion level, or source on ADG or ADFI. Eight experiments evaluated the effect of ingredients on the flow ability of ground corn. Flow ability of feed improved with added glycerol, especially when added to meal diets containing hammer mill ground corn. Specialty protein ingredients in powder form reduce flow ability, while fine lactose sources improved flow ability. Granulated ingredients improved flow ability.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / A series of five trials were conducted to evaluate grain processing, distiller's grains inclusion in finishing diets, interactions between distiller's grains and dry-rolled corn (DRC) or steam-flaked corn (SFC), efficacy of removing roughage in the presence of distiller's grains and the digestibility of distiller's grains in steam-flaked and dry-rolled corn diets. The first trial was designed to determine the optimum flake density of SFC in beef finishing diets. Diets consisted of corn flaked to densities of 360, 411, or 462 g/L. Observed improvements in mill production would support increasing flake density; however numerical decreases in animal performance offset economic benefits of increased productivity. The second trial was conducted to evaluate optimum levels of sorghum wet distiller's grains in finishing diets. Crossbred yearling steers were fed diets containing DRC or SFC and levels of distiller's grains were 0, 10, 20, or 30% of diet dry matter. Distiller's grains can effectively replaced a portion of the corn in finishing diets, but their nutritional value was greater in DRC diets than in SFC diets. In trial 3, crossbred heifers were fed diets containing SFC with 0% DDG and 15% corn silage (CS), 25% DDG and 15% CS, or 25% DDG and 5% CS. In trial 4, crossbreed heifers were fed diets similar containing DRC or SFC with 0% DDG and 15% CS, 25% DDG and 15% CS, or 25% DDG and 5% CS. Results indicate that roughage levels can be reduced in feedlot diets containing DDG with no adverse effects on performance or carcass quality. The fifth trial was a metabolism study conducted to evaluate the digestibility of DDG in beef cattle. Treatments consisted of DRC with 0% DDG, DRC with 25% DDG, SFC with 0% DDG, and SFC with 25% DDG. There were no significant grain processing by distiller's grain interactions observed in main effects. In conclusion optimum flake density was 360 g/L, feeding distiller's grains has a greater value in DRC diets vs. SFC diets, roughage level and type are important in formulating finishing diets, roughage can be reduced when feeding distiller's grains, and ruminal ammonia, and pH are decreased and ruminal lactate is increased when feeding DDG and SFC.

Doctor of Philosophy / Department of Animal Sciences and Industry / Jim L. Nelssen / Four experiments using 350 pigs were conducted to determine the effects of dietary nutrients on the incidence of osteochondrosis (OC) and to evaluate the use of biomarkers to predict its occurrence in growing-finishing pigs. The first experiment was conducted to evaluate the potential of dietary ingredients with known functions in cartilage and bone metabolism on incidence of OC in pigs (PIC 327 × 1050, initially 39 kg). Results suggest that pigs fed high levels of added copper and manganese, silicon, methionine and threonine, or proline and glycine had reduced OC severity scores. A second experiment evaluated other dietary ingredients that may impact OC as well as with or without ractopamine HCl (PIC 327 × 1050, initially 47 kg). Results suggest that feeding a combination of added methionine, manganese, proline, and glycine or added silicon can numerically reduce OC severity scores compared to pigs fed a standard corn-soybean meal based diet. Feeding ractopamine HCl did not affect the incidence or severity of OC. A third experiment was conducted to evaluate the effect of dietary lysine concentration with or without the addition of high methionine, manganese, and copper in a 3 × 2 factorial arrangement in growing-finishing pigs (PIC 327 × 1050, initially 41 kg). Results suggest that increasing dietary lysine concentrations increased the severity of OC. Furthermore, feeding additional methionine, manganese, and copper reduced OC severity scores. A fourth experiment was conducted to determine the usefulness of ten different biomarkers of cartilage and bone metabolism to predict the incidence of OC and the correlation of individual markers with the severity of OC. Results suggest that measuring serum C-propeptide of type II collagen (CPII) will predict animals with OC, as gilts with a two-fold increase in CPII are 97 times more likely to have OC. As well, serum collagen type II carboxy-terminal 3/4 long fragment (C2C) explained 49% of the variation in OC severity scores. The results of these experiments suggest that feeding added copper, manganese, methionine, silicon, or proline and glycine may reduce OC severity scores in pigs, while measuring biomarkers CPII and C2C can aid in determining animals with OC.