Master of Science / Department of Animal Sciences and Industry / R. Scott Beyer / Three experiments were conducted to evaluate the effects of gelatinized starch created during the pelleting process. Effects of gelatinization were first broadly tested to find if either increased or decreased gelatinization levels would increase broiler weight gain and feed efficiency during the starter period, 0 to 21 days of age. Results of the first experiment indicated a decrease (P<0.05) in broiler performance with increased levels of gelatinization, and a significant effect when the inclusion of gelatinized starch in the diet increased from 0 to 35%. A second experiment was conducted using a smaller range, 0 to 21% versus 0 to 35% inclusion of gelatinized starch in the diet and a smaller increment of increase, 3 versus 5%. Results of this experiment confirmed the results of the first experiment, and regression analysis was performed on the data. A linear decrease in body weight gain and quadratic increase in feed:gain (P<0.05) was observed as gelatinized starch was increased from 0 to 21% of the diet. A survey of the literature was conducted showing that most of the simulated levels of gelatinization were larger than those achieved with typical pelleted broiler diets. A third experiment was designed to investigate the levels of gelatinization observed in a pelleted diet and combined with three corn particle sizes, small (466 μm), medium (878 μm), and large (1240 μm), to find if any interactions existed. Chicks fed with the highest gelatinization level of 20%, (7.86% inclusion of pregelatinized starch) had lower body weight gains (P<0.05), and higher feed:gain (P<0.05) compared to chicks fed with 0% gelatinization. Small particle size had the lowest live body weight gain and lowest pen feed intake (P<0.05). There were no interactions found between gelatinization level and particle size (P>0.10). The results demonstrated a negative effect on chick body weight gain and feed efficiency by gelatinization of starch.

Doctor of Philosophy / Department of Animal Sciences and Industry / Evan C. Titgemeyer / Two experiments were conducted to evaluate the effects of late gestation and early lactation on the nutritional status of beef heifers fed low-quality, warm-season grass hay. The first experiment compared DMI, DM digestibility, and ruminal dynamics of pregnant and lactating beef heifers to non-gestating, non-lactating heifers of a similar age and size. This study demonstrated that pregnant heifers ate less than non-pregnant heifers while maintaining similar digestibilities. Intake was similar between lactating and non-lactating, though DM digestibility increased postpartum in lactating heifers. Ruminoreticular fill was less for pregnant than for non-pregnant heifers; ruminoreticular fill was similar regardless of lactation status. Ruminal NH3 increased with increasing intakes throughout the study. Lactating heifers had less ruminal NH3 than non-lactating heifers. Total ruminal VFA concentration was similar from 10 wk prepartum through 10 wk postpartum except at 2 wk prepartum when gestating heifers had less total ruminal VFA concentration. The second experiment compared DMI, DM digestibility, passage rate, and plasma glucose and BHBA concentrations between pregnant heifers, pregnant cows, lactating heifers, and lactating cows which were fed low-quality, warm-season grass hay supplemented with 450 g/d of soybean meal. This study demonstrated that DMI increased with progressing gestation in heifers. Lactating heifers had greater intake than other groups postpartum. DM digestibility decreased with advancing gestation; gestating animals had greater digestibility than non-gestating animals. Lactation status did not influence DM digestibility, though lactating heifers had greater digestibility from 3 to 7 wk postpartum. Digestibility was not influenced by age. Pregnant animals had faster digesta passage rates than non-pregnant counterparts. Plasma glucose concentration increased during the prepartum period; pregnant and lactating animals had lesser plasma glucose concentrations than non-gestating, non-lactating animals. Plasma BHBA concentration was greater in pregnant and lactating animals than in non-pregnant and non-lactating animal; age was not an influence on BHBA concentration. Calves from mature cows grew faster than calves from heifers. These studies showed that beef heifers do not have the same patterns of intake as mature cows during late gestation. Heifers and their calves exhibited poorer performance when compared to mature cows when fed low-quality, warm-season grass hay.

Master of Science / Department of Animal Sciences and Industry / J.S. Drouillard / Three studies were conducted to investigate alternative ingredients and processing methods for manufacturing low-moisture blocks. Study 1 was designed to determine if ruminal lactate could be transiently increased by feeding fructose-based blocks to heifers fed prairie hay, thus providing substrate for establishment of lactate utilizing microbes. Low-moisture blocks comprised of 96% fructose and 4% vegetable oil (DM basis) were manufactured and dosed via ruminal fistulas. Administration of fructose blocks resulted in transient increases in ruminal lactate (P < 0.05), accompanied by transient decreases in pH (P < 0.05). Ruminal fluid incubated with semi-defined lactate medium became more turbid (P < 0.05) as a result of prior exposure to fructose blocks suggesting greater capacity for lactate metabolism. In study 2 a portion of the molasses was replaced by corn steep liquor (CSL) or condensed corn distiller’s solubles (CCDS). Heifers were fed a forage-based diet and supplemented with 1 of 4 supplement blocks. Supplements were a 30% CP molasses block manufactured at ambient pressure and high temperatures (Mol-30). The remaining treatments were manufactured at reduced pressure and temperature and were a 30% CP block with 36% CSL (CSL-30); a 40% CP block with 40% CSL (CSL-40); or a 40% CP block with 25% CCDS (CCDS-40). Supplementing with Mol-30 and CSL-40 resulted in greater DMI (%BW) than with CCDS-40 (P < 0.05). Supplementing with CSL-30 improved efficiency and ADG compared to Mol-30 (P < 0.01). Study 3 evaluated the affect of cooking temperature on blocks containing CSL fed to heifers receiving a forage-based diet. Heifers were offered no supplement (Control) or a 15% CSL block manufactured at ambient pressure and high temperature (HT-15). The remaining treatments were manufactured at reduced pressure and temperature and were a 15% CSL block (LT-15); or 40% CSL block (LT-40). Control heifers had the lowest DMI and LT-40 had the greatest (P < 0.05). Feeding heifers LT-15 or LT-40 improved ADG compared to heifers fed HT-15 or no supplement (P < 0.05). Heifers fed LT-40 tended to be more efficient than those fed HT-15 and Control (P = 0.07).

Master of Science / Department of Animal Sciences and Industry / Robert Goodband / Five experiments were conducted to determine the effects of sorghum dried distiller’s grains with solubles (DDGS) on nursery pig performance, finishing pig performance and meat quality, and lactating sow and litter performance. Experiment 1 established a nutrient database and evaluated the quality and consistency of five ethanol plants in the Western Plains region. Each sample was analyzed for AA, DM, CP, crude fiber, crude fat, ash, NDF, ADF, Ca, P, trace minerals, GE, and starch. In addition, DE, ME, and NE were calculated. Experiments 2 and 3 evaluated the effects of sorghum DDGS on nursery pig performance. In Exp. 2, pigs fed sorghum- or corn-based diets performed similarly; however, as sorghum DDGS increased ADG decreased (linear, P < 0.01). A DDGS×grain source interaction (quadratic, P = 0.03) was observed for G:F. In corn-based diets, G:F was identical for pigs fed 0 to 30% DDGS, but worsened in pigs fed 45% DDGS. In sorghum-based diets, G:F was best for those fed 0% DDGS, but worsened at higher levels. In Exp. 3, pigs fed corn- or sorghum-based diets performed similarly; however, pigs fed DDGS gained less (P < 0.03) than those fed basal diets. Experiment 4 evaluated the effects of sorghum DDGS in sorghum- or corn-based diets on finishing pig growth performance, carcass characteristics, and fat quality. Increasing sorghum DDGS reduced (linear; P < 0.01) ADG and increased (linear; P < 0.01) backfat IV. Pigs fed the sorghum-based diet with 30% sorghum DDGS had decreased backfat IV (P < 0.01) than those fed the sorghum-based diet with corn DDGS. Experiment 5 evaluated the effects of sorghum DDGS on lactating sow and litter performance. Overall, ADFI increased in corn-based diets when DDGS were added, but decreased in sorghum-based diets resulting in a tendency (P < 0.08) for a DDGS × grain source interaction. Pig weaning weights were lower (P < 0.06) for sows fed diets containing DDGS compared with those fed the basal diets. Adding sorghum DDGS reduced pig performance, and sow lactation performance; therefore, its inclusion in swine diets needs to be evaluated on an income over feed cost basis.

Master of Science / Department of Animal Sciences and Industry / Karol E. Fike / This thesis involves two separate studies that evaluate the effects of different beef cattle management practices on reproduction. The objective of the first study was to determine if feedlot heifers administered melengestrol acetate (MGA) and growth promoting implants could serve as viable oocyte donors for in vitro embryo production. Ovaries from heifers administered MGA and growth promotants (MGA-Implant) and ovaries from heifers not administered either substance (Control) were collected from heifers post-slaughter. Oocytes were harvested and in vitro maturation, in vitro fertilization (IVF), and in vitro culture were completed. Treatment and time interacted to affect the number of oocytes aspirated per ovary (P = 0.07) and the number of zygotes per ovary (P = 0.07). Fertilization (P = 0.90) and cleavage rates (P = 0.80) did not differ between treatments. Blastocyst rates (P = 0.30) and the number of embryos per ovary (P = 0.50) did not differ between treatments. We concluded that beef feedlot heifers fed MGA and implanted with growth promotants seem to be a viable source of oocytes for in vitro embryo production. In the second study, we hypothesized that continuous fenceline exposure of prepubertal beef bulls to cycling beef females would hasten the onset of puberty as well as increase the percentage of bulls passing their initial breeding soundness examination (BSE). Bulls were either exposed to estrous females (exposed) or were not exposed (control). Monthly scrotal circumference (SC) measurements, blood samples, semen evaluations, and bull behavior assessments were conducted. Age at puberty (P = 0.40), SC at puberty (P = 0.50), and weight at puberty (P = 0.30) did not differ between treatments. A similar (P = 0.50) percentage of bulls passed their initial BSE at 363 ± 21.5 d of age (exposed: 87.8%; control: 74.2%). Treatment, month, and stage of the estrous cycle of cows interacted to affect the number of mount attempts (P = 0.05) and the number of flehmen responses (P < 0.001). In conclusion, bulls given continuous fenceline exposure to cycling beef females were neither younger at puberty nor did a greater percentage pass their initial BSE.

Master of Science / Department of Animal Sciences and Industry / Daniel W. Moser / Udder quality is an important trait for beef producers because udders impact cow longevity and calf performance. The objective of this study was to estimate the genetic parameters for udder quality in Hereford cattle. The Beef Improvement Federation recommends collecting subjective scores on udder suspension and teat size. Prior to these guidelines, the American Hereford Association (AHA) recorded an overall score, which combines all udder characteristics into a single score. In all cases, scores ranged from 1 to 9 with a score of 9 considered ideal. Records on 78,556 animals and a 3-generation pedigree with 196,540 animals were obtained from the AHA, Kansas City, MO. These records contained repeated observations for overall score (n=126,753), suspension (n=61,758), and teat size (n=61,765). Data were modeled using a multiple trait animal mixed model with random effects of additive genetic and permanent environment and with fixed effects of age and contemporary group (herd-year-season). Variances were estimated with ASREML 3.0. Heritability estimates (standard errors) of overall score, suspension, and teat size were 0.32 (0.01), 0.31 (0.01), and 0.28 (0.01), respectively. These results showed udder quality was moderately heritable, agreeing with previous research. The phenotypic correlation (standard error) between teat size and suspension was 0.64 (0.003). Of the records for suspension and teat size, 57% had the same score for both traits. The genetic correlations (standard errors) between teat size and suspension, overall score and teat size, and overall score and suspension were 0.83 (0.01), 0.72 (0.02), and 0.70 (0.02), respectively. The genetic correlations between traits were extremely strong. In addition, producer education is important to ensure the scoring systems are used correctly.

Master of Science / Animal Sciences and Industry / Evan C. Titgemeyer / Six ruminally-cannulated Holstein steers (202 ± 15 kg) were used to study the effects of ruminal ammonia loading on whole-body lysine utilization. Steers were housed in metabolism crates and used in a 6 × 6 Latin square design. All steers received 2.52 kg of DM/d of a diet (10.1% CP) containing 82% soybean hulls, 8% wheat straw, 5% cane molasses, and 5% vitamins and minerals. Ten g/d of urea was infused continuously into the rumen of all steers to ensure adequate ruminal ammonia concentrations; concurrently, steers were ruminally infused continuously with 200 g/d acetic acid, 200 g/d propionic acid, and 50 g/d of butyric acid and abomasally infused with 300 g/d of glucose continuously to increase energy supply without increasing microbial protein supply. Steers were also abomasally infused continuously with an excess of all essential amino acids except lysine to ensure that lysine was the only limiting amino acid. Treatments were arranged as a 3 × 2 factorial with 3 additional levels of urea (0, 40, or 80 g/d) continuously infused ruminally to induce ammonia loading and 2 levels of lysine (0 or 6 g/d) continuously infused abomasally. Treatments did not affect fecal N output (P = 0.37). Lysine supplementation decreased (P < 0.01) urinary N excretion from 51.9 g/d to 44.3 g/d, increased (P < 0.01) retained N from 24.4 to 33.3 g/d, and tended (P = 0.09) to reduce plasma urea-N. Urea infusions linearly increased retained N (26.7, 28.8, and 31.1 g/d; P = 0.05) and also linearly increased (P < 0.01) urinary N excretion (31.8, 48.1, and 64.4 g/d), urinary urea (21.9, 37.7, and 54.3 g/d), urinary ammonia (1.1, 1.4, and 1.9 g/d), and plasma urea (2.7, 4.0, and 5.1 mM) for 0, 40, and 80 g urea/d, respectively. Assuming that retained protein is 6.25 × retained N and contains 6.4% lysine, the incremental efficiencies of infused lysine utilization were 51, 59, and 69% for steers receiving 0, 40, and 80 g/d of urea, respectively, suggesting that the ruminal ammonia loads might improve the efficiency of lysine utilization; this is supported by the observed increases in whole-body protein deposition in response to ammonia loading of our steers that were, by design, lysine deficient.

Doctor of Philosophy / Department of Grain Science and Industry / Praveen Vadlani / Whole stillage and thin stillage from the ethanol production process were evaluated as substrate sources for the production of [beta]-carotenes using Sporobolomyces Roseus (ATCC 28988). This product has the potential to be used as a novel feed ingredient for poultry, swine, or cattle diets. [Beta]-carotenes have been supplemented in animal diets to improve animal health, enhance meat color and quality and increase vitamin A concentrations in milk and meat. Microbial fermentations involving growth and product kinetics were performed in 500 mL baffled shake flasks and in a 5 L fermentation bioreactor. Media optimization was conducted in shake flasks to evaluate two carbon sources: glucose and glycerol, and two nitrogen sources: ammonium sulfate and urea. Final [beta]-carotene concentration of 272.57±4.34 [mu]g [beta]-carotene/g biomass was found to be highest for the whole stillage, with 10 g/L added glucose and 10 g/L nitrogen added through ammonium sulfate supplementation. Glycerol addition yielded no significant increase (P<.05) in [beta]-carotene yield, while urea addition significantly decreased (P<.05) the final [beta]-carotene concentrations. The resulting fermented product can be blended with regular feed using either whole stillage as a dry feed ingredient or thin stillage as a liquid feed additive. The fermentation of whole stillage significantly influenced the physical and flow properties of the material. Even though there was a significant decrease (P<0.05) in bulk density and increase (P<0.05) in tapped density between DDGS and fermented whole stillage, there was a less pronounced difference between the whole stillage and fermented whole stillage. The fermentation of whole stillage significantly influenced the physical and flow properties of the material. This showed that the fermentation process and resulting nutritional profile had a significant effect on the resulting fermented whole stillage. A 50 L bioreactor was specifically designed to evaluate the scalability of the process and to perform subsequent feed production trails. Pilot scale feed pelleting runs were conducted and the resultant product was put in environmental chambers to determine if [beta]-carotene concentration was reduced as a result of storage. There was a significant decrease (P<0.05) in [beta]-carotene levels after pelleting and after 28 d of storage at elevated temperature and humidity. These decreases were consistent with previous research.

Master of Science / Department of Animal Sciences and Industry / Karol E. Fike / Trace mineral supplementation is necessary for proper reproductive success. Little research has evaluated the effect of an injectable trace mineral product, in conjunction with a dietary mineral supplementation program, on reproduction. This thesis includes two separate studies evaluating the use of an injectable trace mineral product, in addition to a dietary mineral program, on the reproductive success of yearling bulls and heifers. In the first study, we hypothesized that when dietary trace mineral needs are met, administration of an injectable trace mineral product to developing beef bulls would cause a short-term increase in circulating trace mineral concentrations, but not alter semen quality nor ability to pass a breeding soundness examination. Trace mineral treatment did not affect scrotal circumferences and BW of bulls throughout the trial (P [equal to or greater than] 0.20). Trace Mineral bulls had greater (P [equal to or less than] 0.0001) trace mineral concentrations at 8 h post-treatment than Control bulls. Semen trace mineral concentrations on d 42 and 91 were similar (P [equal to or greater than] 0.52) between treatments. Sperm parameters improved (P [equal to or less than] 0.003) from d 42 to 91, but did not differ (P [equal to or greater than] 0.06) between treatments. A similar (P = 0.94) percentage of Trace Mineral (67%) and Control (68%) bulls passed a BSE 91 d post-treatment. In the present study, supplemental trace mineral injection was successful at raising circulating trace mineral levels, but did not alter semen trace mineral levels nor improve semen quality. In the second study we hypothesized that when dietary trace mineral needs are met, the use of an injectable trace mineral product in developing heifers would not affect pregnancy rates at single service fixed-time artificial insemination (FTAI). Trace Mineral heifers had greater (P = 0.02) pregnancy rates (51.28%) than Control heifers (25.58%). The percentage of Trace Mineral (30.77%) and Control heifers (47.50%) that displayed estrous behavior prior to FTAI as indicated by a red estrous detection patch was not different (P = 0.13) between treatments. In the present study, despite dietary trace mineral requirements being met, use of an injectable trace mineral injection improved pregnancy rates following FTAI, but did not affect estrous behavior.

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.