Doctor of Philosophy / Department of Animal Sciences and Industry / Joel M. DeRouchey / A total of 7,061 finishing pigs were used in 7 experiments. Experiment 1 investigated the effects of withdrawing high-fiber ingredients prior to marketing to optimize growth performance, carcass yield, and carcass fat quality. Switching pigs from a high-fiber to a low-fiber corn-soy diet approximately 15 to 19 d before slaughter restored carcass yield and partially decreased carcass fat IV compared to pigs fed the high-fiber diet until slaughter. Experiment 2 studied 30% distillers dried grains with solubles (DDGS) and 5% added fat prior to slaughter on growth performance and carcass characteristics. Adding 5% fat to finishing pig diets containing 30% DDGS approximately 20 d before slaughter improved ADG and G:F but did not overcome the reduction in carcass yield from feeding DDGS. Experiment 3 investigated the Cu source on growth performance and carcass characteristics. Increasing dietary Cu in high byproduct diets improved growth and feed intake, resulting in increased final BW and HCW for pigs fed both Cu sources. Experiment 4 examined added Cu and standardized ileal digestible (SID) lysine (Lys) level on growth performance, carcass characteristics, and carcass fat quality. Feeding 150 mg/kg Cu to pigs in the 100% SID Lys requirement diet had improved growth but in the 85 or 92.5% SID Lys requirement diet no response to added Cu was found. Furthermore, increasing SID Lys increased ADG and HCW, but added Cu did not influence growth when feeding low SID Lys. Experiment 5 investigated diet ingredient type and added Cu on growth performance, carcass characteristics, gross energy digestibility, and small intestine histology and gene expression. When comparing diet type and added Cu, pigs fed a byproduct diet with DDGS and bakery meal tended to have lower G:F and reduced HCW compared to pigs fed a corn-soy diet. Adding Cu did not influence growth or carcass characteristics. However, adding Cu to the byproduct diet improved gross energy digestibility and decreased the crypt depth in the distal small intestine. Finally, a linear programming model was developed as a decision tool for commercial swine producers to help guide pig flow decisions to maximize the return to the operation.

Master of Science / Department of Animal Sciences and Industry / Teresa L. Douthit / Abruptly increasing concentrate in the ration of horses results in altered cecal dynamics which can culminate in digestive distress. Nine Quarter horses previously fitted with cecal cannulae were utilized for 3 consecutive 22-d experiments, each separated by 2 d of rest. During Exp. 1 and 2 horses were acclimated to the same ration for the initial 21 d of each period, followed by a concentrate challenge on d 22. The acclimation ration consisted of a morning meal of 0.5% BW concentrate (Omolene 200, Purina Animal Nutrition, LLC, Gray Summit, MO) fed with 1.5% BW prairie grass hay divided evenly between a morning and evening meal. On d 22 of Exp. 1, horses were fed a morning meal consisting solely of 1.0% BW concentrate while 1.25% BW concentrate was fed on d 22 of Exp. 2. Cecal samples were obtained through cecal cannulae from d 19 to 22 of each experiment every 4 h for h 24 following the morning meal each day. Cecal pH during Exp. 1 was recorded and decreased at h 12 following the concentrate meal on d 22 in comparison to cecal pH at h 12 on d 19 to 21 (P = 0.009). During Exp. 2 cecal pH increased at h 4 (P = 0.02) and decreased at h 12 and 20 (P < 0.0001) following this oncentrate challenge compared to cecal pH recorded at the same time points during the acclimation period. Experiment 3 differed from that of Exp. 2 only in the respect that during the acclimation period horses were fed, in addition to the acclimation ration, either a proprietary supplement (n = 5) or a placebo (n = 5). Cecal samples from d 19 to 22 were analyzed for pH, concentration of lactate, and concentration of VFA. Horses consuming the supplement had increased cecal pH at h 4 (P = 0.009), concurrently decreased cecal lactate (P = 0.02), increased ratio of (acetate+butyrate)/propionate at h 8 and 16 (P ≤ 0.006), and decreased VFA concentration at h 24 (P ≤ 0.05) compared to horses in the control group following the concentrate challenge.

Master of Science / Department of Grain Science and Industry / Keith C. Behnke / Three experiments were conducted to evaluate the effects of distillers dried grains with solubles (DDGS) on pellet quality and pellet mill performance in pelleted swine diets. The experiments were completed at the Feed Processing Research Center in the Department of Grain Science at Kansas State University. In all experiments, pellet durability index (PDI), electrical energy consumption, production rate, and bulk density served as the response criteria. In Exp. 1, DDGS were substituted on an equal weight basis for corn, with substitution levels of 10%, 20%, 30%, and 40%. The diet was not adjusted to maintain equal nutrient levels across the treatments. There were no observed significant differences in pellet quality across all levels of DDGS substitution. Both production rate and bulk density were significantly lowered as DDGS level increased. In Exp. 2, diets were formulated to contain the same levels of DDGS, but all ingredients were allowed to vary to retain nutritionally similar diets. In this case energy consumption showed no significant differences among treatments, while pellet quality, throughput, and bulk density were all negatively affected by increasing levels of DDGS. In Exp. 3, the effect of incorporating pelleted and reground DDGS was evaluated. The levels of DDGS evaluated were 10%, 20%, and 30%, using the same diets as Exp. 2. These diets were then pelleted and compared to a control diet with no added DDGS and to diets with unprocessed DDGS added at the same levels. At levels above 10% the diets containing unprocessed DDGS had significantly lower pellet quality than the control, while the diets containing pelleted and reground DDGS showed no significant difference from the control at any level. Significant effects were also observed for production rate, energy consumption, and bulk density. In conclusion, the use of standard DDGS in pelleted feeds is feasible, and although pellet quality may be significantly lower for feeds containing DDGS, the practical value is likely not affected. Furthermore, the data demonstrates some benefits of using DDGS that have been pelleted and reground.

Master of Science / Department of Animal Sciences and Industry / Joel M. DeRouchey / Seven experiments were conducted to evaluate the effect of alfalfa and cornstalk round bale processing type on animal performance, wastage, preference, and mixing characteristics. All bales were baled using a round baler (John Deere) that had the ability to cut forage being baled prior to wrapping. This machine processed all bales used in these experiments, with those termed conventional being baled with the cutter disengaged. In Exp. 1, 46 heifers (initially 270 kg BW) were used in a 27 d experiment with ADG being higher (P < 0.01) for heifers consuming precut alfalfa compared to conventional alfalfa in ring feeders. However, there was no difference in final BW (P = 0.56) between conventional and precut treatments. In Exp. 2, 46 heifers were used to show there was no (P > 0.05) difference in forage wastage from ring feeders between precut or conventional alfalfa. In Exp. 3, 26 beef heifers, (initially 305 kg) were used to show that there was no (P = 0.48) difference in the preference of conventional alfalfa or precut alfalfa when offered simultaneously in different ring feeders for 2 d. In Exp. 4, 75 bulls (initially 317 kg BW) were used to show that tub ground bales had smaller TMR particle size (P = 0.01) than TMR’s with conventional or precut alfalfa bales. In Exp. 5, 60 heifers (initially 332 kg BW) were used to show that different discharge locations from each of the different cornstalk treatments had similar (P > 0.11) DM, CP, ADF, and NDF. Mixing time and fuel usage of a vertical mixer were evaluated in Exp. 6 and 7. In Exp. 6, bale mixing time was shorter (P < 0.05) for precut alfalfa compared to conventional alfalfa bales. Fuel usage per bale was lower (P < 0.001) for precut alfalfa bales compared to conventional alfalfa bales. In Exp. 7, precut cornstalk bale mixing time was shorter (P < 0.001) than conventional cornstalk bales. Fuel usage was similar (P > 0.05) among precut and conventionally-processed cornstalk bales. In conclusion, precutting alfalfa or cornstalk bales prior to net wrapping improved heifer performance and decreased mixing time and tractor fuel usage, but did not affect wastage and preference.

Doctor of Philosophy / Department of Animal Sciences and Industry / James S. Drouillard / Beta-adrenergic agonists, which are synthetic catecholamines, increase rate of gain, improve feed efficiency, and decrease carcass fat, when fed to cattle before slaughter. However, little attention has been given to the potential effects of beta-adrenergic agonists on the rumen ecosystem. Natural catecholamines, such as norepinephrine, epinephrine, and dopamine, have been observed to stimulate bacterial growth. The objectives of this research were to determine if ractopamine hydrochloride (RAC) a synthetic catecholamine has direct effects on growth and fermentation products of ruminal bacteria, and to determine the effects of protein source on ruminal fermentation and proteolysis when cattle are fed RAC. The effects of varying concentrations of RAC on ruminal fermentation were evaluated in vitro. Ractopamine hydrochloride had a quadratic effect on in vitro gas production (P < 0.05). Total VFA production was not changed with RAC (P > 0.50). Different concentrations of RAC were evaluated in vitro with different nitrogen sources to determine effects of nitrogen degradability on response to RAC. There was an interaction between RAC and nitrogen substrate (P < 0.01), with more degradable forms of nitrogen eliciting greater changes in in vitro dry matter disappearance (IVDMD) with RAC supplementation. Significant main effects also were detected for RAC, substrate, and hour (P < 0.001). In vitro analysis of proteolysis revealed that RAC lowered ammonia and amino acid concentrations (P < 0.001). In vivo ruminal ammonia concentrations also were lower when RAC was fed in combination with dry-rolled corn, but not when fed in conjunction with steam-flaked corn (grain processing × RAC, P < 0.01). Addition of RAC, steam-flaked corn, and distiller’s grains (DG) all resulted in lower ruminal ammonia concentrations (P < 0.01). Amino acid concentrations were decreased when RAC was added to diets with DG but were unchanged in diets without added DG (DG × RAC, P < 0.05). Results from these studies suggest that RAC affects fermentation by ruminal microflora. However, there were no differences in growth or fermentative end products of pure bacterial cultures with the addition of RAC (P > 0.10). Overall beta-adrenergic agonists alter ruminal fermentation, which could have important implications for diet formulation.

Master of Science / Department of Animal Sciences and Industry / Evan C. Titgemeyer / Two experiments quantified effects of supplemental protein and energy on forage digestion and urea kinetics in beef cattle. In experiment 1, energy treatments included: control, 600 g glucose dosed ruminally once daily, and 480 g VFA infused ruminally over 8 h daily. Casein was dosed ruminally once daily (120 or 240 g). Cattle (208 kg) had ad libitum access to low-quality hay (5.8% protein). Infusion of VFA decreased forage intake by 27%. Glucose decreased NDF digestibility. Microbial N flow was greater for 240 than for 120 g/d casein, but was not affected by energy. Retained N increased with casein supply. Urea-N entry rate (UER) and gut entry of urea-N (GER) were not affected by energy, casein, or interactions, but GER/UER was less when 240 rather than 120 g/d casein was provided. Compared to VFA, glucose tended to increase GER/UER. Glucose led to more microbial uptake of recycled urea than VFA. In these young calves, changes in N and energy supply did not greatly impact urea kinetics, likely because increased N was largely retained. In experiment 2, treatments included: 0 or 1.2 kg glucose, and 240 or 480 g casein. Cattle (391 kg) were fed low-quality hay (4.7% protein). Glucose reduced forage intake by 18%, whereas casein did not affect it, and depressed fiber digestion. Microbial N flow to the duodenum and retained N increased as casein increased, but neither was affected by glucose. Increasing casein increased UER 50%. Urinary urea-N increased as casein increased; moreover, GER numerically increased 25% as casein increased. GER/UER decreased as casein increased. Glucose decreased urinary urea, but did not change UER or GER. Microbial uptake of recycled urea was least for steers receiving 480 g/d casein with no glucose, reflecting that this treatment exceeded ruminal requirement for N. In these more mature steers, increases in N intake increased UER, reflecting that only small proportions of the increased N intake were retained. Thus, as steer maturity increased, UER and GER increased, likely because less N was retained. These studies demonstrate the influence of urea recycling in meeting N needs of cattle fed low-quality forage.

Master of Science / Department of Animal Sciences and Industry / Jim L. Nelssen / Seven experiments were conducted to estimate the optimal standardized ileal digestible (SID) lysine:ME ratio for growing and finishing pigs. Experiment 1 determined an optimal SID lysine:ME ratio of 3.16 g/Mcal for 38 to 65 kg gilts. Experiment 2 reported an optimal level of 2.58 g SID lysine/Mcal ME for 55 to 80 kg gilts. Experiment 3 determined an optimal SID lysine:ME ratio of 2.55 g/Mcal for 85 to 110 kg gilts. In Exp. 4 and 5, growth rates were improved with porcine circovirus type 2 vaccine, with the optimal SID lysine:ME ratio for 38 to 65 kg gilts and barrows being 2.99 and 3.36 g SID lysine/Mcal ME, respectively. In Exp. 6 and 7, the optimal SID lysine:ME ratio was 1.86 and 2.61 g/Mcal for 102 to 125 kg gilts and 98 to 118 kg barrows, respectively. These trials indicate the optimal SID lysine:ME ratio for commercial growing and finishing pigs has increased compared with earlier estimates. Four experiments were also performed to determine the effect of copper (Cu) and zinc (Zn) supplementation on growth performance of weanling pigs. In Exp. 1, both 3,000 ppm Zn from zinc oxide (ZnO) and 150 ppm Cu from tri-basic copper chloride (TBCC) independently improved growth performance in weanling pigs due to increased feed intake. Similar results were observed in Exp. 2, where 3,000 ppm Zn from ZnO increased ADG and ADFI. Also, 125 ppm Cu from copper sulfate (CuSO4) increased growth rate due to enhanced feed intake, with Cu supplementation from TBCC offering intermediate results to CuSO4 and no Cu supplementation. For the first 28-d of Exp. 3, similar additive responses were observed to adding Cu and Zn to the diets of weanling pigs. However, from d 28 to 42 the combined use of Cu and Zn produced decreased performance compared each used singularly. Similarly in Exp.4, CuSO4 and ZnO improved growth performance, however the benefit was not additive. These trials showed growth promoting advantages to adding Cu and Zn to weanling diets, but additive responses were inconsistent.

Master of Science / Department of Animal Sciences and Industry / J. Ernest Minton / Mitchell Ricketts / Cattle and other livestock have been identified as leading sources of injuries to workers in agriculture. Cattle handling injuries can be serious and often appear to be under-reported [superscript]3,[superscript]4. Many of these injuries involve predictable patterns of interactions among victims, animals, and fixed farmstead structures or gates. There has been some progress toward developing safer facility designs and work procedures, but continuing reports of injuries suggest further efforts are still needed. The present study focused on worker injuries that involved the interaction of three elements: (a) cattle, (b) cattle handlers, and (c) farm structures or equipment—including swinging gates and stationary barriers. The goal of the study was to identify opportunities for injury prevention. The source of injury cases was the Consumer Product Safety Commission’s National Electronic Injury Surveillance System (NEISS)[superscript]29,[superscript]45. We believe this is the first report of cattle related injuries based on NEISS data. We selected the NEISS database for this investigation because it includes product codes for many farmstead barriers such as fences, walls, and doors. The database was also selected because it contains brief narratives that help to describe the circumstances of each incident. Predictable interactions between humans, animals, and farm structures led to many of the cattle handling injuries reported in the NEISS database. In almost 30% of cases, cattle pushed workers into structures such as fences, gates, posts, and walls. In another 16-19% of injuries, cattle struck gates and other objects, propelling them at the victims. These percentages are similar to findings reported in previous studies that drew on data from New York hospitals[superscript]10, news reports in the central United States[superscript]5, and workers compensation cases in Colorado[superscript]3,[superscript]4. In all, gates and other physical barriers contributed to about 45% of cattle handling injuries in the present study.

Master of Science / Department of Animal Sciences & Industry / Elizabeth A. Boyle / Quality attributes of vacuum packaged, skinless smoked sausage made with a combination of pork, turkey, and beef, cooked to 64, 68, or 72°C internal endpoint temperature following USDA FSIS Appendix A, and displayed at 4°C for up to 120 days under light emitting diode (LED) and fluorescent (FLS) lighting were evaluated. External color, pH, thiobarbituric acid reactive substances (TBARS), proximate analysis, reheat yield, and sensory attributes were measured on day 0, 90, and 120 of display. Purge amount and color were measured on day 10, 90, and 120. Product was displayed in LED or FLS retail display cases set to the same operational and temperature profiles. Lighting type had no effect (P>0.05) on any of the measured attributes. Instrumental external color was less (P<0.05) red by 0.63 units in product thermally processed to 64°C than product processed to 68°C. Product cooked to 72°C was less (P<0.05) yellow externally compared to those processed to 64 and 68°C. Purge color lightness increased (P<0.05) in product thermally processed to 72 compared to 64°C. Purge was more red by 0.36 units (P<0.05) on day 120 compared to day 10. Yellowness of purge color increased at 72°C compared to 64°C by 0.66 units. Purge was more yellow (P<0.05) on d 120 compared to d 10 and 90. TBARS values decreased (P<0.05) from 0.70 mg of malonaldehyde/100g on day 0 to 0.35 and 0.23 on d 90 and 120, respectively. Sensory panel scores showed that flavor intensity decreased (P<0.05) as day of storage increased, and saltiness decreased from d 0 to d 90. Purge content increased (P<0.05) from 1.45% to 1.90% in products cooked to 64 and 68°C, respectively. The amount of purge increased (P<0.05) from 1.58% to 1.92% on day 10 and 90, respectively. While there were slight changes found in quality characteristics of smoked sausages during storage, many of these were minimal. Processors could reduce their internal endpoint temperature following USDA FSIS Appendix A guidelines with minimal effect on product quality. Vacuum packaged pre-cooked smoked sausages could be displayed under LED or FLS lighting with no effect on product quality.

Master of Science / Department of Animal Science and Industry / Barry Bradford / During the past decades, the dairy industry has been challenged to find alternative approaches in order to feed cows without affecting their performance or increasing production costs. To accomplish these objectives, some options that have been implemented are the inclusion of short chain carbohydrates to replace starch and the addition of synthetic supplements to increase feed efficiency. In order to assess the impact of these strategies, an experiment was conducted to evaluate productive responses of lactating dairy cattle when they received sucrose and/or exogenous amylase in low starch diets. The results indicated that milk production, milk component profile, and feed efficiency were not significantly altered by the use of the enzyme, sucrose inclusion, or the combination of both. Comparing these results with the literature revealed apparent inconsistencies in responses to the inclusion of sugar in dairy rations. For that reason, a meta-analysis was performed to determine the impact of different sugar sources on milk production, and also to evaluate the impact of other dietary factors on response to dietary sugar. The results indicated that dry matter intake responses were significantly (P < 0.05) affected by an interaction between added sugar and dietary forage neutral detergent fiber content, but overall, dry matter intake tended to increase when sugar replaced corn grain in diets. Energy corrected milk was not affected by dietary sugar, but milk production showed a tendency to respond to treatment, dependent on an interaction between added sugar and rumen undegradable protein. In summary, sugar inclusion may promote small increases in dry matter intake, but the impact on milk production is inconsistent; both factors may be influenced by the diet to which sugar is added.