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In Chapter 2, an experiment was conducted to evaluate the effect of different mixer types (MTY) and mix times (MTI) on mix uniformity (MU). A 2 (mix time) x 3 (mixer type) factorial was utilized in this experiment to create six treatments, each mixed in three randomized complete blocks. Mix times were designated adequate or inadequate, were based on the manufacturers’ recommendation, and varied based on the mixer utilized. The mixer types utilized included a vertical mixer, horizontal mixer, and transfer mixing system. The transfer mixing system can be described as a batch-to-mix system that simulates the process of conveying batched feed to a mixing location. Chloride ions (Cl-) via salt, crystalline DL-Methionine (Free Met), and crystalline L-Lysine-HCL (Free Lys) were utilized as coefficient of variation (CV) markers, with Cl- being used in a corn-salt (CS) ration and the Free Met and Free Lys being used in a complete diet (CD). An interaction between MTY and MTI affected Free Met CV (P = 0.005). The horizontal mixer and transfer mixing system did not demonstrate changes in the Free Met CV compared to the vertical mixer when MTI was manipulated. The authors hypothesize that additional mixing during load-out and added conveyance caused this interaction. The transfer mixing system resulted in the lowest Free Lys CV (P = 0.017); however, no treatment provided an industry-acceptable MU. In conclusion, Free Lys may not be an appropriate marker for MU, Free Met may be an appropriate marker for MU in complete diets, and the transfer mixing system may contribute to an acceptable MU. In Chapter 3, an experiment was conducted to evaluate the influence of pellet die thickness (PDT) and Azomite® (AZM) on feed manufacture. A 2 (AZM) x 3 (PDT) factorial was utilized in this experiment to create a total of six treatments, each manufactured in every run order position in a Latin Square Design. Azomite inclusion rate was either 0.0% (control) or 0.25%, and 32mm, 38mm, and 45mm PDTs were utilized in their appropriate treatments. The pellet diameter was held to a constant of 4.5mm. The objective of this study was to evaluate the effect of AZM and PDT on pellet production rate (PPR), pellet durability index (PDI), and hot pellet temperature (HPT) in corn, soybean meal, and dried distillers grains with solubles-based poultry diets, manufactured under a constant motor load. The inclusion of AZM increased overall PPR by 7.9% (P < 0.001) and decreased overall PDI by 1.6 percentage points (P < 0.001). As PDT increased from 32mm to the average of the 38 and 45mm treatments, PPR decreased by 28.5% (P < 0.001) and increased PDI by 10.1 percentage points (P < 0.001). A main effect interaction of AZM and PDT was recognized to influence HPT (P < 0.007), however, no difference was observed for the 45mm PDT when AZM was included. Linear contrasts showed that PPR increased by 5.0, 7.9, and 11.8% when comparing AZM treatments to their respective controls (All PDT; P < 0.001). The authors of this experiment concluded that AZM increased PPR across PDT and decreased PDI, albeit to the extent that would likely not affect broiler performance. In Chapter 4, a follow-up experiment to the previous was conducted to evaluate the influence of PDT and AZM inclusion rate on broiler performance and apparent ileal amino acid digestibility (AIAAD). A 2 (AZM) x 2 (PDT) factorial was utilized in this experiment to create a total of four treatments. The dietary treatments were sourced from the previous AZM experiment, and only the treatments utilizing the 32 and 45mm PDT were utilized. All feed was reground and slightly reformulated to reduce the confounding bias of PDI and to ensure an acceptable nutritional density. Ten randomized complete blocks of raised wire cages were utilized with each pen housing ten Ross 308 broilers. The objective of the study was to determine the effect of pelleted feed using AZM (0.0 or 0.25%) and PDT (32 or 45mm; using a constant die diameter of 4.5mm) on Ross 308 male broiler feed intake, live weight gain, feed conversion ratio, and AIAAD from 0 to 21 days of age. Live performance did not differ due to an interaction or independent main effects (P > 0.05). However, AIAAD was influenced by AZM and PDT interactions (P < 0.05). The amino acids Ala, Asp, Glu, Gly, Ile, Lys, Met, Pro, Thr, and Val demonstrated increased digestibility with the 45mm Control treatment. This treatment also produced the highest numerical HPT in the feed manufacture experiment. It was hypothesized that the digestibility resulted from increased frictional heat that deactivated trypsin and chymotrypsin inhibitors or degraded ingredient cell wall structure. While both inhibitors were determined to be present using SDS-PAGE and chemiluminescent detection, quantitative analysis showed no practically influential concentrations of either inhibitor or a decrease large enough to explain the increased AIAAD. The authors, therefore, speculate that the increase in AIAAD of various amino acids was due to the breakdown of the aleurone layer cell walls of the corn kernels caused by increased frictional heat exposure vis the 45mm PDT and the absence of AZM.

Two studies were conducted to evaluate the efficacy of multiple feed additives on the performance of older White Leghorn hens. Study 1 examined the effects of 2 vitamin/mineral supplements and 1 medium chain fatty acid. Study 2 examined the effects of a novel butyric acid product, a tributyrin ester. Both studies followed a completely randomized design with repeated measures and data were analyzed using the Glimmix procedure in SAS version 9.4 for Windows. The first study took place November 2015 to April 2016. Trt 1 was a control diet, Trt 2 was supplemented with a Ca, Fe, Mn, Cu, Zn mixture, Trt 3 with a medium chain fatty acid, Trt 4 and Trt 5 with a Ca, Vitamin D3, Mn, Zn mixture. A total of 270 Bovan White Leghorn hens were housed in 45 cages. Measurements included: egg production, feed intake, mortality, egg weights, eggshell breaking strength, eggshell percent, and Haugh Unit. Significant differences were seen for feed intake (p The second study ran from June to September 2016. Trt 1 was fed a control diet and Trt 2 was supplemented with a tributyrin ester at a rate of 0.055%. A total of 144 Bovan White Leghorn hens were housed in 24 cages. Measurements included: mortality, feed intake, egg production, egg weight, egg mass, eggshell percent, eggshell breaking strength, instance of shell deformities, calcium and phosphorus digestibility. No differences were found for feed intake (p These results show that some improvement can be seen when hens are supplemented with various minerals and fatty acids, with continued research investigating combinations and inclusion rates. Advisor: Sheila E. Purdum

Over the last 60 plus years, broiler breeders have been under an incredible amount of genetic pressure. This genetic pressure comes from the continually increasing consumer demand for poultry products. The objective of this dissertation is to understand the effects of different nutritional and management practices on broiler breeder’s performance. The first series of experiments investigate the impact of broilerization on hen and early progeny performance. Broilerization is a process only used by genetic companies. The results from these experiments showed the adverse effects of broilerization on chick quality and hen performance. Follow up trials were performed to determine the benefits of feeding different dietary oil sources to broilerized hens; additionally, their effects on chick quality and hen performance over a 30-week production period. Broilerized hens were reared as recommended for the industry, and at 5 % production, they were fed diets containing either poultry fat, corn oil, or canola oil as a dietary fat source. Different traits were measured, and the positive effects of corn and canola oil were shown as far as improvement of chick quality and eggs per hen housed. These dietary oil sources were also beneficial for parent stock hens (not broilerized), improving overall hen performance and chick quality at different hen ages. The second series of experiments take a more in-depth look into the effects of varying rearing methods on the performance of parent stock hens. Results from this study showed the efficiency of rearing hens on every day versus a skip a day feeding method. Fatty acids and carbohydrate metabolism play an essential role in the improvement of chick quality. The last few experiments of this dissertation show the effects of hen age on hen performance and chick quality. Results from the two previous studies provide an insight into the possible reason why younger hens and older hens have more challenges producing high-quality chicks. Overall, results from these studies allow for a deeper understanding of the effect of different nutritional and management strategies on the performance of the current broiler breeder.

The inherent variability and lack of standardization of in vivo assays to determine the metabolizable energy (ME) of DDGS has led to inconsistent values and limited its potential to use in broiler diets. Therefore, two experiments were conducted to characterize the content of nitrogen-corrected ME (MEn) in 11 DDGS sources obtained from various ethanol plants using a regression-based broiler assay and to attempt to develop equations to predict MEn based on its chemical composition. In experiment 1, the objectives were to determine the influence of inclusion level and feed intake on the resulting ME and MEn values of a single DDGS source when fed to broilers at multiple dietary inclusion levels. The ME and MEn values of DDGS determined by difference decreased as its dietary concentration increased. Pair-feeding the 30% DDGS diet to the 60% DDGS diet intake reduced the ME and MEn values of DDGS, indicating there was an effect of feed intake on the ME value of DDGS. Additionally, the MEn of DDGS was determined by two regression-based methods. First, the DDGS associated caloric intake was regressed against the amount of DDGS intake to generate linear regression equations with slopes corresponding to the MEn value of DDGS. Secondly, the dietary MEn was regressed against the DDGS inclusion level, and extrapolation of the regression line to 100% DDGS was used to estimate its ME value. Both regression methods yielded similar ME and MEn values of DDGS. Experiment 2 determined the MEn of 11 DDGS samples obtained from different biorefinery locations operated by a single ethanol producer and related these values with chemical composition and physical properties of the DDGS samples. Analyses of DDGS included gross energy, CP, Lys to CP ratio (Lys:CP), ether extract, DM, starch, total dietary fiber (TDF), neutral detergent fiber (NDF), acid detergent fiber (ADF), color scores, and particle size. On a DM basis, MEn of the 11 DDGS sources ranged from 2,284 to 3,088 kcal/kg with a CV of 7%. Hemicellulose was the only component found to be correlated with the MEn of DDGS. As a result, the lack of correlations between DDGS composition and its MEn precluded development of prediction equations. Overall, these results indicate that the MEn of DDGS estimated in MEn assays is influenced by its inclusion level in the test diet and partly due to effects on feed intake While the narrow variability in the chemical composition of the DDGS sources did not allow for the development of prediction equations, these results provide good insight into the energy utilization and uniformity of these sources for poultry feed formulations.

A series of trials were conducted to analyze broiler water consumption behaviors under commercial conditions. The first trial was to quantify the number of broilers drinking at times of peak water demand. Birds were evaluated at time intervals of 5, 10, 15, 30, 45, and 60 minutes from the start of the light period to establish the percentage birds having consumed water by that point in time. Significant differences were found by bird age in the 5, 10, and 15 minute intervals, however there were no significant differences in the percentage of birds having consumed water in the 30, 45, and 60 minute intervals. A second trial was conducted to evaluate the percentage of birds drinking while on pre-slaughter feed withdrawal. Birds were evaluated at four, hourly intervals after feed had been withdrawn. It was found that there was no significant difference between the percentage of birds drinking during each hour of feed withdrawal when compared to birds that had not had feed withdrawn. Additionally, water utilization rates of liters/100 birds in the first, second, and third hour of feed withdrawal were established. A third trial evaluated the daily water to feed intake ratios on a commercial broiler farm and investigated the changes in this ratio by season. It was demonstrated that water to feed intake ratios become smaller as the birds age, ranging from 1.931:1 at 11 days of age to 1.715:1 at 46 days of age. Also, it was found that significant differences exist in daily water to feed ratios by season. A fourth and final trial was conducted to evaluate the relationship between changes in lighting and changes in water intake. Daily records of lighting changes and water consumption were collected from six farms in two different integrator complexes. These records were analyzed and no statistically significant effect (P>0.0554) of changing lighting intensity or duration on daily water consumption by broilers.

Rising feed costs, environmental pollution concerns targeted at animal agriculture, a worldwide focus on sustainability and the never ending battle to improve production and efficiency within the poultry industry challenges nutritionists to focus on products to improve nutrient digestibility and decrease feed costs while at the same time maximizing performance. The research presented in this dissertation focuses on improving nutrient utilization of protein sources with protein liberating enzymes currently available commercially. The research also conducted addresses the addition of crystalline amino acids valine and isoleucine and their effect on improving efficiency of broilers. The first research project compared the efficacy of two commercially available protease enzymes; Ronozyme ProAct (DSM, Parsippany, NJ) and Cibenza DP-100 (Novus International, St. Charles, MO). Both are broad spectrum proteases that claim to improve protein digestibility. The protein source in the broiler diet is one of the most expensive ingredients. For the past fifty years broiler diets have been supplemented with essential amino acids such as methionine and lysine and more recently threonine further reducing crude protein and at the same time decreasing diet cost. The next series of studies were conducted to evaluate the efficacy of reducing crude protein with the addition of the crystalline amino acids valine isoleucine and glycine along with those supplemental amino acids already commercially available.