Master of Science / Department of Agricultural Economics / Ted C. Schroeder / Very rapid growth in the ethanol industry has led to a void of information regarding price dynamics and utilization of distiller's grains. Understanding market conditions is essential for livestock producers to make informed decisions in the procurement of feedstuffs, especially as grain price levels have recently increased substantially. In this study, distiller's grain price discovery dynamics are evaluated to develop an understanding of spatial price relationships. The knowledge of price relationships reveals that users of distiller's grain should shop around when procuring the feedstuff. Additionally, because animal performance may be altered with increased inclusion of distiller's grains, regional competitive advantages could shift fed cattle production to geographic regions characterized by high of ethanol production plants. Therefore, the cost of current grain processing methods are evaluated to enhance the awareness of regional competitiveness and long term sustainability. The combination of these two objectives allows producers to better realize the implications of the ethanol industry on their ability to maintain their operations into the near future.

Master of Science / Department of Animal Sciences and Industry / Christopher D. Reinhardt / Three experiments were conducted to examine nutritional and management strategies for different segments of the beef industry. The first experiment examined the effects of feeding traditional step-up diets (STEP) vs. limit-feeding (LIMIT) the finishing diet to adapt cattle to high-concentrate diets. When all cattle reached ad libitum intake of the finishing diet there was a trend (P = 0.09) for DMI to be different between treatments. During week 1, STEP cattle had higher total VFA concentrations (P = 0.02), while LIMIT cattle had higher valerate absorption (P = 0.02) and disappearance (P = 0.08). During week 4, LIMIT cattle had higher total VFA concentrations (P = 0.03) and lower valerate disappearance and absorption (P = 0.05) than STEP cattle. These results indicate that limit-feeding the finishing diet may inhibit nutrient absorption from the rumen or this method may cause increased production of valerate by lactate utilizing bacteria due to a more acidotic rumen environment. The second experiment examined the effects of feeding 5% (DM basis) dried, full-fat corn germ (GERM) on feedlot performance and carcass characteristics of naturally raised yearling steers and heifers. Carcass-adjusted ADG was higher for GERM cattle (P = 0.04). There were no other differences in performance or carcass characteristics. Total incidence of liver abscesses and the incidence of severe liver abscesses were decreased by 12 and 8.2% (P = 0.01 and 0.02, respectively) when GERM was added to the diet. Corn germ can be added to finishing diets at 5% without affecting performance and carcass characteristics. Producers raising natural cattle may also be able to benefit from the reduced incidence of liver abscesses. The third experiment examined concurrent metaphylactic treatment of high-risk calves with tulathromycin and chlortetracycline. Calves were placed on 1 of 3 treatments: 1) no top-dress pellets; 2) diet top-dressed with pellets containing chlortetracycline; or 3) diet top-dressed with pellets containing no chlortetracycline. There were no differences in the performance or health of these calves (P > 0.25). There are no additive benefits of concurrent metaphylaxis using both tulathromycin and chlortetracycline. This information could assist producers when designing receiving health protocols for high-risk calves.

Master of Science / Department of Animal Sciences and Industry / Bradley J. Johnson / Zilpaterol hydrochloride (ZH) is a growth promotant that is approved for use in finishing cattle to improve growth performance and increase lean tissue accumulation. Little is known about the combined effects of ZH with anabolic steroid hormone implants. There is also little published data on the effect these growth promotants have on genes that play a role in skeletal muscle synthesis and degradation. Therefore, two separate studies were conducted to address these issues. The first study evaluated the effects of ZH and the steroid implant Revalor-S (RS) on animal performance and skeletal muscle gene expression in feedlot steers. Four treatments were used to analyze the effects of RS implanted 58 days before ZH, which was fed for 30 days with a 3 day withdrawal. It was determined that ZH and RS additively contribute to improved live and carcass performance; however these compounds had different effects on the abundance of the receptors for ZH as well as the abundance of myosin heavy chain (MHC) mRNA in skeletal muscle of feedlot steers. It was also determined that ZH can cause a transition in the abundance of MHC mRNA isoforms in skeletal muscle that are available for the translation of larger, faster, more glycolytic fiber types of MHC. The second study evaluated the effects of two types of anabolic steroid hormones on myosin heavy chain gene expression. Four treatments were used to measure the effects of trenbolone acetate (TBA) and estradiol (E[subscript]2) on performance and the amount of MHC mRNA in skeletal muscle of finishing steers. It was determined that anabolic steroid implants improve live animal performance, however there was no alteration in the abundance of MHC mRNA in skeletal muscle of feedlot steer for 28 days after implantation; however there was an increase in intermediate fiber type IIA of MHC mRNA in skeletal muscle with increasing days on feed. From these studies we concluded that ZH and anabolic steroids do have an effect on growth performance; however they may differ in the distinct mechanism of action utilized to enhance lean tissue deposition in feedlot steers.

Master of Science / Department of Animal Sciences and Industry / Twig T. Marston / One hundred ninety-three crossbred steers from two herds were used to determine the association of leptin gene polymorphisms and effects of feedlot management of lean and fat steers on carcass performance. Steers were sorted into FAT and LEAN groups by ultrasound backfat at weaning and randomly assigned to a finishing phase. Steers were assigned to a backgrounding phase (BACK) and were fed a forage-based diet for 90 days or directly entered a feedlot phase (FEED). Genotypes were determined by IGENITY® (Atlanta, GA) for a panel of nine single nucleotide polymorphisms (SNP) in the leptin gene (UASMS1, UASMS2, C963T, E2FB, A1457G, and A252T), leptin receptor (T945M), growth hormone receptor (G200A), and fat metabolism enzyme (K232A). Initial backfat (BF) means for the FAT and LEAN group were 3.4 mm and 1.8 mm, respectively. Mean on-test weight was heavier for FAT (306.5 kg) than LEAN (292.9 kg). Age-adjusted hot carcass weights (HCWT) were heavier for LEAN/BACK when compared to FAT/FEED and FAT/BACK (P<0.05). Dressing percent for the FAT/FEED group tended to be higher (P<0.10) over all groups except LEAN/BACK. Steers that went directly to the feedlot had higher marbling scores than backgrounded groups. FAT/FEED had higher 12th rib BF than the other contemporaries. None of the SNPs were useful for predicting ultrasound BF at weaning. Some association was detected with UASMS2 and HCWT (P<0.10) resulting in an 11 kg difference between genotype CC and CT (P<0.05). Five of the leptin polymorphisms (UASMS1, UASMS2, A1457G, C963T, and E2FB) were associated with adjusted carcass BF (P=0.01, 0.06, 0.01, 0.01, and 0.01, respectively) and calculated yield grade (P<0.01). A252T was associated with REA, and genotype TT was larger than AA and AT (P<0.05). This study suggests that segregation by initial fatness estimates and feedlot management strategies has the opportunity to increase HCWT by 35 kg. Sorting cattle upon feedlot entry by ultrasound BF and segregation using genetic markers are useful tools that can assist in the estimation of carcass composition in the live animal. With additional research, the possibility exists to incorporate genetic markers into feedlot selection to assist in marketing decisions.

Doctor of Philosophy / Department of Animal Sciences and Industry / Michael D. Tokach / Four experiments were conducted to determine the interactive effects of dietary L-carnitine and ractopamine HCl (ractopamine) on finishing pig growth performance. In analysis of treatments common to all experiments, ractopamine increased (P < 0.01) ADG and G:F compared to pigs not fed ractopamine. Added L-carnitine tended to increase (P < 0.07) ADG and improved (P < 0.01) G:F compared to pigs not fed L-carnitine. Three experiments were conducted to determine the effects of L-carnitine and ractopamine on carcass characteristics and meat quality. In Exp. 1, drip loss decreased (linear, P < 0.04) in pigs fed increasing L-carnitine. In Exp. 2, drip loss decreased (P < 0.04) with increasing L-carnitine when fed with ractopamine. Percentage lean was higher (P < 0.01) for pigs fed ractopamine. In Exp. 3, lean percentage increased (P < 0.03) in pigs fed L-carnitine or ractopamine. Pigs fed L-carnitine tended (P < 0.06) to have decreased drip loss. These results suggest that ractopamine increases carcass leanness and L-carnitine reduces drip loss when fed in combination with ractopamine. Two experiments were conducted to determine the effects of L-carnitine and ractopamine on the metabolic response to handling. Non-gentle handling increased (P < 0.01) lactate and rectal temperature, and decreased pH. In Exp. 1, non-gentle handled pigs fed ractopamine had decreased (P < 0.01) pH and increased temperature and tended (P < 0.09) to have higher lactate than other pigs. In Exp. 2, lactate and temperature changes from immediately post-handling to 1 h post-handling were not different for pigs fed L-carnitine or ractopamine suggesting that L-carnitine did not decrease recovery time of pigs subjected to non-gentle handling or fed ractopamine. These results suggest that pigs fed ractopamine are more susceptible to stress when handled aggressively. Because carnitine did not alleviate the negative effects of handling for pigs fed ractopamine, the improvement in drip loss from feeding carnitine must be due to a different mode of action.

Master of Science / Department of Animal Sciences and Industry / Michael E. Dikeman / Objectives were to determine the effects of needle-free (NF) versus needle (N) injection methods and/or solutions for enhancement of beef longissimus lumborum muscle (LM) on color, instrumental tenderness, sensory attributes, pump yields, and cooking losses. In experiment 1, LM (n=15) at 9 d postmortem were halved before random assignment to N or NF injection enhancement with a solution containing 2.2% salt, 4.4% sodium tripolyphosphate (STPP), and 1.5% K lactate. Different steaks from each loin half were either placed on a 5 d color display, frozen for later sensory analysis, or aged until d 13 postmortem for LM slice shear force measurements. Pump yields tended (P=0.08) to be higher for NF injection. Needle injected steaks were darker (P<0.05) on day 1, but not after that. Discoloration was not different (P>0.05) between treatments. The NF treatment had greater (P<0.05) instrumental tenderness and intensity of off-flavors but less (P<0.05) cooking loss and beef flavor. In Experiment 2, LM (n=28) at 5 d postmortem were halved before random assignment to one of four treatments: 1) N, or 2) NF injection with a solution containing 2.2% salt, 4.4% STPP, 15% K lactate, and 0.58% rosemary; 3) N, or 4) NF injection with a solution containing 2.4% Ca lactate and 0.58% rosemary. Steaks from each loin half were either frozen for later sensory analysis or aged until d 14 postmortem for LM slice shear force measurements. Loins phosphate enhanced with the NF injector had the highest (P<0.05) pumped yields with no differences (P>0.05) among other treatment combinations. Instrumental tenderness was not different (P>0.05) between N and NF treatments but was higher with the phosphate solution than the Ca lactate solution. The NF treatment had lower (P<0.05) cooking losses when the phosphate solution was used, which resulted in less (P<0.05) cooking loss than the Ca lactate solution. More (P<0.05) off-flavors and abnormal texture resulted from NF injection. The phosphate solution resulted in greater (P<0.05) myofibrillar and overall tenderness, juiciness, off-flavors and abnormal texture with less (P<0.05) connective tissue than the Ca lactate solution. Enhancing beef LM with a phosphate solution and NF injection might improve yields, tenderness, and juiciness while harming texture and flavor.

Master of Science / Department of Animal Sciences and Industry / J. Ernest Minton / Anabolic steroids are used extensively in beef cattle feeding management to take advantage of well-documented improvements in growth performance and efficiency of implanted cattle. In addition to muscle growth, steroids also impact changes in bone and cartilage formation. In general, these effects can be interpreted as hastening bone aging. The current study was designed to test the hypothesis that recently-identified peripheral indicators of bone and cartilage turnover could be detected in the peripheral circulation. Furthermore, it was hypothesized that these peripheral markers might reflect accelerated aging effects of the widely used steroidal implants trenbolone acetate (TBA) and estradiol-17β (E2). Circulating IGF-I was measured as a positive marker of steroid-induced enhancement of the somatotropic endocrine axis. Thirty-two crossbred yearling steers were blocked by BW and given one of four treatments: non-implanted controls; 25.7 mg estradiol-17beta (E2); 120 mg trenbolone acetate (TBA); or a combination of 120 mg TBA and 24 mg E2 (T+E). Blood samples were collected on d 0, d 7, d 14 and d 28 and serum was analyzed by ELISA for IGF-I concentrations, as well as osteocalcin, C-terminal telopeptides of Type I collagen (CTX-I) and C-terminal telopeptides of Type II collagen (CTX-II), which serve as markers of bone formation, bone resorption and cartilage resorption, respectively. Circulating IGF-I was similar among treatments on d 0 and 28. At d 7 and 14, steers receiving E2 or T+E had greater circulating IGF-I than non-implanted control steers (P < 0.05). In contrast, steers receiving only TBA tended to have elevated IGF-I compared to controls on d 7 and 14 (P = 0.10). Although treatment did not affect serum osteocalcin, concentrations were increased on d 7, 14, and 28 compared to d 0 (P < 0.005 for all). Implant treatment did not affect circulating CTXI, however CTX-II was affected by T+E treatment (P<0.05). The data suggest that, although selected markers of bone and cartilage turnover can be detected in circulation in cattle, implant-induced changes in the concentrations of these markers are not directly evident in the peripheral circulation at least through 28 d following treatment.

Master of Science / Department of Animal Sciences and Industry / Barry J. Bradford / Increased pressure for land use and greater demand for cereal grains have substantially increased feed costs for dairy producers. This has forced nutritionists to devise novel diet formulation strategies to help keep feed costs in check. As a result, dairymen are incorporating wet corn gluten feed (WCGF) into diets. Numerous studies have reported production responses to dietary inclusion of WCGF, but few have reported ruminal effects. Therefore an experiment was conducted to monitor production, while simultaneously measuring ruminal fermentation and total-tract digestion in 8 Holstein cows fed 0, 12, 24, and 36% WCGF (DM basis). Results from this study were consistent with recently published papers indicating that increasing dietary levels of WCGF linearly increases milk and milk component production. However, results demonstrate that this increase in production is related to an increase in feed intake, not improved digestibility. In addition to escalating grain prices, recent pressure for land and water use has led to a decrease in the availability of alfalfa. A second experiment was conducted to determine if forage fiber provided by alfalfa hay is necessary to maintain production in diets containing 31% WCGF (DM basis). Eighty primiparous and multiparous Holstein cows were utilized in two 4 × 4 Latin squares to evaluate the effects of feeding alfalfa at 0, 7, 14, and 21% of diet DM. Feeding higher proportions of alfalfa tended to increase ECM yield and decrease BW gain, suggesting that metabolizable energy supply was repartitioned from BW gain to milk production as more alfalfa was included. However, partial budget analysis determined that decreasing alfalfa inclusion rate may improve farm profitability by reducing feed costs and expenses associated with manure handling, despite small losses in productivity. Overall, these research projects suggest that large proportions of WCGF can effectively be fed to dairy cattle without sacrificing milk production, even without the use of alfalfa hay. Therefore, WCGF can be a cost-effective alternative to traditional dietary ingredients.

Master of Science / Department of Animal Sciences and Industry / John F. Smith / A series of experiments was developed to investigate how Korral Kool® (KK) systems work in arid climates to prevent heat stress on dairy cows. These experiments were conducted during summer on a commercial dairy farm in eastern Saudi Arabia. In the first experiment, the core body temperatures (CBT) of 63 multiparous cows were evaluated when KK were operated for 18, 21 and 24h/d. Animals were housed in 9 different pens, which were randomly assigned to treatment sequence in a 3x3 Latin square design. In the second experiment, 21 multiparous and 21 primiparous cows were housed in 6 different pens, which were randomly assigned to sequence of treatments (KK operated for 21 or 24h/d) in a switchback design. In the third experiment, 7 primiparous and 6 multiparous lactating cows were assigned to one of two pens, which were randomly assigned to treatment sequence in a switchback design. Treatments in the third experiment were KK used with or without feedline soakers 24h/d. In the fourth experiment, 20 multiparous cows were randomly assigned to one of two pens, which were randomly assigned to treatment sequence in a switchback design. Treatments in this experiment were KK operated for 24h/d while feedline soakers were operated for 12h/d. In the fifth experiment, 2 different sizes of KK were compared (BIG and SMALL); 48 multiparous cows were randomly assigned to 8 pens and pens were randomly assigned to sequence of treatments (KK were operated for 21 or 24h/d) in a switchback design. Results demonstrated that for multiparous cows in desert climate conditions, it is advisable to operate KK systems continuously regardless of the size of KK system used, whereas KK operating time could potentially be reduced from 24 to 21h for primiparous cows. Reducing operation time should be done carefully, however, because CBT was elevated in all treatments. Feedline soakers complementing KK systems decreased the CBT of dairy cows housed in desert environments. However, the combined systems were not adequate to lower CBT to normal temperatures in this extreme environment.

Doctor of Philosophy / Department of Animal Sciences and Industry / Joe D. Hancock / A total of 2,840 1-d-old broiler chicks and 450 1-d-old layer chicks were used in three experiments to determine the nutritional value of corn- and sorghum-based diets in poultry reared in West Africa. In the broiler experiments, birds fed corn had greater average daily gain (P < 0.001) with similar carcass weight and yield for birds fed corn- vs sorghum-based diets (P > 0.18). Particle size treatments did not affect growth performance or carcass characteristics (P > 0.20). In the layer experiment, birds fed sorghum had greater body weight at d 126 (P < 0.001), started laying earlier (P < 0.01), ate more feed (P < 0.01), and produced more eggs (P < 0.01) than birds fed the corn-based diet. However, there was no difference in average egg weight among birds fed corn vs sorghum (P > 0.85). In conclusion, sorghums produced in West Africa are a good alternative to corn when fed to broiler chicks and laying hens.