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.

Master of Science / Department of Animal Sciences and Industry / Jim L. Nelssen / Eight experiments used 1,712 pigs to determine influences of dietary enzymes or specialty proteins on nursery pig performance. Experiments 1 and 2 evaluated the effects of fish meal, fermented soybean meal, or dried porcine solubles on performance. Experiment 1 showed pigs fed dried porcine solubles had improved (P = 0.01) ADG and G:F compared to pigs fed the control diet, and improved (P = 0.03) G:F compared to pigs fed the combination of fermented soybean meal and fish meal. Experiment 2 showed pigs fed increasing fermented soybean meal had improved (quadratic, P = 0.03) G:F. Experiments 3 and 4 evaluated the effects of commercial enzyme addition to diets containing dried distillers grains with solubles (DDGS) on performance. In experiment 3, neither DDGS nor enzyme addition influenced (P > 0.10) ADG and G:F. Experiment 4 found there were no (P > 0.32) enzyme × DDGS source interactions. Corn DDGS did not influence pig performance (P > 0.36). Sorghum DDGS reduced (P = 0.003) G:F, with no difference between sorghum DDGS sources. Adding enzymes to 30% DDGS diets did not improve (P > 0.57) performance. Experiments 5 and 6 evaluated the effects of fish meal (SMFM), spray-dried animal plasma (SDAP), or peptone on performance. In Experiment 5, different specialty proteins had similar (P > 0.10) ADG, ADFI, or G:F. Experiment 6 showed pigs fed 4% Peptone 2 during phase 1 and 2% Peptone 2 during phase 2 had improved (P < 0.05) ADG compared to pigs fed SMFM, and improved (P < 0.05) G:F compared to pigs fed all other diets. Experiments 7 and 8 developed an available P release curve for commercial phytase products. In both experiments, pigs fed increasing inorganic P had improved (linear, P < 0.01) G:F and percentage bone ash. Pigs fed increasing OptiPhos 2000-M, Phyzyme XP, or Ronozyme P had improved (P < 0.001) percentage bone ash. Available P release for up to 1,000 FTU/kg of Escherichia coli-derived phytases can be predicted by the equation (y = -0.000000125x[superscript]2 + 0.000236245x + 0.015482), where x is the phytase level in the diet.

Doctor of Philosophy / Department of Animal Sciences and Industry / James S. Drouillard / A series of studies were conducted to evaluate extrusion processing of finishing diets on growth performance, carcass characteristics, and meat quality attributes of feedlot cattle. Extruded diets were processed in a 24:1 (length/diameter) corotating, fully intermeshing twinscrew extruder (model BCTG-62, Bühler AG CH-9240, Uzwil, Switzerland). In Experiment 1, extrusion processing of corn based diets decreased dry matter intake (DMI) and improved gain efficiency (G:F) by 15% compared to heifers fed steam-flaked corn (SFC) diets. Carcass characteristics were not different between treatments. Steaks from heifers fed SFC diets were juicier and had a less pronounced off-flavor than steaks from heifers fed extruded diets. In Experiment 2, average daily gain (ADG), DMI, G:F, carcass characteristics, and meat quality attributes were not different between heifers fed SFC and extruded processed corn diets. In Experiment 3, we evaluated different degrees of extrusion processing by altering the level of process water added to the extruder. Mechanical energy inputs, die pressure, die temperature, and torque of drive motor decreased as the level of water added to the extruder increased from 4% to 12%. Water addition did not affect DMI or ADG of feedlot heifers. However, live body weight (BW) and G:F decreased as the level of process water increased. Gain efficiency (carcass-adjusted basis) was 3% greater for extruded corn diets processed with 4% water compared with SFC diets and was 6% poorer than SFC diets when processed with 12% water. Apparent total tract digestibility was not different, but IVDMD improved with increasing levels of water. Improvements in G:F when fed extruded feed was variable among the 3 studies. This may be due, in part to severe infestation by European Starlings during Experiment 1. Impact of feed depredation by starlings was therefore evaluated. Starlings consumed 86% of the SFC diet offered to them compared to, none of the extruded corn diets. In addition, starlings preferentially selected for the energy dense portion of the rations (steam-flaked corn). Therefore, it is plausible that a portion of the 15% improvement in G:F observed in Experiment 1 for heifers fed extruded corn diets can be attributed to differences in feed depredation by starlings. Finally, two studies were conducted to evaluate extrusion processing of sorghum-based diets. In the first experiment, DMI was greater and G:F was poorer for heifers fed extruded sorghum diets compared to heifers fed steam-flaked sorghum (SFS) diets. However, carcass characteristics and meat quality attributes were not different. In the second study, particle size of the ground sorghum added to the extruder was evaluated. Processing sorghum to a smaller particle size (581 μm) prior to extrusion processing decreased DMI, improved G:F, and increased apparent total tract digestibility compared with larger particle sizes (1,264 μm). However, heifers fed SFS diets were still more efficient that heifers fed extruded diets made with either particle size of sorghum. Overall, this research suggests that extruding complete diets into homogeneous pellets may improve G:F of cattle fed corn-based diets while reducing feed depredation of starlings. It is also clear from our results that G:F is improved to a greater extent to processing diets under high shear conditions (i.e., high mechanical energy inputs) than when processed under low shear conditions.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Two experiments were conducted to evaluate the efficacy of [italic]Megasphaera elsdenii[italic] strain NCIMB 41125 and its potential use in the mitigation of ruminal acidosis. In experiment 1, a metabolism study was conducted to evaluate ruminal parameters, quantify changes in ruminal bacterial populations, and determine in vitro capacity for lactate utilization following intraruminal dosing of a placebo or [italic]M. [italic]elsdenii strain NCIMB 41125 and an abrupt diet change. Angus crossbred steers (n=20; average BW=253 ± 24 kg) fitted with ruminal cannulas were blocked by BW and assigned randomly to treatments. Treatments consisted of intraruminal dosing with a placebo (100 mL of autoclaved culture), or 10, 100, or 1,000 mL of a live culture containing 1.62×108 CFU/mL of [italic]M. elsdenii[italic] strain NCIMB 41125. Prior to inoculation, cattle were placed into individual pens in an enclosed facility and allowed free access to alfalfa hay, salt, and water. Feed and water were removed for 24 h prior to administering treatments, after which, cattle were allowed free access to a diet consisting of 34% alfalfa hay and 66% steam-flaked corn-based concentrate. On d 7, cattle were fed an 80% concentrate diet. On d 12, steers were started on the final finishing diet of 94% concentrate. Ruminal pH and concentrations of lactate and VFAs were monitored following introduction of each concentrate diet. Ruminal samples were collected at 0, 2, 4, 6, 8, and 24 h after feeding for quantitative rt-PCR detection of native and introduced strains of [italic]M. elsdenii[italic], as well as total bacterial genomes. Capacity for metabolism of lactic acid was evaluated by inoculating 0.2 mL of strained ruminal fluid into anaerobic culture tubes containing 15 mL of semi-defined lactate medium. Tubes were incubated at 39˚C, and turbidity changes were determined by measuring absorbance at 2 h intervals up to 12 h. Experiment 2 was conducted in a commercial feedlot to evaluate the efficacy of [italic]M. elsdenii[italic] strain NCIMB 41125 for improving feedlot performance. A second objective of the study was to determine if oral dosing of [italic]M. elsdenii[italic] has the potential for reducing the number of cattle treated for bovine respiratory disease. Angus steers and heifers (n = 3179; average BW = 356 ± 58.4kg) were used in a randomized complete block design with two treatments. Cattle were assigned to treatment on an every-other-head basis such that every-other-animal was orally drenched with 100 mL of a culture medium containing 1.5×108 cfu/mL [italic]M. elsdenii[italic] strain NCIMB 41125 at processing. Cattle were blocked by gender and date of arrival. To maximize profitability, cattle were sorted via visual appraisal to identify cattle that were market ready. Cattle were shipped to a commercial abattoir in Lexington, NE for harvest. Data obtained for each pen of cattle included feedlot performance, morbidity, mortality, carcass characteristics, and grid-based program carcass qualifications. In trial 1, compared to the placebo group, cattle administered [italic]Megasphaera[italic] maintained higher ruminal pH 24 h after the carbohydrate challenge (P < 0.05). Ruminal lactate concentrations increased in response to the diet change (P < 0.05), but concentrations were lower for cattle that received [italic]Megasphaera[italic] compared to the placebo group (P < 0.05). Total number of bacterial genomes 24 h after inoculation was unaffected by intraruminal dosing of [italic]M. elsdenii[italic] strain NCIMB 41125 (P > 0.05), but populations of undifferentiated [italic]M. elsdenii[italic] and strain NCIMB 41125 increased by 24 h after inoculation (P < 0.05). Turbidity of cultures inoculated with ruminal fluid increased in response to [italic]M. elsdenii[italic] administration (P < 0.05), suggesting a greater capacity for lactate utilization in inoculated cattle compared to the placebo group. In trial 2, no differences in feed efficiency were observed (P > 0.05). Compared to cattle dosed with [italic]Megasphaera[italic], the control group had more USDA yield grade 2 carcasses (P < 0.05), and cattle dosed with [italic]M. elsdenii[italic] had more USDA yield grade 5 carcasses (P < 0.05). [italic]Megasphaera[italic] cattle also tended to have more USDA Prime carcasses (P = 0.14). No effects on incidence of liver abscesses were observed. Dosing cattle with [italic]M. elsdenii[italic] prior to introduction of typical concentrate diets may be useful in preventing ruminal lactate accumulation and associated depressions in ruminal pH. Inoculating cattle with [italic]M. elsdenii[italic] is effective in bolstering populations of ruminal lactate utilizers, and may be useful in preventing ruminal lactate accumulation in grain-fed cattle. No effects on reducing episodes of BRD were noted.

Avian leukosis/sarcoma retroviruses can infect chickens and cause various diseases, malignant tumor formations and mortality in infected chickens. The ALSV group of viruses consists of the endogenous virus of subgroup E which occurs in all chickens and does not cause disease but can interact with exogenous viruses of subgroup A,B,C, and D and cause disease in chickens. Avian leukosis viruses cause high economic losses in the poultry industry since infected chickens not only develop neoplasia but also have decreased production efficiency. Besides chicken to chicken horizontal transmission of ALSV viruses, infected chickens can pass the virus congenitally at a high frequency to the egg. To prevent transmission, the poultry industry must effectively identify infected hens and eggs, and remove them from the breeding populations. Current testing methods for ALSV identification are time consuming, lack sensitivity or specificity, or are ineffective in clearing ALSV infection from potentially infected chicken flocks. The objective of this investigation is to develop an RT-PCR detection system that could effectively screen for viral presence in chicken eggs. To achieve this goal, the aims of this research is as follows: (1) to develop a reverse transcription and polymerase chain reaction assay to detect avian leukosis/sarcoma retroviruses in egg albumen, (2) to perform a survey of the handling and storage conditions of commercial chicken eggs in retail stores in New Orleans, LA., and (3) to determine the molecular prevalence of avian leukosis virus in commercial chicken eggs using the RT-PCR detection system A RT-PCR detection system was developed to detect avian leukosis/sarcoma virus in egg albumen obtained from two strains of White Leghorn chickens naturally exposed to these viruses. A modified RNA isolation procedure using the Promega kit for RNA isolation was employed to isolate viral RNA from egg albumen extracted from eggs obtained from two commercial stocks of White Leghorn chickens. In the samples tested, compared to the 45% sensitivity of the IFA method which is commonly used in the poultry industry for ALSV detection, the RT-PCR technique has a sensitivity of 97% and a specificity of 100%. Sequence analyses confirmed avian leukosis viral presence in the RT-PCR generated product. The survey involving the handling and storage conditions of eggs in New Orleans retail store indicated that 75% of the retail stores hold eggs at a temperature compatible with ALSV survival in the eggs. In addition, 22% of participating retail stores reported using cracked eggs for preparing food for self or consumer use. The survey provided a sampling frame for conducting a study of avian leukosis/sarcoma virus prevalence in commercial chicken eggs. Based on a 20% estimate of avian leukosis viral prevalence, 240 eggs were randomly sampled from 20 retail stores in New Orleans, LA. RT-PCR analyses of the eggs indicate that there is at least a 14% prevalence of avian leukosis virus in commercial chicken eggs. In addition, 80% of the egg cartons in the New Orleans area contain an average of two eggs infected with ALV. Therefore, individuals consuming eggs are at risk of exposure to these poultry oncogenic retroviruses / acase@tulane.edu

Two independent studies were conducted to assess the effects of feeding condensed tannin (CT)-containing forages to continuous cultures to evaluate their impacts on ruminal fermentation and digestibility, with an emphasis on methane (CH4) and ammonia-N (NH3-N) production. In Chapter 3, treatments consisted of: 1) 100% alfalfa hay (AH), 2) 50% AH and 50% birdsfoot trefoil hay (dry matter (DM) basis; AHBFTH), and 3) 100% birdsfoot trefoil hay (BFTH). Three replicated runs lasted 8 d each, with the first 5 d allowed for microbial adaptation to the diets, and 3 d for data collection and sampling. Methane, neutral detergent fiber (NDF) degradability, and total volatile fatty acid (VFA) production and profiles were not affected by the dietary treatments. However, NH3-N concentration and flow were reduced when replacing the AH with the BFTH. It was concluded that feeding a CT-containing diet (BFTH) increased the in vitro N utilization. In Chapter 4, five total mixed ration (TMR) diets were evaluated, each containing a different forage source as hay: 1) alfalfa (AHT), 2) cicer milkvetch (CMVHT), 3) Norcen birdsfoot trefoil (NBFTHT), 4) Oberhaunstadter birdsfoot trefoil (OBFTHT), and 5) sainfoin (SFHT). Total VFA production and acetate molar proportion were not influenced by treatments. However, molar proportion of propionate increased by the CMVHT, and decreased by the SFHT. Acetate to propionate ratio decreased with the CMVHT and the OBFTHT, but increased with the SFHT when compared to the AHT. Digestibilities of DM and NDF were not influenced by dietary treatments. Total CH4 production decreased by all treatments when compared to the AHT, whereas CH4 production expressed as mM per g of NDF digested was reduced only by the CMVHT and the OBFTHT. Ammonia-N concentration decreased when feeding the CMVHT and the SFHT. Feeding the CMVHT decreased ruminal concentration of C18:0, while ruminal C18:1 cis and trans isomers were greatest with the CMVHT. Because these effective tannin-free and tanniniferous legumes did not have negative impacts on ruminal fermentation, they can maintain potential productive performance of lactating dairy cows when fed as main forage sources in TMR diets.

In an attempt to further our understanding of the relationship between the calpain system and postmortem tenderization, three muscles [biceps femoris (BF), infraspinatus (IS), and longissimus (LD)] from normal (N = 6) and callipyge (N = 6) sheep were studied. Callipyge is a genetic phenomenon where carriers of the callipyge gene present a hypertrophy of pelvic and torso muscles, such that BF and LD are affected while IS is not. It has been observed characteristically that calpastatin and m-calpain activities are increased in muscles of animals affected by the callipyge phenotype. Soluble calpain and calpastatin, and myofibril-bound μ-calpain activities, and myofibrillar fragmentation index (MFI) were determined at death, 1d, 3d and 10d postmortem. Sarcomere length was determined at 1d and 10d postmortem. Shear force of the longissimus muscle was determined at 1d, 3d and 10d postmortem. Western blots for calpastatin, μ-calpain, desmin, nebulin, titin, troponin-T and α-actinin were performed to follow the degradation pattern of those proteins. The calpastatin and m-calpain activities were more than two-fold greater in BF and LD muscles from callipyge than in the same muscles from normal animals. Calpastatin activities in infraspinatus muscle from normal animals were higher than in the other two muscles of this phenotype. Soluble μ-calpain activities were higher at death for normal phenotype in BF and IS muscles and it decreased rapidly during postmortem storage. However, the rate of this decrease in that activity was faster in normal than in callipyge phenotype. Myofibrils contained calcium dependent protease activity and this activity was inhibited by cysteine proteases inhibitors and by calpastatin to some degree. There was no difference in the myofibril-calcium dependent protease activity between phenotypes at any time postmortem, presenting lower activity at death. The magnitude of protein degradation and tenderization were assessed by MFI and shear force, respectively. Neither the MFI nor shear force changed appreciably during storage of the callipyge affected muscles. Calpastatin level seems to determine the rate of postmortem tenderization.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3516. Adviser: Carl M. Parsons. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.