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Item Analysis of Haplotype Structure in the Bovine Major Histocompatibility Complex(2011-02-22) Fritz, Krista L.The goal of this project was to identify and characterize polymorphic markers spanning regions of the bovine major histocompatibility complex (BoLA) to analyze patterns of genetic variation and haplotype structure across diverse cattle breeds with various breed histories and selection pressures. Genetic markers that demonstrated sufficient levels of polymorphism, locus specificity, Mendelian inheritance, and the accurate typing of alleles across diverse haplotypes were chosen to define separate haplotype structures for the BoLA IIb and BoLA IIa-III-I regions and to evaluate breakpoints in linkage disequilibrium within the regions surrounding BoLA IIa-III-I. A total of 23 microsatellites, two SNPSTRs, 62 SNPs, and the alleles of three class IIa genes were selected for use in this study. These markers revealed eleven recombination events, low levels of recombination in BoLA IIa-III-I, a sharp break in haplotype structure in the region centromeric to class IIa, prolonged linkage disequilibrium in the extended class I region, strong conservation of BoLA IIa-III-I haplotype structure, BoLA IIa-III-I homozygous haplotype identity across seven different breeds of cattle, and a small number of common BoLA IIa-III-I haplotypes within the Angus and Holstein breeds. This work demonstrated that 52 SNPs from the Illumina 50K SNPchip could accurately predict BoLA IIa-III-I haplotypes. These 52 SNPs represent tagSNPs that can predict BoLA IIa-III-I genetic variation and could offer a cost-effective means for screening large sample sizes for haplotype/disease association studies in the future.Item Application of Fecal Near Infrared Reflectance Spectroscopy and N-Alkane Labeled Supplementation Techniques to Predict Voluntary Intake in Beef Cattle(2014-07-17) Johnson, Jocelyn RoseThe objectives of this study were to evaluate the use of fecal NIRS profiling and the n-alkane labeled supplementation method for the prediction of voluntary intake in beef cattle for the identification of animals divergent in feed efficiency. Additionally, the use of fecal NIRS profiling technology was evaluated for the prediction of diet characteristics. To examine the use of fecal NIRS profiling to estimate diet quality and dry matter intake (DMI), fecal samples and phenotype data were collected from 14 beef cattle trials that utilized Calan-gate feeders (American Calan, Northwood, NH) or electronic GrowSafe? feedbunks (GrowSafe? DAQ 4000E; GrowSafe? system Ltd., Airdire, AB, Canada) to measure individual animal feed intake. The coefficient of determination for calibration (R_(c)^(2)) and cross-validation (R_(cv)^(2)) of combined trial equations to predict diet characteristics were least accurate for the prediction of NDF using composite fecal samples (R_(c)^(2) = 0.85; R_(cv)^(2) = 0.82), and most accurate for the prediction of CP using individual-day fecal samples (R_(c)^(2) = 0.94; R_(cv)^(2) = 0.91). For the prediction of DMI, R_(c)^(2) and R_(cv)^(2) ranged from 0.49 and 0.42 for the prediction of average-trial DMI using individual-day fecal samples to 0.76 and 0.73 for the prediction of fecal-collection-period DMI using composite fecal samples. While the values obtained for the prediction of DMI were inferior to those obtained for the prediction of diet quality or digestibility, fecal NIRS prediction equations for DMI were successful in predicting the mean DMI of groups as well as predicting individual-animal DMI for the evaluation of divergent RFI groups. To evaluate the use of an n-alkane labeled supplement for the prediction of intake, 24 mid-gestation heifers, previously identified as having divergent postweaning RFI, were fed chopped sorghum hay and an n-alkane labeled supplement, ad libitum in electronic GrowSafe? feedbunks (GrowSafe? DAQ 4000E; GrowSafe? system Ltd., Airdire, AB, Canada). In this study, accurate intake predictions were not obtained as 6-d forage intake was overestimated by 73.0% when using C_(31):C_(32) alkane pairs and by 38.9% when using C_(33):C_(32) alkane pairs. However, inaccurate measures of supplement and forage intake by the GrowSafe? system, as well as large between-animal variation in supplement intake, feeding behavior, and digestibility may have greatly influenced the accuracy of these results. Results from this study indicate that fecal NIRS profiling can be used to predict dietary characteristics and DMI for the identification of animals divergent in feed efficiency. Conversely, the n-alkane labeled supplement technique was inaccurate in predicting forage intakes in this trial.Item Application of vaccination protocols to manage beef cattle productivity and mitigate production risk(2010-01-16) Horne, Willy J.The U.S. beef industry is very large with many inter-connected facets. Nutrition and health are key components of a system striving to compete economically while striving to produce a high quality product. The decisions made in one part of the system may often determine outcomes in the other parts of the system. Therefore, it is necessary to look at the beef industry in a systems type of framework. Each management decision is likely tied to a result that may alter several other management questions. At the cow/calf level, producers must decide whether or not to vaccinate their calves. Vaccination leads to reduced disease incidence and severity in the feedyard, thus being beneficial to the feeder. However, if the feedlot does not respond economically in any way, producers may feel that it is not warranted to vaccinated calves. Pre-conditioning programs work in the same manner as they may have beneficial effects for the feeder but not for the harvester. Therefore, pre-conditioning may not be a program that is valued back to the farm level. Answers to these kinds of questions are hard to ascertain. Each segment has its own demands and drivers, which determine how much it can reward to other segments for their efforts. Because the market is continuously changing, the target rewards are changing as well. Therefore targets cannot be theorized, rather exact relationships should be shown. In this dissertation, it is intended to characterize the relationships vaccination protocols and other management strategies can have on various aspects of cattle performance in various industry segments.Item Characterization of the Bovine Cathelicidin Gene Family(2012-10-19) Flores, Erin GillenwatersCathelicidins (CATHLs) are small, cationic antimicrobial peptides that establish an early innate immune defense against infections in mammals. Beyond their wide spectrum of antimicrobial activity, these peptides play important roles in wound repair, chemotactic activity, and apoptosis. Thus, comprehensive characterizing of bovine CATHLs could potentially identify underlying inherited differences in innate immunity and disease resistance in cattle. The purpose of the present study was to verify the placement of the CATHL cluster at the distal end of bovine chromosome 22 (BTA22), identify any single nucleotide polymorphisms (SNPs) and insertion-deletion (indel) polymorphisms within the gene family, explore copy number variation, and investigate the functional impact any of these variants may have in overall bovine innate immunity. A framework radiation hybrid map was constructed with 7 markers screened against the bovine 12,000 rad whole genome RH (12K WG-RH) panel, which when compared to the current genome assembly (Btau_4.0) confirmed current gene order. Comparative sequence analysis for 10 domestic cattle breeds representing both Bos taurus taurus and Bos taurus indicus revealed 60 SNPs, 7 of which were nonsynonymous, and 5 indel mutations. Data from array comparative genomic hybridization (aCGH) between four Angus and four Nelore animals showed a 2-fold increase in copy number of the CATHL4 locus, which was verified by quantitative PCR (qPCR) of genomic DNA. Nelore animals showed an approximate 2-fold increase in the CATHL4 gene. Subsequently, the expression of CATHL4 in Nelore neutrophils exhibited a range of 2- to 5-fold increases in CATHL4 gene expression. Finally, a colorimetric bactericidal assay was performed on the neutrophils of the same Angus and Nelore animals previously genotyped for copy number variations (CNVs). After in vitro challenges to Staphylococcus aureus, Salmonella typhimurium, Mannheimia haemolytica, and Pasteurella multocida, the killing capacity of Nelore neutrophils was approximately 20 percent greater than Angus neutrophils for M. haemolytica and 10 percent greater for P. multocida. Characterization of this antimicrobial gene family is central to developing a firm understanding regarding the effects CATHL variation has with respect to bovine innate immunity.Item Effect of Increasing Protein Supplementation on Intake and Digestion of Bermudagrass Hays of Divergent Quality by Beef Cattle(2012-07-16) Payne, Catherine PomeroyBermudagrass (Cynodon dactylon (L) Pers.), one of the predominant forages in the southeastern US, varies in nutritive value in response to management and environmental factors. Beef cattle supplementation decisions are complicated by this variability. Therefore, our objective was to determine the effect of four protein supplementation levels (0, 82, 119 and 155 mg N/kg BW) on the utilization of three bermudagrass hays (5.6, 6.3, and 8.1 percent CP).Thirteen ruminally fistulated Angus x Hereford steers (BW = 330 plus/minus 19 kg) were used in a 13 x 4 incomplete Latin square design with 13 treatments. Treatments were arranged as a 3 x 4 factorial plus a control bermudagrass hay (10.8 percent CP). Hay was provided ad libitum and protein supplements were offered as range cubes once daily. Periods were 15 d with intake determinations made on d 10 through d 13 to correspond with fecal grab samples collected from d 11 through d 14. Acid detergent insoluble ash was used as an internal marker for determination of fecal output. Hay OM intake of unsupplemented steers increased linearly (P < 0.01) as hay nutritive value increased from 75 to 77, 96 and 94 g/kg BW^0.75 for 5.6, 6.3, 8.1 and 10.8 percent CP hays, respectively. A cubic increase (P = 0.03) in OM digestibility for unsupplemented hays was observed with values ranging from 46 to 65 percent. This resulted in a linear increase (P < 0.01) in total digestible OM intake in response to hay nutritive value from 35 to 45, 51, and 60 g/kg BW^0.75 for 5.6, 6.3, 8.1, and 10.8 percent CP hays, respectively. No significant effects on total digestible OM intake were observed when hays were supplemented with protein. There was a tendency for forage OM intake of the 6.3 percent CP hay to increase linearly with supplemental protein (P = 0.08). Total OM intake increased linearly (P < 0.01) when CP was supplemented to the 6.3 percent CP hay from 77 to 88, 92, and 98 g/kg BW^0.75 for 0, 82, 119, and 155 mg N/kg BW, respectively. We conclude that forage CP content was the primary driver in determining total digestible OM intake, and the effects of protein supplementation on utilization of bermudagrass hay were varied.Item Effects of Protein Supplementation and Forage Quality on Intake and Digestion in Cattle(2012-02-14) Kunkel, JamieIn many pasture and rangeland scenarios, low-quality forages (< 6-8% CP) are the primary energy source for some portion of the year. At these times, energy is typically the first limiting nutrient to the ruminant. Low-quality forages are generally not limited in availability; however, the high cell wall content and reduced levels of CP prevent ruminants from being able to extract the harvested energy. Without provision of supplemental nutrients, the available energy may be inadequate to meet performance expectations. Protein supplementation during periods of inadequate forage quality has been observed to alleviate ruminal nitrogen deficiencies and increase forage utilization. Increased forage utilization translates into greater energy extraction allowing for increased animal performance. The first trial was conducted to evaluate the effects of utilizing non-protein nitrogen (a slow-release urea compared to urea) on intake and digestion of beef steers consuming low-quality bermudagrass hay. Steers were provided ad libitum access to a low-quality bermudagrass hay (7.3 % CP and were ruminally dosed once daily with either urea or slow-release urea (SRU) at levels to provide 0, 64, 128, or 192 mg of N/kg of initial BW per day. Additionally, steers were supplemented with glycerol at levels of 0 or 0.1% of initial BW per day. Total OMI and forage OMI (FOMI) increased quadratically (P < 0.01) with NPN supplementation. However there was not a difference in total OMI or FOMI between urea and the SRU (P = 0.24 and 0.21, respectively). The largest increases in FOMI and total OMI occurred with the first level of supplementation (64 mg N/kg BW) for both urea and SRU and intake peaked when 128 mg N/kg BW was supplemented. Total OMD was not affected by N supplementation level however N from urea tended to elicit a greater response than from the SRU (P = 0.01). Ruminal OMD increased linearly (P = 0.07) and ruminal NDF digestion increased quadratically (P = 0.09) with N supplementation. The second experiment was conducted to evaluate the effects of hay crude protein and protein supplementation on intake and digestion in beef steers. Steers received one of three bermudagrass (Cynodon Dactylon) hays of differing nutritive value (7.0, 8.4, or 13.4% CP) and either 0 or 156 mg N/kg BW supplemented as cottonseed meal once daily. No significant Hay x CSM interactions were observed for hay OMI, total OMI, TDOMI, or digestible NDF intake (P >= 0.67). Hay OMI and total OMI increased linearly (P < 0.01) with hay nutritive value. A quadratic response (P = 0.03) was observed for TDOMI with increasing hay nutritive value. This response was largely driven by a quadratic increase (P < 0.01) in OM digestion with increasing nutritive value of hays. Supplementing CSM generally did not affect HOMI (P = 0.63) although TDOMI (P = 0.03) was increased. Similarly, OM digestion (P = 0.61) and NDF digestion (P = 0.11) were not impacted by CSM supplementation.Item Engineering analysis of fugitive particulate matter emissions from cattle feedyards(Texas A&M University, 2006-04-12) Hamm, Lee BradfordAn engineering analysis of the fugitive particulate matter emissions from a feedyard is not simple. The presence of an evening dust peak in concentration measurements downwind of a feedyard complicates the calculation of an average 24-h emission flux for the feedyard. The evening dust peak is a recurring event that occurs during evening hours when particulate matter concentration measurements increase and decrease dramatically during a short period of time. The concentrations measured during the evening can be up to 8 times the concentrations measured throughout the rest of the day. There is a perception that these concentration increases are due to increases in cattle activity as the temperature decreases during the evening. The purpose of Objective 1 of this research was to quantify the changes in concentrations based on changes in meteorological conditions and/or cattle activity. Using ISCST3, a Gaussian-based EPAapproved dispersion model used to predict concentrations downwind of the feedyard , the results of this work indicate that up to 80% of the increase in concentrations can be attributed to changes in meteorological conditions (wind speed, stability class, and mixing height.)The total fugitive particulate matter emissions on a cattle feedyard are due to two sources: unpaved roads (vehicle traffic) and pen surfaces (cattle activity). Objective 2 of this research was to quantify the mass fraction of the concentration measurements that was due to unpaved road emissions (vehicle traffic). A recent finding by Wanjura et al. (2004) reported that as much as 80% of the concentrations measured after a rain event were due to unpaved road emissions. An engineering analysis of the potential of the unpaved road emissions versus the total feedyard emissions using ISCST3 suggests that it is possible for 70 to 80% of the concentration measurements to be attributed to unpaved road emissions. The purpose of Objective 3 was to demonstrate the science used by ISCST3 to predict concentrations downwind of an area source. Results from this study indicate that the ISCST3 model utilizes a form of the Gaussian line source algorithm to predict concentrations downwind of an area source.Item Estimation of Genetic Parameters for Post-Weaning Performance Traits in Brahman and Brahman-Influenced Stocker Cattle on Forage-Based Studies(2014-08-18) Woolfolk, MatthewThe objectives of this study were to estimate heritability of performance traits in Brahman and Brahman-influenced (? or ? Brahman) stocker cattle on cool-season (n = 1,732) and warm-season (n = 1,199) forages. Cattle were born from 1986 to 2011 at the Texas A&M AgriLife Research and Extension Center at Overton, TX. Traits included end of period body weight (BW), average daily gain (ADG), and body condition score (BCS). Data were analyzed for each season using animal models, with main effects including stocking rate (3 levels), breed type (3 levels), supplementation (2 levels), and contemporary groups constructed by sex and year. Age was fit as a linear covariate. Across levels of stocking rate, calves at low stocking rates had heavier BW, higher ADG, and higher BCS than calves at medium and high stocking rates. For cool-season ADG and BCS, an interaction between breed type and supplementation was included (P = 0.002). Supplemented calves had higher BCS across all breed types, while only ? Brahman ADG was greater for supplemented cattle. All warm-season traits differed between levels of supplementation. For warm-season, ? Brahman had the heaviest BW, while ? and purebred Brahman did not differ (P = 0.39). For ADG, ? Brahman was greater than ? Brahmans and purebreds, which did not differ (P = 0.10). No difference in warm-season BCS between breed types was detected. Heritability estimates for cool-season BW, ADG, and BCS were 0.72 ? 0.094, 0.14 ? 0.083, and 0.25 ? 0.099, respectively. For warm-season forages, heritability estimates for BW, ADG, and BCS were 0.44 ? 0.130, 0.15 ? 0.099, and 0.29 ? 0.106, respectively. The estimates for ADG and BCS in both seasons corresponded with estimates of similar traits in other experiments, as did the estimate for warm-season BW. The estimate for cool-season BW seemed high. Potential causes included influence of breed type on heritability estimates, as documented in other studies, as well as differences between traits in seasons, where measurements of the same trait in different environments could differ.Item Evaluation of disposition scores in Bos indicus/Bos taurus cross calves at different stages of production(Texas A&M University, 2008-10-10) Funkhouser, Rena RebeccaAggressiveness, nervousness, flightiness, gregariousness and overall disposition were evaluated in F2 Nellore-Angus embryo transfer calves (n = 443) from 13 full sib families and in half Bos indicus, half Bos taurus natural service calves (n = 259) from 4 paternal half sib families. Calves were born from 2003 to 2007, and evaluated shortly after weaning. Steers were evaluated shortly before slaughter for all 5 disposition traits and at slaughter for overall disposition. Heifers were evaluated for overall disposition at calving every year. Scores ranged from 1 to 9, with 1 being docile and 9 being unruly, except at calving where scores ranged from 1 to 5. Between sires for overall disposition, calves by 297J were lowest at weaning (2.83), before slaughter (2.84), and at slaughter (2.45) and second lowest in first calf heifers (2.27). Calves by 437J were highest at weaning (4.10), before slaughter (3.54), at slaughter (2.89) and in first calf heifers (3.10). Bulls had the lowest scores at weaning (2.54), although the number was small (n=10); females were the highest (4.01), and steers were intermediate (3.70). All 5 weaning traits were correlated (P < 0.05) with each other (0.73 to 0.96). The correlation of recipient disposition and weaning disposition of the calves was 0.12 (P < 0.05). Aggressiveness was not significantly correlated with other component traits before slaughter but was with overall disposition (0.19, P < 0.05). All other traits were significantly inter-correlated (0.60 to 0.97). Disposition at weaning was correlated with disposition before slaughter (0.43, P < 0.05). Slaughter disposition was correlated with weaning disposition (0.30, P < 0.001) and disposition before slaughter (0.27, P < 0.001). Disposition in first calf heifers was correlated with weaning disposition (0.34, P < 0.001) and disposition in second calf females (0.53, P < 0.0001). The results indicate that both genetics and recipient disposition affect calf disposition at weaning, calves with better dispositions at weaning have better dispositions later in life, and there is sufficient variability within and between these full sib and half sib families for use in QTL analysis for major genes for disposition in Nellore-Angus cross cattle.Item Evaluation of Methods to Assess and Reduce Bacterial Contamination of Surface Water from Grazing Lands(2012-10-19) Wagner, KevinExcessive bacterial levels are a major water quality concern. Better methods are needed to quantify the proportion of bacterial loading contributed by various sources, and best management practices are needed to restore water quality. This study assessed the ability of alternative water supplies and grazing management to reduce E. coli loading from cattle and evaluated the ability of quantitative polymerase chain reaction analysis of total and bovine-associated Bacteroides markers (AllBac and BoBac, respectively) to determine the percentage of bovine-associated fecal contamination. Runoff from seven small watersheds, representing ungrazed, properly stocked, and overstocked conditions, was analyzed for E. coli, AllBac, and BoBac to assess grazing management impacts on E. coli runoff and the effectiveness of Bacteroides markers. To determine the effectiveness of alternative water, instream E. coli levels and cattle movement were evaluated before and after alternative water was provided. The study found that when alternative off-stream water was provided, the amount of time cattle spent in the creek was reduced 43 percent and the direct deposition of E. coli into Clear Fork of Plum Creek was estimated to be reduced from 1.11E 07 to 6.34E 06 colony forming units per animal unit per day. Observed pre- and post-treatment E. coli loads suggested similar reductions; however, this study could not conclusively attribute observed E. coli loading reductions to providing alternative water because of the lack of statistical significance of these observations, possibly due to decreased streamflow during Year 2 (due to drought) and a corresponding increase in E. coli levels. The study found that rotational stocking, if timed appropriately, was very effective at reducing E. coli runoff. The impact of grazing timing in relation to runoff events was more significant than the impact of grazing management (i.e. ungrazed properly stocked or overstocked) or stocking rate. When runoff occurred more than two weeks following grazing, E. coli levels in runoff were decreased more than 88 percent. Finally, data suggest that AllBac and BoBac markers are good indicators of recent fecal contamination from cattle. However, although elevated BoBac/AllBac ratios generally aligned well with cattle presence, this ratio appeared to underestimate the percentage of bovine-associated fecal contamination.Item Evaluation of traits associated with bucking bull performance and behavior(2009-05-15) Romero, Natasha ElizabethVideo and industry data were used to assess the inter-relationships of aggression, delivery, coat color, year of birth, number of outs, buckoff percent and score in rodeo bulls. An evaluation of laterality based on observations of how the individual animals were loaded into chutes at 11 bull riding events showed 63% left-handed delivery and 37% right-handed delivery across all observations (n = 525). There was a similar distribution for aggressiveness (based on whether or not the bull charged after the rider dismounted) with 64% of bulls being non-aggressive and 36% of bulls being aggressive. Significant linear relationships existed between score and number of outs and score and buckoff percentage indicating that experience impacted performance. The correlation between number of outs and buckoff percentage was low to moderate (0.06 to 0.30), depending upon the subset of data evaluated. The r-square value for the analysis of score among all bulls was 0.14; however, the r-square value in the subset of bulls with known sires with more than one son was 0.68 when sire was included in the model. Similar increases in r-square values were observed for 2006 average score, career average score, buckoff percentage, and career buckoff percentage, indicating important genetic influences on these traits and/or their component traits. Investigations into the relationship between performance and aggression may help bucking stock producers improve the selection criteria they use. The current trend within the industry is for several breeders to breed ?hot? or flighty, nervous cattle to achieve higher performing offspring. Given that there was no association between aggression and score based on chi-square test, aggression may be removed from the criteria for using certain animals for breeding purposes. Based on results from this work, if bucking stock breeders want to make genetic changes in these traits, documentation of pedigree information is vital.Item Feed efficiency, carcass, and temperament traits in F2 Nellore-Angus steers(2009-05-15) Amen, Tonya SueFeed efficiency in fed F2 Nellore-Angus steers produced through embryo transfer was evaluated using two methods: residual feed intake (RFI) and NRC-based model predicted residual consumption (MPRC). Sire and family(sire) both contributed to differences in model predicted residual consumption (P = 0.036 and P < 0.001, respectively), but not in RFI (P = 0.117 and 0.455, respectively). This indicates that variation exists among the sires and families studied, and the opportunity exists to improve MPRC through selection; it also indicates these 2 evaluation methods could result in different conclusions about feed efficiency. Five aspects of temperament were also evaluated (aggressiveness, nervousness, flightiness, gregariousness, and overall temperament) on a 9-point scale shortly after weaning. Sire had a significant effect on all 5 aspects of temperament evaluated, but family was only responsible for variation in aggressiveness, nervousness, and overall temperament. Contemporary group had no effect on aggressiveness, but did contribute significantly to variation in all other temperament traits. All temperament traits were highly correlated with one another (r = 0.81 to 0.98). Recipient dam temperament was lowly correlated with gregariousness and overall temperament (r = 0.16 and 0.15, respectively), and the correlations with recipient dam temperament approached significance for aggressiveness, nervousness and flightiness. This suggests that the temperament of the recipient female may have a small effect on the temperament of the calf. This population was structured to identify QTL for economically important traits and appears to be useful to identify genetic markers for feed efficiency and animal temperament.Item In vivo infection biology of contagious bovine pleuropneumonia(2009-05-15) Gull, Tamara BrownseyContagious Bovine Pleuropneumonia (CBPP), caused by Mycoplasma mycoides mycoides small colony (MmmSC), is a devastating respiratory disease of cattle in Africa, Asia and the Middle East. Little investigation has been done on molecular disease pathogenesis and host response beyond soluble cytokine detection. This study developed and characterized models for three strains of MmmSC of varying severity. Strains used were Gladysdale, Ondangwa and Shawawa. Samples of bronchoalveolar lavage fluid, bronchial biopsy, nasal epithelial cells and blood were obtained prior to and at weekly time points post-infection. Microarray analysis of RNA extracted from samples revealed host cellular pathways and genes important in the pathogenesis of CBPP, including multiple immune system and inflammatory response pathways. A number of pathways whose influence on disease pathogenesis was not immediately clear were also activated, including pathways involved in amino acid synthesis, fat metabolism, and endocrine hormone responses. Microarray results were confirmed with real-time polymerase chain reaction (RT-PCR) of selected genes. Comparative RT-PCR analysis of selected genes between the three strains of MmmSC revealed genes possibly responsible for differential strain virulence, including interleukins 1B, 6, 8, and 18 and the gene nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor, alpha (NFKBIA). A similar analysis of selected genes between survivors and nonsurvivors of the virulent Gladysdale strain of MmmSC suggested genes involved in survival, including interleukin 8, calmodulin 2 (CALM2), and NFKBIA. Avenues of additional study were identified.Item Increasing ventilation in commercial cattle trailers to decrease shrink, morbidity, and mortality(2009-06-02) Giguere, Nicole MarieA practical method of reducing aerosolized pathogens and environmental contaminants during commercial transportation could prove beneficial to the health and value of cattle. Having previously determined that there was very limited airflow within moving livestock trailers, an experimental treatment that increased cross-ventilation within commercial cattle trailers by installing aluminum scoops to punch-hole trailers was evaluated. Environmental factors including temperature, ammonia and carbon dioxide concentrations, and percent dry matter of excreted urine and fecal matter were evaluated, along with physiological factors, including complete blood count, serum electrolyte concentrations, percent weight loss, the presence of Salmonella, Escherichia coli, or Mannheimia haemolytica, and 30 day health data. The experiment consisted of two trials, each with two truckloads of 80 cattle each, for a total of 320 cattle. Temperature was evaluated in the center compartments of each trailer at five minute intervals throughout both trips. Ammonia concentrations were measured using passive dosimeters. Jugular blood samples, fecal grab samples, swabs of the terminal rectum and nasal swabs were obtained 8.5 to 10 hours post-transport from 20 cattle from each trailer. Increased ventilation resulted in lower temperatures and ammonia concentrations on both trips. Percent dry matter of excreted urine and fecal matter were inconclusive. There were no treatment effects for complete blood counts or electrolyte and basic chemistry panels, possibly because the cattle had access to both hay and water between transport and sampling, which allowed for recovery. Cattle in the ventilated trailer had an average weight loss of 4.7%, compared with 5.75% for the cattle in the control trailers. Sampling for E. coli O157:H7, Salmonella, and M. haemolytica showed very few positives, likely due to the good condition of the cattle prior to transport. During the 30 days post-transport, no cattle from either treatment required veterinary attention related to transport. The results indicate that increasing ventilation through the use of external air scoops has the potential to improve the health and well-being of cattle during transport.Item Influence of Newspaper Images on Student Perceptions of Agricultural Issues(2012-07-16) Dromgoole, AmyIn today's technological environment, there is constant competition for audience readership and viewership between various media outlets. News media provides a great deal of information to the general public through television, print, and web sources, especially in terms of agriculture. This study aimed to discover audience perceptions of two different natural disasters by examining the effects of photographic inclusion in print news articles including agricultural perceptions and content recall. Additionally, differences between self-perceived milk industry advocacy and a milk campaign story are also examined. Newspaper articles about the effects of the 2010-2011 drought in Texas and the aftermath of Tropical Storm Irene were also used. Students in the College of Agriculture and Life Sciences at Texas A&M University were surveyed in online pre and posttests. Student responses displayed a moderate relationship between photos and article content in regards to the Hurricane Irene article. A significant relationship was present between self-perceived non-advocates and their outlook on milk consumption and the dairy industry with the inclusion of photographs. There were differences seen between students who have family who work in agriculture, claim membership in an agriculture association, live on a farm or ranch, and were members of FFA as they viewed the drought article to be more positive than those who did not have these agricultural backgrounds. Furthermore, student responses show a relationship between the milk industry article in the pretest (photos included) and posttest (photos not included) by viewing the photos as positive, humorous, and shocking. This study found student perceptions of the two news articles related to the drought as well as the tropical storm to be the same regardless of photographic presence. This leads the researcher to conclude that photos had no effect on the overall perceptions of the news stories. However, students who received photographs did see a relationship between the photos associated with the flood article and the content presented in the story. This effect was not seen with the photographs of the drought story. Since the photos associated with the flood story were the original photos printed with the news story, it is probable to conclude that students properly associated photographic elements with that of the story's content.Item Morphological and Genetic Comparisons between Babesia bovis and Trypanosoma spp. Found in Cattle and White-tailed Deer(2012-10-19) Fisher, AmandaBabesia bovis has been an important disease agent in the U.S. cattle industry for over a century. Recently, B. bovis-like parasites have been identified in white-tailed deer (WTD; Odocoileus virginianus) in Texas. If the parasites found in the WTD are B. bovis that are able to infect cattle, the disease could re-emerge. Susceptible adult cattle often die from this disease, which would result in severe production losses, as well as a decrease in carcass weights of disease survivors. The B. bovis-like parasite found in WTD was compared to B. bovis from cattle, by ribosomal DNA sequence analysis. Babesia isolated from WTD were found to have 99% identity to B. bovis from GenBank cattle sequences. No cattle samples in this study were found to be positive for B. bovis. On culture of WTD samples, a Babesia parasite could not be visualized based on common morphological features. Trypanosoma cervi has been studied for decades, but all the previous research identified this parasite solely by morphology. Trypanosoma species obtained from different host species was compared by ribosomal DNA sequence analyses. In this study, the Trypanosoma cultured from WTD had the morphological appearance of T. cervi. On sequence analysis, the cattle sequences aligned together with cattle isolates and the WTD sequences aligned closely with elk (Cervus canadensis) sequences, indicating that wild ungulates (WTD and elk) and cattle most likely have separate trypanosome species. On distribution analysis there was a trend in three South Texas counties, where the county with the highest occurrence of Trypanosoma had the lowest occurrence of Babesia; and vice versa. It is possible that Trypanosoma and Babesia blood parasites compete within the mammalian host, but the chi-squared test did not show a significant association between the two parasites in the different counties. On seasonal analysis, the correlation between positive samples and season could not be statistically confirmed, but it appears that Babesia infected animals are found in lowest numbers during hot, dry seasons. It also appears that there is another vector for Trypanosoma in South Texas besides the ked (Lipoptena mazamae) and tabanid fly (Tabanus spp.).Item National Beef Quality Audit - 2011: Survey of Instrument Grading Assessments of Beef Carcass Characteristics(2012-11-16) Gray, Gatlan 1989-The instrument grading assessments for the NBQA-2011 evaluated seasonal trends of beef carcass quality and yield attributes over the course of the year. One week of instrument grading data?HCW, gender, USDA QG, and YG factors?were collected every other month (n = 2,427,074 carcasses) over a 13-month period (November 2010 through November 2011) from four beef processing corporations, encompassing 17 federally inspected beef processing facilities, to create an overview of carcass quality and yield attributes and trends from carcasses representing approximately 8.5% of the U.S. fed steer and heifer population. Mean yield traits were: YG (2.86), HCW (371.3 kg), FT (1.19 cm.), and LM area (88.39 cm^2). The YG distribution was YG 1 (15.7%), YG 2 (41.0%), YG 3 (33.8%), YG 4 (8.5%), and YG 5 (0.9%). Distribution of HCW was <272.2 kg (1.6%), 272.2 kg to 453.6 kg (95.1%), ?453.6 kg (3.3%). Monthly HCW means were: November 2010 (381.3 kg), January 2011 (375.9 kg), March 2011 (366.2 kg), May 2011 (357.9 kg), July 2011 (372.54 kg), September 2011 (376.1 kg), and November 2011 (373.5 kg). The mean FT for each month was November 2010 (1.30 cm), January 2011 (1.22 cm), March 2011 (1.17 cm), May 2011 (1.12 cm), July 2011 (1.19 cm), September 2011 (1.22 cm), and November 2011 (1.22 cm). The mean marbling score was Small49. USDA QG distribution was Prime (2.7%), Top Choice (22.9%), Commodity Choice (38.6%), and Select (31.5%). Interestingly, from November to May, seasonal decreases (P < 0.001) in HCW and FT were accompanied by increases (P < 0.001) in marbling. These data present the opportunity to further investigate the entire array of factors that determine the value of beef. Datasets utilizing the online collection of electronic data will likely be more commonly used when evaluating the U.S. fed steer and heifer population in future studies. These data indicate the wide array of carcasses produced by the beef cattle industry, and how the frequency of both YG and QG traits change from month-to-month.Item Nitrogen Metabolism in Bos indicus and Bos taurus Cattle Consuming Low-quality Forages(2013-05-22) Weldon, KyleFive Angus (Bt) and 5 Brahman steers (Bi) fitted with ruminal and duodenal cannulas were used in concurrent 5 ? 5 Latin squares to determine the effects of supplemental protein degradability and level of supplemental N on utilization of rice straw. Treatments consisted of a control (CON; no supplement) and two levels (50 and 100 mg N/kg BW) of an isonitrogenous supplement (27% CP), either high (H; 72%) or low (L; 28%) in DIP. Forage OM intake (FOMI) was greater for Bt than Bi (P = 0.05). Supplementation increased FOMI in both Bt and Bi (P < 0.05). Organic matter digestibility (OMD) was greater in Bi than Bt (P < 0.01). Supplementation increased OMD for Bi (P = 0.02) but not Bt. Total digestible OM intake (TDOMI) was similar between subspecies (P = 0.12). Bos indicus had greater ruminal NH3-N than Bt (P < 0.01). Plasma urea nitrogen (PUN) was greater for Bi than Bt (P < 0.01) for all treatments and at both 0 and 4 h after feeding. Supplementation tended (P = 0.06) to increase PUN versus CON in Bt, but not Bi (P = 0.82). Bos taurus had numerically (P = 0.19) greater total volatile fatty acids (VFA) across treatments than Bi. Total N intake increased versus CON (P < 0.01), and greater amounts of supplemental N increased total N intake within both subspecies (P < 0.01). Fecal N excretion was greater in Bt than Bi (P = 0.01). Supplementation increased (P < 0.01) fecal N versus CON for both subspecies. Urinary N tended to be higher for Bi than Bt (P = 0.10). Supplementation increased (P < 0.05) urinary N for both subspecies. Retained N was greater for Bt over Bi (P = 0.07). While Bt had greater FOMI, increased OMD for Bi with supplementation resulted in similar TDOMI between subspecies. Overall, Bi had higher NH3-N and PUN than Bt; which increased as level and degradability of supplements increased in both subspecies. Increased supplementation raised N excreted and N balance for both subspecies; fecal N was greater in Bt, while urinary N was greater in Bi.Item Nutritional Programming of Neuroendocrine Pathways Controlling the Onset of Puberty in Heifers(2014-05-01) Alves, Bruna R. C.Accelerated body weight gain during the juvenile period leads to early maturation of the reproductive neuroendocrine system and puberty by advancing the onset of high-frequency release of gonadotropin-releasing hormone (GnRH). In a series of studies conducted as part of this dissertation, it was hypothesized that nutritional regimens that accelerate pubertal development alter the function of kisspeptin and neuropeptide Y (NPY) neurons, known modulators of the release of GnRH. In addition, alterations in the pattern of methylation of target genome sequences were investigated in DNA collected from the arcuate nucleus, a hypothalamic region well-characterized for its role in mediating the metabolic control of reproductive function. Early-weaned crossbred heifers were fed diets to promote an average daily gain of 0.5 Kg (Low Gain; n=12) or 1.0 Kg (High Gain; n=12) from approximately 4 to 8 mo of age. This nutritional regimen has been demonstrated to facilitate early onset of puberty in heifers. At eight mo of age, heifers were slaughtered and a block of tissue containing the preoptic area and hypothalamus was collected and processed for examining the expression of NPY and KISS1, investigating the innervation of GnRH and kisspeptin neurons by NPY fibers, and characterizing the methylation profile of target genomic DNA sequences isolated from the arcuate nucleus. Mean body weight and circulating concentrations of leptin were greater in High-gain than in Low-gain heifers. Elevated rate of body weight gain was associated with reduced expression of NPY in the arcuate nucleus, reduced proportion of GnRH neurons in apposition to NPY-containing varicosities, particularly in GnRH neurons located in the mediobasal hypothalamus, and a reduced number of KISS1-expressing cells in the mid portion of the arcuate nucleus. The rate of body weight gain during the juvenile period did not affect NPY innervation of kisspeptin neurons. Differential methylation of target genomic DNA sequences isolated from the arcuate nucleus was observed in association with rate of body weight gain in juvenile heifers, and genes affected included GHR, IGF2, IGF1R, LEPR, PEG3, LIN28B and HMGA2. Overall, results from these studies support the hypothesis that accelerated body weight gain during the juvenile period promotes alterations in cellular functions within the hypothalamus that facilitate early onset of puberty in heifers.Item Perceptions of beef cattle producers preparedness when dealing with animal activist events(2013-05-03) Bergin, Lauren MarieThe purpose of the study is to identify beef cattle producers? current knowledge level of animal activism and measure the perceived level of an animal activism risk to the operation. This convenience sample consisted of beef cattle producers in attendance at the Texas A&M Beef Cattle Short Course held on August 6-8, 2012, and members of the Angus Journal e-list. Results confirmed that respondents found it fairly likely that an animal activist attack could happen in the United States and that it could likely happen in their home state. Respondents found it less likely that an attack could happen to their operation, but in the instance of an attack, they are to be prepared. Respondents identified two aspects of their operation as susceptible threats: tampering with gates and locks and theft/misuse. Although beef cattle producers recognize the importance of safe guarding their operation against potential threats, most are not implementing the precautions necessary to do so. As far as the preferred source of information about activist threats, respondents were fairly likely to contact law enforcement, the Internet, farm magazines, their Extension agent, and their veterinarian. Most of the producers had never attended an animal activism workshop but did say they would attend one at least once. As a majority, the respondents had not invested time or money to reduce loss of production due to animal activism and did not have access to educational material to answer questions they might have about animal activism. The preferred delivery method of future animal activism educational materials should be offered to beef cattle producers in the evenings. The best method of educating respondents proved to be dinner meetings. Books, computer software and audio disks were the least popular methods of education.