Master of Science / Department of Clinical Sciences / Robert L. Larson / Bradley J. White / We performed research that investigated the ability of three dimensional accelerometers to classify cattle behavior and also describe the circadian patterns within that behavior. The first of three studies (validation study) tested a decision tree classification system and its ability to describe behaviors of lying, standing, and walking. Classification accuracies for lying, standing, and walking behaviors were 99.2%, 98.0%, and 67.8% respectively, with walking behavior having significantly lower accuracy (P<0.01). This study also tested the accuracy of classifying the above behaviors using different device reporting intervals, or epochs. Reporting intervals of 3, 5, and 10 seconds (s) were evaluated in their ability to describe cattle behaviors of lying, standing, and walking. Classification accuracies for the 3s, 5s, and 10s reporting interval were 98.1%, 97.7%, and 85.4% respectively, with no difference in classification accuracy of the 3s and 5s epochs (P=0.73) while the 10s epoch exhibited significantly lower overall accuracy (P<0.01). This validated accelerometer monitoring system was then implemented in two studies (Winter 2007 and Spring 2008) where the devices were used to describe behavior patterns of beef calves in a drylot production setting. Lying behavior of the cattle was analyzed and found to be significantly associated (P<0.001) with hour of the day. Calves in these studies spent most (> 55%) of the nighttime hours (2000 to 0400) involved in lying behavior and spent the least percentage of time lying (<30%) during periods of time where feed was presented at the bunk (0700 and 1700). Mean lying time was also associated with trial day (P<0.01) and most trial days (67.5%) calves spending between 45% and 55% of time lying. Variation of lying behavior was found between individuals (range 29% to 66%); however, consistency in lying behavior was found within individual calves across study periods. The accelerometer monitoring system studies presented here provide evidence these devices have utility in recording behaviors (lying, standing, and walking) of individual beef calves raised in typical production settings.

Master of Science / Department of Anatomy and Physiology / Daniel C. Marcus / Sensory transduction in the cochlea depends on regulated ion secretion and absorption. Results of whole-organ experiments suggested that Reissner’s membrane may play a role in the control of luminal Cl-. We tested for the presence of Cl- transport pathways in isolated mouse Reissner’s membrane using whole-cell patch clamp recordings and gene transcript analyses using RT-PCR. The current-voltage (I-V) relationship in the presence of symmetrical NMDG-Cl was strongly inward-rectifying at negative voltages, with a small outward current at positive voltages. The inward-rectifying component of the I-V curve had several properties similar to those of the ClC-2 Cl- channel. It was stimulated by extracellular acidity and inhibited by extracellular Cd2+, Zn2+, and intracellular ClC-2 antibody. Channel transcripts expressed in Reissner’s membrane include ClC-2, Slc26a7 and ClC-Ka, but not Cftr, ClC-1, ClCa1, ClCa2, ClCa3, ClCa4, Slc26a9, ClC-Kb, Best1, Best2, Best3 or the beta-subunit of ClC-K, barttin. ClC-2 is the only molecularly-identified channel present that is a strong inward rectifier. This thesis incorporates the publication by K.X. Kim and D.C. Marcus, Inward-rectifier chloride currents in Reissner’s membrane epithelial cells. Biochem. Biophys. Res. Commun. 394 (2010) 434-438, with permission of the publisher Elsevier, and is the first report of conductive Cl- transport in epithelial cells of Reissner’s membrane and is consistent with an important role in endolymph anion homeostasis.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Gary A. Anderson / Brucellosis is one of the major endemic zoonotic diseases worldwide, and it has history dating back to 1937 in Iraq when it was first isolated by an Iraqi physician. In order to establish a solution for the continuous devastating impacts of the disease in humans and livestock, the Brucellosis Control Program was established in 1995. The main responsibilities of this program were setting and implementing the appropriate strategies for controlling the disease. After the war in 2003, the United Nation organization for Food and Agriculture (FAO) developed a strategic plan to control the disease. The main goal of the project was to improve productivity in the livestock sector and reduce the prevalence of disease in small ruminants (sheep and goats) to less than 2%, and less than 0.2% in cattle and buffalo. Achieving such goals ultimately would reduce the disease incidence among the human population from more than 27.2 cases/100,000 persons in 2002, to less than 4 cases/100,000 people within 15 years. A serological surveillance was conducted and revealed the apparent prevalence of the disease in sheep and goats, cattle, buffalo, and camels was 6.51%, 1%, 1.48%, and 0.02%, respectively in Iraqi governorates except the three northern governorates of Kurdistan province . Based on surveillance results, a vaccination policy was the only appropriate strategy that could be chosen to control the disease. Four vaccination campaigns were implemented in 2006, 2007, 2008, and 2009, with a total number of vaccinated animals each year at 10099972, 4698482, 753153, and 1833482 head, respectively. The primary satisfactory outcome of the program was the apparent decline in livestock abortions leading to obvious increases in productivity. Regarding the incidence of brucellosis among the human population, the apparent decline in the middle and south of Iraq began with the vaccination phase of the control program in 2006. The results represented a significant decrease in human cases after only four vaccination campaigns of a program that was intended to continue for 15 years.

Doctor of Philosophy / Department of Anatomy and Physiology / David C. Poole / Exercise-induced pulmonary hemorrhage (EIPH) or epistaxis has been recognized in racehorses since the 16th century. Since this time, great strides have been made in terms of identifying the lungs as the source of the hemorrhage via the endoscope, utilization of bronchoalveolar lavage to quantify the hemorrhage, and the discovery of successful treatments such as furosemide and the nasal strip that ameliorate, but do not abolish EIPH. It has been determined that, in addition to extremely high pulmonary arterial pressures and the negative intrapleural pressures being the major physiologic forces causing pulmonary capillary stress failure, other factors have the potential for influencing the severity of EIPH including locomotory impact trauma, inflammatory airway disease (IAD), upper airway obstruction, coagulation anomalies, and high blood viscosity. It has been hypothesized that EIPH is detrimental to performance and this was recently confirmed by Hinchcliff et al. in 2004. EIPH is a complex multi-factorial condition with much still unknown about the etiology, best method for diagnosis, and most effective form of treatment. Chapter one of this dissertation determined the effectiveness of a novel treatment, concentrated equine serum, in ameliorating EIPH via reduction of IAD. Chapter two refuted the hypothesis that herbal formulations commonly used in the field with anecdotal success would decrease EIPH by correcting coagulation deficits during exercise, as scientific efficacy was not evident, at least at the dose and duration used in our investigation. Chapter three addressed the dogma that EIPH only occurs during maximal intensity exercise, and in demonstrating significant EIPH during sub-maximal exercise, emphasized the role that the airways play in contributing to the initiation and severity of EIPH. Chapter four examined the occurrence and severity of EIPH in the horse’s canine counterpart, the racing Greyhound. The demonstrated presence of mild EIPH in the Greyhound, a physiologically similar yet different athlete in comparison to the horse sheds new light on the etiology of this condition in both species. The results of these investigations have advanced the frontiers of our knowledge concerning EIPH. Specifically, they have generated novel information on the mechanistic bases of EIPH and have provided evidence supporting additional treatment options for reducing the severity of EIPH in horses.

Doctor of Philosophy / Department of Family Studies and Human Services / Anthony Jurich / Until recently, minimal research has been done regarding the impact of veterinary student stress on the student’s significant intimate relationships. In this study of 466 veterinary students enrolled in five different accredited U.S. Colleges of Veterinary Medicine, the association of five primary variables, perceived stress, self-esteem, academic satisfaction, relationship satisfaction, and general life satisfaction was investigated, utilizing McCubbin and Patterson’s (1983) Double ABCX Model as a guide. Six of the seven hypotheses were supported and further regression analysis yielded a model of variable associations that supported the Double ABCX Model, though significant gender differences were found. Specifically, female students perceived significantly more stress than did male students. With the exception of academic satisfaction and relationship satisfaction, all of the major variables were strongly correlated with each other. For the women, who comprised a significant majority of the sample, perceived stress had a significant impact on relationship satisfaction, as well as on self-esteem, which in turn significantly impacted academic satisfaction. Relationship satisfaction and academic satisfaction both significantly, and separately, impacted general life satisfaction, suggesting that relationship satisfaction and academic satisfaction are different constructs that operate independently of each other. However, both have a significant impact upon and are significantly associated with general life satisfaction, suggesting that neither can be neglected during veterinary training if a positive outcome is desired. For the men in this sample, stress impacted directly upon academic satisfaction, self-esteem, and general life satisfaction but did not have a direct impact upon relationship satisfaction. Instead, relationship satisfaction and general life satisfaction had a highly correlated relationship, with both significantly and strongly associated with the other. Although academic satisfaction and relationship satisfaction appear to be two separate entities, they are both important elements to achieving general life satisfaction during veterinary training and, therefore, should be equally attended to during the training process. These findings are interpreted and discussed in light of the implications for and importance of continued collaboration between veterinary students and programs and the field of Marriage and Family Therapy in an effort to understand and support students and their significant relationships during the veterinary training process.

Master of Science / Department of Clinical Sciences / Michael W. Sanderson / A Monte Carlo model was developed to determine the cost-effectiveness of different biosecurity strategies for Bovine Viral Diarrhea Virus (BVDV) on cow-calf farms. Where possible, risk distributions were defined in the course of a critical literature review covering all publications since 1990 relevant to BVDV on cow-calf farms. The prevalence of persistent infections (PIs) in adult cows was unknown, so a survey of viremia in 2,990 adult cows for sale in the Midwest during 2006 was performed; prevalence was calculated to be 0.07%. In order to validate a newly developed RT-nPCR for pooled serum used for the survey, sensitivity was determined based on 100 known viremic serum samples; sensitivity was 95%, with no detectable effect of strain type. A Monte Carlo model was developed to calculate the risk of introducing BVDV to a cow-calf herd and number of PIs introduced in one year, based on herd imports and biosecurity strategies. The results of that model were integrated with a stochastic SIR model for the spread and impact of BVDV through a cow-calf herd over 10 years, based on herd size and control strategies. The resulting model was integrated with a stochastic model for the cost of both the biosecurity and control measures used and the financial impact of BVDV infection on the herd over 10 years. The lowest risk option of 14 biosecurity strategies were calculated for 400-, 100-, and 50-head herds with 8 different import profiles, and management factors that increase financial risk due to BVDV were determined.

Master of Science / Department of Clinical Sciences / Michael Sanderson / Biosecurity, biocontainment and security practices are important in production animal agriculture. Procuring cattle from multiple sources and commingling them into a single confinement operation increases risk of disease introduction. The large concentration of animals makes a feedyard a more likely target of a domestic or international terror group. Controlling or eradicating an intentionally introduced pathogen or toxin would be costly. The aim of these surveys was to gather information from experts about perceived risks and mitigation strategies and to assess current practices of biosecurity, biocontainment and security in Central Plains feedyards. Consulting veterinarians and feedyard managers shared similar views on the likelihood of disease caused by terrorism, natural introduction or accidental introduction, and on the importance of on-site security. They disagreed on the importance of preventative products, disease transmission control, and environmental control. Generally speaking, feedyard managers believed environmental control to be more important than consulting veterinarians. In reference to a survey of current practices, some feedyards use equipment for both manure and feed handling. Many feedyards are not cleaning and disinfecting oral treatment equipment, treatment facilities, or unloading facilities on a regular basis which may increases their risk for indirect disease transmission of endemic agents such as Salmonella or BVDV. Most feedyards in this survey import some cattle directly from an auction market, do not require clean boots or foot covering to be worn by visitors, and do not require trailers to be cleaned. Smaller feedyards were more likely to require trailers to be cleaned before loading incoming cattle. Less than half of the feedyards reported having a fence that will stop humans or kept protein supplements or micro-nutrients secured from access. Some feedyards enforced a visitor log or employed a night watchman. Most feedyards learned about a future employee by calling references listed in resume, but some performed a criminal background check. A cost-benefit analysis should be done on all management practices to determine economic benefits. More research is needed to better understand which practices are most beneficial.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Daniel U. Thomson / Escherichia coli O157:H7 is a human food-borne pathogen and cattle feces are a major source of contamination. Immunization against E. coli O157 may be a practical pre-harvest intervention strategy. A siderophore receptor/porin proteins (SRP) based vaccine has been developed to decrease the prevalence of E. coli O157 in cattle. Two studies were conducted to determine the efficacy of the SRP vaccine. In the first study, thirty calves were randomly assigned to one of two groups: control or SRP vaccine. Two weeks after the second vaccination, calves were orally inoculated with nalidixic acid-resistant (Nal[superscriptR]) E. coli O157. Fecal samples were collected for five weeks. Calves were necropsied on day 35 to collect gut contents and tissue swabs to determine Nal[superscriptR] E. coli O157:H7. The number of calves that were culture positive for E. coli O157 were lower (P= 0.07) in vaccinated group compared to the control. In the second study, cattle in two feedlots were randomized to SRP vaccine or control. Cattle were vaccinated on days 0 and 21. Rectal fecal samples were collected on day 0, and pen floor samples were collected on days 21, 35, and 70. Rectal fecal samples, RAMS, and hide swab samples were collected on d 85. Cattle were weighed on days 0, 21, and 85. Vaccination significantly reduced (P = 0.04) fecal E. coli O157 prevalence. There was also a decrease (P < 0.05) in E. coli O157 prevalence on hides and in fecal samples on day 85 in vaccinated cattle compared to the control.

Doctor of Philosophy / Department of Anatomy and Physiology / A. Philine Wangemann / Pendred syndrome is characterized by sensorineural deafness and post-pubertal goiter. It is caused by mutations in the anion exchanger, pendrin (SLC26A4). The purpose of this study was to understand the etiology of Pendred syndrome using a mouse model. Different methods of amplification from nanogram amounts of starting RNA were evaluated for gene array application. Gene arrays were performed and free radical stress markers were compared between the stria vascularis and the thyroid of the Slc26a4+/- and Slc26a4-/- mice. Hearing loss in Slc26a4-/- mice is linked to the loss of Kcnj10 protein expression and consequently the loss of endocochlear potential. To understand the mechanism of hearing loss in Slc26a4-/- mice, progressive loss of Kcnj10 protein expression in stria vascularis of Slc26a4-/- mice was assessed, the modulation of Kcnj10 protein expression by free radical stress in cultured stria vascularis and in an heterologous expression system was evaluated. To characterize the thyroid pathology, pendrin expression in the thyroid of Slc26a4+/- mice was measured in a developmental study and correlated with serum thyroxine (T4) levels of Slc26a4+/- and Slc26a4-/- mice over a developmental time course. All tested methods of RNA amplification were suitable for gene array application and demonstrated high internal consistency. Intermethod comparisons revealed variations in data, suggesting that a single amplification method ought to be used within a given experiment. Markers of free radical stress were increased in the stria vascularis of Slc26a4-/- mice before the onset of hearing. Progressive loss of Kcnj10 expression was seen in Slc26a4-/- mice at the onset of hearing. Furthermore, free radical stress modulated the expression of Kcnj10 in cultured stria vascularis and in a heterologous expression system. The pendrin mRNA expression was marginal in the thyroid and did not correlate with serum T4 levels. Further, absence of pendrin did not affect free radical stress markers in the thyroid. These data suggest that free radical stress-mediated loss of Kcnj10 expression in stria vascularis contributes to deafness in the Pendred syndrome mouse model and that pendrin is not essential for the function of mouse thyroid gland.

Master of Science / Department of Kinesiology / Timothy I. Musch / Advancing age alters the structural and functional determinants of convective and diffusive muscle oxygen (O[subscript]2) flux. However, capillary red blood cell (RBC) hemodynamics have not been investigated during contractions in muscles of old animals. PURPOSE: To test the hypothesis that aging induces significant alterations in capillary hemodynamics during electrically-induced contractions in the spinotrapezius muscle of old Fischer 344 x Brown Norway rats when compared to younger counterparts. METHODS: The spinotrapezius muscle was observed via intravital microscopy in 8 old (O: 26-30 months) and 5 young (Y: 6-8 months) animals. Wire electrodes elicited 1 Hz (6-8 volts) contractions for 3 minutes. RBC flux (FRBC), velocity (VRBC), capillary hematocrit (HCAP), and total microvascular O[subscript]2 delivery (QO[subscript]2m) were measured both at rest and during the steady-state of muscle contractions. RESULTS: At rest F[subscript]RBC and V[subscript]RBC were elevated in O compared to Y rats, while there was no difference in HCAP or QO[subscript]2m between groups. During the contracting steady-state, [Delta]F[subscript]RBC (Y: 28.8 [plus or minus] 7.7, O: -2.9 [plus or minus] 1.4 cells/s), [Delta]V[subscript]RBC (Y: 253 [plus or minus] 68, O: -4 [plus or minus] 15 [Mu]m/s), [Delta]H[subscript]CAP (Y: 0.02 [plus or minus] 0.02, O: -0.03 [plus or minus] 0.01 cells/[Mu]m), and [Delta]QO[subscript]2m (Y: 892 [plus or minus] 255, O: -24 [plus or minus] 30 cells/s/mm) cells/s/mm were all lower (P < 0.05) in O compared to Y rats. CONCLUSION: These results indicate that despite maintained total convective and diffusive O[subscript]2 transport at rest, advancing age results in significant alterations in capillary hemodynamics during electrically-induced contractions. These alterations likely contribute to the mechanisms responsible for the reduced exercise capacity commonly found in elderly populations.