Browsing by Author "Washburn, Kevin"
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Item Evaluation of Immune Response and Performance in Steers of Known Genetic Background Vaccinated and Challenged with Bovine Viral Diarrhea Virus(2011-02-22) Runyan, Chase; Herring, Andy D.; Sawyer, Jason E.; Washburn, KevinThis research was directed at investigating the variation in immune response of cattle when administered a known challenge from Bovine Viral Diarrhea Virus (BVDV) following different Bovine Respiratory Disease (BRD) vaccine treatments. Cattle were assigned vaccine treatments with sire and cow family was stratified across treatments to assess the role genetic differences may impact immune function. The same BVDV strain and challenge technique were used in two trials (2008 and 2009) in Angus-sired yearling steers. Data from these two years were analyzed separately because the cattle were managed and fed differently. Blood antibody Immunoglobulin-G (IgG) titers for IBR, BVD Type 1 and BVD Type 2 were higher for cattle in the Killed vaccine group than the MLV or NON vaccinated groups (P < 0.05) in both years. In the 2008 study, average daily gain (ADG) was higher for cattle from the Killed vaccine group (P < 0.05) for the 28 d following BVDV challenge, but no cattle were classified as morbid based on rectal temperature. In the 2009 study, differences in rectal temperatures were observed, and a total of 35 of 93 having over 40.0 degrees C (28 in the first 14 d following challenge). Cattle in the MLV vaccine group had lower overall mean temperatures, with no animals having rectal temperatures over 40 degrees C 14 d following viral challenges. Differences in rectal temperature were also observed due to sire. Differences in feed intake also occurred due to treatment, day, treatment × day interaction, and maternal-grandsire. The MLV vaccine group maintained more constant levels of intake as compared to Killed and NON vaccinated cattle at days 5 to 12. Although large differences in titers following BVDV challenge were observed, the relationships of this immune response with animal health and performance appears very complex.Item Investigating the Sire Contribution to Embryonic Mortality in Cattle(2021-07-09) Araujo Franco, Gessica; Pohler, Ky; Cooke, Reinaldo; Lamb, Cliff; Washburn, KevinFirst, we characterized the association between sire fertility and pregnancy loss in cattle. Bos Taurus beef cows had a large variance in pregnancy loss between days 24 and 31 of gestation (1.8 to 11.7%) and between days 31 and 60 of gestation (2.3 to 12.6%) among service sires used for timed artificial insemination (TAI). Similarly, same variance was observed among sires used for TAI and timed embryo transfer (TET) in dairy cattle. Pregnancy loss during the second month of gestation ranged from 5 to 35-40% among sires used in both TAI and TET, and no correlation was observed with their respective sire conception rate (SCR) index. These sire phenotype characterization studies suggest that current methods to evaluate sire fertility may be limited in assessing overall reproductive success and incidence of late gestation pregnancy loss should be considered when evaluating sire fertility, as it can significantly affect final pregnancy rate. To investigate the physiological mechanism of paternal contribution to conceptus formation, parthenogenetic embryos (PA) were compared to control embryos (CON) during blastocyst stage and post elongation stage. Pregnancy development was monitored by ultrasonography and blood based placental secretions. In all 19 cows that established a pregnancy with PA embryos, circulating concentration of placental products (PAG and ISG) throughout gestation were lesser compared to cows carrying CON embryos. Even though these embryos survived up to day 40-45 of gestation, no active site of implantation and attachment to endometrium was observed, suggesting that trophoblast tissues are not properly formed in the absence of paternal genes. These findings strongly suggest that paternal genetics contribute significantly to placenta formation in cattle, which could explain most of the sire variance observed in pregnancy loss during the period of active placentation. The development of markers to identify sires of high or low pregnancy loss would improve sire fertility evaluations and increase beef and dairy reproductive efficiency.Item Neurological Examination of the Ruminant and Lesion Localization(2019-06-12) Washburn, KevinItem Nutritional and Regulatory Roles for Branched-Chain Amino Acids in Milk Production by Lactating Sows(2015-01-26) Rezaei, Reza; Wu, Guoyao; Bazer, Fuller; Johnson, Gregory; Porter, Weston; Washburn, KevinBoth feeding and cell culture studies were conducted to test the hypothesis that branched-chain amino acids (BCAA) can enhance milk synthesis by porcine mammary epithelial cells (PMEC). In the first in vivo feeding trial, ten multiparous lactating sows were fed corn-soybean meal-based diets supplemented with 0%, 1.535%, or 3.07% BCAA for 29 d. The number of piglets was standardized to 9 per sow. On d 3,15 and 29 of lactation, body weights of sows and their piglets, as well as milk consumption of piglets were determined. Blood samples were obtained from sows and piglets at 2 and 1 h after feeding, respectively. The second feeding experiment was conducted with dietary supplements containing 0%, 1% or 2% monosodium glutamate (MSG). Data were analyzed by two-way ANOVA. In both feeding trials, plasma concentrations of aspartate, glutamine, citrulline, arginine, and BCAA were higher, compared to the control. Dietary supplementation with 1.535% and 3.07% BCAA increased: 1) concentrations of free and protein-bound glutamate plus glutamine in milk; 2) milk intake of piglets by 14% and 21%; and 3) daily weight gains of piglets by 19% and 28%. Dietary supplementation with 1% and 2% MSG increased: 1) concentrations of free and protein-bound glutamate plus glutamine in milk; 2) milk intake of piglets by 14% and 25%; and 3) daily weight gains of piglets by 23% and 44%. These results indicated that dietary supplementation with up to 3.07% BCAA or 2% MSG was safe and enhanced lactation in sows. To elucidate the mechanisms responsible for the effects of BCAA on milk production, PMEC were cultured in customized medium containing 0.1, 0.25, 0.5, 1 or 2 mM L- leucine, L-isoleucine, or L-valine, or a mixture of those three BCAA. Elevating extracellular concentrations of BCAA from 0.1 to 2 mM increased the phosphorylation of proteins in the mechanistic target of rapamycin pathway, the rate of protein synthesis and cell proliferation, while decreasing the abundance of proteasome and ubiquitinated protein, and the rate of protein degradation in PMEC. The findings not only advance understanding of nutritional regulation of lactation but also provide a new strategy to improve milk production by livestock, women, and other mammals.Item Strategies and Technologies for the Management and Mitigation of Bovine Respiratory Disease(2020-07-23) Wottlin, Lauren Rose; Carstens, Gordon; Pinchak, Bill; Welsh, Thomas; Washburn, KevinOpportunities exist to improve treatment success rates and animal welfare standards through use of remote sensor technologies for early detection of bovine respiratory disease (BRD), which is the most prevalent disease affecting beef cattle. Remote sensor technologies can monitor real-time deviations in physiological and behavioral responses of individual animals, that are not biased by the presence of pen riders, to enable more objective and accurate assessments of an animal’s health status. The objectives of this study were to evaluate behavioral, physiological, and immune alterations in cattle diagnosed with BRD, or in cattle experimentally challenged with BRD pathogens. In Trial 1, physical activity data collected from leg-attached accelerometers from BRD-diagnosed and healthy calves were analyzed using Shewhart statistical process control (SPC) procedures to determine if the activity sensors could detect onset of BRD prior to feedlot personnel. High-risk crossbred steers and bulls were fitted with accelerometers and evaluated for 56 d at a commercial feedlot. Univariate SPC models had moderate sensitivity (40 to 57%) and specificity (23 to 81%) and signaled up to 2 d prior to visual diagnosis. Multivariate SPC models had moderate sensitivity (43.9 to 57.4%) and low specificity (29.2 to 37.2%) and signaled 2 d prior to visual diagnosis. The moderate diagnostic accuracies of the SPC models reported in this study may be due to the relatively high within-animal daily variation in physical activity, and minimal time for early model training. In Trial 2, behavioral, physiological, and immune alterations of steers that mounted substantial or minimal haptoglobin (HPT) responses following an experimental challenge with Mannheimia haemolytica (MH) were compared with PBS-challenged controls. The HPT-responsive steers had greater post-challenge concentrations of neutrophils and lymphocytes, rumen temperature, DMI, and day-to-day variation in feeding behavior than HPT non-responsive steers, but differences in metabolite profiles were not detected between HPT responsive phenotypes. Research has shown lower basal cortisol and increase variation in behavior are associated with decreased disease resilience. Trial 3 was conducted to determine if pulse oximetry could accurately predict SO₂ in hypoxic conditions in anesthetized cattle. As graded levels of hypoxia were induced, heart rate and blood pressure were increased, SpO₂ levels were decreased, but lactate and pH were minimally affected. Trial 4 was conducted to determine time-series deviations in physiological, behavioral and immunological responses following a combined viral (bovine herpes virus-1; BHV-1) and bacterial (MH) challenge (VB) in steers to further explore the use of pulse oximetry for preclinical detection of BRD. The VB-challenged steers exhibited elevated leukocyte, acute phase protein, and febrile responses, and decreased DMI, feeding behavior patterns and physical activity. However, blood gas analysis and pulse oximetry were minimally altered by the VB challenge, indicating that sensors to monitor blood SpO₂ would have more utility as a prognostic than diagnostic tool. Future research should investigate multifactorial algorithms that incorporate multiple sensors to monitor activity, temperature and feeding behavior to improve the accuracy of preclinical detection of BRD detection and animal welfare status in beef cattle.