+publisher:"Texas A&M University" +contributor:("Roussel, Allen J.")

You searched for +publisher:"Texas A&M University" +contributor:("Roussel, Allen J."). Showing records 1 – 5 of 5 total matches.

▼ Search Limiters

Texas A&M University

1. Bhattarai, Bikash. Economic Consequences Associated with Johne’s Disease in Cow-Calf Operations.

Degree: PhD, Biomedical Sciences, 2013, Texas A&M University

URL: http://hdl.handle.net/1969.1/151288

► Johne’s disease (JD) in cattle is a disease of economic importance caused by Mycobacterium avium subspecies paratuberculosis (MAP). Studies were conducted to estimate the losses… (more)

▼ Johne’s disease (JD) in cattle is a disease of economic importance caused by Mycobacterium avium subspecies paratuberculosis (MAP). Studies were conducted to estimate the losses due to lower weaning weight of beef calves from MAP test-positive dams, to compare the perceptions of producers and veterinarians on the burden and economic aspects of MAP infection in cow-calf herds, and to evaluate whether testing and culling MAP test-positive cows is economically beneficial. Calves from cows with strong-positive ELISA results were 21.5 kg lighter at weaning compared to calves from ELISA-negative cows. Calves from heavy MAP shedding cows were 58.5 kg lighter, and calves from moderate shedders were 40.8 kg lighter compared to the calves from fecal-culture negative cows. Based on average feeder calf value during 2007 to 2012, these losses corresponded to US 57 per calf for ELISA strong-positive dams, US 157 per calf for heavy fecal shedder dams, and US 109 per calf for a moderate fecal shedder dam. Seedstock producers and the producers enrolled in control programs were more likely to have MAP uninfected herds. The average prevalence reported by producers was 0.8%. Compared to the small herds (<50 head), the average test-positive percentages and estimated prevalences were reported to be higher in medium (50-149) and highest in large (≥150) herds. Veterinarians reported an overall animal level prevalence in their client herds of 5%. Seedstock herds had a lower prevalence and these producers were more likely to enroll in a JD control program. Income lost due to the presence of JD in an infected cattle herd was perceived to be higher by veterinarians. Compared to the veterinarians, seedstock producers were more likely to perceive genetic losses due to culling MAP positive cows. Average annual loss due to JD in a 100 cow herd with a 7% MAP prevalence was 1,644 and 1,747 based on information provided by producers and veterinarians, respectively. Herd level production decreased with increasing prevalence. Compared to test and cull after ELISA or ELISA followed by fecal culture, using fecal culture alone provided the fastest reduction in herd prevalence. Fecal culture was also the least costly alternative based on long-term cumulative costs of an annual test and cull program. Results from the current study suggest that although testing provides faster progress, limiting within herd transmission by sale of all weaned calves and purchasing only low-risk replacements can also reduce prevalence. Results suggest that MAP infection in cows causes significant losses for the calves that are produced. While the knowledge about JD varied between producers and veterinarians, seedstock producers were more enthusiastic about MAP control programs and had lower MAP prevalence in their herds. Overall losses due to MAP infection in the herd might be substantial. It is very costly to control or eliminate MAP once the infection is established in a herd. Advisors/Committee Members: Welsh, C. Jane (advisor), Osterstock, Jason B. (advisor), Fosgate, Geoffrey T. (committee member), Roussel, Allen J. (committee member), Park, Seong C. (committee member).

Subjects/Keywords: Mycobacterium avium subspecies paratuberculosis; Johne's Disease; Beef, Cow-calf

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bhattarai, B. (2013). Economic Consequences Associated with Johne’s Disease in Cow-Calf Operations. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151288

Chicago Manual of Style (16^th Edition):

Bhattarai, Bikash. “Economic Consequences Associated with Johne’s Disease in Cow-Calf Operations.” 2013. Doctoral Dissertation, Texas A&M University. Accessed March 01, 2021. http://hdl.handle.net/1969.1/151288.

MLA Handbook (7^th Edition):

Bhattarai, Bikash. “Economic Consequences Associated with Johne’s Disease in Cow-Calf Operations.” 2013. Web. 01 Mar 2021.

Vancouver:

Bhattarai B. Economic Consequences Associated with Johne’s Disease in Cow-Calf Operations. [Internet] [Doctoral dissertation]. Texas A&M University; 2013. [cited 2021 Mar 01]. Available from: http://hdl.handle.net/1969.1/151288.

Council of Science Editors:

Bhattarai B. Economic Consequences Associated with Johne’s Disease in Cow-Calf Operations. [Doctoral Dissertation]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151288

2. Rodriguez Frausto, Heriberto. Development and analytical validation of a gas chromatography-mass spectrometry method for the assessment of gastrointestinal permeability and intestinal absorptive capacity in dogs.

Degree: PhD, Veterinary Microbiology, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-3257

► Assessment of gastrointestinal permeability in vivo is considered a suitable method for the evaluation of gastrointestinal mucosal integrity. Probes commonly used include lactulose (L) and… (more)

▼ Assessment of gastrointestinal permeability in vivo is considered a suitable method for the evaluation of gastrointestinal mucosal integrity. Probes commonly used include lactulose (L) and rhamnose (R) for the assessment of intestinal permeability, xylose (X) and 3-O-methylglucose (M) for the evaluation of intestinal absorptive capacity, and sucrose (S) for the assessment of gastric permeability. Traditionally, various methods have been used to quantify these markers in the urine after orogastric administration. However, urine collection is difficult and uncomfortable. A protocol based on the analysis of blood samples would be easier to perform. Thus, the aim of the first part of this project was to develop and validate a new gas chromatography-mass spectrometry (GC-MS) method for the quantification of five sugar probes in canine serum. The method was sensitive, accurate, precise, and reproducible for the simultaneous quantification of 5 sugar probes in serum. The aim of the second part of this project was to assess the kinetic profiles of these 5 sugar probes in serum after orogastric administration in dogs and to determine the optimal time point for sample collection. Dogs received a solution containing L (10 g/L), R (10 g/L), X (10 g/L), M (5 g/L), and S (40 g/L) by orogastric intubation. Baseline blood samples were collected. Subsequent timed blood samples were taken for a 24 hours period. Significant changes in serum concentrations of all 5 sugars were detected after administration of the test dose (p<0.0001 for all 5 probes). Serum concentrations of L and R were significantly different from baseline concentrations from 90 to 240 and from 60 to 300 min post dosing respectively, and those of X, M, and S were significantly different from 30 to 240 min after dosing (p<0.05 for all 5 probes). Variations of the mean sugar concentrations of all dogs at 90, 120, and 180 minutes were analyzed using a Kruskal-Wallis test. Based on the results, only two blood samples, one taken at baseline and a second sample obtained between 90 and 180 after dosing, appear to be sufficient for assessment of intestinal permeability and mucosal absorptive capacity using these sugar probes. Advisors/Committee Members: Steiner, J?M. (advisor), Roussel, Allen J. (committee member), Ball, Judith M. (committee member), Suchodolski, Jan S. (committee member), Williams,David A. (committee member).

Subjects/Keywords: Gas chromatography-Mass Spectrometry; GI Permeabiliy; Intestinal absorption; Sugar probes; Serum

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rodriguez Frausto, H. (2009). Development and analytical validation of a gas chromatography-mass spectrometry method for the assessment of gastrointestinal permeability and intestinal absorptive capacity in dogs. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-3257

Chicago Manual of Style (16^th Edition):

Rodriguez Frausto, Heriberto. “Development and analytical validation of a gas chromatography-mass spectrometry method for the assessment of gastrointestinal permeability and intestinal absorptive capacity in dogs.” 2009. Doctoral Dissertation, Texas A&M University. Accessed March 01, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-3257.

MLA Handbook (7^th Edition):

Vancouver:

Rodriguez Frausto H. Development and analytical validation of a gas chromatography-mass spectrometry method for the assessment of gastrointestinal permeability and intestinal absorptive capacity in dogs. [Internet] [Doctoral dissertation]. Texas A&M University; 2009. [cited 2021 Mar 01]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-3257.

Council of Science Editors:

Rodriguez Frausto H. Development and analytical validation of a gas chromatography-mass spectrometry method for the assessment of gastrointestinal permeability and intestinal absorptive capacity in dogs. [Doctoral Dissertation]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-3257

Texas A&M University

3. Benjamin, Lisa A. An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches.

Degree: PhD, Biomedical Sciences, 2010, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-7202

► Biosecurity practices for Mycobacterium avium subsp. paratuberculosis (Mptb), the etiologic agent for Johne's disease (JD), are predicated on the fact that fecal-oral is the major… (more)

▼ Biosecurity practices for Mycobacterium avium subsp. paratuberculosis (Mptb), the etiologic agent for Johne's disease (JD), are predicated on the fact that fecal-oral is the major route of infection and that Mptb is present in the environment of affected farms. The objectives of these studies were to describe perceived benefits of testnegative Level 4 status in the Voluntary Bovine Johne's Disease Control Program (VBJDCP), describe producer and veterinarian attitudes towards JD relevant biosecurity practices, compare 5 JD control options using a Markov model, determine if tangential flow filtration (TFF) increases the detection sensitivity for Mptb and describe the distribution of environmental predictors for Mptb survival. Twenty-five percent and 39% of beef producers in the VBJDCP reported that they received substantial or marginal benefits (financial and non-financial), respectively, from program participation. Producers suggested increased marketing opportunities to improve the VBJDCP. Producers in a cross-sectional mailed survey of attitudes towards biosecurity practices were more likely than veterinarians to agree that separating JD clinical or suspects from calves or heifers; acquiring replacements or additions from JD low-risk herds, testing for JD every 10 to 14 months and test and culling clinical suspects only were useful for control of JD. A state transition Markov model, with the environment as the source of Mptb, was used to compare 6 alternative control strategies for JD. Management and the probability of Mptb surviving 1 year in the environment were important determinants of the prevalence of subclinical JD on beef farms under the analyzed control strategies. Heterogenous distribution of environmental predictors for Mptb survival was observed in spatial risk maps. In conclusion, although some beef producers experienced gains from participation in the VBJDCP, the perceived program benefits could be improved by increased marketing and education on the advantages of participation. Specific problem areas should be addressed. The length of time Mptb survived in the environment was an important parameter in the Markov chain model. Additionally, due to the heterogenous distribution of environmental predictors, a multiscale approach to sampling and analysis should be useful. Advisors/Committee Members: Fosgate, Geoffrey T. (advisor), Feagin, Russell A. (advisor), Roussel, Allen J. (advisor), Ward, Michael P. (advisor).

Subjects/Keywords: Johne's disease; decision-making; disease control

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Benjamin, L. A. (2010). An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-7202

Chicago Manual of Style (16^th Edition):

Benjamin, Lisa A. “An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches.” 2010. Doctoral Dissertation, Texas A&M University. Accessed March 01, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-7202.

MLA Handbook (7^th Edition):

Benjamin, Lisa A. “An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches.” 2010. Web. 01 Mar 2021.

Vancouver:

Benjamin LA. An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches. [Internet] [Doctoral dissertation]. Texas A&M University; 2010. [cited 2021 Mar 01]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-7202.

Council of Science Editors:

Benjamin LA. An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches. [Doctoral Dissertation]. Texas A&M University; 2010. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-7202

Texas A&M University

4. Osterstock, Jason Barrett. Genetic epidemiology and familial risk factors for paratuberculosis seropositivity in beef cattle.

Degree: PhD, Biomedical Sciences, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2435

► Paratuberculosis is an intestinal infection of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Genetic associations with paratuberculosis have been described in Holstein cattle. The… (more)

▼ Paratuberculosis is an intestinal infection of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Genetic associations with paratuberculosis have been described in Holstein cattle. The objectives were to describe the association between paratuberculosis status of the dam and her offspring in beef cattle, develop methods to assess familial aggregation of paratuberculosis in cattle of unknown pedigree, and model the paratuberculosis status of beef cattle given familial and herdlevel covariates. Texas beef cattle were tested for paratuberculosis using serum antibody and microbiologic culture of feces. Available pedigree data were used to confirm familial relationships. The association between the paratuberculosis ELISA status of the dam and her offspring was assessed using mixed-effects models. Increased odds of being classified as a “suspect” or greater based on ELISA results were observed if the dam was classified as a “suspect” or greater. A positive linear association was observed between the ELISA value of the dam and her offspring. Analysis of pedigree data using conditional logistic regression identified ancestors associated with significantly increased odds of being classified as “low positive” or greater. Microsatellite markers were used to classify cattle into genetically similar groups using allele frequency data. Nine clusters of genetically similar cattle were identified among paratuberculosis test positive cattle, herd matched controls, and pedigreed cattle. Clusters were validated using animals of known pedigree. Increased odds of paratuberculosis seropositivity were observed for some clusters compared to the cluster with the lowest seroprevalence. A predictive model was developed using a Bayesian framework to assess the association between antibody status of the dam and her offspring adjusted for herd-level risk factors. Predictors associated with highly probable increased odds of seropositivity included herd seroprevalence and herd fecal prevalence of MAP. The association between dam and offspring ELISA status was small (OR 1.35) and not highly probable. The results of this work support familial aggregation of paratuberculosis ELISA status, but herd-level risk factors appear to be more important in predicting ELISA status. A large proportion of observed serological reactions were not supported by fecal culture results; therefore, observed associations might be limited to humoral responses to Mycobacterium spp. Advisors/Committee Members: Fosgate, Geoffrey T. (advisor), Cohen, Noah D. (committee member), Derr, James N. (committee member), Roussel, Allen J. (committee member).

Subjects/Keywords: epidemiology; paratuberuclosis; beef cattle; genetics

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Osterstock, J. B. (2009). Genetic epidemiology and familial risk factors for paratuberculosis seropositivity in beef cattle. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2435

Chicago Manual of Style (16^th Edition):

Osterstock, Jason Barrett. “Genetic epidemiology and familial risk factors for paratuberculosis seropositivity in beef cattle.” 2009. Doctoral Dissertation, Texas A&M University. Accessed March 01, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2435.

MLA Handbook (7^th Edition):

Osterstock, Jason Barrett. “Genetic epidemiology and familial risk factors for paratuberculosis seropositivity in beef cattle.” 2009. Web. 01 Mar 2021.

Vancouver:

Osterstock JB. Genetic epidemiology and familial risk factors for paratuberculosis seropositivity in beef cattle. [Internet] [Doctoral dissertation]. Texas A&M University; 2009. [cited 2021 Mar 01]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2435.

Council of Science Editors:

Osterstock JB. Genetic epidemiology and familial risk factors for paratuberculosis seropositivity in beef cattle. [Doctoral Dissertation]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2435

Texas A&M University

5. Taylor, Kristen Hawkins. Genetic analyses of bovine CARD15, a putative disease resistance gene.

Degree: PhD, Genetics, 2004, Texas A&M University

URL: http://hdl.handle.net/1969.1/219

► Through a binding partner the CARD15 gene activates NF-kB, a molecule with a role in the initiation of the inflammatory immune response. The gene is… (more)

▼ Through a binding partner the CARD15 gene activates NF-kB, a molecule with a role in the initiation of the inflammatory immune response. The gene is highly conserved in both structure and function in human and mouse and has recently been implicated as a disease resistance gene in Crohn's disease and Blau Syndrome in human. The gene's relationship to disease and its conservation between species suggests that it may also have a conserved role in bovine disease resistance. To elucidate the potential role of bovine CARD15 in disease resistance, the gene was characterized in cattle. Bovine CARD15 is located 4.2 cR5000 telomeric to ADCY7 on chromosome 18. It spans ~30 kb and is comprised of 12 exons, 11 of which are coding. Bovine CARD15 is expressed in many tissues, but is most abundant in peripheral blood leukocytes. An extensive comparative analysis between the bovine, mouse and human CARD15 genes revealed high levels of inter-species conservation in sequence, genomic structure and protein domains. Conserved putative regulatory motifs were identified in the three species comparison of the 5'UTR, 3'UTR and the intronic sequences flanking exons. Additionally, diverse regulatory motifs were identified in each of the species indicating an evolutionary divergence in the mechanisms of regulation of gene expression. To assess the extent of genetic diversity within bovine CARD15, 41 individuals from nine breeds representing two subspecies were sequenced and screened for polymorphisms. Thirty-six single nucleotide polymorphisms (SNPs) were identified including 26 within the gene transcript. Haplotypes were estimated for each individual and parsimonious SNP sets were identified with which the multi-locus Bos taurus and Bos indicus haplotypes may be reconstructed. There was a significantly higher rate of substitutions within Bos indicus than in Bos taurus. A significantly higher rate of nonsynonymous to synonymous substitutions was found in Bos taurus indicating that positive Darwinian selection is acting on the gene within this subspecies. Association analyses were performed between these SNP loci and haplotypes with Johne's disease. No overwhelming evidence for a simple causal relationship was detected. Assays are provided to screen populations of cattle for variation in the CARD15 gene. Advisors/Committee Members: Womack, James E. (advisor), Derr, James N. (committee member), Adams, L. Garry (committee member), Roussel, Allen J. (committee member).

Subjects/Keywords: CARD15; NOD2; bovine; disease resistance; Crohn's; Johne's

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Taylor, K. H. (2004). Genetic analyses of bovine CARD15, a putative disease resistance gene. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/219

Chicago Manual of Style (16^th Edition):

Taylor, Kristen Hawkins. “Genetic analyses of bovine CARD15, a putative disease resistance gene.” 2004. Doctoral Dissertation, Texas A&M University. Accessed March 01, 2021. http://hdl.handle.net/1969.1/219.

MLA Handbook (7^th Edition):

Taylor, Kristen Hawkins. “Genetic analyses of bovine CARD15, a putative disease resistance gene.” 2004. Web. 01 Mar 2021.

Vancouver:

Taylor KH. Genetic analyses of bovine CARD15, a putative disease resistance gene. [Internet] [Doctoral dissertation]. Texas A&M University; 2004. [cited 2021 Mar 01]. Available from: http://hdl.handle.net/1969.1/219.

Council of Science Editors:

Taylor KH. Genetic analyses of bovine CARD15, a putative disease resistance gene. [Doctoral Dissertation]. Texas A&M University; 2004. Available from: http://hdl.handle.net/1969.1/219

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations