U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Food and Feed Safety Research: College Station, TX
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Plains Area College Station, Texas Southern Plains Agricultural Research Center Food and Feed Safety Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Edrington, Thomasitem
                                            Schultz, Carrieitem
                                            Callaway, Todditem
                                            Genovese, Kenneth

                                                         - *Ken*item
                                            HALLFORD, D - NEW MEXICO STATE UNIVitem
                                            SCHROEDER, SASHA - TX A&M UNIVERSITYitem
                                            Anderson, Robinitem
                                            Nisbet, David
  Submitted to: Comparative Endocrinology International Congress Abstracts
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 2/8/2005
                                    Publication  Date: 5/22/2005
                                    Citation: Edrington, T.S., Schultz, C.L., Callaway, T.R., Genovese, K.J., Hallford, D.M., Schroeder, S.B., Anderson, R.C., Nisbet, D.J. 2005. Effect of exogenous melatonin on fecal shedding of E. coli O157:H7 in naturally-infected beef cattle [abstract]. International Congress of Comparative Endocrinology. p. 65.Interpretive Summary:
                                Technical Abstract: Seasonal shedding of E. coli O157:H7 (EC) in ruminants is well documented, however reasons for this phenomenon are unknown.  We hypothesize that seasonal shedding of EC is a result of physiological responses by the animal to changing daylength.  In a series of experiments utilizing naturally-infected beef cattle and experimentally-infected sheep, we examined the effect of exogenous melatonin administration and chemical inhibition of the thyroid, on fecal shedding and gastro-intestinal (GIT) populations of EC.  Animals treated daily with a low oral dose of melatonin (mg) had shedding patterns and GIT populations of EC similar to controls.  However, when a high dose of melatonin (g) was orally administered to naturally-infected cattle, the number of cattle shedding EC was lower (P = 0.05) compared to control steers.  Chemical inhibition of the thyroid, via administration of propyl-thiouraracil (PTU), had no effect on fecal shedding or GIT populations in naturally- or experimentally-infected cattle and sheep.  However, following termination of the PTU treatment in the naturally-infected cattle, a greater percentage of PTU treated animals shed EC compared to control steers.  Early results indicate that hormones known to respond to changing daylength may play a role in the seasonal shedding of EC in ruminants.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov