Time-dependent changes in plasma concentrations of 3-methylindole and blood concentrations of 3-methyleneindolenine-adduct in feedlot cattle

Guy H. Loneragan, Paul S. Morley, John J. Wagner, Gary L. Mason, Garold S. Yost, Mike A. Thoren, Joni Triantis

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Objective - To describe time-dependent changes in plasma concentrations of 3-methylindole (3MI) and blood concentrations of 3-methyleneindolenine (3MEIN)-adduct in feedlot cattle. Animals - 64 yearling steers. Procedures - Steers were assigned to 2 groups (32 steers/group). During the first 8 weeks, blood samples were collected from group 1 before the morning ration was fed, whereas samples from group 2 were collected 2 to 3 hours after the ration was fed. Blood samples were collected from all steers approximately 4 times/wk for 3 weeks and 3 times/wk for the subsequent 5 weeks. Samples were collected at the same time for all steers for an additional 10 weeks. Plasma samples were analyzed for 3MI concentrations. Blood samples collected from cattle in group 2 during the first 8 weeks were analyzed for 3MEIN-adduct concentrations. Results - Mean blood concentration of 3MEIN-adduct increased to a maximum value on day 33 (0.80 U/μg of protein) and then decreased to a minimum on day 54 0.40 U/μg of protein). Plasma 3MI concentrations initially decreased and remained low until after day 54. Group-1 cattle had lower plasma 3MI concentrations, compared with concentrations for group-2 cattle. Blood 3MEIN-adduct concentrations and plasma 3MI concentrations were not associated with deleterious effects on weight gains. Conclusions and Clinical Relevance - Blood 3MEIN-adduct concentrations peaked during the period of greatest risk for development of bovine respiratory disease complex. Conversely, plasma 3MI concentrations decreased during the same period. Animal-to-animal variation in metabolic capacity to convert 3MI to 3MEIN may be of more importance than differences in plasma 3MI concentration.

Original languageEnglish
Pages (from-to)591-597
Number of pages7
JournalAmerican Journal of Veterinary Research
Volume63
Issue number4
DOIs
StatePublished - 2002

Fingerprint Dive into the research topics of 'Time-dependent changes in plasma concentrations of 3-methylindole and blood concentrations of 3-methyleneindolenine-adduct in feedlot cattle'. Together they form a unique fingerprint.

Cite this