|EGERT, AMANDA - University Of Kentucky|
|MCLEOD, KYLE - University Of Kentucky|
|HARMON, DAVID - University Of Kentucky|
Submitted to: Frontiers in Chemistry: Chemical Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2014
Publication Date: 10/13/2014
Citation: Egert, A.M., Klotz, J.L., McLeod, K.R., Harmon, D.L. 2014. Development of a methodology to measure the effect of ergot alkaloids on forestomach motility using real-time wireless telemetry. Frontiers in Chemistry: Chemical Biology. 2:90.
Interpretive Summary: The objectives of Exp. 1 were to characterize rumen motility patterns relative to feeding using a pressure transducer and real-time, wireless telemetry system and determine when, relative to feeding, to measure motility. Using the time period as determined in Exp. 1, the objective of Exp. 2 was to investigate the effects of ruminal dosing of endophyte-infected tall fescue seed on rumen motility, rumen dry matter contents, and ruminal fill in cattle. The wireless telemetry system can be used as an accurate, effective, and non-invasive tool to measure rumen motility and obtain detailed measurements of ruminal contractions in ruminally cannulated animals. Endophyte-infected tall fescue seed treatment at a dosage of 10 µg ergovaline + ergovalinine / kg BW under thermoneutral conditions for 14 days (which failed to induce acute fescue toxicosis) did not significantly alter rumen motility, ruminal fill, or dry matter of rumen contents. Therefore, it remains unclear as to whether ergot alkaloids or endophyte-infected tall fescue dosed intraruminally decreases rumen motility. Future experiments should focus on the interactions of ergot alkaloid dosage, ambient temperature, and rumen motility.
Technical Abstract: The objectives of these experiments were to characterize rumen motility patterns of cattle fed once daily using a real-time wireless telemetry system, determine when to measure rumen motility with this system, and determine the effect of ruminal dosing of ergot alkaloids on rumen motility. Ruminally cannulated Holstein steers (n = 8) were fed a basal diet of alfalfa cubes once daily. Rumen motility was measured by monitoring real-time pressure changes within the rumen using wireless telemetry and pressure transducers. Experiment 1 consisted of three 24-h rumen pressure collections beginning immediately after feeding. Data were recorded, stored, and analyzed using iox2 software and the rhythmic analyzer. All motility variables differed (P < 0.0001) between hours and thirds (8-h periods) of the day. There were no differences between days for most variables. The variance of the 2nd 8-h period of the day was less than the 1st (P < 0.0001) for area and less than the 3rd for amplitude, frequency, duration, and area (P < 0.05). These data demonstrated that the 2nd 8-h period of the day was the least variable for many measures of motility and would provide the best opportunity for testing differences in motility due to treatments. In Exp. 2, the steers (n = 8) were pair-fed the basal diet of Exp. 1 and dosed with endophye-free (E-) or endophyte-infected (E+; 0 or 10 µg ergovaline + ergovalinine / kg BW; respectively) tall fescue seed before feeding for 15 d. Rumen motility was measured for 8 h beginning 8 h after feeding for the first 14 d of seed dosing. Blood samples were taken on d 1, 7, and 15, and rumen content samples were taken on d 15. Baseline (P = 0.0623) and peak (P = 0.0409) pressure were lower for E+ steers. Water intake tended (P = 0.0961) to be less for E+ steers the first 8 hour period after feeding. The E+ seed treatment at this dosage under thermoneutral conditions did not significantly affect rumen motility, ruminal fill, or dry matter of rumen contents.