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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Livestock, Forage and Pasture Management Research Unit » Research » Publications at this Location » Publication #410567
Research Project: Sustaining Southern Plains Landscapes through Improved Plant Genetics and Sound Forage-Livestock Production Systems

Location: Livestock, Forage and Pasture Management Research Unit

Title: Use of the GreenFeed bait system to assist in measuring fecal output and digesta kinetics

Author
item Gunter, Stacey
item Friend, Emalee
item Beck, Matthew
item Moffet, Corey

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 1/28/2024
Publication Date: 3/2/2024
Citation: Gunter, S.A., Friend, E., Beck, M.R., Moffet, C. 2024. Use of the GreenFeed bait system to assist in measuring fecal output and digesta kinetics. Journal of Animal Science. 102(1):76-77. https://doi.org/10.1093/jas/skae019.089.
DOI: https://doi.org/10.1093/jas/skae019.089

Interpretive Summary:

Technical Abstract: With increased use of automated feeders, like the bait dispenser on an automated head chamber system (AHCS; GreenFeed; C-Lock Inc., Rapid City, SD, USA), more scientists are investigating ways to use this equipment in research. Scientist with the Agricultural Research Service initially conducted an experiment to determine if dosing titanium dioxide (TiO2) through an AHCS is an alternative to the traditional hand-fed dosing method for estimating fecal output (FO). The AHCS used had a 2-hopper bait dispensing system, where one hopper contained alfalfa pellets marked with 1% TiO2 and the other contained alfalfa pellets. During the morning (0800), hand-fed heifers received 32 g of TiO2-marked pellets, whereas AHCS-dosed heifers also received 32 g of marked pellets during their first visit to the AHCS each day. A two one-sided t-test (TOST) indicated the FO estimates were similar between dosing methods (P = 0.04), but the AHCS dosed heifers had greater (P < 0.01) variability. This difference in FO variability is probably due to increased variability in dosing time (0615 ± 6.2 h) compared to hand-fed heifers. This research has highlighted the potential for dosing cattle with an external marker through an AHCS, but conventional fecal marker methods assume steady-state fecal marker concentration. Our research has shown that errors associated with external marker methods are not associated with analytical techniques, but are most influenced by dose size and timing, and sampling accuracy. Hence, irregular voluntary use of an AHCS results in non-steady-state fecal concentrations. To determine whether reliable FO estimates could be obtained under conditions of irregular but known dose times, we designed an experiment where the steady-state assumptions were relaxed, and fit known time measured fecal concentrations to multi-dose digesta kinetics models to estimate FO. In this experiment we used individually penned, rumen fistulated Dexter steers and limit-fed a diet of hay and protein supplement in 2 experiments. First, after a 7-d dietary acclimation, steers were given a dose of TiO2 through the rumen fistula and again on d 14, and over 120 h after each dose, 14 spaced fecal samples were collected. In Exp. 2, steers received the first of 6 daily doses, then on d 7 no dose, and on days 8 to 12 daily dosing resumed. Beginning on d 7, when dosing was skipped, fecal sampling began and over a 120-h period 14 fecal samples were collected. For Exp. 1, marker concentration data were fit to a G2 digesta kinetics model and for Exp. 2, concentration data were fit to a multi-dose G2 digesta kinetics model assuming identical digesta kinetics for each dose and the concentration over time as the sum of each pulse. Measured FO in Exp. 2 was 11% greater than the estimates obtained from fitting measured concentrations to multi-dose digesta kinetics models.