A ring test of a wireless in vitro gas production system

Research output: Contribution to journalJournal articleResearchpeer-review

  • Cecile Cornou
  • Ida Marie Lindhardt Drejer Storm
  • Ida Katarina Auf der M. Hindrichsen
  • Hilary Worgan
  • Eleanor Bakewell
  • David R. Yáñez Ruiz
  • Leticia Abecia
  • Franco Tagliapietra
  • Mirko Cattani
  • Christian Ritz
  • Hansen, Hanne Helene
The in vitro gas production (GP) technique has been widely used for feed evaluation. However, variability in results limits useful comparisons. Results from a ring test undertaken in four laboratories (Italy - IT, Spain - SP, Wales - WA and Denmark - DK) using the same wireless equipment (ANKOM Technology), same substrates and same laboratory protocol are presented, including calculation of repeatability and reproducibility according to ISO 5725-2. Hay, maize starch and straw samples and units without sample (blanks) were incubated in five repetitions using rumen inoculum from cows (DK, IT and WA) or sheep (SP). Curves, corrected for blanks, were fitted using an exponential regression model with a lag time. The following variables were considered: (i) GP24 and GP48: raw values at 24 and 48 h (mL/g DM), corrected for blanks; (ii) A: asymptotic GP (mL/g DM); (iii) T1/2: time when half A is produced (h); (iv) GPMR: maximum predicted GP rate (mL/h); (v) L: lag time (h). A mixed model including laboratories as random effect was used. A significant interaction between substrate and laboratories was found for all variables except A. The most repeatable and reproducible results were observed for A and GP48. The results from this ring test suggest the need for more standardisation, particularly in the procedures that occur outside the laboratory.
Original languageEnglish
JournalAnimal Production Science
Issue number6
Pages (from-to)585-592
Number of pages8
Publication statusPublished - 2013

ID: 45859805