TY - JOUR

T1 - A ring test of a wireless in vitro gas production system

AU - Cornou, Cecile

AU - Storm, Ida Marie Lindhardt Drejer

AU - Hindrichsen, Ida Katarina Auf der M.

AU - Worgan, Hilary

AU - Bakewell, Eleanor

AU - Ruiz, David R. Yáñez

AU - Abecia, Leticia

AU - Tagliapietra, Franco

AU - Cattani, Mirko

AU - Ritz, Christian

AU - Hansen, Hanne Helene

PY - 2013

Y1 - 2013

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84877723830&partnerID=8YFLogxK

U2 - 10.1071/AN12091

DO - 10.1071/AN12091

M3 - Journal article

AN - SCOPUS:84877723830

VL - 53

SP - 585

EP - 592

JO - Animal Production Science

JF - Animal Production Science

SN - 1836-0939

IS - 6

ER -