Cows in a jar - Screening feeds and rations for ruminants and hindgut fermenters.

Project leader in Denmark:  Associate Professor Hanne H. Hansen, e-mail: hhh@sund.ku.dk

Objectives

The overall aim of the current collaborative research agreement is to combine the expertises of Dr. H. Hansen and Professor Anette H. van Dorland in order to investigate specified determinants of variation when using a wireless pressure monitoring in-vitro gas production system. Specifically, technique methodology that may eliminate the need for rumen fluid from surgically altered cows will be investigated. In order to achieve the overall objective, three separate sets of experiments will be run to 1) establish validity of results from the newly established lab, 2) determine variation in inoculum from different sources over time and 3) reduce variation of the standardized protocol with ring test partners.

Project justification

The use of in vitro cumulative gas production (GP) for evaluation of ruminant feeds has been a focus of interest in the last decades (Getachew et al., 1998). This method provides a measure of feed digestibility and fermentation kinetics and allows the determination of fermentation product concentrations (gases, volatile fatty acids and ammonia) (Storm et al., 2012). A common technique is determination of GP by manually measuring the displacement of the plunger in a graduated syringe (Menke et al., 1979). However, this method is time and labor-consuming (Cone et al., 1996). Therefore semi-automated and automated techniques (Theodorou et al., 1994; Mauricio et al., 1999; Pell and Schofield, 1993) have been developed. These systems measure gas accumulation in the headspace of closed bottles. The system used by Mauricio et al. (1999) is based on the one used by Theodorou et al. (1994) system, but allows reading of gas volume without syringe. For both these systems, the accumulated gas is vented at regular intervals. In the Pell and Shofield (1993) system however, the accumulated gas is not vented.

This is a disadvantage, since the accumulation of gas (especially during the rapid gas production phase) may affect the release of gas from the buffered rumen fluid (Tagliapietra et al., 2010) and reduce the rate of fermentation of the substrate (Theodorou et al. 1994). Cone et al. (1996) used a fully automated system with venting to release pressure during incubation. The continuous flow of information during degradation makes it possible to mathematically describe GP curves. Previous inter-laboratory studies have been performed to assess the accuracy of different automated GP systems (Getachew et al., 2002; Rymer et al., 2005; van Gelder et al., 2005; van Laar et al., 2006). These studies are not standardized with regards to the calculation of repeatability (RT) and reproducibility (RP) and have considered laboratory differences as fixed effects. Variability in results from different laboratories limits useful comparisons.

The ANKOM^RF Gas Production System (Ankom, 2011) was installed in 2008 at the IPH Production and Health laboratory and has undergone a significant development including hardware (new radio receivers, new base station, different design of units) and numerous software updates, changes in preferred incubators, as well as development of SOP for each routine. A ring test was undertaken in 4 laboratories using the same wireless equipment (ANKOM ,2011), same substrates and same laboratory protocol  and was published in 2012 (Corneau et al, 2013). The popularity of this in-vitro technique is growing rapidly, although the variation in results still needs to be addressed (Cattani, 2014, in press).

Collaborative Partner

Prof., Dr. Anette H. van Dorland, Bern University of Applied Sciences (BFH), School of Agricultural, Forest and Food Sciences (HAFL)

Project period: February 2014 – January 2015

Funding

The total project budget 1,085,400.00 kr

• Bern University of Applied Sciences; 932,400.00 kr
• UCPH-HEALTH; 153,000.00 kr