Efficient Livestock and Low Emissions (ELLE) from southern grazing systems - Department of Agriculture REF No: 01200.042

Summary

In this project we have addressed the reducing methane emissions priority to identify a wider range of farming practices by which landholders can reduce methane emissions and emissions intensity from grazing systems. Forty commercial, 'pipeline' and/or experimental species of annual and perennial grasses and legumes were used to: (i) identify species with antimethanogenic properties and; (ii) identify species/genotypes with potential to reduce methane emissions intensity via improved nutritional traits including the temporal pattern of digestibility and (iii) demonstrate the effects of the most promising species in vivo.We hypothesized that there would be differences in the potential of pasture species to improve livestock production and reduce methane, and that these differences can be associated with temporal patterns of forage yield and feed quality, or more directly through manipulation of methanogenic bacteria in the rumen.
A total of 450 plots (1.2 m x 8 m) were established of 150 accessions from 109 species, of which 40 were chosen for ELLE. A subset of these plants that werechosen to examine the effect of site and season and to grow material for a proof-of-concept in vivo experiment, were established at two sites (SA and WA) and sampled over years 2 and 3. In addition, individual spaced plants of six chicory cultivars, nine wild accessions and genotypes that have been selected for persistence and grazing tolerance were used to examine intraspecific variation. We measured the herbage production, nutritive value and in vitro methane production on all samples collected across season (years), site and phenological stage (over 4385 samples). We also used these samples to examine the potential for NIR spectrometry to provide rapid and inexpensive predictions of methanogenic properties of pasture species. To ensure these laboratory-based measurement and predictions of reduced methane and improved efficiency will translatedinto the field, we assessed in vivo the effects of the most promising plant species on ruminal methane production and animal productivity such as intake, diet selection, nitrogen balance and growth.