Methane emissions from sheep fed Eragrostis curvula hay substituted with Lespedeza cuneata

CONTEXT : Reducing emissions of greenhouse gases from livestock production systems is a global research priority. Forages that contain condensed tannins, such as the perennial legume Lespedeza cuneata, may help to reduce ruminant methane (CH4) emissions. AIMS : The objective of this study was to investigate the effect of feeding different levels of L. cuneata hay on feed intake and enteric CH4 emissions of sheep fed a basal diet of subtropical Eragrostis curvula hay. METHODS : Four adult ruminally cannulated Dohne Merino wethers with initial bodyweight of 65.5 ± 3.5 kg were used in the experiment in a 4 × 4 Latin square design. The four experimental treatments were E. curvula hay substituted with 0%, 30%, 60% and 90% L. cuneata hay. Each of four experimental periods lasted 27 days, which consisted of a 14-day adaptation period, a 7-day digestibility trial, and a 6-day CH4-measurement period. During the 6-day CH4-measurement period, CH4 emissions were measured continuously over a 24-h period by using an open circuit respiration system. KEY RESULTS : Dry matter intake (DMI, g/kg W0.75) was higher (P 0.05) by 30% inclusion of L. cuneata (17.6 g CH4/kg DMI) but decreased (P < 0.05) as the inclusion level increased to 60% and 90% (13.8 and 14.3 g CH4/kg DMI). CONCLUSIONS : Inclusion of L. cuneata hay in a diet based on E. curvula hay improved diet digestibility, and led to increased concentrations of crude protein, neutral detergent fibre and non-fibre carbohydrates. Substituting E. curvula hay with 60% L. cuneata on a DM basis resulted in the greatest reduction in CH4 yield of 21.4% compared with a diet of 100% E. curvula. IMPLICATIONS : The results suggest that L. cuneata has the potential to reduce CH4 yield and possibly increase production from sheep by improving diet DM digestibility and through improved DMI.The Red Meat Research and Development Trust of South Africa and the National Research Foundation of South Africa.http://www.publish.csiro.au/anhj2020Animal and Wildlife Science