Supplementation with sodium and calcium salts of malic acid positively impacts productivity and mitigates methane emissions in ruminants: Goats and dairy cattle as case studies

This study aimed to evaluate the effects of malate salts supplementation on rumen fermentation, CH 4 emissions and productivity parameters in ruminants. Three studies were conducted. The first two trials, carried out with goats, included both in vitro (trial 1) and in vivo (trial 2) trials under controlled conditions using respiration chambers to measure CH 4 . Trial 3 involved dairy cows managed under commercial conditions with an automatic milking system. In the in vitro trial, various dosages of calcium and sodium salts of malic acid were tested (0, 12, 24.4,50, and 120 mg/L), showing a shift towards more efficient rumen fermentation routes, with an increase in the proportion of propionate (up to 39.8%) and a reduction in the acetate-to-propionate ratio with the increasing levels of malate salts (up to 34%) observed in the Trial 1. This suggests a potential decrease in methanogenesis, as evidenced by a 20% reduction in CH 4 relative to total VFAs (p