Effect of a blend of cinnamaldehyde, eugenol and capsicum oleoresin on methane emission and lactation performance of Nordic Red dairy cows fed grass silage-based diets

The objective of this study was to investigate the effect of administering a blend of cinnamaldehyde, eugenol, and capsicum oleoresin (CEC) to lactating dairy cattle for 105 days (i.e., 15 weeks) on enteric methane emission, feed intake, milk yield and composition, and body weight. The experiment utilized 40 Nordic Red lactating dairy cows (97 ± 59 days in milk at the start of the trial; mean ± SD) blocked into pairs based on dry matter intake (DMI), milk yield, parity, and lactation stage. Cows within block were randomly assigned to 1 of 2 dietary treatments; 1) CEC supplemented at 1.2 g/cow/d or 2) a control diet without CEC. Cows were offered ad libitum a basal diet of grass silage and concentrate fed separately in a 55:45 forage to concentrate ratio on a dry matter (DM) basis. A GreenFeed system was used to measure emissions of carbon dioxide (CO₂), methane (CH₄) and hydrogen (H₂). Supplementation with CEC decreased daily CH₄ production (g/d; 3.4%) and yield (g/kg DMI; 4.2%) and daily CO₂ production and yield (3.3% and 4.0%, respectively) whereas CH₄ and CO₂ intensities were not affected by treatment. Daily CEC supplementation tended to reduce H₂ production and intensity by 21% compared with control. Additionally, feed intake, milk production, milk composition, body weight, and body condition score were not influenced by dietary CEC supplementation. These results indicate that CEC supplementation can reduce CH₄ production without affecting performance of lactating dairy cows.