Environmental impact reduction: Strategies for mitigating enteric methane in dairy farming

Rising concerns about greenhouse gas emissions from dairy farming emphasize the need for strategies to reduce methane (CH₄) emissions from cattle. Enteric CH₄, generated by rumen microbial fermentation, accounts for 35–55% of on-farm greenhouse gas emissions, with dairy production responsible for over 70% of agricultural outputs [1]. This study evaluates nutritional strategies to mitigate enteric CH₄, focusing on natural feed additives to improve nutrient utilization and lower emissions. Certain studies propose that substituting grass silage with maize silage enhances rumen fermentation of propionate over acetate, thereby diminishing CH₄ emissions in dairy cows. When maize silage entirely supplanted grass silage in the diet of dairy cows, CH₄ emissions diminished by 8–11% [2]. Feeding cows the red seaweed Chondrus crispus, comprising 6% of the dry matter, resulted in a 13.9% reduction in CH₄ [3] large-scale adoption depends on technical and financial factors, as well as validation from pilot studies.</ p></sec><sec><title>Methods</title> A survey was developed to identify barriers and drivers towards the adoption of CH₄-reducing algal-based feeds. Concurrently, a randomized complete block design study was conducted to investigate the effect of <italic>C. crispus</italic> on enteric CH<sub>4</ sub> emissions and milk production in a typical Maine organic dairy farm. Twenty-two organically certified Holstein and Jersey cows averaging 29 ± 6.8 kg of milk/d and 150 ± 69 days in milk, were blocked and randomly assigned to a control diet without <italic>C. crispus</italic> (0CC. Cows fed daily with a 1 g blend of essential oils exhaled less CH₄ (444 ± 12.5 L/d) than cows fed a feed without the mixture (479 ± 12.5 L/d) [4]mainly in the form of methane. Essential oils are a group of plant secondary metabolites obtained from volatile fractions of plants that have been shown to exert changes in the rumen fermentation and may alter feed efficiency and to reduce methane production. The objective of this study was to investigate the effect on rumen microbial population, CH4 emissions and milking performance of a mixture of essential oils (Agolin Ruminant, Switzerland. The utilization of tannin or saponin-rich flora has become increasingly favoured for mitigating or eradicating protozoa in the rumen. Another study has shown that a commercial citrus extract diminished methane production while enhancing propionate concentration and the concentration of propionate-producing bacteria Megasphaera elsdenii [5]. The incorporation of 41 g of oilseed rape oil per kg of dry matter in the diet resulted in a 22.5% reduction in daily CH4 emissions from dairy cows [6]. Incorporating specific compounds into cattle diets can reduce methane emissions, improve feed efficiency, and support animal health, offering a sustainable approach to mitigating agriculture’s climate impact while maintaining farm profitability.