Can Natural Malate Production in Forages Reduce Methane Emissions in Grazing Cattle?

Background

Malate, in synthetic form, is an approved feed additive and an antimicrobial alternative that alters the rumen microbiome and rumen metabolism. These changes have been shown to reduce acidosis risk as well as reduce the production of methane. Malate has also been shown to improve feed efficiency by diverting energy used for methane production to energy available for growth and development. Despite the benefits, it is not cost effective to supplement malate in its synthetic form. However, malate is naturally present in forages like alfalfa and red clover, though the amount is highly variable depending on variety and maturity of the forage. Understanding which varieties have a naturally high malate concentration and at what levels throughout the growth stage could potentially open the door to a cost-effective strategy of malate supplementation in grazing systems.

Objectives

• Evaluate the variation of malate content in different forage species and varieties at different maturity stages
• Determine the effect of malate as a feed additive on beef cow efficiency and methane emission
• Assess the effect of dietary malate on the rumen microbiome

What they will do

This team will conduct 2 studies- a small plot agronomy trial and a winter-feeding trial; to determine the actual levels of malate in forage, and the production effects of supplementing malate to pregnant cows.

Small plot agronomy trial: At Lakeland College for three replications, eight alfalfa and red clover varieties will be analyzed at different stages for nutrient and malate content. The team will then evaluate the effects of forage type and stage of maturity on malate concentration.

Winter feeding trial: At Lacombe Research and Development Centre, cows will be fed in confinement and supplemented with synthetic malate during a winter-feeding trial for two years.  Synthetic malate will be supplemented to at least 54 pregnant cows each year at a rate of 0, 1.5, and 3% of DM on a forage based TMR for a three-month period. There will be three pens with 6-8 cows per treatment. Cattle will be weighed monthly as well as at the start and end of the trial period. Rumen fluid will be collected three times during each winter-feeding trial to characterize the rumen microbial community and monitor for any changes, including any impact on methanogens.

Implications

If malate content can reliably be predicted in known high-malate forages, there is potential to take advantage of improved feed efficiency and reduce methane production in a grazing based system. This could not only improve cow performance on cow-calf operations and better report the contribution of GHG emissions from Canadian cow-calf operations, but also provide a means to supplement malate in a cost-effective way.