Does Supplementing BioChar to Grazing Cattle Improve Performance and Reduce GHG emmissions?

Background

Biochar is engineered activated charcoal derived from many different sources (e.g., woodchips, plant residue, manure, agricultural waste etc.) and has several agricultural and environmental uses. Traditionally, biochar has been used to improve soil, but evidence suggests that using biochar as a feed additive could reduce enteric methane emissions and improve livestock efficiency. Due to this, biochar has evolved into a CFIA approved and commercially available feed additive for beef cattle among other livestock.

Using biochar as a feed additive has become of interest to beef cattle producers for its claims to improve animal health, increase nutrient intake and reduce methane emissions. Although, this is mainly demonstrated in in-vitro rumen simulation and feedlot experiments. Many questions remain concerning it’s applicability on cow-calf operations.  The lack of exploration into supplementing biochar on primarily forage-based diets stresses the need to determine the potential of biochar to reduce enteric methane in grazing cattle and the ideal dose that can accomplish this without compromising animal health and performance.

Objectives

• Determine biochar dose that results in the greatest reduction of GHG emissions
• Determine the impact biochar supplementation has on enteric GHG emissions
• Determine the impact of biochar on parasite load
• Determine impact of biochar supplementation on grazing cow and calf performance and dry matter intake (DMI)
• Determine impact of biochar supplementation on fecal nutrient excretion and rumen microbial community
• Evaluate the effect of biochar supplementation on the economic of grazing systems

What they DID  

Researchers at the University of Saskatchewan and University of Guelph performed complimentary trials at their respective locations to properly investigate the impacts of biochar supplementation.

Experiment one focused on identifying the optimum dose of pine-sourced biochar for grazing beef cattle to reduce methane without impacting performance. Each team provided two groups (n=8) of cows at a similar stage of pregnancy fed a forage-based diet and supplemented a fibre pellet with or without biochar. They measured methane emissions, body weight, body condition score (BCS), backfat, dry matter intake (DMI), forage quality, manure samples, rumen fermentation, and rumen microbiome population diversity. They also looked at the economics of supplementation.

Experiment two, conducted at the UofG, took to the fields to measure the parameters mentioned above in a real grazing scenario with 64 cow-calf pairs on pasture that had a mix of grass and legume species. Cows were split into one of two treatments i) biochar supplemented as a pellet at 3% of DMI or ii) no biochar (control). Experiment three was a three-year study at the UofS to further evaluate the effects of biochar supplementation on animal performance and health. 48 cow-calf pairs grazing on 48-ha of bromegrass-alfalfa pasture were assigned to be supplemented with a biochar pellet at 3% of DMI or given no biochar supplement (control).  Cow and calf body weight, average daily gain (ADG), rib fat, rump fate, BCS, enteric emissions (CO₂ and CH₄), fecal worm burden, manure nutrients, and economic analysis were used to draw conclusions.

What They Learned

There were no reduced methane emissions from any animals supplemented biochar over the three experiments. Biochar supplementation had no effect on DMI, body weight, or short-chain fatty acid (SCFA) and ammonia production. Additionally, there was nothing to support that manure nutrient composition was improved on pasture. However, there was some evidence that suggests biochar has the potential to reduce internal parasites while grazing.

Overall, all three experiments showed that supplementing biochar at 3% of DMI to pregnant and lactating cows on pasture did not improve emissions from cattle or have positive impacts to animal performance. Additionally, supplementing biochar over the summer grazing was found to not be profitable.  

What this means

This study showed that supplementing biochar to cows on pasture had no benefits to animal performance or menthane production and therefore, it is not a profitable to supplement biochar on pasture to reduce emissions.

However, there was evidence to suggest biochar supplementation could reduce the parasitic load of grazing cows and further research is needed to better understand this finding.