A Pine Enhanced Biochar Does Not Decrease Enteric CH4 Emissions, but Alters the Rumen Microbiota

Biochar effect on sheep feed intake, growth rate and ruminant in vitro and in vivo methane production

Biochar, which is the product of biomass pyrolysis, has been suggested as a feed supplement to improve performance in livestock systems and reduce greenhouse gas emissions. The aim of the current study was to investigate in vitro and in vivo potential of biochar to favourably modify rumen fermentation (e.g., an increase in total Short Chained Fatty Acid (SCFA) concentration and a change in SCFA profile), reduce methane emission and increase sheep growth performance. Four concentrates were produced with biochar inclusion of 0, 10, 23 and 46 g/kg DM. The experimental diets for the in vitro experiments consisted of straw and concentrate in a 60:40 ratio and included measurements of total gas and methane (CH4) production, pH, ammonia nitrogen, SCFA, and microbial assays (total bacteria and methanogenic archaea). Two in vivo experiments were performed where the animals received ad libitum forage with 0.4 kg concentrate daily. Experiment 1 investigated the daily DM intake of sheep while experiment 2 investigated daily growth rate and CH4 emission of lambs. The inclusion of biochar had no impact on in vitro total gas production (ml/200 mg DM substrate) (P = 0.81) and CH4 production (ml/200 mg DM substrate) (P = 0.93). In vitro total SCFA concentration increased (P < 0.05) while acetate to propionate ratio (A:P) tended to decrease (P = 0.05) with both doses of biochar. Total bacteria decreased with the highest biochar inclusion in vitro (P < 0.05). Sheep's DM intake (kg/d) increased when low and medium levels but not when a higher level of biochar was added to the diet (P < 0.001). The inclusion of biochar did not significantly impact the lamb's daily growth rate (g/d) (P = 0.61) or enteric CH4 emissions (g/kg DM) (P = 0.43). We conclude that biochar supplementation had no favourable impacts on in vitro and in vivo CH4 production or on lamb's growth rate. Further research with well-characterised biochar is needed to gain a better understanding of the potential of biochar as a feed additive for ruminant livestock.

Quantifying the Impact of Different Dietary Rumen Modulating Strategies on Enteric Methane Emission and Productivity in Ruminant Livestock: A Meta-Analysis

A meta-analysis was conducted with an aim to quantify the beneficial effects of nine different dietary rumen modulating strategies which includes: the use of plant-based bioactive compounds (saponin, tannins, oils, and ether extract), feed additives (nitrate, biochar, seaweed, and 3-nitroxy propanol), and diet manipulation (concentrate feeding) on rumen fermentation, enteric methane (CH4) production (g/day), CH4 yield (g/kg dry matter intake) and CH4 emission intensity (g/kg meat or milk), and production performance parameters (the average daily gain, milk yield and milk quality) of ruminant livestock. The dataset was constructed by compiling global data from 110 refereed publications on in vivo studies conducted in ruminants from 2005 to 2023 and anlayzed using a meta-analytical approach.. Of these dietary rumen manipulation strategies, saponin and biochar reduced CH4 production on average by 21%. Equally, CH4 yield was reduced by 15% on average in response to nitrate, oils, and 3-nitroxy propanol (3-NOP). In dairy ruminants, nitrate, oils, and 3-NOP reduced the intensity of CH4 emission (CH4 in g/kg milk) on average by 28.7%. Tannins and 3-NOP increased on average ruminal propionate and butyrate while reducing the acetate:propionate (A:P) ratio by 12%, 13.5% and 13%, respectively. Oils increased propionate by 2% while reducing butyrate and the A:P ratio by 2.9% and 3.8%, respectively. Use of 3-NOP increased the production of milk fat (g/kg DMI) by 15% whereas oils improved the yield of milk fat and protein (kg/d) by 16% and 20%, respectively. On the other hand, concentrate feeding improved dry matter intake and milk yield (g/kg DMI) by 23.4% and 19%, respectively. However, feed efficiency was not affected by any of the dietary rumen modulating strategies. Generally, the use of nitrate, saponin, oils, biochar and 3-NOP were effective as CH4 mitigating strategies, and specifically oils and 3-NOP provided a co-benefit of improving production parameters in ruminant livestock. Equally concentrate feeding improved production parameters in ruminant livestock without any significant effect on enteric methane emission. Therefore, it is advisable to refine further these strategies through life cycle assessment or modelling approaches to accurately capture their influence on farm-scale production, profitability and net greenhouse gas emissions. The adoption of the most viable, region-specific strategies should be based on factors such as the availability and cost of the strategy in the region, the specific goals to be achieved, and the cost-benefit ratio associated with implementing these strategies in ruminant livestock production systems.

Drinking Warm Water Promotes Performance by Regulating Ruminal Microbial Composition and Serum Metabolites in Yak Calves

Yaks live in the harsh environment of the Qinghai-Tibet Plateau, and the cold climate causes lower growth efficiency. The aim of this experiment was to explore the effects of drinking warm water on the growth performance in yak calves and investigate the underlying physiological mechanisms. A total of 24 Datong yak calves were selected and randomly assigned into the cold water group (group C, water temperature around 0-10 °C without any heating; 58.03 ± 3.111 kg) and the warm water group (group W, water constantly heated at 2 °C; 59.62 ± 2.771 kg). After the 60-day experiment, body weight was measured, and rumen fluid and blood serum samples were collected for analysis. The results show that the body weight and average daily gain of yaks that drank warm water were higher compared to those that drank cold water (p < 0.05). The acetic, propionic, isobutyric, valeric, and isovaleric acid concentrations were higher in group W than in group C (p < 0.05). Additionally, warm water changed the ruminal microbes at different levels. At the phylum level, the relative abundance of Tenericutes, Kiritimatiellaeota, and Elusimicrobiota was higher in group C (p < 0.05). At the genus level, three genera were increased by warm water, including Ruminococcoides and Eubacteriales Family XIII. Incertae Sedis, and 12 genera were decreased, including Ruminococcus (p < 0.05). At the species level, unclassified Prevotellaceae and Ruminococcoides bili were increased by warm water compared to cold water (p < 0.05). According to the metabolomics results, metabolites, including valine, isoleucine, PC (15:0/22:2(13Z,16Z)), and LysoPC (18:0/0:0), were increased in the warm water group compared to the cold water group (p < 0.05), and were enriched in glycerophospholipid and amino acid metabolism pathways. This study analyzed the differences in ruminal microbes and metabolomes of yak calves provided with water at different temperatures and revealed the potential mechanism for better performance promoted by warm drinking water.

Evaluation of the effects of pine-sourced biochar on cattle performance and methane and carbon dioxide production from growing and finishing steers

A feedlot growing (77-d) and finishing (111-d) experiment was conducted to evaluate the effects of feeding biochar on steer performance, methane and carbon dioxide emissions, and carcass characteristics. Two treatments were evaluated, a control diet without biochar and the same diet with biochar included at 0.8% of dietary DM (growing) or 1.0% of dietary DM (finishing). The growing diet consisted of 40% corn silage, 40% wheat straw, 15% modified distillers grains plus solubles, and 5% supplement, with 0.8% biochar replacing fine ground corn in supplement. The finishing diet consisted of 55% high-moisture corn (HMC), 35% Sweet Bran, 5% wheat straw, and 5% supplement, with biochar replacing 1.0% HMC and added as an ingredient. Biochar was sourced from ponderosa pine wood waste (High Plains Biochar, Laramie, WY) and was 83% C with 426 m²/g surface area for both experiments. Crossbred steers were utilized in the growing (n = 160; initial BW = 363 kg; SD = 16 kg) and finishing (n = 128; initial; BW = 480 kg; SD = 17 kg) experiments, blocked by BW, and assigned randomly to 16 pens. Pens were assigned randomly to one of two treatments (biochar vs. control) with eight replications per treatment. Four pen replications per treatment were paired within BW block and rotated randomly through an emissions barn with two chambers (each treatment was evaluated simultaneously and for two rotations) to capture average weekly emissions of CH₄ and CO₂. Pen was the experimental unit and chamber was included as a fixed effect for emissions data. There were no statistical differences (P ≥ 0.23) in performance outcomes between treatments for the growing experiment. Dry matter intake (DMI; P < 0.01) and average daily gain (ADG; P = 0.02) were 2.2% and 5.9% lower for biochar-fed steers in the finishing experiment, respectively, resulting in a lighter hot carcass weight (P = 0.10) and lower calculated USDA yield grade (P = 0.02). Emissions of CH₄ and CO₂ were not affected by biochar inclusion in the growing (P ≥ 0.22) or finishing experiment (P ≥ 0.60). Results from these experiments show no indication that feeding biochar, supplemented at 0.8% (growing), and 1.0% (finishing) of the diet DM, reduces methane emissions in growing or finishing cattle.

Can Biochar Improve the Sustainability of Animal Production?

Animal production is a significant contributor of organic and inorganic contaminants in air, soil, and water systems. These pollutants are present beginning in animal houses and impacts continue through manure storage, treatment, and land application. As the industry is expected to expand, there is still a lack of affordable, sustainable solutions to many environmental concerns in animal production. Biochar is a low-cost, sustainable biomaterial with many environmental remediation applications. Its physicochemical properties have been proven to provide environmental benefits via the adsorption of organic and inorganic contaminants, promote plant growth, improve soil quality, and provide a form of carbon sequestration. For these reasons, biochar has been researched regarding biochar production, and application methods to biological systems have a significant influence on the moisture content, pH, microbial communities, and carbon and nitrogen retention. There remain unanswered questions about how we can manipulate biochar via physical and chemical activation methods to enhance the performance for specific applications. This review article addresses the positive and negative impacts of biochar addition at various stages in animal production from feed intake to manure land application.

Effects of feeding a pine-based biochar to beef cattle on subsequent manure nutrients, organic matter composition and greenhouse gas emissions

Biochar in ruminant diets is being assessed as a method for simultaneously improving animal production and reducing enteric CH₄ emissions, but little is known about subsequent biochar-manure interactions post-excretion. We examined chemical properties, greenhouse gas (GHG) emissions and organic matter (OM) composition during farm scale stockpiling (SP) or composting (CP) of manure from cattle that either received a pine-based biochar in their diet (BM) or did not (RM). Manure piles were monitored hourly for temperature and weekly for top surface CO₂, N₂O and CH₄ fluxes over 90 d in a semiarid location near Lethbridge, AB, Canada. Results indicate that cumulative CO₂, N₂O and CH₄ emissions were not affected by biochar, implying that BM was as labile as RM. The pH, total C (TC), NO₃-N and Olsen P were also not influenced by biochar, although it was observed that NH₄-N and OM extractability were both 13% lower in BM than RM. Solid-state ¹³C nuclear magnetic resonance (NMR) showed that biochar increased stockpile/compost aromaticity, yet it did not alter the bulk C speciation of manure OM. Further analysis by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed that dissolved OM was enriched by strongly reduced chemical constituents, with BM providing more humic-like OM precursors than RM. Inclusion of a pine-based biochar in cattle diets to generate BM is consistent with current trends in the circular economy, "closing the loop" in agricultural supply chains by returning C-rich organic amendments to croplands. Stockpiling/composting the resulting BM, however, may not provide a clear advantage over directly mixing low levels of biochar with manure. Further research is required to validate BM as a tool to reduce the C footprint of livestock waste management.

Evaluation of biochar products at two inclusion levels on ruminal in vitro methane production and fermentation parameters in a Timothy hay-based diet

This study evaluated the effects of seven biochar products at two levels of inclusion [2.25% or 4.50% diet dry matter (DM)] on DM disappearance (DMD), cumulative gas and methane (CH4) production, ammonia-nitrogen, and volatile fatty acid (VFA) production from Timothy grass hay over 48 h of incubation. Biochar did not affect gas and CH4 production (P ≥ 0.17) nor the DMD or ruminal fermentation (P ≥ 0.12). In conclusion, the biochar, irrespective of level of inclusion, did not exhibit potential to mitigate CH4 emission in a grass hay diet.

Effects of biochar source, level of inclusion, and particle size on in vitro dry matter disappearance, total gas, and methane production and ruminal fermentation parameters in a barley silage-based diet

This study evaluated the effects of biochar differing in source, inclusion level, and particle size on dry matter disappearance (DMD), total gas and methane (CH4) production, and ruminal fermentation in a barley silage-based diet. The seven biochar products used were coconut (CP001 and CP014) or pine (CP002, CP015, CP016, CP023, CP024)-based. Experiment 1 (Exp. 1) evaluated these biochars at 4.5%, 13.5%, and 22.5% level of diet inclusion, whereas Experiment 2 (Exp. 2) evaluated CP002, CP016, and CP023 at 2.25% and 4.50% of the diet at <0.5, 0.5–2.0, >2.0 mm particle size. Data were analyzed using PROC MIXED in SAS as a randomized complete block design, with biochar source, inclusion level, and particle size (Exp. 2 only) as fixed effects with run and replicate as random effects. Increasing level of biochar inclusion linearly (P < 0.01) decreased DMD in Exp. 1 and did not influence DMD (P > 0.05) in Exp. 2. Total gas, CH4 (mL·g−1 DMD), and ruminal fermentation parameters were not affected by product, inclusion level, or particle size (P > 0.05). In conclusion, biochar of varying source and particle size did not mitigate CH4 production, but reduced DMD at higher inclusion levels in the barley silage-based diet.

Biochar for agronomy, animal farming, anaerobic digestion, composting, water treatment, soil remediation, construction, energy storage, and carbon sequestration: a review

In the context of climate change and the circular economy, biochar has recently found many applications in various sectors as a versatile and recycled material. Here, we review application of biochar-based for carbon sink, covering agronomy, animal farming, anaerobic digestion, composting, environmental remediation, construction, and energy storage. The ultimate storage reservoirs for biochar are soils, civil infrastructure, and landfills. Biochar-based fertilisers, which combine traditional fertilisers with biochar as a nutrient carrier, are promising in agronomy. The use of biochar as a feed additive for animals shows benefits in terms of animal growth, gut microbiota, reduced enteric methane production, egg yield, and endo-toxicant mitigation. Biochar enhances anaerobic digestion operations, primarily for biogas generation and upgrading, performance and sustainability, and the mitigation of inhibitory impurities. In composts, biochar controls the release of greenhouse gases and enhances microbial activity. Co-composted biochar improves soil properties and enhances crop productivity. Pristine and engineered biochar can also be employed for water and soil remediation to remove pollutants. In construction, biochar can be added to cement or asphalt, thus conferring structural and functional advantages. Incorporating biochar in biocomposites improves insulation, electromagnetic radiation protection and moisture control. Finally, synthesising biochar-based materials for energy storage applications requires additional functionalisation.

Effect of pine-based biochars with differing physiochemical properties on methane production, ruminal fermentation, and rumen microbiota in an artificial rumen (RUSITEC) fed barley silage

This study investigated the effects of three pine-based biochar products on nutrient disappearance, total gas and methane (CH4) production, rumen fermentation, microbial protein synthesis, and rumen microbiota in a rumen simulation technique (RUSITEC) fed a barley-silage-based total mixed ration (TMR). Treatments consisted of 10 g TMR supplemented with no biochar (control) and three different biochars (CP016, CP024, and CP028) included at 20 g·kg−1 DM. Treatments were assigned to 16 fermenters (n = 4 per treatment) in two RUSITEC units in a randomized block design for a 17 d experimental period. Data were analyzed using MIXED procedure in SAS, with treatment and day of sampling as fixed effects and RUSITEC unit and fermenters as random effects. Biochar did not affect nutrient disappearance (P > 0.05), nor total gas or CH4, irrespective of unit of expression. The volatile fatty acid, NH3-N, total protozoa, and microbial protein synthesis were not affected by biochar inclusion (P > 0.05). Alpha and beta diversity and rumen microbiota families were not affected by biochar inclusion (P > 0.05). In conclusion, biochar did not reduce CH4 emissions nor affect nutrient disappearance, rumen fermentation, microbial protein synthesis, or rumen microbiota in the RUSITEC.

Dose response of biochar and wood vinegar on in vitro batch culture ruminal fermentation using contrasting feed substrates

Within Australia, approximately 6.4% of total greenhouse gas emissions are from animal methane (CH₄) derived from enteric fermentation. Mitigation of ruminant CH₄ is a key concept in support of sustainable agriculture production; dietary manipulations a viable strategy to lower CH₄ release during enteric fermentation. In order to determine the effects of dose response of biochar and wood vinegar supplementation on fermentation parameters and CH₄ production, this study utilized in vitro batch culture incubations. It is hypothesized that the addition of either biochar or wood vinegar will successfully reduce enteric CH₄ emissions without negative modification of other fermentation parameters. Three feed substrates (vegetable mixed ration, maize silage, and winter pasture) were separated into treatments containing either biochar at 0%, 0.5%, 1%, 2%, and 4% DM replacing substrate (w/w basis), or wood vinegar at 0%, 0.25%, 0.5%, 1%, and 2% into incubation media volume (v/v). At 6, 12, and 24 hours after inoculation, total gas volume, and methane (CH₄ %) were measured. Volatile fatty acid (VFA) concentrations, media pH, and in vitro dry matter digestibility were measured at 24 hours. Biochar at various dosages had no effect (P > 0.05) on fermentation characteristics other than decreased in vitro dry matter digestibility (IVDMD; P = 0.01) at 2% and 4% (DM basis) inclusion. Similar to biochar, dose response of wood vinegar had no effect on in vitro fermentation characteristics. However, feed substrate had major effects on all fermentation parameters (P = 0.01) where winter pasture > vegetable mixed ration > maize silage for all recorded fermentation characteristics. Biochar and wood vinegar supplementation were ineffectual in mitigating CH₄ production or modifying fermentation characteristics, thus rejecting the initial hypothesis. These results suggest the use of biochar is not an effective tool for methane mitigation in ruminant livestock and infers that studies previously reporting success must better define the systemic mechanisms responsible for the reduction in CH₄.

Methane Emissions from Ruminants in Australia: Mitigation Potential and Applicability of Mitigation Strategies

Anthropomorphic greenhouse gases are raising the temperature of the earth and threatening ecosystems. Since 1950 atmospheric carbon dioxide has increased 28%, while methane has increased 70%. Methane, over the first 20 years after release, has 80-times more warming potential as a greenhouse gas than carbon dioxide. Enteric methane from microbial fermentation of plant material by ruminants contributes 30% of methane released into the atmosphere, which is more than any other single source. Numerous strategies were reviewed to quantify their methane mitigation potential, their impact on animal productivity and their likelihood of adoption. The supplements, 3-nitrooxypropanol and the seaweed, Asparagopsis, reduced methane emissions by 40+% and 90%, respectively, with increases in animal productivity and small effects on animal health or product quality. Manipulation of the rumen microbial population can potentially provide intergenerational reduction in methane emissions, if treated animals remain isolated. Genetic selection, vaccination, grape marc, nitrate or biochar reduced methane emissions by 10% or less. Best management practices and cattle browsing legumes, Desmanthus or Leucaena species, result in small levels of methane mitigation and improved animal productivity. Feeding large amounts daily of ground wheat reduced methane emissions by around 35% in dairy cows but was not sustained over time.

Molecular speciation and aromaticity of biochar-manure: Insights from elemental, stable isotope and solid-state DPMAS 13C NMR analyses

The use of biochar (BC) in feedlot cattle diets has recently been explored as an approach to simultaneously improving animal production and reducing enteric methane (CH₄) emissions. This study examines the impact of BC on manure properties and whether BC affects manure composition and carbon (C) and nitrogen (N) outputs from feedlot steers offered a barley-based diet with BC at 0.0, 0.5, 1.0 and 2.0% (BC₀, BC_0.5, BC₁ and BC₂) of diet dry matter. Manure was sampled three times over a 235 day feeding trial conducted in southern Alberta, Canada. Results showed that BC₂ increased total C and the C/N ratio by 5.7 and 6.6% relative to BC₀, respectively (P < 0.05), while total N exhibited a quadratic response from BC₀ to BC₂ (P = 0.005). Manure ¹⁵δN signatures, ranging from +3.83 to +7.34‰, were not affected (P > 0.05) by BC treatment. DPMAS ¹³C NMR revealed similar structural features among BC₀ and BC₂; indigestible BC had a minor impact on the bulk-C speciation of manure organic matter (OM). Compositional changes were limited to the aromatic-C region of the ¹³C NMR spectra. Fused-ring domains, mainly pyrogenic-C, were increased by 1.56-fold at BC₂ relative to BC₀. Overall, results demonstrated that BC stabilizes recalcitrant-C in manure OM, potentially sequestering soil-C when applied to croplands. This approach provides an added value to its use in ruminant diets, mainly from a nutrient cycling perspective. However, whole-farm studies are further required to validate the incorporation of BC into beef production systems.

Effect of Two Different Biochars as a Component of Compound Feed on Nutrient Digestibility and Performance Parameters in Growing Pigs

The objective of this study was to examine two different biochars as a component of compound feed regarding their effects on nutrient digestibility and performance parameters in growing pigs. A total of 18 male, intact piglets (N = 18) with 26 days of age and an initial bodyweight of 6.88 kg were divided into three homogeneous groups of six animals each (n = 6). Treatments were control (CON, no addition of biochar), 2% biochar 1 (BC 1, diet containing 2% biochar 1), and 2% biochar 2 (BC 2, diet containing 2% biochar 2). Before the start of the trials, the biochars were characterized regarding Brunnauer-Emmet-Teller (BET) surface area, surface energy, humidity, and ash content. During the first trial (weeks 1–6) a 3 × 3 Latin square was used to determine the apparent total tract digestibility (ATTD) of all three feed in each animal (N = 54, n = 18). By start of the second trial on day 42, three new homogenous groups were formed with two animals from each of the previous groups. Each group received one of the three diets for 4 weeks. In the first trial, the ATTD of dry matter, organic matter, ether extract, crude fiber, and N-free extract was higher (p &lt; 0.05) in pigs fed the biochar diets (BC1 and BC2) than in those animals fed the control diet. The greatest difference was found for ATTD of crude fiber, which was increased by 19.8 and 23.8%, respectively (CON: 30.8b ± 13.4%; BC 1: 38.4a ± 8.2%; BC 2: 40.4a ± 12.2%). ATTD of crude protein was only higher in BC 2 compared to CON (CON: 81.0b ± 4.1%; BC 1: 82.4ab ± 3.6%; BC 2: 84.2a ± 3.4%). In both trials, the different treatments revealed no effects on ADFI, ADWG or G:F (p &gt; 0.05). The results indicate that no negative effects can be expected when 2% biochar is included in the feed for growing pigs.

Assessment of potato peel and agro-forestry biochars supplementation on in vitro ruminal fermentation

Background

The awareness of environmental and socio-economic impacts caused by greenhouse gas emissions from the livestock sector leverages the adoption of strategies to counteract it. Feed supplements can play an important role in the reduction of the main greenhouse gas produced by ruminants—methane (CH₄). In this context, this study aims to assess the effect of two biochar sources and inclusion levels on rumen fermentation parameters in vitro.

Methods

Two sources of biochar (agro-forestry residues, AFB, and potato peel, PPB) were added at two levels (5 and 10%, dry matter (DM) basis) to two basal substrates (haylage and corn silage) and incubated 24-h with rumen inocula to assess the effects on CH₄ production and main rumen fermentation parameters in vitro.

Results

AFB and PPB were obtained at different carbonization conditions resulting in different apparent surface areas, ash content, pH at the point of zero charge (pHpzc), and elemental analysis. Relative to control (0% biochar), biochar supplementation kept unaffected total gas production and yield (mL and mL/g DM, p = 0.140 and p = 0.240, respectively) and fermentation pH (p = 0.666), increased CH₄production and yield (mL and mL/g DM, respectively, p = 0.001) and ammonia-N (NH₃-N, p = 0.040), and decreased total volatile fatty acids (VFA) production (p < 0.001) and H₂ generated and consumed (p ≤ 0.001). Biochar sources and inclusion levels had no negative effect on most of the fermentation parameters and efficiency. Acetic:propionic acid ratio (p = 0.048) and H₂ consumed (p = 0.019) were lower with AFB inclusion when compared to PPB. Biochar inclusion at 10% reduced H₂ consumed (p < 0.001) and tended to reduce total gas production (p = 0.055). Total VFA production (p = 0.019), acetic acid proportion (p = 0.011) and H₂ generated (p = 0.048) were the lowest with AFB supplemented at 10%, no differences being observed among the other treatments. The basal substrate affected most fermentation parameters independently of biochar source and level used.

Discussion

Biochar supplementation increased NH₃-N content, iso-butyric, iso-valeric and valeric acid proportions, and decreased VFA production suggesting a reduced energy supply for microbial growth, higher proteolysis and deamination of substrate N, and a decrease of NH₃-N incorporation into microbial protein. No interaction was found between substrate and biochar source or level on any of the parameters measured. Although AFB and PPB had different textural and compositional characteristics, their effects on the rumen fermentation parameters were similar, the only observed effects being due to AFB included at 10%. Biochar supplementation promoted CH₄ production regardless of the source and inclusion level, suggesting that there may be other effects beyond biomass and temperature of production of biochar, highlighting the need to consider other characteristics to better identify the mechanism by which biochar may influence CH₄ production.

Effect of a pine enhanced biochar on growth performance, carcass quality, and feeding behavior of feedlot steers

The objective of this study was to evaluate the effect of enhanced biochar (EB) on growth performance, carcass quality, and feeding behavior of feedlot steers fed high-forage and high-grain diets. A total of 160 crossbred steers (initial 286 ± 26 kg body weight [BW]) were blocked by BW and randomly assigned to 16 pens (10 steers per pen), 8 of which were equipped with the GrowSafe system for monitoring feeding behavior. Treatments were EB included in the diet at 0% (control), 0.5%, 1.0%, or 2.0% (dry matter [DM] basis) with four pens per treatment. The backgrounding phase (84 d) was divided into four 21-d periods, and the finishing phase (112 d) was divided into four 28-d periods, with a 28-d transition period for dietary adaptation. Pen was the experimental unit for all parameters except for feeding behavior, where steer was considered the experimental unit. Treatment was included as a fixed effect, and period was considered a repeated measure. Total weight gain and overall average daily gain (ADG) tended to decrease (P = 0.06) with 2.0% EB. There was no effect (P ≥ 0.13) of EB on dry matter intake (DMI), gain-to-feed ratio (G:F), net energy for gain, ADG, or final BW for the backgrounding or finishing phases. There was a treatment × period effect (P < 0.05) of EB on DMI, ADG, and G:F for both backgrounding and finishing phases. Hot carcass weight, dressing %, back fat, rib-eye area, and meat yield were not affected (P ≥ 0.26) by EB. Lean meat yield was increased (P = 0.03) by 2.0% EB compared to all other treatments. Compared to the control, 2.0% EB increased (P = 0.02) the number of carcasses that achieved Canada 1 grade. More (P = 0.05) carcasses from control steers were graded as Canada 3 as compared to those fed 0.5% or 2.0% EB. Quality grade and incidences of liver abscesses were not affected (P ≥ 0.44) by EB. Enhanced biochar had no effect (P ≥ 0.11) on feeding behavior during backgrounding or finishing phases. In conclusion, EB did not result in changes in growth rate, feed efficiency, or feeding behavior in feedlot cattle, but 2.0% EB increased lean carcass yield grade.