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The objective of this study was to investigate the effects of adding engineered biocarbon to a high-forage diet on ruminal fermentation, nutrient digestion, and enteric methane (CH4) production in a semi-continuous culture artificial rumen system (RUSITEC). The experiment was a completely randomized block design with four treatments assigned to sixteen fermentation vessels (four/treatment) in two RUSITEC apparatuses. The basal diet consisted of 60% barley silage, 27% barley grain, 10% canola meal, and 3% supplement (DM basis) with biocarbon added at 0, 0.5, 1, and 2% of substrate DM. The study period was 17 d, with a 10-d adaptation and 7-d sample collection period. Increasing biocarbon linearly increased (P < 0.05) disappearance of DM, OM, CP, ADF and NDF. Compared to control, increasing biocarbon enhanced (P < 0.01) production of total VFA, acetate, propionate, branch-chained VFAs, and tended to increase (P = 0.06) NH3-N. Microbial protein synthesis linearly increased (P = 0.01) with increasing biocarbon. Addition of biocarbon reduced overall CH4 production compared with the control (P ≤ 0.05). There were no differences (P > 0.05) in production of total gas, large or small peptides, or in the number of protozoa as a result of addition of biocarbon to the diet. Addition of biocarbon to a forage diet increased DM digestibility by up to 2%, while lowering enteric CH4 production and enhancing microbial protein synthesis in in vitro semi- continuous culture fermenters.

Grasslands across the Canadian prairies are crucial for maintaining biodiversity and ensuring landscape connectivity. In Alberta, a large portion of natural grasslands has been converted to agricultural cropland or other land uses, while the remaining natural grasslands are mainly used as rangeland. However, with increasing crop demand and food security concerns, there is a potential risk of further grassland conversion to cropland, particularly in areas where climate change may enhance suitability for farming. Here, we (1) quantified the impact of the present state of grasslands on maintaining landscape permeability; and (2) determined how the conversion of remaining grasslands to croplands could affect structural landscape connectivity at multiple spatial scales. We simulated four progressive scenarios of grassland conversion to cropland, starting with grasslands identified as most suitable for farming. Our results revealed that structural landscape connectivity, quantified as mean normalized current density with resistance values based on naturalness, decreased by up to 43% in southwestern and central areas of the Parkland and Grassland regions with higher rates of conversion. Conversion scenarios introduced new areas with notably constrained ecological flow in the Grassland region in the southeastern part of the province. Conversely, increased current density was observed in the Rocky Mountain and Boreal regions, which appear to act as alternative pathways for redirected ecological flow. Future grassland conversion is expected to further shift current flow from the grasslands westward through the foothills of the Rocky Mountain and northward into the Parkland and Boreal regions. These findings underscore the critical role of grasslands in maintaining structural landscape connectivity across Alberta, which is essential for supporting biodiversity and gene flow among species. Simulated changes in connectivity were most pronounced at the finer spatial scale, revealing key areas of past and future permeability shifts. Incorporating local land management decisions is crucial for improving landscape permeability and effective connectivity planning province-wide.

Background Carbohydrate-active enzymes (CAZymes) form the most widespread and structurally diverse set of enzymes involved in the breakdown, biosynthesis, or modification of lignocellulose that can be found in living organisms. However, the structural diversity of CAZymes has rendered the targeted discovery of novel enzymes extremely challenging, as these proteins catalyze many different chemical reactions and are sourced by a vast array of microbes. Consequently, many uncharacterized members of CAZyme families of interest have been overlooked by current methodologies (e.g., metagenomic screening) used to discover lignocellulolytic enzymes. Results In the present study, we combined phenotype-based selective pressure on the rumen microbiota with targeted functional profiling to guide the discovery of unknown CAZymes. In this study, we found 61 families of glycoside hydrolases (GH) (out of 182 CAZymes) from protein sequences deposited in the CAZy database—currently associated with more than 20,324 microbial genomes. Phenotype-based selective pressure on the rumen microbiome showed that lignocellulolytic bacteria (e.g., Fibrobacter succinogenes, Butyrivibrio proteoclasticus ) and three GH families (e.g., GH11, GH13, GH45) exhibited an increased relative abundance in the rumen of feed efficient cattle when compared to their inefficient counterparts. These results paved the way for the application of targeted functional profiling to screen members of the GH11 and GH45 families against a de novo protein reference database comprised of 1184 uncharacterized enzymes, which led to the identification of 18 putative xylanases (GH11) and three putative endoglucanases (GH45). The biochemical proof of the xylanolytic activity of the newly discovered enzyme validated the computational simulations and demonstrated the stability of the most abundant xylanase. Conclusions These findings contribute to the discovery of novel enzymes for the breakdown, biosynthesis, or modification of lignocellulose and demonstrate that the rumen microbiome is a source of promising enzyme candidates for the biotechnology industry. The combined approaches conceptualized in this study can be adapted to any microbial environment, provided that the targeted microbiome is easy to manipulate and facilitates enrichment for the microbes of interest. 87nDLj8bXvsK4GSUzRX-xV Video Abstract

Purpose In Canada, 95–99% of produced forages are consumed domestically each year, mainly by beef cattle. Despite their importance, their contribution to the Canadian livestock industry and associated ecosystem services has not been investigated. This study developed a life cycle inventory (LCI) of perennial forage production in Canada averaged from 2009 to 2018. Methods LCI data were sourced or calculated from up-to-date, regionally resolved sources and models. Inputs to perennial forage production included the following: concrete, steel, and plastic usage; machinery fuel consumption; electricity, natural gas, and water use for irrigation; and synthetic and organic fertilizer, lime, and herbicide use. Assessed emissions included ammonia and nitrous oxide (N 2 O); carbon dioxide from energy use; herbicide, nitrate, and phosphate losses; and soil carbon accumulation. Results were expressed per metric tonne of harvested perennial forage dry matter at provincial and regional scales—Western Canada [British Columbia (BC), Alberta (AB), Saskatchewan (SK), Manitoba (MB)] and Eastern Canada [Ontario (ON), Québec (QC)]. Results and discussion Rates of inputs varied, with generally lower nutrient but higher herbicide application in West vs. East. Irrigation was highest in BC, followed by AB and SK; energy consumption was highest in BC and lowest in QC. Higher N 2 O losses and nutrient losses via leaching and runoff in the East were partially due to greater soil moisture. Although total harvested perennial forage area declined from 6.43 to 5.23 million hectares from 2009 to 2018, these lands continued to accumulate soil carbon. The time period used to calculate average yields affected LCI estimates, as prairie yields were lower 1994–2003/1999–2008 due to drought. Furthermore, soil carbon sequestration estimates were affected by the annual change coefficients employed, underscoring the need for careful interpretation of LCI outputs. Results were compared to other studies and highlighted the importance of the choice of data and methods in creating LCI, and the need for transparency. Conclusions This first national LCI of perennial forage production in Canada provides a baseline for LCI inputs and outputs associated with this sector, highlighting provincial and regional differences. Outputs can be used to conduct future life cycle assessments to assess the environmental impacts of forage production and generate recommendations to improve sustainability, and for education and marketing purposes. This study demonstrates methodological best practices for LCI data mining and calculations, within available data and model limitations, thereby identifying gaps and providing a roadmap for other countries or sectors to develop detailed forage LCI.

The rumen microbiome plays a pivotal role in modulating feed efficiency in ruminants, yet the ecological mechanisms mediating the active interactions among microbial adaptations, dietary inputs, and host feed efficiency within the rumen remain poorly understood. To address this gap, we analyzed 120 metatranscriptomic datasets obtained from 30 purebred Angus bulls (each sampled four times) classified as high-feed-efficiency or low-feed-efficiency based on feed conversion ratio, and fed either forage-based (n = 15) or grain-based (n = 15) diets. We constructed a comprehensive active gene catalog comprising 1 744 067 non-redundant genes and compiled a reference set of 25 115 ruminant microbial genomes. Using integrated Neutral Community Model analysis and carbohydrate-active enzyme profiling, we examined how ecological processes and functional capacities differed across host phenotypes and diets. Neutral Community Model fits revealed that stochastic processes broadly governed rumen microbial community structures (R2 = 0.779 for high-feed-efficiency; R2 = 0.781 for low-feed-efficiency). Within the predominantly stochastic processes, however, high-feed-efficiency bulls exhibited strong positive selection for diet-responsive microbial lineages: Fibrobacter spp. (positively selected species-level genome bins: 61.3%–76.0%; negatively selected: 0%–1.3%), Butyrivibrio spp. (positively selected: 13.3%–46.0%; negatively selected: 1.0%–11.2%) under forage feeding, and UBA1067 spp. (positively selected: 33.3%–48.5%; negatively selected: 0%–8.3%) under grain feeding. These lineages encoded catalytic domains appended with carbohydrate-binding modules, such as tandem carbohydrate-binding modules linked to glycoside hydrolases, thereby enhancing substrate adhesion and degradation. In contrast, low-feed-efficiency bulls showed more random community structures and reduced functional specialization. Therefore, these suggest that cattle hosts with higher feed efficiency promote microbial populations functionally aligned with dietary inputs, a process we define as efficient host-mediated microbial amplification. These findings offer new insight into how ecological assembly and functional adaptation of the microbiome contribute to feed efficiency and lay the foundation for microbiome-informed strategies to enhance ruminant production sustainability.

The rumen microbiome is central to feed digestion and host performance, making it an important target for improving ruminant productivity and sustainability. This study investigated how feed composition influences rumen microbial abundance and phenotypic traits in beef cattle. Fifty-nine Angus bulls were assigned to forage- and grain-based diets in a randomized block design, evaluating microbial dynamics, methane emissions, and feed efficiency. Quantitative PCR (qPCR) quantified bacterial, archaeal, fungal, and protozoal populations. Grain-based diets reduced bacterial and fungal counts compared to forage diets (1.1 × 1011 vs. 2.8 × 1011 copies of 16S rRNA genes and 1.5 × 103 vs. 3.5 × 104 copies of 18S rRNA genes/mL, respectively), while protozoan and methanogen populations remained stable. Microbial abundance correlated with feed intake metrics, including dry matter and neutral detergent fiber intakes. Methane emissions were lower in grain-fed bulls (14.8 vs. 18.0 L CH4/kg DMI), though feed efficiency metrics showed no direct association with microbial abundance. Comparative analysis revealed adaptive microbial shifts in response to dietary changes, with functional redundancy maintaining rumen stability and supporting host performance. These findings provide insights into how feed composition shapes rumen microbial dynamics and host phenotypes, highlighting the functional adaptability of the rumen microbiome during dietary transitions.

Use of productivity-enhancing technologies (PET: growth hormones, ionophores, and beta-adrenergic agonists) to improve productivity has recently garnered public attention regarding environmentally sustainability, animal welfare, and human health. These consumer perceptions and increased demand for PET-free beef offer opportunities for the beef industry to target niche premium markets, domestically and internationally. However, there is a need to critically examine the trade-offs and benefits of beef raised with and without the use of PETs. This review contains a summary of the current literature regarding PET products available. The implications of their use on resource utilization, food safety and security, as well as animal health and welfare are discussed. Furthermore, we identified gaps in knowledge and future research questions related to the sustainability of these technologies in beef production systems. This work highlights the tradeoffs between environmental sustainability of beef and supplying the dietary needs of a growing population.

In Canada, approximately 11.2 million metric tons of avoidable food waste (FW) is produced per year. Preservation of a greater proportion of this FW for use as livestock feed would have significant environmental and socioeconomic benefits. Therefore, this study blended discarded fruits, vegetables, and bakery products from grocery stores into silage to assess the ability to preserve their nutritional value and contribute to the feed supply. Two treatments for reducing the water content of FW were evaluated, sun-dried (SD) and passive-dried (PD), and compared to control (C) using laboratory mini-silos over 60 days of ensiling. Although dry matter (DM) was increased by 1–5% for PD and SD, respectively, up to 41.9% of bread products were required to produce a targeted silage DM of 38%. All mature silages were high in crude protein (15.2 to 15.7%), crude fat (6.0 to 6.3%), sodium (0.48 to 0.52%), and sugars (0.95 to 1.53%) and were low in neutral detergent fiber (6.2 to 7.6%) as compared to traditional silages used as livestock feed. Mold and other signs of spoilage were visible on FW, but mycophenolic acid was the only mycotoxin above the limit of detection in material prior to ensiling. Plate counts of molds and yeasts declined (p < 0.001) by 5–7 log colony-forming units (CFU) over 60 days of fermentation and were not detected in mature silage. All silages were aerobically stable over 20 days. This study indicates that FW can produce good-quality silage but approaches other than SD and PD are required for increasing silage DM as insufficient bread products may be available for this purpose in all batches of FW.

The objective of this study was to evaluate the effect of dried distillers grains with solubles (DDGS) and red-osier dogwood (ROD) extract on in vitro fermentation characteristics, nutrient disappearance, and microbial profiles using the rumen simulation technique. The experiment was a completely randomized design with a 2 × 2 factorial arrangement of treatments and four replicates per treatment. A basal diet [10% barley silage, 87% dry-rolled barley grain, and 3% vitamin and mineral supplement, dry matter (DM) basis] and a DDGS diet (as per basal diet with 25% of wheat DDGS replacing an equal portion of barley grain) were supplemented with ROD extract at 0 and 1% (DM basis), respectively. The experimental period was 17 d, consisting 10 days of adaptation and 7 days of data and sample collection. The substitution of wheat DDGS for barley grain did not affect gas production; disappearances of DM, organic matter, and crude protein; total volatile fatty acid (VFA) production; and microbial protein production. However, replacing barley grain with wheat DDGS increased ( P = 0.01) fermenter pH and molar proportion of branched-chain VFA, switched ( P = 0.06) the fermentation pattern to higher acetate production due to increased ( P = 0.01) disappearance of neutral detergent fiber (NDF), and decreased ( P = 0.08) methane (CH 4 ) production. In the basal barley diet, the ROD extract increased the acetate to propionate (A:P) ratio ( P = 0.08) and reduced the disappearance of starch ( P = 0.06) with no effect on any other variables. No effects of ROD in the DDGS diet were observed. The number of operational taxonomic unit (OTUs) and the Shannon diversity index of the microbial community had little variation among treatments. Taxonomic analysis revealed no effect of adding the ROD extract on the relative abundance of bacteria at the phylum level with either the basal diet or DDGS diet, while at the genus level, the microbial community was affected by the addition of both DDGS and the ROD extract. Prevotella and Fibrobacter were the most abundant genera in the basal diet; however, Treponema became the most abundant genus with the addition of the ROD extract. These results indicated that the substitution of wheat DDGS for barley grain may mitigate enteric CH 4 emissions. The trend of reduced starch fermentability and increased NDF disappearance with the addition of ROD extract suggests a reduced risk of rumen acidosis and an improvement in the utilization of fiber for cattle-fed high-grain diet.

Abstract The objective of this study was to evaluate the effects of using conventional productivity-enhancing technologies (PETs) with or without other natural PETs on the growth performance, carcass traits, and environmental impacts of feedlot cattle. A total of 768 cross-bred yearling steers (499 ± 28.6 kg; n = 384) and heifers (390 ± 34.9 kg; n = 384) were offered a barley grain-based basal diet and divided into implanted or non-implanted groups. Steers were then allocated to diets that contained either: (i) no additive (control); natural feed additives including (ii) fibrolytic enzymes (Enz), (iii) essential oil (Oleo), (iv) direct-fed microbial (DFM), (v) DFM + Enz + Oleo combination; conventional feed additives including (vi) Conv (monensin, tylosin, and beta-adrenergic agonists [βAA]); or Conv with natural feed additives including (vii) Conv + DFM + Enz; (viii) Conv + DFM + Enz + Oleo. Heifers received one of the first three dietary treatments or the following: (iv) probiotic (Citr); (v) Oleo + Citr; (vi) Melengesterol acetate (MGA) + Oleo + βAA; (vii) Conv (monensin, tylosin, βAA, and MGA); or (viii) Conv + Oleo (ConvOleo). Data were used to estimate greenhouse gas (GHG) and ammonia (NH3) emissions, as well as land and water use. Implant and Conv-treated cattle exhibited improvements in growth and carcass traits as compared to the other treatments (P < 0.05). Improvements in the performance of Conv-cattle illustrated that replacing conventional feed additives with natural feed additives would increase both the land and water required to satisfy the feed demand of steers and heifers by 7.9% and 10.5%, respectively. Further, GHG emission intensity for steers and heifers increased by 5.8% and 6.7%, and NH3 emission intensity by 4.3% and 6.7%, respectively. Eliminating the use of implants in cattle increased both land and water use by 14.6% and 19.5%, GHG emission intensity by 10.5% and 15.8%, and NH3 emission intensity by 3.4% and 11.0% for heifers and steers, respectively. These results demonstrate that the use of conventional PETs increases animal performance while reducing the environmental impacts of beef production. Restricting use would increase the environmental footprint of beef produced for both domestic and international markets.