Effect of ground soybean and starch on intake, digestibility, performance, and methane production of Nellore bulls

Meta-analysis quantifying the potential of dietary additives and rumen modifiers for methane mitigation in ruminant production systems

Increasingly countries are seeking to reduce emission of greenhouse gases from the agricultural industries, and livestock production in particular, as part of their climate change management. While many reviews update progress in mitigation research, a quantitative assessment of the efficacy and performance-consequences of nutritional strategies to mitigate enteric methane (CH₄) emissions from ruminants has been lacking. A meta-analysis was conducted based on 108 refereed papers from recent animal studies (2000–2020) to report effects on CH₄ production, CH₄ yield and CH₄ emission intensity from 8 dietary interventions. The interventions (oils, microalgae, nitrate, ionophores, protozoal control, phytochemicals, essential oils and 3-nitrooxypropanol). Of these, macroalgae and 3-nitrooxypropanol showed greatest efficacy in reducing CH₄ yield (g CH₄/kg of dry matter intake) at the doses trialled. The confidence intervals derived for the mitigation efficacies could be applied to estimate the potential to reduce national livestock emissions through the implementation of these dietary interventions.

Pasture intensification in beef cattle production can affect methane emission intensity

Increasing greenhouse gas (GHG) emissions from anthropogenic activities have contributed to global warming and consequently to climate change. Among all sources of emissions, the agricultural sector accounts for just under a quarter, mainly because of the intensification of food production systems necessary to supply the growing demand of the population. As ruminal fermentation is the largest source of methane emission in the livestock industry, emission by cattle has become the focus of studies. The aim of this study was to evaluate enteric methane emission and emission intensities of Nellore cattle at different ages submitted to levels of intensification of the grazing system. Twenty-four animals per cycle (age of 21.8 and 13.1 mo in cycles 1 and 2, respectively) were randomly distributed across different grazing systems: irrigated pasture with a high stocking rate (IHS), dryland pasture with a high stocking rate (DHS), recovering dryland pasture with a moderate stocking rate (DMS), and degraded pasture with a low stocking rate (DP). Methane emission was measured using the sulfur hexafluoride technique in each season of the cycle. Intensive systems provided higher yields of good-quality forage as well as superior animal performance when compared with DP. Methane yields were different between seasons and cycles. Methane emissions per average daily weight gain and dry matter digestible intake were different between treatments. Differences in the results were observed when they were analyzed per hectare, with the highest gain yield (P = 0.0134), stocking rate, weight gain, carcass production, and total methane emission (P < 0.0001) being found for the intensive systems. There were no differences in emissions per weight gain or carcass production between production systems, while a difference was observed between cycles (P = 0.0189 and P = 0.0255, respectively), resulting in lower emission intensities for younger animals. We conclude that more intensive systems resulted in a higher kilograms production of carcass per hectare; however, animals at 19 mo of age raised in the IHS and DMS systems had a lower emission intensity in kilogram of CO2-eq. per kilogram of carcass. Moderate intensification (DMS) using animals at about 19 mo of age might be an effective strategy to mitigate GHG emissions from Brazilian tropical pastures. Further studies are needed to understand the relationship between increasing productivity and decreasing environmental impacts, especially methane emission from ruminants.

Effects of soybean meal versus processed whole soybean diets on the performance of young bulls and the fatty acid composition of intramuscular fat

Context It is hypothesised that the use of processed soybean for feedlot beef cattle improves feed efficiency and produces beef with a better fatty acid profile for human health. Aims This study aimed to evaluate average daily gain, feed efficiency, carcass traits, chemical composition, fatty acid profile and colour in the beef of young bulls fed diets with ground or extruded soybean. Methods A total of 60 young Zebu bulls (Nellore or Nellore crossed with other Zebu breeds) with an average initial liveweight of 320 ± 8.12 kg and an average initial age of 20 ± 2 months were randomly assigned to receive one of the following diets for 84 days: dehulled and defatted soybean meal (3.22% of ether extract), ground soybean (6.51% of ether extract) or extruded soybean (6.37% of ether extract). The fatty acid profiles of these animals were analysed using high-resolution gas chromatography. The CIE L*a*b* colour space model was used to numerically describe the colour during the aging period (0, 7, 14 and 21 days). Key results Diet had no effect on the average daily gain, feed efficiency or carcass traits of the animals (P &gt; 0.05). Protein, ether extract and ash composition of the Longissimus lumborum (LL) muscle were not affected (P &gt; 0.30) by the use of processed soybean grains. The ground soybean diet decreased oleic acid and C18:2 c9, t11 concentrations, but increased C18:2 t10, c12 and trans-octadecenoic acid isomer concentrations in the LL muscle compared with those in the dehulled and defatted soybean meal and extruded soybean diets (P &lt; 0.05). Muscle from bulls fed processed soybean exhibited greater concentrations of stearic acid and saturated fatty acids, and a lower concentration of unsaturated fatty acids, as well as a decreased unsaturated fatty acids:saturated fatty acids ratio (P &lt; 0.05). Processed soybean grains did not affect (P &gt; 0.05) the LL muscle pH or colour. Conclusions The use of ground or extruded soybean did not affect the performance, carcass traits, LL protein, ether extract or ash composition, and had no impact on beef colour compared with the diet containing soybean meal. Processed whole soybeans in the diet did not increase unsaturated fatty acids or conjugated linoleic acid in beef compared with a diet without soybean meal. Implications Up to 20% of ground or extruded soybean in feedlot beef cattle can be used as a replacement for soybean meal and corn.

Effect of substituting soybean meal with euglena (Euglena gracilis) on methane emission and nitrogen efficiency in sheep

This study evaluated methane (CH4 ) emission, intake, digestibility, and nitrogen efficiency in sheep fed diets containing replacement levels (0%, 33%, 50%, and 67% of soybean meal with euglena). In this experiment, four Corriedale wether sheep with an initial body weight of 53.8 ± 4.6 were arranged in a 4 × 4 Latin square design. This experiment lasted 84 days, divided into four experimental periods. Each period lasted 21 days, which consists of 14 days of adaptation to the diets, 5 days to collect samples, and 2 days to collect gas emission from sheep. Methane emission expressed as L/kg DM intake or g/kg DM intake reduced by up to 37% and the energy loss via CH4 (% of GE intake) reduced by up to 34%. No differences (p > 0.05) were observed in DM and OM intake and whole tract apparent DM digestibility due to substitution of soybean meal with euglena. The total CP loss reduced significantly (linear, p < 0.001) and CP efficiency increased linearly (p = 0.03) with increasing concentration of euglena. As a result, nitrogen balance and average daily weight gain remained unchanged despite higher nitrogen concentration in soybean supplemented group. In conclusion, substitution of soybean meal with euglena reduced methane emission without affecting the performance of animals.