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Simple Summary: The beef industry faces significant challenges in increasing red protein production given the growing population, with projections to be approximately 28% higher by 2050. Additionally, there are increasing government and public pressures for all industries to mitigate greenhouse gases, which include methane. The livestock industry contributes approximately 14.5% of greenhouse gas emissions attributed to human activities. This study investigated the combination of the methane inhibitor 3-nitrooxypropanol with monensin sodium or a feed additive package consisting of essential oils, 25-Hydroxy-Vitamin-D3, an active metabolite of vitamin D3, and carbo-amino-phospho-chelated minerals such as chromium and zinc. The results showed that 3-nitrooxypropanol, regardless of the combination used, reduced daily enteric methane emissions by over 38%, in addition to increasing feed conversion by over 6% when combined with monensin sodium compared to the treatment without 3-nitrooxypropanol. Furthermore, the combination of 3-nitrooxypropanol with the additive package showed better conditions in growth performance, carcass traits, meat quality, blood parameters, and nutrient intake and digestibility. This offers the meat industry more nutritional strategies to meet the growing demand for protein while reducing environmental impacts. The objective of this study was to evaluate the effect of 3-nitrooxypropanol (3-NOP) in combination with different feed additives on growth performance, carcass traits, meat quality, enteric methane (CH4) emissions, nutrient intake and digestibility, and blood parameters in feedlot beef cattle. In experiment (Exp.) 1, one hundred sixty-eight Nellore bulls (initial bodyweight (BW) 410 ± 8 kg) were allocated to 24 pens in a completely randomized block design. In Exp. 2, thirty Nellore bulls (initial BW 410 ± 3 kg) were allocated to a collective pen as one group, and treatments were allocated in a completely randomized design. Three treatments were applied: Control (CTL): monensin sodium (26 mg/kg of dry matter, DM); M3NOP: CTL with 3-NOP (100 mg/kg DM); and Combo: 3-NOP (100 mg/kg DM) with essential oils (100 mg/kg DM), 25-Hydroxy-Vitamin-D3 (0.10 mg/kg DM), organic chromium (4 mg/kg DM), and zinc (60 mg/kg DM). In Exp. 1, bulls in the Combo group had greater (p < 0.01) dry matter intake (DMI) at d 28 compared to the CTL and M3NOP groups. During d 0 to 102, bulls' final BW and average daily gain (ADG) were greater (p ≤ 0.03) for the Combo group compared to the CTL. The bulls in the Combo and M3NOP groups had better (p < 0.01) feed conversion (FC) and feed efficiency (FE) compared to the CTL. Hot carcass weight (HCW), carcass ADG, and carcass yield were greater (p ≤ 0.05) for bulls in the Combo group compared to the CTL and M3NOP groups. The bulls in the Combo group had greater (p = 0.01) dressing compared to the M3NOP group. Combo bulls had better (p = 0.02) biological efficiency compared to the CTL. The bulls in the Combo group had lower (p < 0.01) carcass pH compared to the CTL and M3NOP groups. In Exp. 2, bulls in the Combo group had greater (p = 0.04) DMI at d 28 compared to the CTL and had greater (p < 0.01) DMI at d 102 compared to the CTL and M3NOP groups. The bulls in the Combo group had greater (p = 0.04) HCW compared to the CTL and M3NOP groups and carcass ADG was greater (p = 0.04) for bulls in the Combo group compared to the M3NOP group. The bulls in the Combo and M3NOP groups had lower (p < 0.01) CH4 production (38.8%, g/d), yield (41.1%, g/kg DMI), and intensity (40.8%, g/kg carcass ADG) and higher (p < 0.01) H2 emissions (291%, g/d) compared to the CTL. Combo bulls had lower (p < 0.01) blood glucose and insulin, and higher nutrient intake and digestibility (p ≤ 0.05) compared to the CTL and M3NOP groups. Combining 3-NOP with different feed additives improved FC and FE, and reduced enteric CH4 emissions. Combo treatment improved growth performance, carcass traits, nutrient intake, and digestibility, and improved glucose and insulin responses in feedlot beef cattle on a high-concentrate finishing diet. [ABSTRACT FROM AUTHOR]

Two studies were carried out, the first with the objective to evaluate performance, beef quality and expression of genes involved in lipid metabolism in the muscle of bulls fed with or without low-fat dried distillers grains with solubles (DDGS, 21% DM) in the diet. In the second, eight rumen-fistulated bulls were assigned in a switch back design to evaluate the fatty acid profile of omasal fluid. We hypothesized that bulls fed DDGS may have an improved fatty acid profile and expression of genes involved in lipid metabolism may be altered, without affecting performance. Bulls fed DDGS had greater (P <.05) concentrations of PUFA n-6 in the omasum and muscle. CLA t10, c12 content was higher and there was lower expression of the LPL gene (P =.05) in the muscle of animals fed DDGS (P =.03). In conclusion, DDGS can be used as a protein feedstuff because it maintains beef quality. [ABSTRACT FROM AUTHOR]

Typical successions in land use affect the dynamics of carbon (C) and nitrogen (N) in the soil. This study aimed to determine the effects of land use change on soil organic carbon and N content and stocks in pastures, crops, and forests in the Amazon. Soil C and N stocks were assessed at depths of 30 and 100 cm to determine 13C isotopic abundance. The concentrations of C and N in crops were lower (p < 0.05) than those in other land use types. Soil organic C and soil N stocks for pasture (67.6, 144.8, 5.7, and 13.3) and forest (77.1, 137.5, 6.3, and 13.8) systems were similar, but greater than those of the crop area (36.4, 63.9, 3.0, and 6.0), regardless of depth (30 and 100 cm for C and N). Land use change for pastures in the Arc of Deforestation region of the Amazon maintains SOC and N stocks in the soil and is more sustainable than the agricultural system with black pepper, as long as the conditions of soil, climate, and cultivation are similar. Part of the C3-derived carbon from the forest was replaced by C4-derived C from grasses at soil depths up to 100 cm. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of supplementation with non-protein nitrogen (NPN) or ruminal undegradable protein (RUP) on intake, digestibility, and amino acid (AA) use efficiency of Nellore cattle grazing during the dry season. Eight Nellore steers (12 ± 2 months old) were used in quadruplicate Latin squares (2 × 2). The animals were placed on Urochloa brizantha cv. Xaraés under continuous grazing. The treatments included the following: (1) urea supplementation (NPN) and (2) supplementation of corn gluten meal 60 (CGM, RUP). Animals supplemented with CGM showed higher intakes of dry matter (DM) supplement, total AA, essential AA, and individual AA. The supplementation did not affect the total AA digestibility, total AA flux, and the AA fluxes of microbial origin and RUP from the diet (p > 0.05). The ruminal microorganism origin flux of total AA to the duodenum was 44.5% and 52.7% for animals supplemented with NPN and CGM, respectively. Animals supplemented with CGM showed an increase in blood concentrations of isoleucine (+19.09 μmol/L), cystine (+27.29 μmol/L), and albumin (+0.11 g/dL) (p < 0.05), but this increase was not accompanied by an improvement in N use efficiency of steers (p > 0.05). RUP supplementation via CGM can be an efficient nutritional strategy to enhance the intake and absorption of AA by Nellore cattle grazing low-quality forage during the dry season. [ABSTRACT FROM AUTHOR]

Animal supplementation during the background phase may increase greenhouse gas emissions (GHG). The inclusion of tannins in the diet of Nellore bulls can mitigate nitrous oxide (N2O), methane (CH4), and ammonia (NH3) production. The objective of this study was to quantify the effect of energy supplementation associated with sources of tannins in the diet of young Nellore bulls backgrounded in pastures with N2O, CH4, and NH3 emissions. Two experiments were conducted in a completely randomized design. The treatments were three supplementation strategies: (1) soybean hulls 0.3% of body weight (BW), (2) sorghum grain 0.3% of the BW, and (3) peanut peel 0.3% of BW, the last two being sources of tannin. The static closed chambers method was used to quantify N2O and CH4 emissions and the semi-open chamber technique to estimate NH3 volatilization. Supplementation strategies did not affect the N2O emissions (p = 0.9116). The soil water-filled pore space explained the variation in the N2O fluxes (p = 0.0071). The treatments did not change the total CH4 emissions (p = 0.3599), and no explanatory variable was correlated with the CH4 fluxes. The NH3 volatilization did not vary according to the supplements or tannin inclusion (p = 0.5170). However, the type of excreta affected the NH3 volatilization (p < 0.0001). Ammonia volatilization averaged 14.05, 4.16, and 2.25% of the applied N for urine, urine + dung, and dung, respectively. The energetic supplementation of Nellore bulls containing sources of tannins in the evaluated dosages was not a mitigation strategy for the emissions of N2O, CH4, and NH3. [ABSTRACT FROM AUTHOR]

Context: Energy supplementation with highly fermentable carbohydrates can be a strategy to maximise the efficiency of nitrogen use (ENU) from high-nutritional value forages. Aims: The study aimed to investigate the independent or associated effects of two diurnal feeding times (0900 or 1700 hours) with two sources of energy supplementation (corn or citrus pulp) in the growing of F1 Angus × Nellore young bulls on palisade grass pastures, and their implications on the forage chemical composition, nutrient intake and digestibility, ENU, microbial protein synthesis, animal performance, and gain per area. Methods: There were 36 bulls used as experimental animals, with initial bodyweight (BW) of 290 ± 5 kg, and 32 similar bulls were used in a put-and-take system to maintain sward characteristics. The experiment was conducted in a complete randomised design with four treatments and three replications (paddocks). The treatments consisted of energy supplementation at 0.3% BW with corn or citrus pulp fed at 0900 or 1700 hours for four periods of 28 days. For evaluation of ruminal and blood parameters, ENU, intake, and nutrient digestibility, eight ruminal cannulated 1/2 Aberdeen Angus × 1/2 Nellore young bulls were used, with 280 ± 7 kg of initial BW, distributed in a 4 × 4 double Latin square design, consisting of four periods and four treatments. Key results: Supplementation at 0.3% of BW with corn or citrus pulp at 0900 or 1700 hours can reach up to 1.06 kg/day of young bulls reared on palisade grass pastures fertilised with 180 kg nitrogen/ha/year and managed at 25 cm of height compared with corn-based supplements. There were no effects on microbial protein synthesis or its efficiency. Conclusions: Citrus pulp can be used as an alternative energy source to corn, because it has the same potential for animal performance, ENU and microbial protein synthesis in tropical pastures with a high proportion of soluble protein, and structural and non-fibrous carbohydrates with high dry matter digestibility. Implications: Supplementing grazing beef cattle at 0.3% BW with corn or citrus pulp in the morning or afternoon is an efficient nutritional strategy to improve animal performance. Different responses of energy supplementation to grazing beef cattle may occur due to the type of energy substrate and the supplementation time. Citrus pulp supplied in the afternoon can improve beef cattle performance. Citrus pulp can replace corn as an energy supplement and it is a non-human edible food. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the emission factor of N2O, CH4, and the volatilization of NH3 for the combination of feces or urine with increasing doses of ammonium nitrate in tropical palisade grass pastures. The emission of greenhouse gases was assessed in eight treatments combining feces and urine with doses (75 and 150 kg of N ha−1) of ammonium nitrate, (32% N). The emission factor of N2O was 0.11, 0.19, and 0.17% for feces, urine, and 75 kg N ha−1 year−1 (as ammonium nitrate) and showed an additive linear effect when feces or urine were combined with increasing doses of N fertilizer. The emission factor of CH4 of feces (0.18 kg CH4 animal−1 year−1) was similar irrespective of combination with ammonium nitrate. The N loss by volatilized NH3 has a decreasing linear effect (p < 0.05) for the combination of feces or urine with ammonium nitrate. We concluded that N2O and CH4 emission factors of feces and urine in tropical climate conditions are lower than those reported by the IPCC. However, their N2O emission factors are sharply enhanced when combined with ammonium nitrate. These results may contribute to improvements in national and regional greenhouse gas inventories of livestock production. [ABSTRACT FROM AUTHOR]

Grazing management and N-fertilizer have been reported to improve tropical forage productivity and quality, however, their effect on methane emission of grazing animals remains uncertain. Therefore, this study aimed to assess the effects of increasing application rates of nitrogen (N) fertilization of Marandu palisadegrass under continuous stocking on intake, digestibility, nitrogen balance, and enteric methane emissions of Nellore growing bulls. We hypothesized that changes in the forage nutritive value caused by N fertilization of pastures combined with adequate grazing management (e.g. greater crude protein [ CP ] and digestibility) would lead to an increase in animal productivity (e.g. greater average daily gain [ ADG ] and gain per area), and then, to a decrease in methane emission intensity. Treatments consisted of different annual application rates of nitrogen fertilization: 0, 75, and 150 kg N/ha using ammonium nitrate (32% N) as the nitrogen source. The experimental design was completely randomized, with three treatments and four replications (12 paddocks). Intake, digestibility, N balance, and methane emissions were measured in eight animals per treatment. CP intake, digestibility and N balance increased linearly with the increase in N fertilization (P < 0.05). In addition, stocking rate (SR) and ADG linearly increased from 1.75 animal unit (AU = 450 kg)/ha and 0.62 kg/d (0 kg N/ha) to 3.75 AU/ha and 0.82 kg/d (150 kg N/ha), respectively. Individual methane emissions nor methane emission intensity were affected by treatment with an average of 164.7 g/d and 199.7 g/kg ADG (P > 0.05). Annual N fertilization with ammonium nitrate between 75 and 150 kg N/ha in palisadegrass pastures under continuous stocking enhances animal performance per unit area yet not affecting neither methane production nor intensity. [ABSTRACT FROM AUTHOR]

Abstract: Two experiments were conducted to evaluate effects of tannin levels in sorghum silages supplemented, or not, with polyethylene glycol (PEG) on silage chemical composition and fermentative characteristics as well as aerobic stability of silages supplemented with urea or concentrate. A completely randomized experimental design was applied in both experiments. Silages without PEG had higher CP levels and lower ammonia N concentration (81.8g/kg DM and 55.3g/kg N, respectively) as compared to silages with PEG (70.6 and 63.4, respectively). High-tannin sorghum levels were not able to maintain silage aerobic stability, probably due to their low concentrations in the silages. [Copyright &y& Elsevier]

The aim of this study was to evaluate a commercial sensor—a three-axis accelerometer—to predict animal behavior with a variety of conditions in tropical grazing systems. The sensor was positioned on the underjaw of young bulls to detect the animals' movements. A total of 22 animals were monitored in a grazing system, during both seasons (wet and dry), with different quality and quantity forage allowance. The machine learning (ML) methods used were random forest (RF), convolutional neural net and linear discriminant analysis; the metrics used to determine the best method were accuracy, Kappa coefficient, and a confusion matrix. After predicting animal behavior using the best ML method, a forecast for animal performance was developed using a mechanistic model: multiple linear regression to correlate intermediate average daily gain (iADG) observed versus iADG predicted. The best ML method yielded accuracy of 0.821 and Kappa coefficient of 0.704, was RF. From the forecast for animal performance, the Pearson correlation was 0.795 and the mean square error was 0.062. Hence, the commercial Ovi-bovi sensor, which is a three-axis accelerometer, can act as a powerful tool for predicting animal behavior in beef cattle production developed under a variety tropical grazing condition. [ABSTRACT FROM AUTHOR]

• Condensed tannins are an efficient natural and organic compound to increase nitrogen use efficiency. • Pasture composition directly influences the supplementation strategy used and the response to the supplement. • Peanut skin is an efficient alternative supplement for pasture ruminant diets. • Alternative energy feedstuff supplementation increases animal performance and gain per area. This study aims to investigate the effects of alternative energy feedstuff supplementation containing condensed tannin (CT) on palisade grass pastures, focusing on intake, nutrient digestibility, animal performance, ruminal and blood parameters, nitrogen use efficiency (NUE), and its impacts on the ruminal bacterial community in backgrounding Nellore young bulls. Two experiments were conducted simultaneously. Animal performance was evaluated in Experiment 1. The experimental design was a completely randomized block; ninety Nellore bulls (Bos taurus indicus) with an average initial body weight (BW) of approximately 240 ± 5 kg were used (64 as testers and 26 as regulators). The feed intake, digestibility of dry matter and nutrients, ruminal parameters, NUE, and the impact on the ruminal bacterial community were evaluated in Experiment 2. The experimental design was a 4 × 4 double Latin square involving eight Nellore bulls with an average initial BW of 290 ± 8 kg, all of which were cannulated in the rumen. The treatments consisted of energy supplementation at 0.3 % of BW with peanut skin (PS), 0.3 % of BW with sorghum grain (SG), 0.3 % of BW with soybean hulls (SHs), and a control treatment with a supply of mineral salt ad libitum. The total digestible nutrient intake was lower in animals that received only mineral supplements (p < 0.005). The dry matter (DM) intake decreased with treatment PS, while the DM and nutrient digestibility increased (p < 0.005). There was a reduction in ruminal ammonia nitrogen and an improvement in NUE in the PS treatment (p < 0.005). However, the bacterial and Archaea populations were unaffected (p = 0.619). Individual animal performance and gain per kg were increased in the treatment with supplements containing or without CT compared to the mineral supplement (p < 0.001). The NUE improved in treatments PS, SG, and SH (p < 0.01). Feedstuff supplementation using no edible foods by products containing CTs is an effective alternative energy source for Nellore bulls grazing on palisade grass during the rainy season. Additionally, it can be used to mitigate the environmental impacts of N excretion. [ABSTRACT FROM AUTHOR]

The effects of nitrogen (N) fertilization levels on protein and carbohydrate fractions in Marandu palisadegrass pasture [Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster] were investigated in a pasture over five years. The experimental design was completely randomized with four levels of N (0, 90, 180, and 270 kg N ha-1, as urea) for five years, and with three replicates. The study was conducted in a continuously stocked pasture during the forage growing season (December to April) in a tropical region. The effects of N fertilization were similar across the five years. With increasing N fertilization, the concentrations of crude protein (CP) increased from 103 to 173 g kg−1 (P < 0.001), soluble fractions (Fraction A + B1) increased from 363 to 434 g kg−1 of total CP (P = 0.006); neutral detergent fiber (NDF) decreased from 609 to 556 g kg−1 (P = 0.037); indigestible NDF (P = 0.046), potentially degradable neutral detergent fiber (P = 0.037), and acid detergent fiber decreased (P = 0.05), and total digestible nutrient (TDN) increased (P < 0.001). Increasing N fertilization decreased the concentrations of Fraction C (P = 0.014) and total carbohydrates (P < 0.0001), and increased CP:organic matter digestibility (P < 0.01). Concentrations of neutral detergent fiber free of ash and protein (P = 0.003), indigestible neutral detergent fiber (P < 0.001), neutral detergent fiber potentially degradable (P = 0.11), CP (P < 0.001), Fraction A + B1 (P < 0.001), Fraction B2 (P < 0.001), Fraction B3 (P < 0.01), and non-structural carbohydrates differed (P < 0.001) across years. Therefore, N fertilization can be used to increase CP, soluble protein, and TDN. [ABSTRACT FROM AUTHOR]

To evaluate the foraging behaviour of yearling bulls grazing on Marandu grass, we conducted two experiments. In the first experiment (Exp. 1), three grazing heights of 15, 25, and 35 cm were evaluated, with bulls receiving 0.3% of body weight (BW) of supplement (161 g kg-1 crude protein (CP) and 20.1 MJ kg-1 gross energy (GE)); in the second experiment (Exp. 2), supplementation levels were decreased as grazing height increased: (1) low height (15 cm) and high supplementation (0.6% BW: 142 g kg-1 CP and 18.9 MJ kg-1 GE (LH-HS)); (2) moderate height (25 cm) and moderate supplementation (0.3% BW: 161 g kg-1 CP and 20.1 MJ kg-1 GE (MH-MS)) or (3) high height (35 cm) without supplementation (HH-WS). Ingestive behaviour was evaluated by direct visual observations, and intake using markers. It was used 9 paddocks each experiment. The experimental design was completely randomized, analysing effects by polynomial orthogonal contrasts (Exp. 1) and Tukey test (Exp. 2). In Exp. 1, a linear decreasing response to daily grazing time (P <0.01) was observed, whereas a linear increasing response to herbage intake (P <0.01) was observed with increased grazing height. In Exp. 2, LH-HS bulls had lower herbage intake (P <0.01) than their counterparts. Bulls from both experiments showed increased grazing activity after 12 PM (P <0.05). The herbage intake substitution effect of supplements can be explored as a production strategy, as the adjustment of supplementation levels can promote high dry matter intake as well as performance in beef cattle, in conditions of low grazing height or low forage allowance, even with a high stocking rate. [ABSTRACT FROM AUTHOR]

Soil moisture and compaction, and source of N and bovine urine can reduce methane (CH4) rates from agricultural soils. However, the magnitude of the effect is unknown in tropical soil under different conditions, as well as the potential of different urine-N concentration, volume, and sources of N in such an effect. This study aimed to investigate the effects of different soil conditions (moist, dry, compacted, moist-dung, moist-dung-compacted), N concentration in urine (2.5, 5.0, 10.0, and 15.0 g N L−1), volume of urine (25, 50, 100, and 200 ml kg−1 dry soil), and source of N (ammonium, nitrate, and urea) on CH4 emissions. A tropical Ferralsol soil from marandu-grass pasture was incubated during 106 days and the CH4 concentration determined by gas chromatography. The CH4 rates varied significantly according to the soil conditions when manipulated the urine-N (p < 0.01) and averaged 0.75, − 0.50, 1.14, 6.23, and 8.17 μg C–CH4 m−2 h−1for the moist, dry, compacted, moist-dung, and moist-dung-compacted soil, respectively, and, not responded to the level of N (p = 0.73) averaging 2.57 μg C–CH4 m−2 h−1. When evaluated, the volumes of urine cumulative CH4 averages were − 0.52, − 1.24, − 0.88, 14.48, and 18.56 μg C–CH4 m−2 h−1 for the moist, dry, compacted, moist-dung, and moist-dung-compacted, respectively. Soils were affected by soil treatments (p < 0.001) but not by urine volumes (p = 0.30). The source of N did not influence the CH4 rates (p = 0.1) averaging 0.88, − 1.26, and − 1.19 μg C–CH4 m−2 h−1 respectively, for urea, nitrate, and ammonium. The CH4 fluxes in tropical Ferralsols are controlled by the soil characteristics and dung addition. [ABSTRACT FROM AUTHOR]

Organic additives are recently being used in animal diets owing to their ability to control metabolic issues and result in better animal performance. Specifically, the organic additive Fator P® presents an additional advantage that is to cause a lesser greenhouse gas emission. This study evaluated whether Fator P® intake changes ruminal parameters or animal performance of beef cattle. Evaluations were carried out in a feedlot experiment divided into growing (46 days; two diets [control mix—CM and standard mix—SM] and finishing (lasted 83 days; four diets: CM, SM, Fator P® + virginiamycin, and Fator P® alone [FP]) trials. Animal performance study involved 48 animals allocated to 12 collective pens in completely randomized experimental design. Ruminal parameters were evaluated in separate metabolism study developed carried out using individual pen with four steers. During growing trial, FP diet resulted in higher (p < 0.05) dry matter intake (DMI) and ruminating time. In the finishing trial, diets containing Fator P® resulted in higher DMI than obtained with CM. Most of the ruminal parameters did not differ (p > 0.05) among dietary treatments. Therefore, Fator P® represents a viable and safe strategy for supplementation to beef cattle finished using high‐concentrate diet in feedlot systems. [ABSTRACT FROM AUTHOR]

Highlights • Tropical pasture management using 95% LI allow high efficiency utilization. • The management used resulted higher NDFpd intake from herbage. • The combining of supplements and height sward not alter animal metabolic parameters. • The nutrient digestibility were similar among the treatments evaluated. Abstract Improving animal performance on pasture requires grazing management that optimizes forage intake in combination with the appropriate supplementation strategy. The objective was to determine the effects of sward canopy height and level of supplementation on forage intake, digestibility, and ruminal fermentation kinetics of Nellore steers in a double Latin square design with repeated measures. Treatments were three sward heights with differing levels of supplementation and included: (1) short height with high supplementation (SH-HS, 15 cm and 0.6% BW); (2) short height with moderate supplementation (SH-MS, 15 cm and 0.3% BW); (3) moderate height with moderate supplementation (MH-MS, 25 cm and 0.3% BW); (4) moderate height with low supplementation (MH-LS, 25 cm and 0.1% BW); (5) tall height with low supplementation (TH-LS, 35 cm and 0.1% BW); and (6) tall height with no supplementation (TH-WS, 35 cm). Intake of crude protein and total digestible nutrients was greater (P < 0.05) with tall swards and moderate supplementation rates. Nutrient digestibility among treatments did not differ (P ≥ 0.21), possibly due to the availability of high-quality forage during the wet season. Likewise, rate of neutral detergent fiber degradability did not differ (P ≥ 0.19) among treatments. Ruminal ammonia nitrogen differed (P = 0.02) among treatments with moderate supplementation having the greatest (SH-MS) and lowest (MH-MS) concentrations (13.6 and 9.7 mg/dL, respectively). Ruminal pH and volatile fatty acid concentrations did not differ (P ≥ 0.18) among treatments. Microbial N flow to the small intestine and efficiency of microbial synthesis exhibited a quadratic response with moderate sward height treatments having greater values. With these treatments and under the conditions of this study, various combinations of sward height and supplementation level did not alter rumen fermentation kinetics. [ABSTRACT FROM AUTHOR]

Increasing attention is being paid to the importance of N 2 O emissions due to livestock activities in tropical countries. Understanding the key variables driving N 2 O emission could help minimize impacts of N 2 O release and improve the accuracy of N 2 O inventories. We aimed to investigate the effects of soil moisture, soil compaction, urine composition, urine volume, and dung addition on N 2 O emissions from a urine-treated tropical Ferralsol under controlled conditions. Manipulated soil conditions (e.g., moisture content, compaction, and dung addition) affected N 2 O emissions when varying quantities of urine-N ( p = 0.02) were applied (urine volumes remained equal) and when varying urine volumes ( p = 0.04) were applied (quantities of urine-N remained equal). When the amount of urine-N applied was varied, the estimated N 2 O emission factor (EF) was 3.14 ± 0.70%, 2.29 ± 1.25%, 3.90 ± 0.64%, 4.73 ± 0.88%, and 6.62 ± 1.10% for moist soil, dry soil, compacted soil, plus dung, and plus dung and compacted soil treatments, respectively. While varying the volume of urine, the estimated N 2 O EF was 4.96 ± 1.66%, 4.27 ± 1.42%, 3.99 ± 1.19%, 6.50 ± 0.35%, and 7.37 ± 0.76% for moist, dry soil, compacted soil, plus dung, and plus dung and compacted soils treatments, respectively. The urine-N concentration influenced N 2 O emissions ( p = 0.02) [which decreased linearly ( p = 0.062)] as well the volume of urine ( p < 0.01) [which increased linearly ( p < 0.01)]. The chemical form of the applied urine-N (urea, nitrate, or ammonium) did not affect N 2 O emissions and the emissions factor averaged 1.40 ± 0.38%. N 2 O production was affected by the KCl concentration in the urine ( p < 0.01), and the effect was curvilinear. The key driving factor affecting N 2 O emissions was soil moisture content. The N 2 O response varied when the urine volume differed (in both moist and dry soil conditions), and with the addition of dung. [ABSTRACT FROM AUTHOR]

Using condensed tannins (CT) in ruminant nutrition yields many benefits, especially regarding better dietary protein utilization and decreased methane (CH 4) emission by altering ruminal fermentation kinetics. A meta-analysis was conducted to develop and analyze a database from published studies and verify the effects of CT inclusion on enteric CH 4 emission by cattle, nutrient digestibility and ruminal parameters, and their interactions. The study aimed to develop regression equations based on the significant components and their interactions to target a specific ruminal CH 4 mitigation when correctly associating CT inclusion level and diet composition. A database was developed from 40 published studies that measured cattle CH 4 emission using in vitro or in vivo methods and reported the source and inclusion levels of CT as well as typical diet characteristics, including crude protein (CP), organic matter (OM), neutral detergent fiber (NDF), and ether extract (EE). Other related parameters were also included in the database when reported, such as dry matter intake (DMI) and digestibility, OM digestibility, NDF digestibility, and ruminal parameters, including pH, ruminal ammonia nitrogen, total volatile fatty acids (VFA), acetate, propionate, butyrate, and the acetate-to-propionate ratio. The meta-analysis was conducted by multiple linear regression, using the nlme package of R 4.2.1, in which studies were assumed as random variables affecting the intercept and slopes. The CH 4 emission, expressed in L/kg of DMI, decreased with increasing levels of dietary CT when in vitro and in vivo were analyzed together (P < 0.001) or in vivo alone (P < 0.001). Total VFA concentration (P = 0.049), propionate (P = 0.042), and butyrate (P = 0.047) increased with increasing levels of dietary CT on in vitro + in vivo methods, suggesting improved fermentability. When analyzing all chemical components of the diet, OM (P = 0.043) and CP (P = 0.010) decreased CH 4 production with in vitro methods, EE decreased CH 4 production on in vivo method (P = 0.001), while dietary NDF increased CH 4 production on in vitro + in vivo (P = 0.016), and also separately for in vivo (P = 0.058) and in vitro method (P = 0.022). There was an interaction between CT and CP for in vivo experiments (P = 0.010): CH 4 = 35.64 – 6.87 ×CT – 0.49 ×CP + 0.33 ×CT*CP. Across many experiments, increasing the level of dietary CT led to a decrease in ruminal CH 4 concentrations for in vitro and in vivo fermentation conditions and an increase in molar proportions of propionate, butyrate, and total VFA, indicating that it is an efficient natural alternative to reduce environmental impacts of ruminant production systems possibly. Our meta-analysis identified diet components that significantly affect enteric CH 4 emissions by cattle and developed a prediction model based on these components, including OM, CP, NDF, and EE. The in vivo CH 4 method showed that an interaction between CT and CP diet content affects CH 4 emissions. Future research and meta-analysis must focus on CT biological activity along with percent content to dictate ideal diet inclusion to suppress CH 4 emissions without depressing animal performance. • Condensed tannins are an efficient natural, organic additive to mitigate CH 4 emissions from cattle. • Diet composition directly influences CH 4 emissions. • Prediction models of CH 4 emissions based on CT and diet composition can determine mitigation strategies. [ABSTRACT FROM AUTHOR]

Integrated Systems (IS) have been identified as an efficient land-management strategy for restoring degraded areas worldwide, increasing crops and beef yields and providing technical potential for carbon (C) sequestration in soil and trees as an option for offsetting CH 4 and N 2 O emissions from cattle production. The aim of our study is to estimate the greenhouse gas (GHG) balance and the C footprint of beef cattle (fattening cycle) in three contrasting production scenarios on the Brachiaria pasture in Brazil—1) degraded pasture (DP), 2) managed pasture (MP), and 3) the crop-livestock-forest integrated system (CLFIS)—presenting new alternatives of land use as a GHG mitigation strategy. Area-scaled total GHG emissions were highest in MP (84,541 kg CO 2 eq ha −1 ), followed by CLFIS (64,519 kg CO 2 eq ha −1 ) and DP (8004 kg CO 2 eq ha −1 ) over a 10-yr period. Our results note that the highest C footprint of beef cattle was in the DP, 18.5 kg CO 2 eq per kg LW (live weight), followed by 12.6 kg CO 2 eq per kg LW in the CLFIS and 9.4 kg CO 2 eq per kg LW in the MP, without taking into account the technical potential for C sequestration in MP (soil C) and CLFIS (soil and Eucalyptus C). Considering the potential for soil C sequestration in the MP and CLFIS, the C footprint of beef cattle could be reduced to 7.6 and −28.1 kg CO 2 eq per kg LW in the MP and CLFIS, respectively. The conversion of the degraded pasture to a well-managed pasture and the introduction of CLFIS can reduce their associated GHG emissions in terms of kg CO 2 eq emitted per kg of cattle LW produced, increasing the production of meat, grains and timber. This reduction is primarily due to pasture improvement and increases in cattle yields and the provision of technical potential for C sinks in soil and biomass to offset cattle-related emissions. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of sources of soybean oil [ground soybean (GS), soybean oil (SO) and calcium salts of soybean oil (CS)] on DM intake (DMI), ingestive behaviour and average daily gain (ADG) of heifers grazing marandu palisadegrass (Brachiaria brizantha cv. Marandu) supplemented in two frequencies [daily and 3 days a week (Monday, Wednesday and Friday -- MWF)]. The experiment was conducted from July until November of 2007. Forty-two crossbred heifers (1/4 Nellore × 1/4 Santa Gertrudis × 1/2 Braunvieh), 17-months old and 297.1 kg ± 30.5 BW ± s.e.m., were used. Supplements were offered at 0.75% BW.day. Treatments were allocated in a completely randomised design and distributed in a factorial arrangement (3 × 2 -- SO from three different sources and two supplementation frequencies). Total DMI was greater in August and October (2.2 kg DM/kg BW) than in November (1.5 kg DM/kg BW). There was an effect of SO source on total DM, herbage and nutrients intake, but no effects of supplementation frequency. The animals supplemented with SO had greater DMI (P < 0.05) than the ones fed GS and CS. Average daily gain (0.580 g) was not affected by supplement sources or feeding frequency. Therefore, GS and CS are more efficient supplements. Supplementation frequency altered grazing time differently according to source. The MWF treatment resulted in a decreased grazing time when GS and SO were fed. However, in days when supplements were not offered, grazing time was increased for GS and CS. It was concluded that a decreased frequency of supplementation may be implemented without effect on weight gain and will reduce labour and machinery costs. [ABSTRACT FROM AUTHOR]

• Nitrogen fertilizer sources affect the fractionation of forage nitrogen compounds. • Sulfate and ammonium nitrate fertilizers increase nitrogen use efficiency by plants. • The lack of nitrogen fertilization can promote nutrient deficiency in plants. • Beef cattle kept on pastures fertilized with ammonium nitrate lose less nitrogen. • Also, they exhibit improved microbial protein synthesis. We evaluated the effects of different sources of nitrogen (N) applied to pastures of Urochloa brizantha cv. Marandu during the rainy season on the efficiency of N use in plants and animals. Continuous grazing with variable stocking rates was employed to maintain 25 cm pasture height, corresponding to 95% light interception. The experimental design consisted of randomized blocks with four treatments and three replications (paddocks per treatment). The applied N sources were urea, ammonium sulfate, and ammonium nitrate, at a respective dosage of 150 kg N per ha, in three treatments, in addition to a control treatment without N fertilization. N recovery by plants differed between fertilizers (p = 0.047) and was highest in the ammonium sulfate treatment. The proportion of retained N was higher in animals kept on fertilized pastures (p < 0.01). Different sources of N in pasture system, or its non-use, affected the efficiency of N use by animals, and ammonium sulfate and ammonium nitrate were more efficient with respect to the N balance. [ABSTRACT FROM AUTHOR]

In Brazil beef cattle production is one of the most important activities in the agricultural sector and has an important impact on environmental and resources consumption. In this study assessed greenhouses gases (GHG) impacts from on farms representative productive system and the possible improvements of the production chain. Primary data from animal production index and feeding were collected from 17 farms, which covers 300.000 animals and 220.000 hectares. Emissions of methane, nitrous oxide and carbon dioxide were made using intergovernmental panel on climate change (IPCC) guidelines for national inventories. The GHG inventory included emissions from animals, feeds and operations for animal operation from "cradle to farm gate". Emissions of each farm were converted to carbon dioxide equivalent (CO2eq) and divided by carcass production. Regression analysis between carbon dioxide equivalent and productive index was run to identify possible hotspot of GHG emissions. A large variation between farms were observed. The GHG yield ranged from 8.63 kg to 50.88 CO2eq kg carcass-1. The productive index age of slaughtering (P < 0.0001), average daily gain (P < 0.0001) and productivity (P = 0.058) per area were positive correlated to GHG yield. While no correlation was found with stocking rate (P = 0.21). Improvements of the production chain could be realized by accurate animal management strategies that reduce the age of slaughtering (feeding and genetic improvements) and gain individual or per area using strategic animal supplementation and pasture management, in order to obtains reduction of GHG emissions of beef cattle. [ABSTRACT FROM AUTHOR]

Simple Summary: Dried distillers' grains (DDG), a co-product of ethanol production from corn, is gaining attention for its efficiency in ruminant nutrition, as it meets both the energy and protein demands of livestock and is less costly than the popular alternatives. The aim of this study was to evaluate the effect of replacing cottonseed meal with DDG at two levels (50 and 100%) on young Nellore bulls grazing Marandu grass in the rainy season, focusing on ruminal parameters, animal performance, and methane (CH4) emissions. When replacing 50% of cottonseed meal with DDG, animals presented higher intakes of dry matter, organic matter, forage, and digestible organic matter, compared to 100% DDG. Ruminal parameters, including pH, acetate, and acetate: propionate, were higher when animals received only mineral supplementation. Animals supplemented with concentrate (cottonseed meal and/or DDG) presented greater daily weight gain and final body weight than the animals consuming mineral supplementation. Replacing cottonseed meal with DDG does not cause great variations in ruminal parameters, animal performance, and enteric CH4 emissions in grazing Nellore cattle during the rearing phase in the wet season. However, supplementation of 0.3% body weight with the concentrate can improve the productive performance of grazing animals. Both protein sources, DDG or cottonseed meal, can be used to intensify grazing beef cattle production. Two experiments were conducted to evaluate the effect of replacing cottonseed meal with DDG on ruminal parameters, methane (CH4) emissions (Experiment 1), and animal performance (Experiment 2) of young Nellore bulls grazing Marandu grass during the rainy season. Four supplementation strategies were used in both experiments: (1) Mineral supplementation (MS); (2) conventional multiple supplement (energy/protein) with cottonseed meal and citrus pulp (CMS); (3) CMS with 50% cottonseed meal replaced by DDG (50DDG); and (4) CMS with 100% cottonseed meal replaced by DDG (100DDG). The 50DDG condition resulted in greater intake of dry matter (p = 0.033), organic matter (OM) (p = 0.050), forage (p = 0.035), and digestible OM (p = 0.031) than 100DDG. The supplemented animals presented greater final body weight (BW) and average daily gain than the animals consuming MS (p = 0.011), and lower pH, acetate, and acetate:propionate (p < 0.05). However, the treatments had no influence on stocking rate, gain per area, and enteric CH4 emissions (p > 0.05). Replacing cottonseed meal with DDG does not result in great variations in ruminal parameters, animal performance, and enteric CH4 emissions of grazing Nellore cattle during the rearing phase in the wet season. Both protein sources in 0.3% BW supplementation can be used to intensify beef cattle production in pastures. [ABSTRACT FROM AUTHOR]

The reduction in ammonia (NH3) losses from volatilization has significant implications in forage production. The objective of this study was to evaluate the impact of N fertilizers (urea, ammonium nitrate, and ammonium sulfate) and four doses (0, 90, 180 and 270 kg N ha−1) on N losses by NH3 volatilization, accumulation, and forage chemical composition of Urochloa brizantha cv Marandu. Two field experiments were conducted to measure NH3 losses using semi-open chambers. The forage accumulation and chemical composition were evaluated in the third experiment; the response variables included forage accumulation, crude protein (CP), and neutral detergent fiber (NDF). Compared to urea, ammonium nitrate and ammonium sulfate reduced NH3 losses by 84% and 87% and increased total forage accumulation by 14% and 23%, respectively. Forage accumulation rate and CP increased linearly with the N levels, while NDF contents decreased linearly with the N levels. In both experiments, NH3 losses and forage characteristics were different according to the rainfall pattern and temperature variations. Our results indicate that the use of nitric and ammoniacal fertilizers and the application of fertilizer in the rainy season constitute an efficient fertilizer management strategy to increase forage yield and decrease losses from volatilization of NH3. [ABSTRACT FROM AUTHOR]

Pasture intensification through higher stocking rates, nitrogen fertilization and intensified grazing management in beef cattle production optimizes pasture use by increasing the forage harvested. We aimed to assess its effects on the morphogenesis and canopy structure of Urochloa brizantha 'Marandu' (marandu palisadegrass) pastures. The treatments consisted of marandu palisadegrass pastures managed under continuous stocking and a canopy height of 25 cm, with different levels of intensification: extensive, semi-intensive, and intensive systems N-fertilized with 0 kg, 75 kg, and 150 kg N ha−1 year−1, respectively, as ammonium nitrate (32% of N), with four replicates (paddocks) in a completely randomized design. Phyllochron (9.8 days) and leaf lifespan (34.7 days) were shorter in intensified pastures, whereas herbage mass was similar among treatments. Extensive pastures had a higher proportion of senescent material; thus, more intensive systems showed higher proportions of leaves and stems, although the leaves-to-stem ratio remained similar across production systems. The defoliation interval was lower in intensive (14.4 days) and higher in extensive (18.7 days) treatments. Thus, pasture intensification accelerates leaf appearance, decreases leaf lifespan, shortens the tiller defoliation interval and increased herbage accumulation rate but does not change herbage mass. The extensive system produces excessive forage losses due to dead material. [ABSTRACT FROM AUTHOR]

• We evaluated GHG emission of Nellore and F1 Angus x Nellore yearling bulls. • They were raised under two beef production systems (lenient and intensified) in tropical pasture. • F1Angus grew faster and are heavier than Nellore bulls. • Carbon footprint of F1Angus in intensified production system were the lowest. • Improvement of genetic merit and pasture management decreases environmental impact. This study investigated the performance, carcass traits, and greenhouse gas emission of Nellore and F1 Angus × Nellore yearling bulls raised under two [lenient (S1) and intensified (S2)] production systems during the backgrounding and finishing phases. S1 was practiced on a 18.6 ha palisade grass pasture, divided into eight paddocks, which was not fertilized and managed using continuous stocking at a constant rate of two animals per hectare during backgrounding. Then, 20 Nellore [initial body weight (BWi), 277±13 kg; initial age, 15.2±1.1 months] and 20 F1 Angus × Nellore (BWi, 304±21 kg; initial age, 15.8±0.44 months) yearling bulls were randomly allocated to four paddocks for each breed. During finishing, animals remained on the pasture and received high supplementation (at rate of 2.0 kg•100 kg−1 BW). S2 was practiced on a 11.4 ha palisade grass pasture, divided into six paddocks, which was fertilized (150 kg N•ha−1•year−1) and managed using continuous stocking at variables rates during backgrounding. Then, 24 Nellore (BWi, 288±16 kg; initial age, 15.6±0.65 months) and 24 F1 Angus × Nellore (BWi, 325±18 kg; initial age, 15.8±0.42 months) yearling bulls were randomly allocated to three paddocks for each breed. During finishing, the bulls were moved to feedlots. During backgrounding, F1 Angus × Nellore bulls in S2 achieved the highest average daily gain (ADG) and final shrunk body weight (SBWf), whereas Nellore bulls in S1 achieved the lowest ADG and SBWf. During finishing, ADG and SBWf were greater in S2 than in S1 as well as for F1 Angus × Nellore bulls than for Nellore bulls. From the beginning of backgrounding until the end of finishing, the ribeye area of F1 Angus × Nellore bulls in S2 was larger than that of other bulls. The greatest backfat deposition occurred during finishing, resulting in greater backfat thickness of bulls in S2 than that of bulls in S1. The carbon footprint of F1 Angus × Nellore bulls in S2 (10.8 kg•CO 2 e•kg−1 carcass) was similar to that of Nellore bulls in S1, but it was approximately 13% and 11.5% lower than that of Nellore bulls in S2 and F1 Angus × Nellore bulls in S1, respectively. This study demonstrated that the enhancement of productivity through improving genetic merit and pasture management is a suitable strategy to reduce environmental impact and achieve environmental sustainability. [ABSTRACT FROM AUTHOR]

Simple Summary: Greater metabolic needs in high-producing beef cattle might lead to mineral and vitamin deficiency. Previous studies have shown the benefits of B-vitamin and trace mineral supplementation in animal performance of ruminants; however, little is known about the effects of supplementing finishing beef cattle with rumen-protected forms on the liver metabolism. Therefore, the aim of the present study was to determinate the impact of rumen-protected B-vitamin blend and hydroxy trace mineral supplementation on the hepatic proteome of finishing steers. This study reports the first evidence indicating that the supplementation of these micronutrients induces protein changes concerning oxidative metabolism and responses to oxidative stress in the liver tissue. Vitamin B and trace minerals are crucial molecular signals involved in many biological pathways; however, their bioavailability is compromised in high-producing ruminant animals. So far, studies have mainly focused on the effects of these micronutrients on animal performance, but their use in a rumen-protected form and their impact on liver metabolism in finishing beef cattle is poorly known. We used a shotgun proteomic approach combined with biological network analyses to assess the effects of a rumen-protected B-vitamin blend, as well as those of hydroxy trace minerals, on the hepatic proteome. A total of 20 non-castrated Nellore males with 353 ± 43 kg of initial body weight were randomly assigned to one of the following treatments: CTRL—inorganic trace minerals without supplementation of a protected vitamin B blend, or SUP—supplementation of hydroxy trace minerals and a protected vitamin B blend. All animals were fed the same amount of the experimental diet for 106 days, and liver biopsies were performed at the end of the experimental period. Supplemented animals showed 37 up-regulated proteins (p < 0.10), and the enrichment analysis revealed that these proteins were involved in protein folding (p = 0.04), mitochondrial respiratory chain complex I (p = 0.01) and IV (p = 0.01), chaperonin-containing T-complex 2 (p = 0.01), glutathione metabolism (p < 0.01), and other aspects linked to oxidative-stress responses. These results indicate that rumen-protected vitamin B and hydroxy trace mineral supplementation during the finishing phase alters the abundance of proteins associated with the electron transport chain and other oxidation–reduction pathways, boosting the production of reactive oxygen species, which appear to modulate proteins linked to oxidative-damage responses to maintain cellular homeostasis. [ABSTRACT FROM AUTHOR]

The intensification of pasture production has increased the use of N fertilizers—a practice that can alter soil greenhouse gas (GHG) fluxes. The objective of the present study was to evaluate the fluxes of CH4, CO2, and N2O in the soil of Urochloa brizantha 'Marandu' pastures fertilized with different sources and doses of N. Two field experiments were conducted to evaluate GHG fluxes following N fertilization with urea, ammonium nitrate, and ammonium sulfate at doses of 0, 90, 180, and 270 kg N ha−1. GHG fluxes were quantified using the static chamber technique and gas chromatography. In both experiments, the sources and doses of N did not significantly affect cumulative GHG emissions, while N fertilization significantly affected cumulative N2O and CO2 emissions compared to the control treatment. The N2O emission factor following fertilization with urea, ammonium nitrate, and ammonium sulfate was lower than the United Nations' Intergovernmental Panel on Climate Change standard (0.35%, 0.24%, and 0.21%, respectively, with fractionation fertilization and 1.00%, 0.83%, and 1.03%, respectively, with single fertilization). These findings are important for integrating national inventories and improving GHG estimation in tropical regions. [ABSTRACT FROM AUTHOR]

• Growing phase supplementation does not affect meat traits of bulls at finishing phase. • Feedlot system improves meat tenderness. • Meat lightness was reduced in bulls finished in pasture plus concentrate. One hundred and twenty bulls were used in a randomized complete block design in 2 × 2 factorial arrangement; two supplements during the growing phase: mineral (ad libitum ; MIN) or protein + energy [0.3% of body weight (BW)/animal/day; PRE] and two finishing systems: pasture plus concentrate supplementation (2% BW/animal/day; PASCO) and feedlot (25:75% corn silage:concentrate; FLOT). The supplementation strategy at growing phase did not affect (P > 0.050) the pH, shear force, sarcomere length and myofibrillar fragmentation index of the animals. Backfat thickness was increased and meat shear force was decreased (P < 0.050) when the bulls were finished in FLOT. Bulls from PASCO presented an increase (P < 0.050) in the yellowness subcutaneous fat and myoglobin concentration, and a decrease in L* and a* values in meat during storage days. Meat lipid oxidation was decreased (P < 0.011) in bulls fed MIN during the growing phase followed by PASCO. Supplementation used at growing phase did not affect the meat quality of the bulls and the feedlot system slightly improved beef tenderness and colour compared to pasture plus supplementation. [ABSTRACT FROM AUTHOR]

Simple Summary: The use of less costly products that are not consumed by humans in animal feed has gained increasing attention in the context of sustainable production. Dried distiller's grains (DDG), a co-product of the production of ethanol from corn, stands out for being efficient in the nutrition of ruminants, meeting both the energy and protein demands of the diets, when the cattle are kept in the pasture or feedlot. The study aimed to evaluate the effect of replacing cottonseed meal (CM) by DDG in two levels (50% (50DDG) and 100% (100DDG)), in terms of efficiency in the productive aspects of cattle finishing phase comparing pasture versus feedlot. The effect of replacing CM by DDG on dry matter, nutrients intake and nutrients digestibility depends on finishing system. While in the pasture system animal consumed more nutrients in the CM, a greater intake was observed in the 100DDG in feedlot. The nutrients digestibility was lower in the pasture. Animal performance and final body weight were higher in the feedlot. The use of DDG does not change the animal performance finished in pasture or feedlot, and it is a viable alternative to replace conventional supplements in finishing phase in both systems in tropical environment. The study aimed to evaluate the effect of replacing cottonseed meal by dried distiller's grains (DDG) in terms of efficiency in the productive aspects of beef cattle finishing in pasture versus feedlot. The experiment was conducted in a completely randomized design in a 2 × 3 factorial arrangement, with two production systems (pasture versus feedlot) and three supplements: CM, conventional supplement with cottonseed meal (CM) as a protein source; 50DDG: supplement with 50% replacement of CM by DDG; and 100DDG: 100% replacement. The effect of replacing CM by DDG on dry matter and nutrients intake and nutrients digestibility depends on the finishing system (p < 0.05). While in the pasture system animal consumed more nutrients in the CM, a greater intake was observed in the 100DDG in feedlot. The nutrients digestibility was lower in the pasture (p < 0.05). Animal performance and final body weight were higher in the feedlot (p < 0.0001), with averages of 1.57 kg/d and 566 kg of final body weight (FBW) for feedlot, and 0.99 kg/d and 504 kg FBW for pasture. The use of DDG does not change the animal performance finished in pasture or feedlot, and it is a viable alternative to replace conventional supplements in finishing phase in both systems in tropical environment. [ABSTRACT FROM AUTHOR]

A 7 year experiment (2008–2014) evaluated cattle grazing intensity (sward height) effects on herbage mass, forage quality, and greenhouse gas emissions in continuously stocked pastures containing the tropical 'Marandu' palisade grass (Brachiaria brizantha (Hochst. ex A. Rich) Stapf cv. Marandu). The experiment consisted of three sward height treatments (15, 25, and 35 cm) and six replicates. There were four periods each year during the rearing phase. Significant effects were found for herbage mass, proportions of leaf and stem, crude protein, neutral detergent fiber, acid detergent fiber, lignin, animal performance, enteric methane (CH4), and greenhouse gas (GHG) emissions from soils. When the canopy height increased from 15 to 35 cm, the herbage mass rose from 5.23 to 9.86 kg t ha−1, leaf percentage decreased, and stem percentage increased. Crude protein content averaged 14.2%, and neutral detergent fiber averaged 58%. Average daily gain averaged 0.67, 0.81, and 0.90 kg −1 head−1, while live weight gain ha–1 was 649, 530, and 439 kg for the 15, 25, and 35 cm treatments, respectively. The weather variables explained the GHG emissions, interannual herbage mass, and structure variations. [ABSTRACT FROM AUTHOR]

• We measured the effect of excreta type and season on NH 3 , N 2 O and CH 4 emissions. • Type of excreta significantly affect NH 3 , N 2 O and CH 4 emissions. • N 2 O and CH 4 emissions were significantly lower in the dry season (May to October). • NH 3 volatilization was higher during the dry season (May to October) for the urine and dung + urine treatments. • Ammonia volatilization, N 2 O and CH 4 emissions differed of IPCC default emissions factor. In this study we conducted four field trials (two wet- and two dry-season) to quantify N 2 O and CH 4 emissions, NH 3 volatilization, and N 2 O emission factors (EF 3PRP) following the application of cattle dung, urine, dung plus urine, and urea fertilizer on a palisade-grass pastureland in Brazil. The EF 3PRP differed with treatment and season. Wet season EF 3PRP were 0.36%, 1.02%, and 0.84% and dry season EF 3PRP were 0.32%, 0.47%, and 0.34% for dung, urine, and dung plus urine, respectively. These emission factors are maybe lower than the default proposed by the Intergovernmental Panel on Climate Change (IPCC; 2%). Methane emissions also differed according to the treatment and season, and annualized dung emissions were 0.54 kg CH 4 head−1 year−1. The fraction of total-N from animal manure and urine emitted as NH 3 (FracGASM) in the wet season for dung, urine and dung plus urine was 7.2%, 6.3%, and 6.4%, respectively; lower than the rate of dry season volatilization from urine (14.2%) and dung plus urine (11.5%). Observed FracGASM is probably lower than the IPCC guideline (20%). Emissions of N 2 O, CH 4 , and the volatilization of NH 3 after urea treatment were not influenced by season; N 2 O emissions from urea were 0.85%, CH 4 emissions were 112 g CH 4 -C ha−1, and N-fertilizer lost as NH 3 was 16.9%. The emission factors observed in this experiment differed from the IPCC Guidelines; observed N 2 O emissions were lower than the guideline (1%), and FracGASF was higher than the 10% guideline. [ABSTRACT FROM AUTHOR]

Three sward heights (15, 25 and 35 cm) and three supplement types (energy, energy-protein, and a mineral mix supplement) were evaluated in a 3 × 3 factorial arrangement distributed in a completely randomized design to study changes in forage search patterns in Nellore heifers in a continuous grazing system. Pasture data were collected using two replicates (paddocks) per treatment over four periods during the rainy season. The behavior assessments were made in the first and fourth grazing seasons. It was hypothesized that supplements and pasture management would modify ingestive behavior, considering that animals would require less time grazing if they had energy requirements met through higher digestibility of better managed paddocks, or use of supplements high in energy. Total and green forage masses along with green : dead material ratio were greater in treatments managed with higher sward heights. Sward managed with 35 cm height resulted in lower leaf : stem ratio compared with 15 cm sward height treatments. The animals on the 15 cm pastures spent more time grazing overall and during each meal, but there were no differences observed in meal numbers in comparison to 35 cm treatments. Heifers fed protein and/or energy supplements spent less time grazing in the early afternoon, but overall grazing time was the same for all animals. [ABSTRACT FROM AUTHOR]