RESUMO

The transformation of pastures from a degraded state to sustainable productivity is a major challenge in tropical livestock production. Stoloniferous forage legumes such as Arachis pintoi (forage peanut) are one of the most promising alternatives for intensifying pasture-based beef livestock operations with reduced greenhouse gas (GHG) emissions. This 2-year study assessed beef cattle performance, nutrient intake and digestibility, and balance of GHG emissions in three pasture types (PT): (1) mixed Palisade grass - Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster (syn. Brachiaria brizantha Stapf cv. Marandu) and forage peanut (A. pintoi Krapov. & W.C. Greg. cv. BRS Mandobi) pastures (Mixed), (2) monoculture Palisade grass pastures with 150 kg of N/ha per year (Fertilised), and (3) monoculture Palisade grass without N fertiliser (Control). Continuous stocking with a variable stocking rate was used in a randomised complete block design, with four replicates per treatment. The average daily gain and carcass gain were not influenced by the PT (P = 0.439 and P = 0.100, respectively) and were, on average, 0.433 kg/animal per day and 83.4 kg/animal, respectively. Fertilised and Mixed pastures increased by 102 and 31.5%, respectively, the liveweight gain per area (kg/ha/yr) compared to the Control pasture (P < 0.001). The heifers in the Mixed pasture had lower CH4 emissions (g/animal per day; P = 0.009), achieving a reduction of 12.6 and 10.1% when compared to the Fertilised and Control pastures, respectively. Annual (N2O) emissions (g/animal) and per kg carcass weight gain were 59.8 and 63.1% lower, respectively, in the Mixed pasture compared to the Fertilised pasture (P < 0.001). Mixed pasture mitigated approximately 23% of kg CO2eq/kg of carcass when substituting 150 kg of N/ha per year via fertiliser. Mixed pastures with forage peanut are a promising solution to recover degraded tropical pastures by providing increased animal production with lower GHG emissions.

Assuntos

RESUMO

The inclusion of corn-dried distillers' grains (DDG) could be an alternative supplement to increase animal performance, nitrogen efficiency usage (NEU), and decrease enteric methane (CH4) emissions. Our goal was to determine whether DDG could replace a traditional supplement (cottonseed meal) without affecting animal performance, N balance, and CH4 emissions. The experiment was conducted during the forage growing season (December to April), with 15 d adaptation, and a 112 d experimental period. The experimental design was completely randomized with four treatments: a mineral supplement (MS), cottonseed meal supplement (CS), 50% replacement of CS by DDG (50DDG), and 100% replacement of CS by DDG (100DDG). Cottonseed meal and DDG were used as protein supplement. A total of 12 paddocks, 3 per treatment, were used to measure forage mass: morphological and chemical composition of forage, forage allowance, and animal performance. Six animals per treatment were used to evaluate DM intake, digestibility, CH4 emissions, microbial protein production (MCP), and NEU of each treatment. Eighty-one Young Nellore bulls (48 testers, 12 per treatments and 33 adjusters) with initial BW of 255 ±â€¯5 kg (10-12 months old) were supplemented with each supplement type at a level of 0.3% of BW. Pasture management was continuous stocking with a variable stocking rate (put-and-take). Enteric CH4 was measured using the gas tracer technique. The MCP was quantified using purine derivatives and the NEU mass balance. No differences were found in nutrient intake (P > 0.228). Individual animal performance and gain per area were higher in the treatments with concentrates compared with that of MS; however, there was no difference among treatments CS, 50DDG, and 100DDG. The ADG was 0.83 for MS and 1.08 kg/animal/d when supplemented (P < 0.05). Gain per hectare was 709 kg/ha for MS and 915 kg/ha when supplemented with concentrates (P < 0.05). There was no difference in CH4 production among treatments that average 180 g/animal/d; however, CH4 per kg of gain was reduced with CS. The CH4 conversion factor averaged 5.91%. There was no difference in the synthesis of MCP and NEU. Corn DDG can replace 100% of cottonseed meal as a protein source for supplementation of young Nellore bulls grazing in tropical pastures without affecting animal performance, NEU, MCP, and CH4 emissions.

Assuntos

RESUMO

The production of beef cattle in the Atlantic Forest biome mostly takes place in pastoral production systems. There are millions of hectares covered with pastures in this biome, including degraded pasture (DP), and only small area of the original Atlantic Forest has been preserved in tropics, implying that actions must be taken by the livestock sector to improve sustainability. Intensification makes it possible to produce the same amount, or more beef, in a smaller area; however, the environmental impacts must be assessed. Regarding climate change, the C dynamics is essential to define which beef cattle systems are sustainable. The objectives of this study were to investigate the C balance (t CO2e./ha per year), the intensity of C emission (kg CO2e./kg BW or carcass) and the C footprint (t CO2e./ha per year) of pasture-based beef cattle production systems, inside the farm gate and considering the inputs. The results were used to calculate the number of trees to be planted in beef cattle production systems to mitigate greenhouse gas (GHG) emissions. The GHG emission and C balance, for 2 years, were calculated based on the global warming potential (GWP) of AR4 and GWP of AR5. Forty-eight steers were allotted to four grazing systems: DP, irrigated high stocking rate pasture (IHS), rainfed high stocking rate pasture (RHS) and rainfed medium stocking rate pasture (RMS). The rainfed systems (RHS and RMS) presented the lowest C footprints (-1.22 and 0.45 t CO2e./ha per year, respectively), with C credits to RMS when using the GWP of AR4. The IHS system showed less favorable results for C footprint (-15.71 t CO2e./ha per year), but results were better when emissions were expressed in relation to the annual BW gain (-10.21 kg CO2e./kg BW) because of its higher yield. Although the DP system had an intermediate result for C footprint (-6.23 t CO2e./ha per year), the result was the worst (-30.21 CO2e./kg BW) when the index was expressed in relation to the annual BW gain, because in addition to GHG emissions from the animals in the system there were also losses in the annual rate of C sequestration. Notably, the intensification in pasture management had a land-saving effect (3.63 ha for IHS, 1.90 for RHS and 1.19 for RMS), contributing to the preservation of the tropical forest.

Assuntos

RESUMO

This study was carried out to evaluate the effects of four levels of intensification of grazing systems: 1) degraded pasture - DP; 2) irrigated pasture with high stocking rate - IHS; 3) dryland pasture with high stocking rate - DHS; 4) dryland pasture with moderate stocking rate - DMS; on growth, muscle development and meat quality of Nellore steers (271±2.2kg of live body weight - BW; 15months old) during two consecutive periods (17 and 15months). The final BW, the average daily BW gain, the hot carcass weight and the dress percentage were greater (P<0.0001), and the ribeye area tended to be greater (P=0.085), in the intensified systems compared to the degraded system. Animals in all systems presented similar back fat. Muscle development increased with the intensification of the grazing systems and meat quality was not affected.

Assuntos

RESUMO

Este estudo teve como objetivo avaliar silagem de cana-de-açúcar (Saccharum officinarum L) tratada com hidróxido de cálcio - Ca(OH)2 - (cal hidratada) como único volumoso em ração para confinamento de gado de corte, com respeito ao desempenho e qualidade da carne dos animais. Quarenta e cinco novilhos Canchim (22 meses de idade, 345 kg de peso vivo- PV) foram distribuídos, em um delineamento em blocos casualizados, em três tratamentos (rações totais - RTs - com 35% de volumoso): T1 - RT com cana-de-açúcar fresca; T2 - RT com silagem de cana-de-açúcar tratada com hidróxido de cálcio (10 g Ca(OH)2/kg de forragem fresca); T3 - RT com silagem de milho. Foram avaliados o consumo de matéria seca (CMS), consumo de MS digestível (CMSD), consumo de proteína bruta (CPB), eficiência alimentar (EA), ganho médio diário (GMD) e rendimento de carcaça (RC). A carne foi avaliada quanto a parâmetros de qualidade (pH, capacidade de retenção de água, perdas no cozimento, cor e força de cisalhamento) e de análise sensorial descritiva. Os novilhos alimentados com a silagem de cana-de-açúcar tratada com hidróxido de cálcio apresentaram similares (P>0.05) CMS (10,8 kg/d), CMSD (8,5 kg/d) e RC (52,6%); mais alto (P<0.05) CPB (1,8 vs. 1,4 kg/d) e menor (P<0.05) GMD (1,58 vs. 1,81 kg PV/d) comparados aos que receberam silagem de milho. Comparados aos animais alimentados com cana-de-açúcar fresca, os novilhos alimentados com silagem de cana-de-açúcar tratada com hidróxido de cálcio apresentaram maior (P<0.05) CMS (10,9 vs. 9,4 kg MS/d), CMSD (8,70 vs. 7,4 kg/d), CPB (1,8 vs. 1,1 kg/d) e RC (52,7 vs. 51,2%), mas o GMD e EA foram similares (P>0.05) (1,5 kg PV/d e 0,15 kg PV/kg CMS, respectivamente). As diferentes rações não afetaram (P>0.05) os parâmetros de qualidade e os atributos sensoriais da carne, com exceção da cor da gordura e sabor estranho na carne. Concluiu-se que o hidróxido de cálcio pode ser indicado como um eficiente aditivo para...(AU)

This study aimed to evaluate sugarcane (Saccharum officinarum L) silage treated with calcium hydroxide - Ca(OH)2 - (slacked lime) as the only roughage source in a feedlot ration, regarding animal performance and meat quality. Forty five Canchim steers (22 months old, 345 kg body weight - BW) were assigned, in a complete randomized block design, to three treatments (total mixed rations - TMRs - with 35% roughage): T1- TMR with fresh sugarcane; T2 - TMR with sugarcane silage treated with calcium hydroxide (10 g Ca(OH)2/kg of fresh forage); T3 - TMR with corn silage. Dry matter intake (DMI), digestible DM intake (DDMI), crude protein intake (CPI), feed efficiency (FE), average daily gain (ADG) and dressing percentage (DP) were evaluated. Meat was analyzed for quality parameters (pH, water holding capacity, cooking loss, color and shear force) and sensory attributes. Steers fed the silage treated with calcium hydroxide presented similar (P>0.05) DMI (10.8 kg DM/d), DDMI (8.5 kg/d) and DP (52.6%); higher CPI (1.8 vs. 1.4 kg/d) and lower (P<0.05) ADG (1.58 vs. 1.81 kg BW/d) and FE (0.15 vs. 0.17 kg BW/kg DMI) in comparison to those receiving corn silage. Compared to animals fed the fresh sugarcane, steers fed sugarcane silage treated with calcium hydroxide presented higher (P<0.05) DMI (10.9 vs. 9.4 kg DM/d), DDMI (8.7 vs. 7.4 kg/d), CPI (1.8 vs. 1.1 kg/d) and DP (52.7% vs. 51.2%) but similar (P>0.05) ADG and FE (1.5 kg BW/d and 0.15 kg BW/kg DMI, respectively). The different rations did not affect (P>0.05) meat quality parameters and sensory attributes, except for fat color and off flavor sensory attribute. It was concluded that calcium hydroxide can be indicated as an efficient additive for sugarcane ensilage. Feedlot cattle fed TMR containing sugarcane silage treated with Ca (OH)2, as the only roughage source, presented adequate performance and meat quality.(AU)

Assuntos

RESUMO

Este estudo teve como objetivo avaliar silagem de cana-de-açúcar (Saccharum officinarum L) tratada com hidróxido de cálcio - Ca(OH)2 - (cal hidratada) como único volumoso em ração para confinamento de gado de corte, com respeito ao desempenho e qualidade da carne dos animais. Quarenta e cinco novilhos Canchim (22 meses de idade, 345 kg de peso vivo- PV) foram distribuídos, em um delineamento em blocos casualizados, em três tratamentos (rações totais - RTs - com 35% de volumoso): T1 - RT com cana-de-açúcar fresca; T2 - RT com silagem de cana-de-açúcar tratada com hidróxido de cálcio (10 g Ca(OH)2/kg de forragem fresca); T3 - RT com silagem de milho. Foram avaliados o consumo de matéria seca (CMS), consumo de MS digestível (CMSD), consumo de proteína bruta (CPB), eficiência alimentar (EA), ganho médio diário (GMD) e rendimento de carcaça (RC). A carne foi avaliada quanto a parâmetros de qualidade (pH, capacidade de retenção de água, perdas no cozimento, cor e força de cisalhamento) e de análise sensorial descritiva. Os novilhos alimentados com a silagem de cana-de-açúcar tratada com hidróxido de cálcio apresentaram similares (P>0.05) CMS (10,8 kg/d), CMSD (8,5 kg/d) e RC (52,6%); mais alto (P0.05) (1,5 kg PV/d e 0,15 kg PV/kg CMS, respectivamente). As diferentes rações não afetaram (P>0.05) os parâmetros de qualidade e os atributos sensoriais da carne, com exceção da cor da gordura e sabor estranho na carne. Concluiu-se que o hidróxido de cálcio pode ser indicado como um eficiente aditivo para...

This study aimed to evaluate sugarcane (Saccharum officinarum L) silage treated with calcium hydroxide - Ca(OH)2 - (slacked lime) as the only roughage source in a feedlot ration, regarding animal performance and meat quality. Forty five Canchim steers (22 months old, 345 kg body weight - BW) were assigned, in a complete randomized block design, to three treatments (total mixed rations - TMRs - with 35% roughage): T1- TMR with fresh sugarcane; T2 - TMR with sugarcane silage treated with calcium hydroxide (10 g Ca(OH)2/kg of fresh forage); T3 - TMR with corn silage. Dry matter intake (DMI), digestible DM intake (DDMI), crude protein intake (CPI), feed efficiency (FE), average daily gain (ADG) and dressing percentage (DP) were evaluated. Meat was analyzed for quality parameters (pH, water holding capacity, cooking loss, color and shear force) and sensory attributes. Steers fed the silage treated with calcium hydroxide presented similar (P>0.05) DMI (10.8 kg DM/d), DDMI (8.5 kg/d) and DP (52.6%); higher CPI (1.8 vs. 1.4 kg/d) and lower (P0.05) ADG and FE (1.5 kg BW/d and 0.15 kg BW/kg DMI, respectively). The different rations did not affect (P>0.05) meat quality parameters and sensory attributes, except for fat color and off flavor sensory attribute. It was concluded that calcium hydroxide can be indicated as an efficient additive for sugarcane ensilage. Feedlot cattle fed TMR containing sugarcane silage treated with Ca (OH)2, as the only roughage source, presented adequate performance and meat quality.

Assuntos

RESUMO

The crossbreeding of two or more breeds from the Bos taurus and Bos indicus species is an alternative for obtaining high-quality meat from animals adapted to tropical climates. Quality and sensory attributes of beef, mainly its tenderness and flavour, are very important with regard to the consumer's point of view. This study aimed to evaluate the physico-chemical and sensory characteristics of crossbred young bulls and heifers, the offspring of Angus or Limousin bulls and 1/2 Angus + 1/2 Nellore or 1/2 Simental + 1/2 Nellore cows that were finished on feedlot or pasture. Meat quality traits (pH, colour, cooking loss, water holding capacity and shear force) and sensory parameters (characteristic beef aroma/flavour intensity, strange aroma/flavour intensity, tenderness and juiciness descriptive attributes, flavour, texture (tenderness) and overall acceptance) were evaluated. The genetic group had an effect on the beef pH, but it was not as relevant as the effect of the combination between the production system and the sex or genetic group, which affected many of the quality and sensory traits.

Assuntos

RESUMO

Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with LQR resulted in a 17% better efficiency of ME use for gain (P < 0.01), which was associated with a greater partial efficiency of energy retention as fat (P < 0.01). This increased nutritional efficiency, however, should be viewed with caution because it is related to visceral fat deposition, a nonedible tissue.

Assuntos

RESUMO

The growing global demand for food of animal origin will be the incentive for countries such as Australia and Brazil to increase their beef production and international exports. This increased supply of beef is expected to occur primarily through on-farm productivity increases. The strategies for reducing resultant greenhouse gas (GHG) emissions should be evaluated in the context of the production system and should encompass a broader analysis, which would include the emissions of methane (CH4) and nitrous oxide (N2O) and carbon sequestration. This paper provides an insight into CH4 measurement techniques applicable to grazing environments and proposed mitigation strategies, with relevance to the production systems that are predominant in grazing systems of Australia and Brazil. Research and technology investment in both Australia and Brazil is aimed at developing measurement techniques and increasing the efficiency of cattle production by improving herd genetics, utilization of the seasonal feed-base and reducing the proportion of metabolizable energy lost as CH4. Concerted efforts in these areas can be expected to reduce the number of unproductive animals, reduce age at slaughter and inevitably reduce emission intensity (EI) from beef production systems. Improving efficiency of livestock production systems in tropical grazing systems for Australia and Brazil will be based on cultivated and existing native pastures and the use of additives and by-products from other agricultural sectors. This approach spares grain-based feed reserves typically used for human consumption, but potentially incurs a heavier EI than current intensive feeding systems. The determination of GHG emissions and the value of mitigation outcomes for entire beef production systems in the extensive grazing systems is complex and require a multidisciplinary approach. It is fortunate that governments in both Australia and Brazil are supporting ongoing research activities. Nevertheless, to achieve an outcome that feeds a growing population while reducing emissions on a global scale continues to be a monumental challenge for ruminant nutritionists.

Assuntos