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Climate change is a very relevant and worrying topic today and is present in the agendas of different spheres of society. High concentrations of greenhouse gases (GHGs) are released into the atmosphere, causing global temperatures to rise. In agricultural production, methane (CH4) is considered one of the highest GHG emissions, causing a negative impact on natural resources and accelerating climate change. In the coming years, with the increase in the world population, food production should be implemented in self-sufficient, quality, and sustainable production systems to meet the need for high consumption. The reduction in CH4 production is related to the better efficiency of energy use of the feed by the animals; therefore, the knowledge of the ruminal fermentation parameters, identification of the ruminal microbiota, and selection of more efficient animals, with lower consumption and greater weight gain, in addition to producing less GHGs like CH4, have a less negative impact on the environment and are economically viable. This review presents some aspects of selection for feed efficiency in sheep as a strategy to mitigate GHG emission and some techniques for measuring these gases.

As alterações climáticas são tema muito relevante e preocupante na atualidade e está presente nas pautas de diferentes esferas da sociedade. Altas concentrações de gases de efeito estufa são lançados na atmosfera, fazendo com que a tem-peratura global se eleve. Na produção agrícola, o metano (CH4) é considerado uma das maiores emissões de GEE, causando impacto negativo nos recursos naturais e acelerando as mudanças climáticas. Nos próximos anos, com o aumento da população mundial, a produção de alimentos deverá estar implementada em sistemas produtivos autossuficientes, de qualidade e sustentáveis para suprir a necessidade do elevado consumo. A redução na produção de CH4 está relacionada com a melhor eficiência do uso de energia da ração pelos animais; portanto, o conhecimento dos parâmetros da fermentação ruminal, identificação da microbiota ruminal e seleção de animais mais eficientes, com menor consumo e maior ganho de peso, além de produzirem menos GEEs como o CH4, impactam menos o meio ambiente e são economicamente viável. Esta revisão apresenta alguns aspectos da seleção para eficiência alimentar em ovinos como estratégia para mitigar a emissão de GEE e algumas técnicas para mensuração desses gases

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This study aimed to evaluate the effects of partial replacement (750g/kg) of Tifton hay by two cactus cladodes (Nopalea or Opuntia) on the metabolic profile of lambs. Thirty-six uncastrated male Santa Inês lambs (22.0±2.9kg initial body weight) were distributed in a completely randomized design, with three treatments and 12 repetitions. The animals were fed a control diet (Tifton hay as exclusive roughage), Miúda cactus cladodes-based diet or Orelha de Elefante Mexicana (O.E.M.) cactus cladodes-based diet. Blood samples were collected one day before (baseline) and 45 days after the introduction of the tested diets. The Miúda cactus cladodes caused an increase (P=0.055) in the serum activity of the gamma-glutamyl transferase enzyme (53.66U/L) and in the blood content of glucose and fructosamine. The O.E.M. cactus cladodes caused lower (P=0.038) serum cholesterol content (41.33mg/dL). Regardless of the variety, there was a decrease (P=0.001) in the serum content of indirect bilirubin, urea, and sodium, and increase in the serum magnesium concentration. The partial replacement of the Tifton hay by Miúda or O.E.M. cactus cladodes in lamb feeding increases the enzyme activity, indicating liver and/or kidney changes, but does not cause relevant damage to energy, protein, and mineral metabolism.

Este trabalho teve como objetivo avaliar os efeitos da substituição parcial (750g/kg) do feno de Tifton por duas variedades de palma forrageira (Nopalea ou Opuntia) no perfil metabólico de cordeiros. Trinta e seis cordeiros Santa Inês, machos, não castrados (22,0 ± 2,9kg de peso corporal inicial), foram distribuídos em delineamento inteiramente ao acaso, com três tratamentos e 12 repetições. Os animais foram alimentados com dieta controle (feno de Tifton como volumoso exclusivo), dieta à base de palma forrageira Miúda ou dieta à base de palma forrageira Orelha de Elefante Mexicana (OEM). Amostras de sangue foram coletadas um dia antes (baseline) e 45 dias após a introdução das dietas testadas. A palma Miúda causou aumento (P=0,055) na atividade sérica da enzima gamaglutamiltransferase (53,66U/L) e no teor sanguíneo de glicose e frutosamina. A palma OEM causou menor teor (P=0,038) de colesterol sérico (41,33mg/dL). Independentemente da variedade, houve diminuição (P=0,001) do teor sérico de bilirrubina indireta, ureia e sódio, e aumento na concentração sérica de magnésio. A substituição parcial do feno de Tifton por palma Miúda ou por OEM na alimentação de cordeiros aumenta a atividade enzimática, o que indica alterações hepáticas e/ou renais, mas não causa danos relevantes nos metabolismos energético, proteico e mineral.

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To verify if strategies to reduce the height of Marandu grass pasture at beginning of the deferral period change intake and metabolic parameters in sheep during the dry season, 18 crossbred females, ½ Dorper + ½ Santa Inês were used, distributed in 9 Marandu grass paddock handles to 3 drawdown strategies at the beginning of deferral period: 1) maintenance of grass with 15cm for 5 months before deferral start (15/15cm); 2) maintenance of marandu grass with 25 cm for 5 months, but at the beginning of deferral it was reduced to 15cm (25/15cm); 3) maintenance of 35 cm grass for 5 months, but at the beginning of deferral it was reduced to 15cm (35/15cm). The experiment was conducted in a completely randomized design (CRD), with 6 repetitions and repeated measures over time. Strategies to reduce the height of Marandu grass pasture, at the beginning of the deferral period, do not change nutrient intake and energy and protein metabolism. However, changes occurring in the pasture during the dry season alter these variables, and deferral is an interesting strategy to be used for forage production in winter, however, to optimize its use, it is necessary to use supplementation with concentrated rich in fermentable carbohydrates.

Para verificar se estratégias de redução da altura do pasto de capim-marandu, no início do período de diferimento, alteram consumo e parâmetros metabólicos em ovinos durante o período seco, foram utilizadas 18 fêmeas, mestiças, ½ Dorper + ½ Santa Inês, que foram distribuídas em nove piquetes de capim-marandu, com três estratégias de rebaixamento no início do período de diferimento: 1) manutenção do capim com 15cm, por cinco meses, antes do início do diferimento (15/15cm); 2) manutenção do capim-marandu com 25cm, por cinco meses, rebaixado, no início do diferimento, para 15cm (25/15cm); e 3) manutenção do capim com 35cm durante cinco meses, rebaixado, no início do diferimento, para 15cm (35/15cm). O experimento foi conduzido em delineamento inteiramente ao acaso (DIC), com seis repetições e medidas repetidas no tempo. Estratégias de redução da altura do pasto, no início do período de diferimento, não alteram o consumo de nutrientes e metabolismo energético e proteico. Porém, as mudanças no pasto durante o período seco alteram essas variáveis, sendo o diferimento uma estratégia interessante para utilizar na produção de forragem no inverno. Para otimizar seu uso, faz-se necessária, entretanto, a utilização da suplementação com concentrados ricos em carboidratos rapidamente fermentáveis.

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Vinte e quatro cordeiros cruzados, machos inteiros em terminação, foram utilizados para avaliar a influência da substituição do feno de Tifton 85 por silagem de rama de mandioca sobre o desempenho animal e as características de carcaças. Os animais foram distribuídos nos tratamentos que consistiram em quatro níveis de substituição do feno por silagem de rama de mandioca (0, 33, 67 e 100%) em dietas que continham 60% de concentrado e 40% de volumoso. A silagem de rama de mandioca apresentou menor teor de fibra em detergente neutro (56,81%) que o feno (79,71%), com teor de lignina mais elevado (14,37 e 5,24%, respectivamente), levando a menores valores de degradabilidade efetiva (5%/h) e degradabilidade potencial, além de apresentar maior não degradável. O ganho de peso corporal (302 g/dia), a ingestão de matéria seca (93,79 g/kg 0,75) e a conversão alimentar (4,63) não apresentaram diferenças entre tratamentos. As características de carcaças foram afetadas através da diminuição da área de olho de lombo e espessura de gordura de cobertura com o aumento da substituição do feno de Tifton 85 pela silagem de rama de mandioca. Conclui-se que a silagem de rama de mandioca tem valor nutritivo inferior, com maior quantidade de fibra lignificada do que o feno, prejudicando a terminação das carcaças dos cordeiros, mas sem afetar o desempenho dos animais.

Twenty-four crossbred lambs, complete males in finishing, were used to evaluate the replacement of Tifton 85 hay by cassava foliage silage on animal performance and carcass characteristics. The animals were distributed in treatments that consisted of 4 levels of replacement of hay by cassava foliage silage (0, 33, 67 and 100%) in diets containing 60% concentrate and 40% roughage. Cassava foliage silage had lower neutral detergent fiber content (56.81%) than hay (79.71%), with higher lignin content (14.37 and 5.24%, respectively), leading at lower values of effective degradability (5%/h) and potential degradability, with greater non-degradable residue for cassava foliage silage. Body weight gain (302 g/day), dry matter intake (93.79 g/kg0.75) and feed conversion (4.63) did not differ between treatments. The carcass characteristics were affected, with a decrease in rib eye area and cover fat thickness with an increase in the replacement of Tifton 85 hay by cassava foliage silage. Cassava silage has lower nutritional value, with a higher amount of lignified fiber than hay, damaging the finishing of the lamb carcasses, but without affecting the performance of the animals.

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The objective of this study was to evaluate in vitro rumen fermentation and methane production under the influence of two sources of phytochemicals: essential oils (EOs) and aqueous extracts (AEs). Treatments were set up in a completely randomized block design, with 4×2+1 factorial arrangement of four species, S (garlic, G; cinnamon, C; rosemary, R; eucalyptus; EU) × two types of presentation, P (essential oil, EO; aqueous extract, AE) and a basal diet, BD (50% concentrate, 20% alfalfa and 30% corn silage). Rumen fermentation was evaluated using the in vitro gas production technique. All experimental units were incubated with 500 mg of BD for 72 hours. Treatments were added at a single dose of 900 mg/L of rumen inoculum. Gas pressure was recorded at 0, 2, 4, 6, 8, 10, 14, 18, 24, 30, 36, 42, 48, 60 and 72 h postincubation. There was an interaction effect (P × S) between plant extract presentation (P) and plant species (S) for all variables. Treatments GEO, CEO, REO decreased volatile fatty acids (mmol/200 mg), microbial mass production (mg/g), CH4 production (mL/g), in vitro dry matter digestibility (P < 0.05), and total gas production at 24 and 72 h post-incubation (P < 0.05; mL/g DM, mL/g OM). No differences (P > 0.05) were observed between AEs and BD. In conclusion, the use of EOs negatively affected rumen fermentation parameters and the production of CH4. Garlic and cinnamon EOs effectively reduced methane emissions; however, they also reduced in vitro dry matter digestibility.

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This study aimed to evaluate the dry matter digestibility, intake and metabolic profile of ewe lambs fed active or inactive yeasts in the diet containing fibrolytic enzyme. Twenty crossbred animals with an average weight of 33.4kg and an average age of six months were distributed in a completely randomized design. The treatments consisted of yeasts: Control (no yeast), Milk Sacc X® (active yeast), Active Flora®(active yeast + inactive yeast) and Rumen Yeast®(inactive yeast). Analysis of variance and SNK test were applied with a significance level of 5% for type I error. There was no difference for dry matter intake between treatments (P>0.05). There was a significant trend (P=0.0596) for dry matter digestibility, with higher values for the control treatment. There was a significant trend for blood metabolites (P=0.0705), in which the diet containing Milk Sacc® was superior to the other treatments for total protein concentration. In addition, there was a statistical difference (P<0.05) for urea concentration, in which control and Active Flora® treatments were superior to the others. The inclusion of active or inactive yeasts in the diet for ewe lambs containing fibrolytic enzyme reduces dietary digestibility, without affecting the dry matter intake, in addition, it increases urea and total protein levels without causing liver or kidney damage in ewe lambs.

Objetivou-se avaliar a digestibilidade da matéria seca, consumo e perfil metabólico de borregas alimentadas com leveduras vivas e inativadas na ração contendo enzima fibrolítica. Foram utilizados vinte animais mestiços com peso médio de 33,4kg e idade média de seis meses, distribuídas em delineamento inteiramente casualizado. Os tratamentos consistiram nas leveduras: Controle (sem levedura), Milk Sacc X® (levedura ativa), Active Flora®(levedura viva mais levedura inativada) e Rúmen Yeast® (levedura inativa). Foi realizada à análise variância e teste SNK com nível de significância de 5% para o erro tipo I. Não houve diferença entre tratamentos para consumo de matéria seca com uso ou não de levedura na dieta (P>0,05). Houve tendência significativa (P=0,0596) para a digestibilidade da matéria seca sendo superior para com o tratamento sem inclusão de leveduras. Para os metabólitos sanguíneos houve tendência significativa (P=0,0705) sendo o Milk Sacc® superior aos demais tratamentos para concentração de proteínas totais. Além disso, houve diferença estatística (P<0,05) para concentração de ureia cujos tratamentos controle e Active Flora® foram superiores aos demais. A inclusão de leveduras vivas ou inativadas na dieta para borregas contendo enzima fibrolítica diminui a digestibilidade da dieta, sem afetar o consumo de matéria seca, além disso, aumenta teores de ureia e proteínas totais sem causar prejuízos hepáticos ou renais as borregas.

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This study aimed to evaluate the effects of chitosan and homolactic microbial inoculant on fermentative losses, chemical composition, fermentative profile, and aerobic stability of whole-plant soybean silage (WPSS). Additionally, it was evaluated nutrients intake and digestibility of sheep fed increasing levels of WPSS. Thirty experimental silos were randomly allocated to one of the following treatments: 1) CON: control, WPSS without additives; 2) LPPA: WPSS with Lactobacillus plantarum and Pediococcus acidilactici; and 3) CHI: chitosan, WPSS with 5 g/kg of chitosan. Ten male sheep were used to evaluate increasing dietary levels of WPSS: 0, 200, 400, 600, and 800 g/kg of diet dry matter (DM). Additives increased silage lactic acid bacteria and decreased the count of mold and yeast, gas, and total losses. Silages treated with additives had lower pH, NH3-N, and ethanol concentrations and higher lactic and propionic acids relative to CON. LPPA-treated silos showed higher organic matter and non-fiber carbohydrates content than CHI-ones. Additives increased the aerobic stability of WPSS. The addition of WPSS in sheep diets linearly increased nutrients intake and digestibility. Chitosan and LPPA improve WPSS fermentation, aerobic stability, and nutritional value. The WPSS in substitution to Cynodon hay increases sheep feed intake and nutrients digestibility.

Este estudo objetivou avaliar os efeitos da adição de quitosana e inoculante homolático sobre as perdas fermentativas, composição química, perfil fermentativo e estabilidade aeróbia da silagem de planta inteira de soja (SPIS). Em adição, foi avaliado o consumo e a digestibilidade de nutrientes em ovinos alimentados com dietas contendo níveis crescentes de SPIS. Trinta silos experimentais foram aleatoriamente alocados a um dos seguintes tratamentos: 1) CON: controle, SPIS sem aditivos; 2) LPPA: SPIS com Lactobacillus plantarum e Pediococcus acidilactici; e 3) QUI: quitosana, SPIS com 5 g/kg de quitosana. Dez ovinos machos foram usados para avaliar os níveis dietéticos de SPIS: 0, 200, 400, 600 e 800 g/kg da matéria seca (MS). Os aditivos aumentaram a contagem de bactérias láticas e reduziram a contagem de fungos e leveduras e as perdas fermentativas totais da SPIS. Silagens tratadas com aditivos tiveram menores pH, N-NH3 e etanol e maiores concentrações de ácido lático e propiônico, quando comparadas ao tratamento controle. Silos tratados com LPPA apresentaram maiores teores de matéria orgânica e carboidratos não fibrosos do que aqueles do tratamento QUI. Os aditivos aumentaram a estabilidade aeróbia da SPIS. A adição de SPIS na dieta de ovinos aumentou linearmente o consumo e a digestibilidade dos nutrientes. Quitosana e inoculante microbiano homolático melhoram a fermentação, estabilidade aeróbia e o valor nutricional da SPIS. A substituição de feno de Cynodon por SIPS aumenta o consumo e a digestibilidade dos nutrientes em ovinos.

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The purpose was to evaluate the effect of extruded roughage Foragge®with different additives onintake, digestibility nutrients and nitrogen balance of sheep. Twenty adults, non-pregnant ewes with average weight 68 kg were used. The treatments were extruded roughage with additives (essential oil, virginiamycin, unpurified inactive yeast, tannin and purified inactive yeast). The design was in randomized blocks. The means were contrasted by SNK test, and the fecal score was tested by the Kruskal Wallis test (1952), at 5% significance.There was no difference in the intake of dry matter, crude protein, nitrogen, water, water in relation to dry matter, neutral detergent fiber (NDF), and acid detergent fiber (p>0.05).As well as the digestibility of dry matter, crude protein and neutral detergent fiber, the fecal weight, fecal nitrogen, retained nitrogenand nitrogen retained in relation to nitrogen ingested (p>0.05).However, dry matter intake as a function of body weight and metabolic weight, urinary nitrogen, hemicellulose intake, and hemicellulose as a function of NDF, were higher in the Foragge Factor®treatment (p<0.05). The inclusion of different additives in the extruded roughage improved nutritional parameters, without causing disturbances.(AU)

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We aimed to determine the effect of relocation of whole-plant corn silage (WPCS) with different fermentation profiles on ingestive behavior of lambs. Twenty-four male Santa Inês lambs, were used in a completely randomized block design based on initial bodyweight (17.5 ± 1.8 kg) for the following treatments: CS: WPCS (not inoculated and not relocated); R-12h: WPCS relocated for 12h; IR-12h: WPCS inoculated with Lactobacillus plantarumand relocated for 12h; and R-24h: WPCS not inoculated and relocated for 24h. Ingestive behavior was observed as continuous (feeding, ruminating, and idling) and specific (urination, defecation, and water and salt access frequency) activities for 48h (3h intervals for a total of eight periods in 24h). The behavioral activities were affected only by periods (p = 0.0001). Feeding peaks was high at 8:00–11:00am(54.2%) and 5:00-8:00pm(54.9%) in compare to ruminating and idling at the same period. Rumination time was intense at night, at 63.7% (2:00–5:00am) and 69.7% (5:00–8:00am). Idling time (49.7%) was long after silage supply. The specific activities were intense during the morning periods. Supply of WPCS relocated up to 24h did not alter the ingestive behavior.(AU)

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This study aims to evaluate the use of active, inactive plus active, and inactive yeasts on the consumption of dry matter, water, and the apparent digestibility of dry matter, urinary parameters, and serum metabolites of lambs. Twenty crossbred lambs (Dorper x Santa Inês) were used, with an initial average body weight of 31.89 kg and seven months of age, distributed in a completely randomized design. Treatments were Control group (without yeasts); Active Flora® (ICC), live yeast plus inactivated yeast (Saccharomyces cerevisiae, 2.0 x 1010 UFC g-1) in the dose of 0.003 kg of animal dry matter -1 day-1,; Milk Sacc X® (Alltech®), active yeast - Saccharomyces cerevisiae strain 1026, 5.0 x 108 UFC g-1 - at the dose of 0.0015 kg of animal dry matter-1 day-1; and Rumen Yeast® (York Ag Products INC.), inactive yeast - Saccharomyces cerevisiae,1.5 x 104 UFC g-1 - in the dose of 0.0045 kg of animal dry matter-1 day-1. Variance analysis and the SNK (Student-Newman-Keuls) test were performed considering 5% significance. For glycemic concentrations over time, regression analysis at 5% significance were performed. The fecal score, as a non-parametric variable, was assessed by the Kruskal and Wallis test at a 5% significance level. There was a statistical difference (P< 0.05) in fecal dry matter (FDM), where the Active Flora® treatment was inferior to the others. The use of different yeasts did not change the intake and digestibility of dry matter, water, urinary parameters, and serum concentrations of energy, protein, and liver metabolites (P> 0.05). The average dry matter intake was 1.16 ± 0.16 kg day-1, whereas the dry matter digestibility was 85.40 ± 2.73%. It was concluded that active and/or inactive yeasts can be used as additives in the diet of lambs, maintaining the intake and digestibility of dry matter without causing metabolic disturbances.(AU)

Objetivou-se avaliar o efeito de leveduras ativas, inativas mais ativas e inativas sobre o consumo e digestibilidade aparente da matéria seca, de água, dos parâmetros urinários e dos metabólitos séricos de borregas. Utilizou-se 20 borregas mestiças Dorper x Santa Inês, com peso corporal médio inicial de 31,89 kg e sete meses de idade, distribuídas em delineamento inteiramente casualizado. Os tratamentos consistiram em Controle, sem uso de enzimas, e no uso das leveduras Active Flora® (levedura viva junto a levedura inativada - Saccharomyces Cerevisiae, com 2,0 x 1010 UFC g-1), Milk Sacc X® (levedura ativa - Saccharomyces C. 1026, 5,0 x 108 UFC g-1) e Rúmen Yeast® (levedura inativa - Saccharomyces C. com 1,5 x 104 UFC g-1). Foi realizado uma análise de variância e um teste SNK considerando 5% de significância. Para as concentrações glicêmicas ao longo do tempo foi realizada uma análise de regressão a 5% de significância. O escore fecal, por ser uma variável não paramétrica, foi avaliado pelo teste Kruskal e Wallis à significância de 5%. Observou-se a diferença estatística (P< 0,05) na matéria seca fecal (MSF), onde o tratamento Active Flora® se mostrou inferior aos demais. O uso de diferentes leveduras não modificou o consumo e a digestibilidade da matéria seca, de água, dos parâmetros urinários e das concentrações séricas dos metabólitos energéticos, proteicos e hepáticos (P> 0,05). A média de consumo da matéria seca foi de 1,16±0,16 kg dia-1, já a digestibilidade da matéria seca foi de 85,40 ±2,73%. Concluiu-se que as leveduras ativas e/ou inativas podem ser utilizadas como aditivos na dieta de borregas, mantendo o consumo e a digestibilidade da matéria seca sem causar distúrbios metabólicos.(AU)

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