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We investigated the consequences of fat supplementation (free oil and rumen-protected oil) on the nutrient intake and digestion of beef cattle at pasture. Five rumen-cannulated Nelore bulls, with a median body weight (BW) of 467.8 ± 32.8 kg and an age of 26 months, were distributed in a Latin square design (5 × 5). The treatments were as follows: WF, no additional fat; PA, rumen-protected palm oil; PS, rumen-protected soybean oil; SO, soybean-free oil and CO, free corn oil. Nutrient intake and digestibility, ruminal pH and ammonia (NH3-N), serum urea and nitrogen balance were analysed. The supplements with different oil sources did not alter (P > 0.05) the intake and digestibility of dry matter (DM), forage DM intake (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), neutral detergent fibre-corrected ash and protein (apNDF), nonfibre carbohydrates (NFC) or total digestible nutrients (TDN) compared to WF. An increase (P < 0.05) in the intake and digestibility of EE was observed with the inclusion of fat, independent of the source. No differences were observed between WF and other supplements with regard to ruminal parameters (pH and NH3-N) (P > 0.05) and serum urea (P > 0.05). The nitrogen balance was not affected by the fat source (P > 0.05). Supplementation of grazing beef cattle (2 g/kg BW) with free oil (130 g/kg DM supplement) or rumen-protected oil (160 g/kg DM supplement) did not interfere with nutrient intake and digestibility.

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This study evaluated the influence of the quantitative traits measured by real-time ultrasound (adjusted longissimus muscle area [AdjLMA], adjusted rump fat thickness [AdjRFT], and adjusted marbling [AdjMAR]) as well as age at first breeding [AFB] and adjusted weight [AdjWeight], on the probability of occurrence of early pregnancy (EP) in 55 Nellore heifers, and also performed an economic analysis. All calves received supplementation in creep-feeding (ad libitum), and at weaning (average age= 210 ± 30 days; average weight= 241 ± 33 kg) until first breeding by artificial insemination (May to November) all heifers were managed in the same group (two paddocks of 25 ha each evenly covered with Urochloa Marandu Grass) and received protein-energy supplementation (1% of average BW per animal/day). The quantitative variables were collected immediately after timed artificial insemination (average age= 392 ± 27 days; average weight= 431.90 kg), and the pregnancy diagnosis was completed at 30 days following insemination. For economic analysis, two systems were compared (age at first breeding at 13 and 24 months). The greater adjusted weight on the first breeding increased the probability of occurrence of early pregnancy, while the greater adjusted longissimus muscle area reduced. In addition, intensive meat production systems provide greater economic return throughout cow-calf operation.(AU)

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The search for healthy food leads to demand for functional foods that do not harm the health of the consumers. The objective was to evaluate the impact of the supply of cottonseed and crude glycerin as modulators of the lipid profile of the beef produced on pasture. The concentrated supplement was formulated with two levels of cottonseed (0 and 25%) and/or two levels of crude glycerin (0 and 15%), totaling four experimental groups. Two experiments were conducted; the first experiment was outlined in a 5 × 5 Latin square design, contrasting the protein-energy supplementation with the mineral supplementation. The concentrate supplementation allowed the increase in intake and digestibility of the dry matter (P = 0.03), ether extract, crude protein, and non-fibrous carbohydrate (P < 0.01). However, the results showed no effect of crude glycerin or cottonseed inclusion on intake or nutrients digestibility. The second experiment evaluated the protein-energy supplementation and its impact on the lipid profile of meat produced, carcass characteristics, and animal performance. There was no influence of cottonseed or crude glycerin in performance or carcass characteristics. However, the use of the cottonseed reduced the content of short-chain fatty acids, omega 3 linolenic acid, conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P < 0.01), and the inclusion of crude glycerin led to increased conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P = 0.04). An important result is given by illustrating the impact of these fatty acids in the nutritional quality of the meat. Thus, it is possible to manipulate the lipid profile of meat produced by cottonseed or crude glycerin supplementation, without affecting the animal performance.

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The objective of this study was to evaluate increasing levels of inclusion of dry distillery grains (DDGs) in substitution of corn and urea in multiple supplements for beef cattle of Urochloa brizantha cv. Marandu on the consumption, digestibility, and efficiency of microbial synthesis and use of nitrogen. We used four Nellore bulls cannulated in the rumen with an average age of 24 months and 445.12 ± 34.4 kg of body weight (BW), in a 4 × 4 Latin square design. Supplements differed by the inclusion level of DDG (0%, 31.5%, 63.0%, and 94.5%). Increasing levels of DDG inclusion decreased dry matter intake (DMI) (P = 0.002), forage (P = 0.002), organic matter (OM) (P = 0.001), crude protein (CP) (P = 0.037), and total digestible nutrients (TDN) (P < 0.001) and had a quadratic effect on the intake of non-fibrous carbohydrates (NFC) (P = 0.002). It was observed an increase in the digestibility of ether extract (EE) (P = 0.005), however a decrease in the digestibility of NFC (P = 0.001). Inclusion of DDG did not influence ruminal pH. There was a quadratic effect at collection times for ruminal ammoniacal nitrogen (P < 0.05), except for the supplement with 94.5% DDG where the effect was linear (P = 0.002). Nitrogen intake was 10.9% higher when there was no DDG in the supplement, compared with the supplement with 94.5% DDG (P = 0.039). The excretion of N by feces was greater when there was a greater amount of DDG in the supplement (P = 0.027), the opposite occurred with urine excretion of N, being higher when there was less amount of DDG in the supplement (P = 0.027). Increasing levels of DDG did not affect ruminal microbial protein yield (P > 0.05). Replacing corn and urea with up to 94.5% DDGs in multiple supplements resulted in no adverse effect efficiency of microbial synthesis, although nutrient intake, total digestible nutrients, and use of nitrogen were reduced at 94.5% DDG inclusion.

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The objective of this study was to evaluate the effects of rumen-protected oil (soybean and palm oil) in supplements for beef cattle during the fattening phase in pastures on the intake and digestibility of nutrients, animal performance, and carcass characteristics. Forty-eight noncastrated male Nellore cattle (15 ± 2 months and 389.5 ± 20 kg of body weight) were used in a completely randomized design to evaluate the following treatments: protein-energy supplement (PES) without rumen-protected oil (control: CO), PES containing palm rumen-protected oil (PRPO), PES containing soybean rumen-protected oil (SRPO), and PES containing a mixture of soybean and palm rumen-protected oil (SPRPO). The study lasted 112 days, and there was a decrease in crude protein intake (P < 0.05) and an increase in ether extract intake (P < 0.05) when rumen-protected oil was included in the supplements. In comparison to the palm rumen-protected oil supplement, the soybean rumen-protected oil supplement promoted a lower average daily gain (ADG) (P < 0.05); however, regardless of the rumen-protected oil source, an increase in the fat thickness of the subcutaneous tissue was observed. In addition, there was no difference in carcass gain (P > 0.05) regardless of oil source. Rumen-protected oil is a tool to increase the finishing of pasture-finished young beef cattle in the dry season.

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Objetivou-se avaliar a qualidade espermática do sêmen de touros suplementados com selênio (Se) na dieta. Foram utilizados 16 touros Brangus, igualmente distribuídos em grupo controle (GC) e grupo Se (GSe − 0,1mg de Se/kg de MS de dieta). O experimento teve duração de 75 dias, e os animais foram suplementados por 60 dias. Foram realizadas quatro coletas de sêmen durante o período (0, 30, 60 e 75 dias) por animal. As amostras foram avaliadas quanto a motilidade e vigor espermáticos, integridade e funcionalidade da membrana plasmática (teste de expansão hiposmótico - HIPO) e viabilidade espermática e reação acrossomal (coloração tripla - TRI). Após avaliação, estas foram diluídas em meio Tris-gema com 5% de glicerol, envasadas (40x106 espermatozoides/palheta), resfriadas, congeladas e armazenadas em nitrogênio líquido até a análise. Após descongelação, foram submetidas às mesmas avaliações descritas para o sêmen fresco. Não houve interferência da suplementação com Se nas variáveis vigor espermático, HIPO e TRI do sêmen fresco e descongelado. Porém, constatou-se queda na motilidade espermática do GSe comparativamente ao GC no sêmen fresco (P=0,0035) e descongelado (P=0,0067) após 60 dias de suplementação. Portanto, a suplementação de Se na dieta não foi efetiva na promoção de melhorias dos parâmetros espermáticos de touros Brangus.(AU)

The aim of the present study was to evaluate sperm quality of bulls supplemented with selenium (Se) in the diet. Sixteen Brangus bulls were randomly divided in two groups: control (GC) and Se (GSe - 0.1mg Se/kg dietary DM). The experiment lasted 75 days and the animals were supplemented for 60 days. Four semen collections (0, 30, 60 and 75 days) per animal, were performed during the experimental period. Sperm motility and vigor, plasma membrane integrity and functionality (hyposmotic swelling test - HOST) and sperm viability and acrosome reaction (triple staining -TRI) were assessed. After immediate analysis, samples were diluted in Tris-egg yolk extender with 5% glycerol, packed (40x106 spermatozoa / straw), chilled, frozen and stored in liquid nitrogen until analysis. After thawing, sperm motility and vigor, HOST and TRI were performed. No significance was noticed on sperm vigor, HOST and TRI of fresh and post-thawed semen after dietary selenium supplementation. However, sperm motility decreased in GSe compared to GC in fresh (P = 0.0035) and post- thawed (P = 0.0067) semen samples after 60 days of supplementation. Therefore, dietary selenium supplementation was ineffective to improve semen parameters of fresh and post-thawed semen of Brangus bulls.(AU)

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We tested the hypothesis that supplementation with protein improves fermentation parameters without damaging the rumen microbial populations of beef cattle grazing Urochloa brizantha cv. Marandu during the dry season. Four rumen-cannulated Nellore bulls (571 ± 31 kg of body weight) were used in a 4 × 4 Latin square design. The treatments were not supplemented with concentrate (only free-choice mineral salt ad libitum) and supplemented (supplements with low-LPSU, medium-MPS, and high protein supplement-HPS), supplying 155, 515, and 875 g/animal/day of crude protein (CP), respectively. The abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and domain bacteria primers. There was no difference (P > 0.05) across treatments for intakes of dry matter (DM), forage and neutral detergent fiber (NDF), digestibility of DM and NDF, and ruminal pH. Animals supplemented with concentrate had greater (P < 0.05) intakes and digestibility of CP, ether extract and non-fibrous carbohydrate contents of the substrates (EE + NFC), and ruminal ammonia nitrogen (RAN) compared to control. Bulls that received only mineral salt had lower proportions of Butyrivibrio fibrisolvens and had greater (P < 0.05) proportions of Fibrobacter succinogenes, Ruminococcus albus, Ruminococcus flavefaciens, Methanogen archaea than bulls supplemented with concentrate. The MPS animals had greater (P < 0.05) intake and digestibility of CP, RAN concentration, and had lower (P < 0.05) proportions of Fibrobacter succinogenes, Ruminococcus flavefaciens, and Selenomonas ruminantium than LPSU animals. The HPS provided higher (P < 0.05) intake of CP, RAN and proportion of Ruminococcus albus when compared with MPS. In conclusion, supply of 515 g/animal/day of protein via supplement provides better ruminal conditions for the growth of cellulolytic bacteria of bulls on pasture during dry season.

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The objective of this study was to evaluate the effects of tannins versus Monensin on in vitro ruminal fermentation of a feedlot diet. The treatments were: control (no additives); low tannin (2 mg g DM-1); medium tannin (4 mg g DM-1), high tannin (6 mg g DM-1), and Monensin (0.02 mg g DM-1). The substrate was a feedlot diet composed by hay and concentrate (15:85 w/w; DM basis). Ruminal fluid was obtained from three rumen-cannulated male Santa Inês sheep. In vitro incubations were carried out during four consecutive weeks (run). Gas production (GP) was recorded at 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24, 30, 36, 42, 48, 60, 72, 84, and 96 h of incubation. At 48 and 96 h, two bottles per treatment were withdrawn to measure pH, ammonia concentration (NH3), volatile fatty acid (VFA), in vitro dry matter digestibility (IVDMD), and in vitro neutral detergent fiber digestibility (IVNDFD). Addition of tannin or Monensin did not affect (P > 0.05) the kinetics parameters. Tannin supplementation reduced (P < 0.05) the GP at 24 h compared to Monensin. Addition of Monensin decreased (P < 0.05) IVDMD at 96 h and IVNDFD at 48 and 96 h compared to the control. The IVNDFD was lower (P < 0.05) with Monensin than with tannin at 48 and 96 h. The NH3 was lower (P < 0.05) with tannin compared with Monensin. By increasing tannin dosage, NH3 levels changed quadratically (P < 0.05). The inclusion of tannin in vitro reduced the NH3 concentration considerably when used in low dose.

O objetivo com este estudo foi avaliar os efeitos de taninos versus monensina sobre a fermentação ruminal in vitro de uma ração para ovinos em confinamento. Os tratamentos foram: controle (sem a inclusão de aditivos); baixa dose de tanino (2 mg g MS-1); média dose de tanino (4 mg g MS-1), alta dose de tanino (6 mg g MS-1), e monensina (0,02 mg g MS-1). O substrato utilizado foi uma ração para ovinos em confinamento composta por feno e concentrado (15:85 w/w; base da MS). O fluido ruminal foi obtido de três ovinos Santa Inês, machos não castrados, com cânula ruminal. As incubações in vitro foram realizadas em quatro semanas consecutivas (uma incubação por semana). A produção de gás (PG) foi mensurada nos tempos 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24, 30, 36, 42, 48, 60, 72, 84 e 96 horas de incubação. Nos tempos de 48 e 96 horas, dois frascos/tratamento foram retirados para mensurar pH, concentração de amônia (NH3), ácidos graxos voláteis (AGV), digestibilidade in vitro da matéria seca (DIVMS) e digestibilidade in vitro da fibra em detergente neutro (DIVFDN). A adição de tanino ou monensina não afetaram (P > 0,05) os parâmetros cinéticos. A suplementação de tanino reduz (P < 0,05) a PG em 24 horas de incubação comparado com a monensina. A inclusão de monensina reduz (P < 0,05) a DIVMS em 96 horas e a DIVFDN em 48 e 96 horas comparada ao controle. A DIVFDN foi menor (P < 0,05) com monensina que com tanino em 48 e 96 horas. A NH3 foi menor (P < 0,05) com tanino comparado à monensina. Aumentando a dose de tanino, a NH3 altera de forma quadrática (P < 0,05). A inclusão de tanino reduz consideravelmente as concentrações in vitro de NH3 quando usado em baixas doses.

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This study was designed to evaluate the effects of different supplementation plans on the nutrient intake, apparent total-tract digestibility, grazing behavior, growth performance, and carcass characteristics of beef cattle under grazing conditions from ages 4 to 18 months old. The beef calves grazed Brachiaria decumbens in four seasons: rainy-dry transition, dry, dry-rainy transition, and rainy. Forty-four animals (11 per treatment) were randomly assigned to one of four nutritional plans of supplementation defined by the quantity of supplement offered: control, low, medium, and high supplementation. There was no difference (P > 0.10) in dry matter intake (DMI). However, animals receiving medium and high supplementation had decreased (P < 0.10) forage dry matter intake (FDMI) compared with those under non- and low supplementation. The DMI and FDMI were lower (P < 0.10) in the dry season. During the rainy season, the grazing time decreased (P < 0.10) for animals receiving supplementation compared with non-supplemented ones, but was similar between medium and high supplementation. The performance and carcass characteristics were greater (P < 0.10) for high and medium supplementation compared with low and control. In conclusion, increasing the supplementation plans for beef cattle in tropical pastures increases the nutrient intake but decreases FDMI. The performance also increases with the supplementation plan; however, the growth rate is affected by the grazing season.

Este estudo foi conduzido para avaliar os efeitos de diferentes planos de suplementação sobre o consumo de nutrientes, digestibilidade aparente total, comportamento ingestivo, crescimento e características de carcaça de bovinos de corte de 4 a 18 meses de idade, em pastejo. Os animais foram mantidos em pastagem com Brachiaria decumbens em quatro períodos: transição águas-seca, seca, transição seca-águas e águas. Quarenta e quatro animais (11 por tratamento) foram distribuídos aleatoriamente em um dos quatro planos nutricionais de suplementação definidos pela quantidade de suplemento ofertada: controle (somente mistura mineral), baixo, médio e alto plano de suplementação. Não houve diferença (P > 0,10) no consumo de matéria seca (CMS). No entanto, os animais que receberam médio e alto plano de suplementação reduziram (P < 0,10) o consumo de matéria seca de forragem (CMSF) comparado ao controle e baixo plano. O CMS e CMSF foram menores (P < 0,10) durante o período seco. Durante a estação chuvosa, o tempo de pastejo reduziu (P < 0,10) para os animais que receberam suplementação em comparação ao controle, mas foi semelhante entre os planos médio e alto. O desempenho e as características de carcaça foram maiores (P < 0,10) para o alto e médio plano comparados ao baixo e controle. Conclui-se que o aumento nas suplementações para bovinos de corte em pastagens tropicais aumenta a ingestão de nutrientes, mas diminui o consumo de forragem. O desempenho também aumenta com o plano de suplementação; no entanto, a taxa de crescimento é afetada pela época do ano.

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RESUMEN

Objetivou-se avaliar a qualidade espermática do sêmen de touros suplementados com selênio (Se) na dieta. Foram utilizados 16 touros Brangus, igualmente distribuídos em grupo controle (GC) e grupo Se (GSe − 0,1mg de Se/kg de MS de dieta). O experimento teve duração de 75 dias, e os animais foram suplementados por 60 dias. Foram realizadas quatro coletas de sêmen durante o período (0, 30, 60 e 75 dias) por animal. As amostras foram avaliadas quanto a motilidade e vigor espermáticos, integridade e funcionalidade da membrana plasmática (teste de expansão hiposmótico - HIPO) e viabilidade espermática e reação acrossomal (coloração tripla - TRI). Após avaliação, estas foram diluídas em meio Tris-gema com 5% de glicerol, envasadas (40x106 espermatozoides/palheta), resfriadas, congeladas e armazenadas em nitrogênio líquido até a análise. Após descongelação, foram submetidas às mesmas avaliações descritas para o sêmen fresco. Não houve interferência da suplementação com Se nas variáveis vigor espermático, HIPO e TRI do sêmen fresco e descongelado. Porém, constatou-se queda na motilidade espermática do GSe comparativamente ao GC no sêmen fresco (P=0,0035) e descongelado (P=0,0067) após 60 dias de suplementação. Portanto, a suplementação de Se na dieta não foi efetiva na promoção de melhorias dos parâmetros espermáticos de touros Brangus.

The aim of the present study was to evaluate sperm quality of bulls supplemented with selenium (Se) in the diet. Sixteen Brangus bulls were randomly divided in two groups: control (GC) and Se (GSe - 0.1mg Se/kg dietary DM). The experiment lasted 75 days and the animals were supplemented for 60 days. Four semen collections (0, 30, 60 and 75 days) per animal, were performed during the experimental period. Sperm motility and vigor, plasma membrane integrity and functionality (hyposmotic swelling test - HOST) and sperm viability and acrosome reaction (triple staining -TRI) were assessed. After immediate analysis, samples were diluted in Tris-egg yolk extender with 5% glycerol, packed (40x106 spermatozoa / straw), chilled, frozen and stored in liquid nitrogen until analysis. After thawing, sperm motility and vigor, HOST and TRI were performed. No significance was noticed on sperm vigor, HOST and TRI of fresh and post-thawed semen after dietary selenium supplementation. However, sperm motility decreased in GSe compared to GC in fresh (P = 0.0035) and post- thawed (P = 0.0067) semen samples after 60 days of supplementation. Therefore, dietary selenium supplementation was ineffective to improve semen parameters of fresh and post-thawed semen of Brangus bulls.

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RESUMEN

The objective of this study was to evaluate the effects of tannins versus Monensin on in vitro ruminal fermentation of a feedlot diet. The treatments were: control (no additives); low tannin (2 mg g DM-1); medium tannin (4 mg g DM-1), high tannin (6 mg g DM-1), and Monensin (0.02 mg g DM-1). The substrate was a feedlot diet composed by hay and concentrate (15:85 w/w; DM basis). Ruminal fluid was obtained from three rumen-cannulated male Santa Inês sheep. In vitro incubations were carried out during four consecutive weeks (run). Gas production (GP) was recorded at 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24, 30, 36, 42, 48, 60, 72, 84, and 96 h of incubation. At 48 and 96 h, two bottles per treatment were withdrawn to measure pH, ammonia concentration (NH3), volatile fatty acid (VFA), in vitro dry matter digestibility (IVDMD), and in vitro neutral detergent fiber digestibility (IVNDFD). Addition of tannin or Monensin did not affect (P > 0.05) the kinetics parameters. Tannin supplementation reduced (P < 0.05) the GP at 24 h compared to Monensin. Addition of Monensin decreased (P < 0.05) IVDMD at 96 h and IVNDFD at 48 and 96 h compared to the control. The IVNDFD was lower (P < 0.05) with Monensin than with tannin at 48 and 96 h. The NH3 was lower (P < 0.05) with tannin compared with Monensin. By increasing tannin dosage, NH3 levels changed quadratically (P < 0.05). The inclusion of tannin in vitro reduced the NH3 concentration considerably when used in low dose.(AU)

O objetivo com este estudo foi avaliar os efeitos de taninos versus monensina sobre a fermentação ruminal in vitro de uma ração para ovinos em confinamento. Os tratamentos foram: controle (sem a inclusão de aditivos); baixa dose de tanino (2 mg g MS-1); média dose de tanino (4 mg g MS-1), alta dose de tanino (6 mg g MS-1), e monensina (0,02 mg g MS-1). O substrato utilizado foi uma ração para ovinos em confinamento composta por feno e concentrado (15:85 w/w; base da MS). O fluido ruminal foi obtido de três ovinos Santa Inês, machos não castrados, com cânula ruminal. As incubações in vitro foram realizadas em quatro semanas consecutivas (uma incubação por semana). A produção de gás (PG) foi mensurada nos tempos 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24, 30, 36, 42, 48, 60, 72, 84 e 96 horas de incubação. Nos tempos de 48 e 96 horas, dois frascos/tratamento foram retirados para mensurar pH, concentração de amônia (NH3), ácidos graxos voláteis (AGV), digestibilidade in vitro da matéria seca (DIVMS) e digestibilidade in vitro da fibra em detergente neutro (DIVFDN). A adição de tanino ou monensina não afetaram (P > 0,05) os parâmetros cinéticos. A suplementação de tanino reduz (P < 0,05) a PG em 24 horas de incubação comparado com a monensina. A inclusão de monensina reduz (P < 0,05) a DIVMS em 96 horas e a DIVFDN em 48 e 96 horas comparada ao controle. A DIVFDN foi menor (P < 0,05) com monensina que com tanino em 48 e 96 horas. A NH3 foi menor (P < 0,05) com tanino comparado à monensina. Aumentando a dose de tanino, a NH3 altera de forma quadrática (P < 0,05). A inclusão de tanino reduz consideravelmente as concentrações in vitro de NH3 quando usado em baixas doses.(AU)

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RESUMEN

This study was designed to evaluate the effects of different supplementation plans on the nutrient intake, apparent total-tract digestibility, grazing behavior, growth performance, and carcass characteristics of beef cattle under grazing conditions from ages 4 to 18 months old. The beef calves grazed Brachiaria decumbens in four seasons: rainy-dry transition, dry, dry-rainy transition, and rainy. Forty-four animals (11 per treatment) were randomly assigned to one of four nutritional plans of supplementation defined by the quantity of supplement offered: control, low, medium, and high supplementation. There was no difference (P > 0.10) in dry matter intake (DMI). However, animals receiving medium and high supplementation had decreased (P < 0.10) forage dry matter intake (FDMI) compared with those under non- and low supplementation. The DMI and FDMI were lower (P < 0.10) in the dry season. During the rainy season, the grazing time decreased (P < 0.10) for animals receiving supplementation compared with non-supplemented ones, but was similar between medium and high supplementation. The performance and carcass characteristics were greater (P < 0.10) for high and medium supplementation compared with low and control. In conclusion, increasing the supplementation plans for beef cattle in tropical pastures increases the nutrient intake but decreases FDMI. The performance also increases with the supplementation plan; however, the growth rate is affected by the grazing season.(AU)

Este estudo foi conduzido para avaliar os efeitos de diferentes planos de suplementação sobre o consumo de nutrientes, digestibilidade aparente total, comportamento ingestivo, crescimento e características de carcaça de bovinos de corte de 4 a 18 meses de idade, em pastejo. Os animais foram mantidos em pastagem com Brachiaria decumbens em quatro períodos: transição águas-seca, seca, transição seca-águas e águas. Quarenta e quatro animais (11 por tratamento) foram distribuídos aleatoriamente em um dos quatro planos nutricionais de suplementação definidos pela quantidade de suplemento ofertada: controle (somente mistura mineral), baixo, médio e alto plano de suplementação. Não houve diferença (P > 0,10) no consumo de matéria seca (CMS). No entanto, os animais que receberam médio e alto plano de suplementação reduziram (P < 0,10) o consumo de matéria seca de forragem (CMSF) comparado ao controle e baixo plano. O CMS e CMSF foram menores (P < 0,10) durante o período seco. Durante a estação chuvosa, o tempo de pastejo reduziu (P < 0,10) para os animais que receberam suplementação em comparação ao controle, mas foi semelhante entre os planos médio e alto. O desempenho e as características de carcaça foram maiores (P < 0,10) para o alto e médio plano comparados ao baixo e controle. Conclui-se que o aumento nas suplementações para bovinos de corte em pastagens tropicais aumenta a ingestão de nutrientes, mas diminui o consumo de forragem. O desempenho também aumenta com o plano de suplementação; no entanto, a taxa de crescimento é afetada pela época do ano.(AU)

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RESUMEN

Exogenous enzyme preparations (fibrolytic activity (FIB), 0, 0.6, 1.2, 1.8, and 2.4 mg/ml liquid volume incubated; amylolytic activity (AMZ), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated; proteolytic activity (PRO), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated) were incubated in vitro. Their fermentation effects were assessed based on accumulated gas production, kinetic parameters, and fermentation profile using the technique of gas fermentation. Ruminal liquid was obtained from two rumen cannulated Santa Inês sheep, fed a diet with roughage-to-concentrate ratio of 20:80. Accumulated gas production was during 96 h of incubation, measured at 18 different times. After incubation, pH, dry matter degradability (DMD), organic matter in vitro digestibility (OMD), metabolisable energy (ME), partitioning factor (PF96), gas yield (GY24), short chain fatty acids (SCFA), and microbial protein production (MCP) were evaluated. Increasing FIB dose linearly decreased (P 0.05) lag time without affecting others kinetic parameters. However, FIB increased the accumulated gas production, resulting in improved DMD, OMD, ME, GY24 and SCFA. The addition of AMZ decreased linearly (P 0.05) lag time and increased (P 0.05) gas production on initial times of incubation without altering the fermentation profile. The inclusion of PRO did not affect (P>0.05) the evaluated parameters. The addition of these exogenous enzyme preparations with fibrolytic activity altered ruminal fermentation in vitro of diets containing high levels of concentrates.

Preparações de enzimas exógenas (atividade fibrolítica (FIB); 0,0; 0,6; 1,2; 1,8 e 2,4 mg/ml do volume de líquido incubado; atividade amilolítica (AMZ); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado; atividade proteolítica (PRO); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado) incubado in vitro. Os efeitos de fermentação foram avaliados com base na produção de gás acumulado, parâmetros cinéticos e, perfil de fermentação usando a técnica de fermentação in vitro. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, alimentados com dieta relação volumoso:concentrado de 20:80. A produção de gás acumulada foi durante 96 h de incubação, mensurados em 18 tempos diferentes. Após a incubação foi avaliado pH, digestibilidade da material seca (DMS), digestibilidade da material orgânica (DMO), energia metabolizável (EM), fator de partição (FP96), rendimento de gás (RG24), ácidos graxos de cadeia curta (AGCC), e produção de proteína microbiana (PPM). O incremento de doses linear de FIB diminuiu (P 0,05) o lag time sem afetar outros parâmetros cinéticos. No entanto, adição de FIB aumentou a produção de gás acumulado, resultando em incremento na DMS, DMO, EM, RG24 e AGCC. A adição de AMZ diminuiu linearmente (P 0,05) lag time e incrementou (P 0,05) produção de gás nos tempos iniciais de incubação sem alterar o perfil de fermentação. A inclusão de PRO não afetou (P>0,05) os parâmetros avaliados. As adições de preparações enzimáticas exógenas com atividades fibrolíticas alteram fermentação ruminal in vitro de dieta de alta níveis de concentrado.

Asunto(s)

RESUMEN

Exogenous enzyme preparations (fibrolytic activity (FIB), 0, 0.6, 1.2, 1.8, and 2.4 mg/ml liquid volume incubated; amylolytic activity (AMZ), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated; proteolytic activity (PRO), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated) were incubated in vitro. Their fermentation effects were assessed based on accumulated gas production, kinetic parameters, and fermentation profile using the technique of gas fermentation. Ruminal liquid was obtained from two rumen cannulated Santa Inês sheep, fed a diet with roughage-to-concentrate ratio of 20:80. Accumulated gas production was during 96 h of incubation, measured at 18 different times. After incubation, pH, dry matter degradability (DMD), organic matter in vitro digestibility (OMD), metabolisable energy (ME), partitioning factor (PF96), gas yield (GY24), short chain fatty acids (SCFA), and microbial protein production (MCP) were evaluated. Increasing FIB dose linearly decreased (P 0.05) lag time without affecting others kinetic parameters. However, FIB increased the accumulated gas production, resulting in improved DMD, OMD, ME, GY24 and SCFA. The addition of AMZ decreased linearly (P 0.05) lag time and increased (P 0.05) gas production on initial times of incubation without altering the fermentation profile. The inclusion of PRO did not affect (P>0.05) the evaluated parameters. The addition of these exogenous enzyme preparations with fibrolytic activity altered ruminal fermentation in vitro of diets containing high levels of concentrates.(AU)

Preparações de enzimas exógenas (atividade fibrolítica (FIB); 0,0; 0,6; 1,2; 1,8 e 2,4 mg/ml do volume de líquido incubado; atividade amilolítica (AMZ); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado; atividade proteolítica (PRO); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado) incubado in vitro. Os efeitos de fermentação foram avaliados com base na produção de gás acumulado, parâmetros cinéticos e, perfil de fermentação usando a técnica de fermentação in vitro. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, alimentados com dieta relação volumoso:concentrado de 20:80. A produção de gás acumulada foi durante 96 h de incubação, mensurados em 18 tempos diferentes. Após a incubação foi avaliado pH, digestibilidade da material seca (DMS), digestibilidade da material orgânica (DMO), energia metabolizável (EM), fator de partição (FP96), rendimento de gás (RG24), ácidos graxos de cadeia curta (AGCC), e produção de proteína microbiana (PPM). O incremento de doses linear de FIB diminuiu (P 0,05) o lag time sem afetar outros parâmetros cinéticos. No entanto, adição de FIB aumentou a produção de gás acumulado, resultando em incremento na DMS, DMO, EM, RG24 e AGCC. A adição de AMZ diminuiu linearmente (P 0,05) lag time e incrementou (P 0,05) produção de gás nos tempos iniciais de incubação sem alterar o perfil de fermentação. A inclusão de PRO não afetou (P>0,05) os parâmetros avaliados. As adições de preparações enzimáticas exógenas com atividades fibrolíticas alteram fermentação ruminal in vitro de dieta de alta níveis de concentrado.(AU)

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RESUMEN

We tested the hypothesis that supplementation with three protein levels improves fermentation parameters without changing the rumen microbial population of grazing beef cattle in the rainy season. Four rumen-cannulated Nellore bulls (432 ± 21 kg of body weight) were used in a 4 × 4 Latin square design with four supplements and four experimental periods of 21 days each. The treatments were mineral supplement (ad libitum) and supplements with low, medium (MPS), and high protein supplement (HPS), supplying 106, 408, and 601 g/day of CP, respectively. The abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and domain bacteria primers. Supplemented animals showed lower (P < 0.05) proportions of Ruminococcus flavefaciens and greater (P < 0.05) proportions of Ruminococcus albus and Butyrivibrio fibrisolvens than animals that received only the mineral supplement. The HPS supplement resulted in higher (P < 0.05) proportions of Fibrobacter succinogenes, R. flavefaciens, and B. fibrisolvens and lower (P < 0.05) proportions of R. albus than the MPS supplement. Based on our results, high protein supplementation improves the ruminal conditions and facilitates the growth of cellulolytic bacteria in the rumen of bulls on pastures during the rainy season.

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This study evaluated the effects of eight combinations of three exogenous enzymes with fibrolytic activity (FIB), amylolytic activity (AMZ), and proteolytic activity (PRO) on the accumulated gas production (PG) and kinetic parameters in simulated fermentations in two diet production systems using the in vitro gas production technique. In experiment 1, ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, kept in a feedlot and fed a diet containing a roughage:concentrate ratio of 20:80. In experiment 2, the ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, and kept on pasture (Brachiaria brizantha cv. Marandu). The accumulated gas production was measured during a 96-hour incubation, measured at 18 different time points. After incubation, the pH, dry matter degradability, organic matter in vitro digestibility, digestibility of neutral detergent insoluble fiber, metabolizable energy, partitioning factor, gas yield, short chain fatty acids and microbial protein production were determined. In the in vitro fermentation using the feedlot diet, the increased use of fibrolytic enzymes increased PG and improved the profile characteristics and kinetic parameters of the fermentation, regardless of the combination with other enzymes. In the in vitro fermentation using the forage diet, increased fibrolytic enzymes also increased PG, with improvements in the kinetic parameters and the profile of the fermentation, independent of the use of the other enzymes. The addition only of fibrolytic enzymes has major potential to optimize the use of feedlot diets as well of forage in ruminant feed.

Objetivou-se avaliar oito combinações entre três enzimas exógenas fibrolíticas (FIB), amilolíticas (AMZ), e proteolíticas (PRO), sobre a produção acumulada de gás (PG), parâmetros cinéticos e perfil da fermentação simulando dietas de dois sistemas de produção através da técnica de produção de gás in vitro. No experimento 1, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos em confinamento, alimentados com dieta com relação volumoso:concentrado 20:80. No experimento 2, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos no pasto (Brachiaria brizantha cv. Marandu). A produção de gás acumulada foi obtida em 96 h de incubação, mensurada em 18 horários. Ao final da incubação determinaramse o pH, degradabilidade da matéria seca, digestibilidade in vitro da matéria orgânica, desaparecimento da fibra insolúvel de detergente neutro, energia metabolizável, fator de partição, rendimento de gás, ácidos graxos de cadeia curta, produção de biomassa de proteína microbiana. A fermentação in vitro simulando dietas de confinamento, determinou-se que a participação de enzimas fibrolíticas aumentou PG, e melhorou as características dos parâmetros cinéticos e perfil da fermentação, independente da combinação ou/não com outras enzimas. A fermentação in vitro simulando dietas de forragem, a participação de enzimas fibrolíticas aumentou PG, com melhorias nos parâmetros cinéticos e perfil da fermentação, com ou sem a combinação de outras enzimas. A inclusão apenas de enzimas fibrolíticas tem o maior potencial de otimizar a utilização de dieta de confinamento como também em forragens na alimentação de ruminantes.

Asunto(s)

RESUMEN

This study evaluated the effects of eight combinations of three exogenous enzymes with fibrolytic activity (FIB), amylolytic activity (AMZ), and proteolytic activity (PRO) on the accumulated gas production (PG) and kinetic parameters in simulated fermentations in two diet production systems using the in vitro gas production technique. In experiment 1, ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, kept in a feedlot and fed a diet containing a roughage:concentrate ratio of 20:80. In experiment 2, the ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, and kept on pasture (Brachiaria brizantha cv. Marandu). The accumulated gas production was measured during a 96-hour incubation, measured at 18 different time points. After incubation, the pH, dry matter degradability, organic matter in vitro digestibility, digestibility of neutral detergent insoluble fiber, metabolizable energy, partitioning factor, gas yield, short chain fatty acids and microbial protein production were determined. In the in vitro fermentation using the feedlot diet, the increased use of fibrolytic enzymes increased PG and improved the profile characteristics and kinetic parameters of the fermentation, regardless of the combination with other enzymes. In the in vitro fermentation using the forage diet, increased fibrolytic enzymes also increased PG, with improvements in the kinetic parameters and the profile of the fermentation, independent of the use of the other enzymes. The addition only of fibrolytic enzymes has major potential to optimize the use of feedlot diets as well of forage in ruminant feed.(AU)

Objetivou-se avaliar oito combinações entre três enzimas exógenas fibrolíticas (FIB), amilolíticas (AMZ), e proteolíticas (PRO), sobre a produção acumulada de gás (PG), parâmetros cinéticos e perfil da fermentação simulando dietas de dois sistemas de produção através da técnica de produção de gás in vitro. No experimento 1, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos em confinamento, alimentados com dieta com relação volumoso:concentrado 20:80. No experimento 2, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos no pasto (Brachiaria brizantha cv. Marandu). A produção de gás acumulada foi obtida em 96 h de incubação, mensurada em 18 horários. Ao final da incubação determinaramse o pH, degradabilidade da matéria seca, digestibilidade in vitro da matéria orgânica, desaparecimento da fibra insolúvel de detergente neutro, energia metabolizável, fator de partição, rendimento de gás, ácidos graxos de cadeia curta, produção de biomassa de proteína microbiana. A fermentação in vitro simulando dietas de confinamento, determinou-se que a participação de enzimas fibrolíticas aumentou PG, e melhorou as características dos parâmetros cinéticos e perfil da fermentação, independente da combinação ou/não com outras enzimas. A fermentação in vitro simulando dietas de forragem, a participação de enzimas fibrolíticas aumentou PG, com melhorias nos parâmetros cinéticos e perfil da fermentação, com ou sem a combinação de outras enzimas. A inclusão apenas de enzimas fibrolíticas tem o maior potencial de otimizar a utilização de dieta de confinamento como também em forragens na alimentação de ruminantes.(AU)

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RESUMEN

Two experiments were conducted to evaluate reduced supplementation frequencies for grazing beef cattle in rainy season. In experiment 1, evaluating the nutritional parameters, four rumen-cannulated Nellore bulls (BW = 410 kg) were used. In experiment 2, evaluating animal performance, 48 Nellore bulls (BW = 358 kg) were used. The treatments were as follows: mineral supplement (MS) alone and MS plus protein-energy supplement provided 3×, 5× and 7×/week. Supplementation frequency did not affect (P > 0.05) intake and digestibility. Average daily gain was greater (P < 0.001) to supplementation compared with MS. The supplementation 5×/week resulted in greater weight gain per hectare (9.24) and higher economic returns during the study period (1.64%) compared to other supplementations. Supplementation 5×/week increased animal performance and positively influenced economic returns.

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RESUMEN

Supplementation of animals in the rainy season is essential to maximise weight gain. Thus, the objective was to evaluate the effects of supplementation with low-, medium- and high-protein levels on nutritional parameters of grazing beef cattle in the rainy season. Eight rumen-cannulated Nellore bulls (437 kg body weight) were used in a 4 × 4 double Latin square design with four supplements and four experimental periods. The treatments were mineral supplement (ad libitum) and supplements with low-protein (LPSU), medium-protein (MPS) and high-protein (HPS) levels, providing 106, 408 and 601 g/day of crude protein (CP), respectively. There was no difference (P > 0.05) between treatments for dry matter and forage intake, ruminal pH, ruminal ammonia nitrogen (RAN) at time 0 (before supplementation) and microbial protein yield. Animals on MPS had a higher (P > 0.05) intake and digestibility of CP, higher RAN levels (3 and 6 h after supplementation), increased nitrogen intake and a better nitrogen balance than animals on LPSU. The HPS provided higher (P > 0.05) RAN at time 6 and a better nitrogen balance when compared with MPS. We therefore infer that the high-protein supplement positively impacts nitrogen metabolism and efficiency in grazing beef cattle during the rainy season.

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We evaluated the effects of increasing levels of crude glycerin in multiple supplements for grazing beef cattle on intake, nutrient digestibility, pH, ruminal ammoniacal nitrogen, and serum glucose. Five Nellore steers (initial BW of 480 kg [SD 15]), grazing a tropical pasture, were used in a 5 × 5 Latin square design. The treatments used were control (no supplementation; only a mineral mixture ad libitum) and four levels of crude glycerin (0, 80, 160, 240 g/kg of supplements). Supplementation type had no impact (P > 0.05) on pH at 0 and 4 h after supplementation. Animals supplemented with different levels of crude glycerin showed higher N-NH3 values (P 0.05), increasing dry matter intake (P > 0.05) due to increased organic matter digestibility (P > 0.05). Supplementation of 4 kg/animal with crude glycerin (240 g/kg supplement) did not reduce pasture intake and organic matter digestibility.

Objetivou-se avaliar o efeito de níveis crescentes de glicerina bruta em suplementos múltiplos, sobre consumo, digestibilidade dos nutrientes, pH, nitrogênio amoniacal ruminal e glicose sérica. Foram utilizados cinco novilhos, Nelore (peso inicial de 480 kg ± 15), em pastejo de forragem tropical, em delineamento experimental Quadrado Latino 5X5. Os tratamentos utilizados foram controle (apenas suplementação mineral) e quatro níveis de glicerina bruta (0, 80, 160, 240 g/kg de suplemento). Não houve influencia do tipo de suplementação (P>0,05) para pH no tempo zero ou quatro horas após a suplementação. Os animais suplementados com níveis de glicerina bruta apresentaram maior N-NH3 (P>0,05) quatro horas após a suplementação, e o consumo de pasto não foi afetado (P>0,05), com incremento no consumo de matéria seca total (P<0,05), devido o aumento da digestibilidade da matéria orgânica (P<0,05). Os suplementos concentrados fornecidos na quantidade de 4 kg por animal a inclusão de glicerina bruta (240 g/kg de suplemento) não altera o consumo de pasto, suplemento e matéria orgânica digerida.

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