ABSTRACT. The aim of this study was to evaluate the feeding behavior of sheep fed sugarcane silage enriched with increasing levels of detoxified castor bean meal. Twenty-four non-castrated male Santa Inês sheep with an average body weight of 25.34 kg and four months of age, were distributed in four treatments - 0, 7, 14 and 21% of the natural matter of detoxified castor bean meal in sugarcane silage. There was a linear increase (p < 0.05) in time spent eating and feeding and rumination efficiency (g MS and NDF/h) with the inclusion of castor bean meal in silage. However, there was a linear decreasing response for time spent resting (p < 0.05). Time spent ruminating, number of boluses per day and numbers of chews per day per bolus were not affected (p > 0.05) by the inclusion of castor bean meal. The addition of detoxified castor bean meal to sugarcane silage reduces time spent eating and increases feed and rumination efficiency in sheep.

ABSTRACT. The aim of this study was to evaluate the effect of increasing levels of supplementation on body weight components of Nellore cattle grazing in Urochloa brizantha. Twenty-four steers with initial body weight (BW) of 371 ± 14 kg and average age of 26 months were used. Four animals were slaughtered at the beginning of the experiment as a reference and the others were distributed in 4 treatments [0.0% (mineral salt), 0.3%, 0.6% and 0.9% supplement BW]. The slaughter of the experimental group was performed when the animals reached 450 kg and the body weight components were weighed. Data were submitted to analysis of variance and regression. The increase in supplementation level reduced (p < 0.05) pasture dry matter intake, but did not influence (p > 0.05) on empty body weight (EBW) (380.3 kg) and cold carcass weight (CCW) (247.5 kg). The weights of skin, liver, rumen and fat were not influenced (p > 0.05) by supplementation level. The animals gained, on average, 75.3 kg EBW and 50.7 kg CCW, but the treatments did not influence (p > 0.05) the gains of body weight components. The increasing of energetic-protein supplement level for Nellore steers in Urochloa brizantha pasture does not affect carcass and non-carcass components.

RESUMO O experimento foi desenvolvido para avaliar os efeitos do emurchecimento e da inclusão de níveis de farelo de mandioca sobre o valor nutritivo, as características fermentativas e as perdas por gases e efluente da silagem de capim-elefante. Foi adotado o esquema fatorial 4 x 2, com quatro repetições, no delineamento inteiramente casualizado. Os fatores avaliados foram níveis de farelo de mandioca (0; 7,5; 15 e 22,5 % da matéria natural, MN) e emurchecimento (com e sem). Foram usados silos de PVC, com 50 cm de altura e 10 cm de diâmetro para a produção das silagens, que foram abertos após 60 dias. O emurchecimento e a adição do farelo de mandioca tiveram efeito linear crescente sobre o teor de matéria seca (MS). As silagens com farelo de mandioca apresentaram redução dos teores de nitrogênio total, extrato etéreo, nitrogênio insolúvel em detergente ácido, fibra em detergente neutro isenta de cinzas e proteína, fibra em detergente ácido, celulose, hemicelulose e lignina e elevação do teor de matéria orgânica, da digestibilidade in vitro da MS e dos nutrientes digestíveis totais. No que concerne às características fermentativas das silagens, o pH apresentou comportamento quadrático. Quanto ao nitrogênio amoniacal, observou-se comportamento quadrático e linear decrescente para as silagens sem e com emurchecimento, respectivamente. O emurchecimento e a inclusão do farelo de mandioca propiciaram menores perdas por efluente. O emurchecimento e a adição de farelo de mandioca melhora o valor nutritivo e as características fermentativas das silagens estudadas.

SUMMARY The experiment was developed to evaluate the effects of wilting and inclusion of cassava meal level on nutritive value, fermentative characteristics and losses of elephant grass silage. The 4 x 2 factorial scheme was adopted, with four repetitions, in a completely randomized design. The factors evaluated were wilting (without and with) and cassava meal level (0; 7.5; 15 and 22.5% of natural matter, DN). PVC silos with 50 cm height and 10 cm diameter were used for silages production, which were opened after 60 days. The wilting and cassava meal addition had increasing linear effect on DM content. Silages with cassava meal showed reduction of total nitrogen, ether extract, acid detergent insoluble nitrogen, neutral detergent fiber ash and protein free, acid detergent fiber, celluloses, hemicelluloses and lignin contents and increase of organic matter content, DM in vitro digestibility and total digestible nutrients. Relative to variables inherent to silages’ fermentative characteristics, pH presented quadratic behavior. Concerning to ammonia nitrogen, it was observed quadratic and decreasing linear behavior for silages without and with wilting, respectively. Wilting and cassava meal inclusion provided smaller effluent losses.

The objective of this study was to evaluate the economic returns of crossbred calves grazing on pastures formed by Urochloa brizantha fed crude glycerin as a supplement. Thirty-six crossbred calves with initial average weight of 301.5 kg were distributed in a completely randomized design with four treatments and nine replicates per treatment. The animals were maintained on rotational grazing production of Urochloa brizantha cv. Marandu. The tested treatments were 0.0, 3.33, 6.66 and 9.99% inclusion of crude glycerin in the total dry matter as a substitute for corn. The production of meat was not altered by the inclusion of glycerin in the diet. The inclusion of glycerin caused a reduction of up to 14.93% in the price of the concentrate. There was a significant increase in the total balance, which rose from 3.76 to 91.89 R$/ha with the inclusion of glycerin. The inclusion of crude glycerin in the supplement was capable of raising the net present value and the internal rate of return, proving to be an alternative to reduce the cost of production of supplemented pastured animals.

Objetivou-se determinar as frações que compõem os carboidratos e as proteínas, bem como as características fermentativas da silagem de capim-elefante, sem e com emurchecimento, e acrescida de farelo de mandioca. Foi adotado o esquema fatorial 4 x 2, com quatro repetições no delineamento inteiramente casualizado. Os fatores avaliados foram níveis de farelo de mandioca (0; 7,5; 15 e 22,5% MN) e emurchecimento (sem e com). Foram usados silos de PVC, com 50 cm de altura e 10cm de diâmetro para a produção das silagens. As frações de CHO (A+B1 e B2) e as frações nitrogenadas B3 e C foram influenciadas pela associação do emurchecimento aos níveis de farelo de mandioca, o que não ocorreu com as frações nitrogenadas (A e B1+B2) das silagens. A adição de farelo de mandioca reduziu linearmente a fração C dos carboidratos. No que concerne às características fermentativas das silagens, o pH apresentou comportamento quadrático. O nitrogênio amoniacal apresentou comportamento quadrático e linear decrescente para as silagens sem e com emurchecimento, respectivamente. A utilização do farelo de mandioca reduz a fração B2 e a porção de carboidratos indisponíveis. As principais frações proteicas das silagens estudadas são as frações A e B1+B2. O emurchecimento e a adição de farelo de mandioca melhoram o valor nutritivo e as características fermentativas das silagens estudadas.

The objective of this work was to determine the fractions that compose the carbohydrates (CHO) and proteins and fermentative characteristics of elephant grass silage without or with wilting and added of cassava meal. The 4 x 2 factorial scheme was adopted, with four repetitions, in a completely randomized design. The factors evaluated were wilting (without and with) and cassava meal levels (0; 7.5; 15 and 22.5 % DN). PVC silos with 50cm height and 10cm diameter were used for silages production. A+B1 and B2 CHO fractions and B3 and C nitrogen fractions of silages were influenced by association of wilting with cassava meal levels, the wilting and the cassava meal inclusion had no effect on A and B1+B2 nitrogen fractions. The cassava meal addiction linearly reduced the CHO C fraction. Relative to variables inherent to silages' fermentative characteristics, pH presented quadratic behavior. Ammonia nitrogen, presented quadratic and decreasing linear behavior for silages without and with wilting, respectively. The use of cassava meal reduces the B2 and unavailable carbohydrates fraction. The main protein fractions of the silages studied are A and B1 + B2 fractions. Wilting and the addition of cassava meal improved the nutritive value and fermentation characteristics of the silages studied.

Com o objetivo de determinar as exigências de energia e proteína de novilhos Nelore sob pastejo, foi conduzido um experimento utilizando 24 novilhos da raça Nelore, castrados, com peso inicial de 371 ± 14 kg e 26 meses de idade. Quatro novilhos foram abatidos no início do experimento (grupo referência) para servir de referência nos estudos subsequentes. Os animais restantes (20) foram pesados e distribuídos em delineamento inteiramente casualizado com quatro níveis de suplementação: 0,0 (mistura mineral - controle); 0,3; 0,6 e 0,9% do PC e cinco repetições. Os suplementos, à base de milho, farelo de soja e/ou uréia, foram balanceados previamente para promover ganhos médios diários de 350, 650 e 850 g, respectivamente. Os conteúdos de proteína, gordura e energia retidos no corpo foram estimados por meio de equações de regressão do logaritmo do conteúdo corporal de proteína, gordura ou energia, em função do logaritmo do PCVZ. Derivando-se as equações de predição do conteúdo corporal de proteína, gordura, ou energia em função do logaritmo do PCVZ, foram obtidas as exigências líquidas de proteína e energia, para ganho de 1 kg de PCVZ. As exigências de energia líquida para ganho de peso de zebuínos castrados podem ser obtidas pela equação: ELg = 0,05764 x PCVZ0,75 × GDPCVZ0,8328. Foi obtida a seguinte equação para estimativa da proteína retida (PR), em função do GMD e da energia retida (ER): PR = 28,9199 + 85,7301 GPVJ + 8,0669 ER. A exigência líquida de proteína para animais Nelore castrados diminui com o aumento do peso vivo e corresponde a 174,62 e 163,10 g/kg GPCVZ em animais de 300 e 450 kg de peso vivo, respectivamente.

This experimentwas carried out with the objective of determining the energy and protein requirements of grazing Nellore steers. Twenty four Nellore steers (average 371 ± 14 kg of BW and 26 months old) were used. Four steers were slaughtered at the beginning of the experiment (reference group), serving as a reference for the subsequent study. The remaining 20 animals were weighed and distributed in a randomized complete block design with four levels of supplementation offers: 0.0 (mineral mixture - control), 0.3, 0.6 and 0.9% BW, with five replications. The supplements, based on ground corn, soybean meal and/or urea, were previously balanced to achieve an average daily gain of 350, 650 and 850g, respectively, for the different levels of supplementation offers. The protein, fat and energy contents retained in the animal body were determined by regression equations of the logarithm of the protein, fat and energy in the animal body contents, in function of the logarithm of empty body weight (EBW). Net requirements of protein and energy for a gain of 1kg of EBW were obtained by deriving the prediction equations of the animal body content of protein, fat, or energy in function of the EBW logarithm. The net energy requirements for weight gain of Nellore steer can be obtained by the equation: NEg = 0.05764 × EBW0,75 × DEBWG0.8328. The following equation was obtained to estimate the retained protein (RP), in function of the average daily gain (ADG) and retained energy (RE): RP = 28.9199 + 85.7301 FBWG + 8.0669 RE. The net protein requirement for Nellore steers decreased as the body weight increased, with values of 174.62 and 163.10 g/kg EBG for animals of 300 and 450 kg BW, respectively.

Com o objetivo de determinar as exigências de macrominerais (Ca, P, Mg, K e Na) de bovinos Nelore castrados sob pastejo, foi conduzido um experimento com 24 novilhos da raça Nelore, castrados, com peso inicial de 371 ± 14 kg e 26 meses de idade. Quatro novilhos foram abatidos no início do experimento (grupo referência) para servir de referência nos estudos subsequentes. Os animais restantes (20) foram pesados e distribuídos em delineamento inteiramente casualizado com quatro níveis de suplementação: 0,0 (mistura mineral - controle); 0,3; 0,6 e 0,9% do peso corporal e cinco repetições. Os suplementos, à base de milho, farelo de soja e/ou uréia, foram balanceados previamente para promover ganhos médios diários de 350, 650 e 850 g, respectivamente. Os conteúdos de macrominerais retidos no corpo animal foram estimados por meio de equações de regressão do logaritmo do conteúdo corporal dos macrominerais, em função do logaritmo do peso de corpo vazio (PCVZ). As exigências líquidas dos macrominerais para ganho de 1 kg de PCVZ foram obtidas utilizando-se a equação Y' = b.10ª. Xb-1, em que a e b são o intercepto e o coeficiente de regressão, respectivamente, das equações de predição dos conteúdos corporais de cada macromineral considerado. As concentrações de todos os macrosminerais estudados, no corpo vazio e no ganho de corpo vazio, diminuíram com o aumento do peso vivo. As exigências dietéticas totais de cálcio e fósforo são superiores às recomendadas na literatura.

This experiment was carried out with the objective of determining the macrominerals (Ca, P, Mg, K and Na) requirements of Nellore steers under grazing. Twenty four Nellore steers (371 ± 14 kg of BW and 26 mo old) were used. Four steers were slaughtered at the beginning of the experiment (reference group), serving as a reference in subsequent study. The remaining 20 animals were weighed and distributed into a completely randomized design with four supplementation levels offer: 0.0 (mineral mixture - control), 0.3, 0.6 and 0.9% of BW, with five replications. The supplements, based on ground corn, soybean meal and/or urea, were previously balanced to achieve an average daily gain of 350, 650 and 850g, respectively, for the different supplementation levels offer. The contents of macrominerals retained in the animal body were determined by regression equations of the macrominerals body content logarithm in function of the empty body weight logarithm (EBW). Net macrominerals requirements for a gain of 1kg of EBW were obtained using the equation Y'= b.10ª.Xb-1, with a and b, respectively, the intercept and the regression coefficient of the prediction equations of macrominerals in the animal body contents for each macromineral considered. The concentrations of all macrominerals, in the empty body weight and gain of the empty body weight, decreased with the increase in the body weight. Total calcium and phosphorus dietary requirements are higher than those recommended in the literature.

O experimento foi realizado em casa de vegetação com o objetivo de avaliar o efeito da adubação nitrogenada e fosfatada sobre a produção de matéria seca (MS) da parte aérea e das raízes, o teor e a produção de proteína bruta (PB) e de fibra em detergente neutro (FDN). Utilizou-se o delineamento experimental inteiramente casualizado em esquema fatorial 4 × 2, composto de quatro doses de nitrogênio (0, 50, 100 e 150 mg/dm³) e duas doses de P2O5 (0 e 45 mg/dm³) com quatro repetições. As sementes da gramínea foram estabelecidas em vasos com capacidade de 6,3 L, de modo que, após desbaste, permaneceram três plantas por vaso. Observou-se interação entre doses de nitrogênio e a produção de MS da parte aérea e de raízes. As produções estimadas de MS da parte aérea obtidas com associação de nitrogênio (0, 50, 100 e 150 mg/dm³) e P2O5 (45 mg/dm³) foram de 4,7; 18,5; 32,3 e 46,1 g/vaso e a produção de MS de raízes, de 6,3; 41,7; 77,1 e 112,5 g/vaso, respectivamente. As doses de nitrogênio e fósforo não influenciaram o teor de FDN, mas afetaram o de PB, que foi maior nas doses mais altas de nitrogênio sem adição de fósforo. A adubação com doses crescentes de nitrogênio associadas a P2O5 aumenta a produção e o valor nutritivo do capim-tanzânia.

The experiment was conducted in a greenhouse and aimed to evaluate the effect of N and P fertilization on dry matter (DM) production of shoots and roots, crude protein (CP) production and concentration, and neutral detergent fiber (NDF) concentration of Tanzania grass. It was used a completely randomized experimental design in a 4 × 2 factorial scheme, being four N doses (0, 50, 100, and 150 mg N/dm³) and two doses of P2O5 (0 and 45 mg P2O5/dm³), with four replicates. It was used pots with 6.3 L capacity, in which the grass seeds were sawed, leaving three plants in each pot. It was observed interaction among N and P doses for shoot and root DM production. Shoot DM production at the 45 mg of P2O5/dm³ dose were 4.7, 18.5, 32.3, and 46.1 g/pot whereas root production at the same P level were 6.3, 41.7, 77.1, and 112.5 g/pot, for 0, 50, 100, and 150 mg of N/dm³, respectively. There was no difference for NDF concentration as a function of N and P doses, but CP concentration increased with increasing N fertilization when P was not added. Increasing N fertilization in the presence of P fertilization increased the production and nutritive value of tanzaniagrass.