Two studies were conducted to evaluate the effects of crude glycerin on feed intake, performance, carcass characteristics, and total digestibility of Nellore bulls. In experiment 1, cattle (n = 30) were fed a control diet without crude glycerin and diets containing 7.5, 15, 22.5, and 30% crude glycerin, for 103 d. Animals were harvested and data of carcass characteristics were collected. In experiment 2, a digestibility trial was performed using indigestible acid detergent fiber (iADF) as internal marker, and five rumen-cannulated steers. Both experiments were conducted as a randomized complete block design and data were analyzed using mixed procedures. In experiment 1 no differences were observed among treatments on dry matter intake, and performance variables. Regarding carcass characteristics, no effect was observed, except for carcass fat estimates, which were greater in treatments with crude glycerin. In experiment 2, crude glycerin promoted a decrease in digestibility of fibrous fractions NDF and HEM, and increased digestibility of crude protein by 6%. Although it caused negative effect on digestibility of fibrous fraction of diets, crude glycerin can be a good energy source for Nellore bulls, since no losses are observed on performance and carcass characteristics when animals are fed up to 30% of this by-product.

Objetivou-se avaliar a composição químico-bromatológica e a digestibilidade "in vitro" da matéria seca (DIVMS) de silagens de capim-elefante em diferentes tempos (70; 90 e 110 dias) de crescimento do capim, com inclusão (0, 5, 10 e 15%) do farelo da vagem de algaroba. Foi utilizado um delineamento inteiramente casualizado (DIC), arranjado em um esquema fatorial, com quatro repetições. Como silos experimentais foram utilizados tubos do tipo PVC com 100 mm de diâmetro. Passados 30 dias da ensilagem, os silos foram abertos e retiradas amostras para determinação da composição químico-bromatológica e DIVMS. A inclusão do farelo da vagem de algaroba (FVA) elevou os teores de MS e PB. Não foi observada interação (p > 0,01) concentração do FVA × idade de corte do capim-elefante nos teores de MS, PB e FDN das silagens. Foi observada diminuição (p < 0,01) nos teores de FDN, FDA e MM com a inclusão do FVA. Houve aumento linear (p < 0,01) na DIVMS com o aumento na concentração do FVA e diminuição (p < 0,01) na DIVMS com o aumento da idade de corte do capim-elefante. A inclusão do farelo da vagem de algaroba contribui para melhorar a composição química e a digestibilidade das silagens.

This study evaluated the chemical composition and in vitro dry matter digestibility (IVDMD) of elephant grass silages at different growth stages (70, 90 and 110 days), with the addition (0, 5, 10 and 15%, on a fresh matter basis) of mesquite pod meal. A completely randomized design (CRD) was used in a factorial arrangement with four replications. PVC pipes 100 mm in diameter were used as experimental silos. After 30 days of ensilage, samples were taken from the open silos to determine chemical composition and IVDMD. The inclusion of mesquite pod meal (MPM) increased (p < 0.01) the concentrations of DM and CP. No interaction (p > 0.01) was detected between MPM concentrations and elephant grass cutting age for DM, CP and NDF contents in the silages. A decrease (p < 0.01) was observed in NDF, ADF and MM concentrations with the inclusion of MPM. There was a linear increase (p < 0.01) in IVDMD with increasing levels of MPM; and IVDMD decreased (p < 0.01) with increasing cutting age of the elephant grass. The inclusion of mesquite pod meal contributed to improve the chemical composition and digestibility of silages.

Objetivou-se avaliar o consumo e a digestibilidade total e parcial de dietas utilizando milho, casca de soja e polpa cítrica associados ao farelo de girassol ou ureia em novilhos confinados. Foram utilizados quatro novilhos ½ Aberdeen Angus vs. ½ Nelore, providos de cânulas no rúmen e duodeno, com 18 meses de idade e 360 kg de peso médio inicial. As dietas foram constituídas por duas fontes energéticas (milho grão e polpa cítrica) associadas a duas fontes nitrogenadas (ureia e farelo de girassol), totalizando quatro tratamentos, numa proporção volumoso:concentrado de 40:60. O delineamento utilizado foi o quadrado latino com quatro tratamentos e quatro períodos de 21 dias cada. O consumo médio diário de matéria seca foi influenciado (p < 0,05) entre as dietas, e o maior valor foi atribuído à dieta milho e farelo de girassol. A digestibilidade aparente de todos os componentes, exceto da proteína bruta, foi maior (p < 0,05) para as dietas com polpa cítrica. Não houve efeito (p > 0,05) entre as dietas para as digestibilidades ruminal e intestinal. A utilização de coprodutos na alimentação animal não prejudicou a digestibilidade das dietas, sendo indicados como ingredientes de elevado potencial de utilização em dietas para bovinos de corte.

The aim of this study was to evaluate the intake and total and partial digestibility of diets using corn, soybean hulls and citrus pulp associated with sunflower meal or urea in feedlot steers. Four steers ½ Aberdeen Angus vs. ½ Nellore, fitted with rumen and duodenum cannulas, with 18 months old and 360 kg of initial weight. The diets were composed of two energy sources (corn and citrus pulp) associated with two nitrogen sources (urea and sunflower meal), in a total of four treatments, with forage:concentrate ratio of 40:60. The statistical design was a Latin square with four treatments and four periods of 21 days each. The average daily dry matter intake was influenced (p < 0.05) by the diets, with the highest value was observed in corn and sunflower meal diet. The apparent digestibility of all components, except the crude protein, was higher (p < 0.05) for diets with citrus pulp. There was no effect (p > 0.05) among diets for ruminal and intestinal digestibility. The use of co-products in animal feed did not impair the digestibility of diets and are shown as high potential ingredients for use in beef cattle diets.

Esta pesquisa foi realizada visando-se avaliar a degradação ruminal da matéria seca (MS), proteína bruta (PB) e fibra em detergente neutro (FDN) de silagens de capim-elefante colhido aos 70; 90 e 110 dias após rebrota, com inclusão de 0; 5; 10 e 15% de vagem de algaroba triturada, com base na matéria natural, em delineamento inteiramente casualizado arranjado em parcelas subdivididas. Amostras de cada silagem foram incubadas no rúmen de duas vacas Jersey por 3; 6; 12; 24; 48; 72 e 96 h, sendo os saquinhos referentes ao tempo zero apenas lavados em água para determinação da fração solúvel. Não houve interação (P > 0,05) tempo de incubação x inclusão de vagem de algaroba x idade de corte para degradabilidade da MS, embora tenha ocorrido interação destes fatores para degradabilidade da PB e FDN. A maior degradabilidade efetiva (DE) da MS (42,54%) foi observada para 15% de inclusão de vagem de algaroba. A DE da PB foi maior (69,04%) para silagem de capim-elefante com 70 dias de idade com 15% de vagem de algaroba. A inclusão de vagem de algaroba triturada à silagem de capim-elefante melhora a degradabilidade da MS, PB e FDN, enquanto o avanço da idade após rebrota resulta em redução destes parâmetros.

This research was carried out to evaluate the ruminal degradation of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of silages of elephant grass (Pennisetum purpureum) cutting in 70; 90 and 110 days after regrowth with inclusion of 0; 5; 10 and 15% of mesquite (Prosopis juliflora) meal, based on natural matter in a completely randomized design, in split plot arrangement. Samples of silages were incubated in the rumen of two Jersey cows for 3; 6; 12; 24; 48; 72 and 96 h, and the bags at time "zero" were only washed with water to determine the soluble fraction. There was not interaction (P > 0.05) incubation time × inclusion of mesquite pods × cutting age of the grass for DM degradability, there was only interaction (P < 0.05) between these factors for CP and NDF degradability. The most effective DM degradability (42.54%) was observed for 15% inclusion of mesquite pods. The effective CP degradability was higher (69.04%) for elephant grass silage with 70 days after regrowth with 15% of mesquite pods. The inclusion of mesquite pods in elephant grass silages improve DM, CP and NDF degradability, while increment of the age after regrowth result in reduction of this parameters.