ABSTRACT. The aim of this work was to determine ruminal degradation of neutral detergent fiber of grasses of the genus Cynodon, harvested at four cutting ages. It was used a randomized block design, with five treatments arranged in a split plot, the five evaluated genotypes: Tifton 85, Jiggs, Russel, Tifton 68 and Vaquero; were the plots and ages of cutting were the subplots: 28, 48, 63 and 79 days. By adding one day in the cutting age, there was a linear reduction in the effective degradability of neutral detergent fiber of blade and stem of 0.16 and 0.18%, respectively. The increase in the cutting age had a linear and positive influence on the undegradable neutral detergent fiber with daily increments for leaf and stem of 0.12 and 0.18%, respectively. At the 28 regrowth day, all genotypes showed higher content of potentially degradable insoluble fraction, effective degradability and lower undegradable fraction of the neutral detergent fiber of blade and stem in relation to other ages, in this way this interval is recommended for cutting management.Keywords: degradation, forage, ruminants, management.Degradabilidade ruminal da fibra em detergente neutro de gramíneas Cynodon spp. em quatro idades de rebrota RESUMO. Objetivou-se por meio deste trabalho determinar a degradação ruminal da fibra em detergente neutro de gramíneas do gênero Cynodon, colhidas em quatro idades de corte. Foi utilizado o delineamento em blocos ao acaso, com cinco tratamentos arranjados em um esquema de parcelas subdivididas, sendo os cinco genótipos: Tifton 85, Jiggs, Russel, Tifton 68 e Vaqueiro; estudadas as parcelas e as quatro idades de corte as subparcelas: 28, 48, 63 e 79 dias. À medida que aumentou um dia na idade de corte, houve redução linear da degradabilidade efetiva da fibra em detergente neutro da lâmina e do colmo em 0,16 e 0,18%, respectivamente. O avanço na idade de corte influenciou linearmente e positivamente a fração indegradável da fibra em detergente neutro com incrementos diários para a lâmina foliar e para o colmo de 0,12 e 0,18%, respectivamente. Na idade de 28 dias de rebrota, todos os genótipos apresentaram maiores teores de fração insolúvel potencialmente degradável, degradabilidade efetiva e menor fração indegradável da fibra em detergente neutro da lâmina e do colmo em relação às demais idades, sendo desta forma recomendado esse intervalo para manejo de corte.Palavras-chave: degradação, forragem, ruminantes, manejo.

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ResumoObjetivou-se avaliar a composição química da silagem de capim-mombaça associada com diferentes aditivos em quatro tempos de abertura do silo. O experimento foi conduzido na UFGD. Após a colheita da forragem, a biomassa in natura triturada, foi levada ao laboratório, homogeneizada e enriquecida, na base da massa natural, com os seguintes aditivos: 5% de farelo de trigo, 5% de resíduos (grão quebrado e casquinha de soja) de soja, 5% de ureia da matéria natural e a testemunha (sem aditivo). Os silos foram abertos após (matéria in natura), 15, 30 e 45 dias, para a análise da composição química. Os dados obtidos foram analisados por meio do programa estatístico SISVAR e as médias foram comparadas a 5% de probabilidade, pelo teste de Skott-Knot. A silagem de capim-mombaça sem aditivo apresentou maior (P<0,05) teor de matéria seca em relação aos demais tratamentos no tempo 0 e 30 dias de ensilado e não diferiu (P>0,05) da silagem de capim-mombaça associada com 5% de ureia nos dias 15 e 45 de ensilagem. A silagem de capim-mombaça com 5% de ureia apresentou maior teor de proteína bruta no tempo 0 de abertura e diferiu dos demais tratamentos. A silagem de mombaça associada com 5% de ureia proporcionou maior digestibilidade in vitro da matéria seca aos 15 dias de ensiladas. Palavras-chave: Conservação de forragens, nutrição animal, panicum maximum, valor nutricional AbstractIt was aimed to evaluate the chemical composition of grass silage-mombasa associated with different additives in four times of opening the silo. The experiment was conducted in UFGD. After harvesting the forage, biomass in natura crushed, was taken to the lab, homogenized and enriched on the basis of natural mass, with the following additives: 5% wheat bran, 5% of waste (broken grain and soy ice cream cone) of soybean, 5% urea in natural matter and the witness (without additive).The silos were opened after (unprocessed material), 15, 30 and 45 days, for the analysis of chemical composition. The data obtained were analyzed through the statistical programme SISVAR and averages were compared to 5% of probability, by Skott-Knot. The grass silage-mombasa without additive presented major (P<0.05) dry matter content compared to other treatments at time 0 and 30 days of silage and did not differ (P>0.05) of grass silage-mombasa associated with 5 of urea in 15 days and 45 of silage. The grass

This study aimed to evaluate the performance of feedlot lambs fed diets formulated with hay of different genotypes of Cynodon spp. and to compare the dry matter digestibility of diets using different evaluation methods (total fecal collection and chromium oxide). Suffolk crossbred neutered male lambs (n=30), with an average age of 90 days and average body weight of 21.5 kg ± 1.6. Diets were formulated using a standard concentrate and hay of the following genotypes of Cynodon dactylon: Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell, in a 60:40 forage concentrate ratio, composing the treatments distributed in a randomized block design in a factorial 5 x 2 arrangement of 5 diets and 2 digestibility evaluation methods. Animals receiving Vaquero hay showed dry matter intake of 18.3; 16.9; 25.6; 20.7 and 24.2% higher than those fed hay of Jiggs, Tifton 68, Coast Cross, Tifton 85 and Russell, respectively. There was no difference between diets for digestibility using total fecal collection, chromium oxide and final weight of animals. Jiggs hay based diets allowed greater daily weight gain and better feed conversion.

This study aimed to evaluate animal performance and economic performance of feedlot crossbred lambs (½ Santa Inês+ ½ Suffolk) fed different diets based on hay from Cynodon dactylon genotypes, through the use of financial measures considering only the period of feedlot, without relating it to the complete management cycle. A total of 30 intact crossbred Suffolk lambs, identified with earrings, with an average age of 90 days and an average body weight of 21.5 kg were used in this study. Diets were formulated using as treatments a standard concentrate and hay of the Cynodon dactylon genotypes Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell in a 60:40 forage-to-concentrate ratio. The treatments were distributed in a randomized complete block design with five replicates. There were significant differences between diets in terms of total expenditure on food, and the highest values were obtained for the Jiggs genotype (BRL 48.96/animal). The animals fed diets based on Tifton 68 hay had a higher rate of return (2.16%) and profitability (34.63%) compared to the other diets. The use of diets based on Tifton 68 hay for feedlot lambs in the finishing phase brings higher economic returns compared to the remaining diets. relação volumoso concentrado de 60:40, constituindo os tratamentos, distribuídos em um delineamento em blocos casualizados com 5 repetições. Houve diferença significativa entre as dietas para as despesas totais com a alimentação, sendo os maiores valores para o Jiggs (BRL 48,96/animal). Os animais que receberam dietas a base de feno de Tifton 68 apresentaram maior taxa de retorno (2,16%) e lucratividade (34,63%) em relação às demais dietas. A utilização de dietas a base de feno de Tifton 68 para cordeiros em fase terminação, em confinamento, permite obter maior rentabilidade econômica em relação às demais dietas.