Although Brazil holds one of the largest commercial cattle herd in the world, about 209 million head (IBGE, 2011), it is observed that the average stocking rate is very low, resulting in lower potential productivity of the livestock sector. Among the various factors that contribute to this low productivity, can highlight the seasonality in food supply as an aggravating factor for the productive sector. Basically, in all regions of Brazil, seasonality is characterized by variations in the availability and quality of forage in response to changes in climatic conditions which do not allow forage plants have uniform growth throughout the year. The choice of forage grass to form a pasture, must be very careful to increase their productivity of dry matter and crude protein content, with seasonal balance and acceptability by animals. The pasture management aims to achieve balance between the performance / quality of forage produced, maintaining the desired botanical composition. Associated with these factors has been able to obtain good results by field of animal production. To obtain proper pasture management, it is necessary to know beyond the physical, structural and anatomical characteristics of forage species, the amount of forage offered to animals and nutritive value, but also the amount of forage being consumed by the animal and nutritional value the forage actually consumed.

The objective with this study was to evaluate the effect of including dried distillers grains with solubles (DDGS) as a replacement for soybean meal on feed intake, digestibility, and total digestible nutrients (TDN), as well as plasmatic glucose and serum urea concentrations. Fifteen Saanen goats were distributed in a completely randomized design with three treatments and five replicates. Treatments were soybean meal (SBM), SBM+DDGS (12.28% of dry matter [DM]), and DDGS (23.16% of DM), as protein source in diets, common to all corn ground and mineral-vitamin supplement, and corn silage (60% of DM). Response variables were evaluated every 30 d, from 1 to 120 d after parturition. Measurements included body weight, DM intake, DM and nutrient digestibility, and blood samples. Indigestible neutral detergent fiber was used to estimate fecal excretion. There was a difference in neutral detergent fiber intake from 1 to 30 d after parturition. In the four phases of lactation evaluated, there were treatment effects on DM, organic matter, ether extract, and total carbohydrate digestibility, as well as on TDN concentration. Neutral detergent fiber digestibility was affected by treatments, except from d 61 to 90. There was no treatment effect on non-fibrous carbohydrate digestibility, regardless of period. Therefore, SBM+DDGS (12.28% of DM), as protein source on diets may be used in Saanen goat diets from 1 to 120 d of lactation without negative effects on feed intake, digestibility, and plasma glucose and urea concentrations.

No sistema de criação a pasto ainda predominante no Brasil o período seco apresenta baixo potencial de ganho de peso devido à escassez de chuvas que comprometem a qualidade e quantidade forrageira limitando a produção. A utilização de co-produtos pode levar o barateamento do custo de produção de ruminantes, principalmente na utilização de suplementos fornecido no período seco do ano. Co-produto pode ser obtido através do processamento de frutas de indústrias de suco e da indústria do biodiesel que utiliza culturas oleaginosas para a extração do óleo. Pesquisas recentes vêm apresentando resultados que mostram um melhor desempenho quando se trabalha com estratégias de manejo do pastejo e também de suplementação concentrada na produção de bovinos de corte a pasto.Palavras-chave: bovinos de corte, desempenho, nutrição animal.

RESUMO Objetivou-se com este estudo avaliar os parâmetros da cinética de degradação ruminal dos concentrados protéicos, farelo de soja(FS) e torta de algodão(TA). Para estimativa dos parâmetros da cinética de degradação in situ da matéria seca (MS) e proteína bruta (PB) dos concentrados, foi realizado o ajuste de 5 diferentes modelos matemáticos não-lineares: Exponencial, Van Milgen, Logístico, Gompertz e Richards. Para avaliação in situ dos alimentos, foram utilizados dois bovinos adultoscanuladosno rúmen. As amostras foram incubadas nos tempos 0; 2; 4; 6; 12; 16; 24; 36; 48 e 72 horas, nos resíduos de incubação foram determinados os teores de MS e PB, e sua degradabilidade potencial e efetiva. Os valores de degradabilidade efetiva da MS do FS foram de 86,35; 74,23 e 65,50%,e da TA de 53,44; 41,70 e 35,21% nas taxas de passagem de 0,02; 0,05 e 0,08.h-1, respectivamente. O FS e a TA apresentaram valores para a fração A da PB de 18,15 e 34,77% e para a fração B, 79,76 e 55,10%, respectivamente. De acordo com a ponderação de Akaike (Wi) o modelo de Richards apresenta; 95,45 e 49,64% de chance de ser o modelo mais adequado, para caracterizar a cinética de degradação in situ da MS do, FS e da TA, respectivamente. Contudo, o modelo de Gompertz apresenta 63,86 e 66,49 % de chance de ser o modelo mais adequado para caracterizar a degradação da PB do FS e TA.