This study evaluates the effect of dry-season concentrate supplementation on growing cattle performance grazing tropical pasture and the impact of nitrogen fertilization on the growth rate of tropical pasture (tons of dry herbage mass/ha/110 days) and on the subsequent stocking rate and cattle performance during the rainy season (kg body weight gain/ha/110 days). The animal and plant responses were curvilinear to the increasing amount of nutrient supply and followed the typical saturation kinetics of enzyme systems, a Michaelis-Menten relationship. The Lineweaver-Burk data transformation explained efficiently the animal and plant responses to the nutrient supply. This methodology consists in evaluating the linear regressions of the reciprocal of animal and plant responses as a function of the reciprocal of nutrient supply. The half maximum growth rates for plant and animal to nutrient supply were verified with the proportions from .048 to .056 of the amount needed to cause .95 of theoretical maximum responses. From the curvilinear response, it can be verified that the marginal increase in animal and plant growth rate reduces as the amount of nutrient supply increases. D

O trabalho foi conduzido no período de abril a novembro de 2012, em uma propriedade de produção leiteira, no município de Mariluz, Região Noroeste do Paraná, com o objetivo de avaliar a produtividade, a composição botânica e o valor nutritivo do capim Tifton 85 sobressemeado com aveia, na presença e ausência de irrigação. O delineamento experimental foi de blocos casualizados em parcelas sub-subdivididas, com 4 repetições. As parcelas foram sem e com irrigação. As subparcelas foram constituídas de sobressemeaduras de aveia: FMS 2, IAPAR 61, IPR 126 e um tratamento com o Tifton 85 exclusivo. Os ciclos de coleta compuseram as sub-subparcelas. A irrigação incrementou a produtividade da pastagem com média de 2760,4 kg ha-1 ciclo-1, com a maior relação folha/colmo de 2,8, aumentando a digestibilidade da matéria seca. Os valores de proteína bruta foram maiores no irrigado e na média do irrigado e não irrigado, diminuíram ao longo dos ciclos de coleta de 18,6 para 13,6%. As maiores produtividades foram obtidas por meio das sobressemeaduras das aveias FMS 2 e IPR 126. O Tifton 85 exclusivo apresentou o maior valor de fibra em detergente neutro e o menor valor de digestibilidade.

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The purpose of the current study was to evaluate the effects of inoculants on chemical composition, dry matter (DM) and neutral detergent fiber (aNDF) in vitro degradation, fermentative and effluent losses, microbiology, fermentative profile, and aerobic stability of sugarcane mini-silos. Treatments were randomly distributed to the mini-silos, in which: (1) Control (CON); (2) Lactobacillus buchneri (Lb), addition of Lb at 2.6 × 10 10 cfu/g; (3) Lactobacillus buchneri and Bacillus subtilis (Lb + Bs), addition of Lb at 2.6 × 10 10 cfu/g and Bs at 1 × 10 9 cfu/g; and (4) Chitosan (CHI), addition of 1% of CHI on wet basis of sugarcane ensiled. Treatments 2 and 3 were incorporated to the silage at 2 g/t of natural matter ensiled. Lb and Lb + Bs did not alter the in vitro degradation of DM and NDF. Chitosan incorporation increased the DM content (P = 0.013, 18.7 g/kg DM) and improved (P = 0.029, 45.6 g/kg DM) the NDF in vitro degradation of sugarcane silage. In addition, CHI incorporation showed higher (P = 0.002) DM content in silage than Lb and Lb + Bs. Microbial inoculants (Lb and Lb + Bs) reduced the total losses (P = 0.009) of sugarcane silage. Moreover, CHI incorporation showed lower (P = 0.001, 84.9 g/kg DM) total losses and higher (P = 0.031, 84.8 g/kg DM) dry matter recovery than Lb and Lb + Bs. Lactic acid bacteria concentration was increased (P = 0.001) with additives, and CHI incorporation showed higher (P = 0.001) lactic acid bacteria concentration than silages treated Lb and Lb + Bs. All additives decreased the ethanol concentration in sugarcane silage, but CHI showed lower (P = 0.002) ethanol concentration compared to Lb and Lb + Bs. Inoculants improved the aerobic stability of sugarcane silage. In general, the incorporation of CHI to sugarcane silage showed better results of NDF in vitro degradation and gas and effluent losses than Lb and Lb + Bs. Moreover,

-This study was undertaken to determine the effects of chitosan and whole raw soybean on nutrient intake and total tract digestion, nitrogen utilization, microbial protein synthesis, blood metabolites, and energy balance of dairy heifers. Twelve Jersey heifers (6±0.5 months of age and 139.50±25.56 kg of live weight; mean ± standard deviation) were randomly assigned to a replicated Latin square design with a 2 × 2 factorial arrangement. The experimental period consisted of 14 days of adaptation to diets, six days of sampling, and five days of washout. The experimental diets were: control (CO); chitosan (CHI, inclusion of 2.0 g kg −1 DM of chitosan); whole raw soybean (WS, 163.0 g kg −1 of WS on diet DM basis); and chitosan + whole raw soybean (CHI+WS). Chitosan decreased dry matter and neutral detergent fiber intakes; however, CHI increased DM total tract digestion. An interaction effect was observed on retained nitrogen, which increased when animals were fed CHI+WS compared with CO or CHI, but did not differ from that of animals fed WS. Chitosan decreased microbial nitrogen and crude protein flow of heifers. Energy balance was improved when heifers received diets containing WS. Efficiency of energy utilization was not affected by experimental diets. An interaction effect was observed for blood high-density lipoprotein (HDL) concentration, which increased with both dietary inclusion of CHI and WS compared with the other diets, and CHI provided the lowest value of HDL cholesterol. Chitosan and whole raw soybean do not alter nutrient intake and total tract digestion; however, they decrease nitrogen urinary excretion and increase blood HDL cholesterol of heifers.

RESUMO. Avaliou-se a degradabilidade ruminal in situ, em ovinos dos grãos e coprodutos de girassol, soja e crambe, em três ovinos da raça Santa Inês com peso de 40 kg, fistulados e providos de cânulas ruminais, mantidos em baias individuais. Os alimentos foram incubados em ordem decrescente de 72, 48, 24, 18, 6, 3 e 0h. A fração potencialmente degradável da MS para a torta de girassol foi 73,7% e da PB 34,6%, o que proporcionou média degradação ruminal para PB. O grão de girassol apresentou baixa degradabilidade ruminal para a MS e PB (33,55 e 25,98%). A torta de soja apresentou fração solúvel de 23,15 e 7,79%, para a MS e PB, com uma degradabilidade efetiva de 75,6 e 70,89%, enquanto que o grão de soja apresentou baixa fração solúvel para MS e PB (4,79 e 8,73%), acarretando baixa degradabilidade ruminal. O grão de crambe e a torta de crambe apresentaram os maiores teores de FDA, e baixa degradabilidade ruminal, tanto para a MS como para a PB. Os valores para a fração potencialmente degradável e fração solúvel foram semelhantes. Os alimentos avaliados apresentaram média degradabilidade ruminal, exceto a torta de soja que apresentou maior valor de degradabilidade ruminal.Palavras-chave: composição química, matéria seca, proteína, sacos de náilon, tempo de colonização.ABSTRACT. In situ ruminal degradability of crambe, sunflower and soybean seeds and their by-products in sheep feeding. Ruminal degradability of crambe, sunflower and soybean grains and their by-products in sheep was evaluated by an "in situ" technique. Three 40 kg-Santa Ines fistulated sheep provided with ruminal cannula and kept in individual pens were analyzed. Feeds were incubated in the rumen in the following decreasing order 72, 48, 24, 18, 6, 3 and 0h. The potentially degradable fraction for DM in sunflower meal amounted to 73.7%, whereas it reached 34.6% in the case of CP, with medium ruminal degradation. Sunflower grain had low ruminal degradability for DM and CP (33.55 and 25.98%). Crushed soybean grain had soluble fraction of 23.15 and 7.79% respectively for DM and CP, with an effective degradability of 75.6 and 70.89%. Further, soybean whole grain presented low soluble fraction for DM and CP, respectively 4.79 and 8.73%, with low ruminal degradability. Crambe whole grain and crushed meal had the highest ADF rates, with low ruminal degradability for DM and CP. Rates for potentially degradable and soluble fraction were similar. Evaluated feeds had medium ruminal degradability, except for soybean crushed meal with the highest rate in ruminal degradability.

Objetivou-se avaliar a qualidade da pastagem de Brachiaria arrecta, classificada anteriormente como B. radicans utilizando-se as metodologias da extrusa, pastejo simulado e disponibilidade total. Para a coleta da extrusa, utilizaram-se três novilhos fistulados no esôfago. A disponibilidade total do pasto foi obtida pelo corte rente ao solo, com um quadrado metálico (0,5 x 0,5 m), e o pastejo simulado foi colhido manualmente. Para a digestibilidade in vitro da matéria seca, ocorreu efeito do mês de amostragem, mas não entre as metodologias de coleta utilizadas, em que a extrusa apresentou maiores valores (62,10%). Não ocorreu diferença para os teores de proteína bruta, entre os métodos do pastejo simulado e da extrusa. Os valores de PB para o método de disponibilidade total foram abaixo de 7% e os de FDN (72,3%) e FDA (38,2%), encontrados para os três métodos, confirmaram que as forrageiras tropicais são ricas em parede celular. As amostras obtidas pela disponibilidade total não foram representativas da dieta ingerida pelos bovinos. O método de amostragem influiu na determinação da composição química da pastagem. O pastejo simulado pode servir para uma estimativa satisfatória da dieta selecionada por bovinos.