No abstract

To evaluate the grass B. brizantha cv. Marandu, under grazing, we use three sampling methods: total availability (TA), hand plucked (HP) and extrusa (EXT) in a completely randomized design with four replications. The hand plucked method was collected manually after observing the behavior of grazing animals. TA was determined by cutting at ground level, using a metallic square (0.25 m²) and EXT was collected by rumen evacuation. The values for dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF), were 27.20, 88.52 and 43.70% in the treatment and HP, and 25.53, 87.70 and 45.50% in TA. The extrusa had the lowest DM content (15.88%) and higher crude protein (CP) (15.22%), possibly due to the presence of saliva. The levels checked for extrusa NDF, ADF and in vitro digestibility of dry matter were 81.98, 36.90 and 79.10%, demonstrating the selectivity of the animals. The high levels of FDA for TA reflect the composition of the forage with the high proportion of senescent material. The samples obtained by the total availability were not representative of the diet consumed by cattle. The different sampling methods influence the chemical composition of B. Brizantha cv. Marandu.

To evaluate of the sunflower crushed in nutritional parameters in steers, supplemented at pasture, we used four steers in 4x4 Latin square design. The supplements were provided in 6 g/kg of body weight/animal/day, consisting of sunflower crushed, corn, soybean meal and mineral. All the supplements was isonitrogenous and soybean meal was replaced in 0, 20, 40, and 60% for sunflower crushed. The determination of ruminal pH and ammonia was at 0, 2, 4, 6 and 8 h. after feeding and for short-chain fatty acids it was collected at 0 and 6 h. post-feeding. The dry matter intake was not affected (P>0.05) by inclusion of sunflower crushed (mean=6.59 kg/day). There was no significant effect (P>0.05) for pH for the inclusion of sunflower crushed (mean=6.41). For contents of ruminal NH 3 -N was a significant effect (P <0.05) only for collection time, and ammonia peaks occurred between 2 and 4 h after feeding, with values of 22.56 and 21.40 mg/dL. The total concentration of short chain fatty acids and the C2:C3 ratio was reduced in 9.6 and 15.43%. The ruminal degradability of NDF was not affected by the supplements. The supplementation with sunflower crushed to beef steers grazing, in partial replacement of soybean meal did not alter nutrition parameters.

Trabalho de conclusão de curso do segundo autor. Trabalho financiado pelo CNPq. Fundect/MS e UFGD. ResumoAvaliou-se a degradabilidade ruminal pelo uso da técnica in situ, em ovinos, de resíduos da pré-limpeza da soja. Foram utilizados três ovinos da raça Santa GOES, R.H.T.B. et al. Composição bromatológica e degradabilidade ruminal de resíduos da pré-limpeza de soja utilizados na alimentação de ovinos. PUBVET,

ABSTRACT. Four steers in individual paddocks with Marandu grass (B. Brizantha) in 4x4 square design were used to evaluate sunflower crushed supplementation in pasture-grazing animals on nitrogen balance and microbial protein synthesis. Supplements at 6 g kg -1 body weight comprised corn, soybean meal, and mineral and soybean meal substituted at proportions 0, 20, 40 and 60%. Diet contained averages 6.79, 6.96, 7.10 and 6.87% nitrogen respectively for substitution levels 0, 20, 40 and 60%. The inclusion of sunflower crushed (SC) increased nitrogen intake and fecal excretion of nitrogen while providing a positive balance. Animals' plasma urea concentration supplemented with SC was 28.13% lower than that of supplemented animals without SC. SC inclusion did not change allantoin concentration, purine derivatives, microbial nitrogen, crude microbial protein and microbial efficiency microbial, with mean rates totaling 150.98 mmol day Keywords: creatinine, microbial efficiency, plasma urea, purine derivatives, urea.Balanço de compostos nitrogenados e síntese de proteína microbiana em novilhos suplementados com torta de girassol em substituição parcial ao farelo de soja RESUMO. Para se avaliar a suplementação de torta de girassol em novilhos mantidos a pasto, sobre o balanço de nitrogênio e a síntese de proteína microbiana, foram utilizados quatro animais em piquetes com capim Marandu (B. Brizantha), em quadrado latino 4x4. Os suplementos foram fornecidos na quantidade de 6 g kg -1de peso vivo dia -1 ; constituídos de milho, farelo de soja e mineral, sendo o farelo de soja substituído nas proporções de 0, 20, 40, e 60%. A dieta disponível apresentava em média 6,79; 6,96; 7,10 e 6,87% de nitrogênio, para os níveis de substituição de 0, 20, 40 e 60%. A inclusão da torta de girassol (TG) elevou o N ingerido e o N fecal, proporcionando balanço positivo. A concentração plasmática de ureia dos animais suplementados com TG foi 28,13% inferior aos animais suplementados sem TG. A inclusão de TG não alterou a concentração de alantoína, os derivados de purina, o nitrogênio microbiano, proteína bruta microbiana e eficiência microbiana, apresentando valores médios de 150,98 mmol dia ; 146,41 proteína bruta microbiana kg -1 NDT. A substituição parcial do farelo de soja pela torta de girassol melhorou o balanço de nitrogênio, sem alterar a síntese de proteína microbiana e a excreção de ureia e creatinina.Palavras-chave: creatinina, eficiência microbiana, ureia plasmática, derivados de purina, ureia.

SUMMARYThe main objective of this study the Marandu grass using total dry matter (CS), hand-plucking sample (PS) and extrusa (EXT) in a completely randomized design. The samples were analyzed for dry matter (DM), crude protein, ether extract, neutral (NDF) and acid-detergent fiber (ADF), hemicellulose, cellulose, lignin, ash, in vitro dry matter digestibility, total, and non fiber carbohydrates. The samples for PS presented DM, NDF and ADF values of 25.19, 65.31, and 28.91 %. The EXT values for NDF and ADF were 73.21 and 33.46 %, respectively, reflecting the selectivity of the animal. The ADF value for CS was 36.01 %, due to the high proportion of senescent material in the forage. The CS and hand plucked samples obtained did not represent the diet consumed by the animals. The chemical composition of the forage is influenced by the different sampling methods. INTRODUÇÃOAs pastagens totalizam aproximadamente ¼ da superfície terrestre e consistem na opção alimentar mais abundante para a produção de proteína animal. No entanto, determinar precisamente a dieta de animais em pastejo é um grande desafio, diversas metodologias são utilizadas com o intuito de caracterizar o alimento ingerido pelos animais. O corte da forragem rente ao solo difere nutricionalmente da forragem consumida, porém é uma técnica simples de ser realizada (Moraes et al., 2005). O pastejo simulado possibilita a obtenção de amostras mais próxima à dieta consumida (Silveira et al., 2005), porém está sujeita a falhas na amostragem, sendo mais indicada para áreas com grande quantidade de forragem disponível e uso de animais dóceis. A extrusa através do esvaziamento total do rúmen, Agradecimentos: À UFGD; FUNDETC-MS, e CNPq pelo apoio financeiro e bolsas concedidas.