Foram conduzidos dois experimentos no Departamento de Zootecnia da ESALQ/USP com o objetivo de estudar a substituição do milho moído fino pelos co-produtos farelo de glúten de milho e polpa cítrica peletizada em rações para bovinos terminados em confinamento. No Experimento 1 foram utilizados 88 machos cruzados (½ Braunvieh ¼ Angus ¼ Nelore) não castrados (407 kg), distribuídos em 24 baias por 57 dias. As rações continham 12% de bagaço de cana in natura e 88% de concentrado. Os tratamentos foram: (1) milho moído fino (M); (2) milho moído fino e farelo úmido de glúten de milho (MFUG); (3) polpa cítrica peletizada (P); (4) polpa cítrica peletizada e farelo úmido de glúten de milho (PFUG). O GPD e a EA dos animais não diferiram entre os tratamentos (P>0,05), porém houve efeito da fonte energética sobre a IMS, que foi maior para as rações com milho (P<0,05). Não foi observado efeito de fonte energética ou nível de farelo úmido de glúten de milho nos valores de ELm e ELg observados neste experimento (P>0,05), mas houve interação (P<0,05) com valores de energia mais altos para o tratamento PFUG em relação aos demais. No Experimento 2, foram utilizados 99 machos Nelore não castrados (348 kg), distribuídos em 20 baias por 85 dias. Os tratamentos foram: (1) milho moído fino (M); (2) milho moído fino e polpa cítrica peletizada (MPC); (3) milho moído fino e farelo úmido de glúten de milho (MFUG); (4) polpa cítrica peletizada e farelo úmido de glúten de milho (PFUG); (5) polpa cítrica peletizada e farelo seco de glúten de milho (PFSG). As rações continham de 5 a 11% de feno de gramínea como fonte de volumoso, formuladas para serem isoprotéicas. Não houve diferença (P>0,05) na IMS, GPD e EA para os tratamentos utilizados. A área de olho de lombo e espessura de gordura não foram afetadas pelos tratamentos, bem como as características qualitativas de carne (P>0,05). Acompanhando os resultados de desempenho, o valor energético das rações não diferiram entre si (P>0,05). Através dos resultados de ELm e ELg observados/esperados, concluiu-se que o milho brasileiro tem seu valor energético inferior ao milho descrito pelo NRC (1996). Os valores de energia do milho (ELm e ELg de 2,24 e 1,55 Mcal/kg) preditos através do amido fecal são semelhantes aos valores tabulados para o milho quebrado americano e superiores ao do milho moído. Com os resultados obtidos é possível afirmar que o farelo de glúten de milho e a polpa cítrica peletizada podem ser utilizados em substituição parcial ao milho moído fino e quando combinados, em substituição total ao milho moído fino em rações com altos teores de concentrado para bovinos em terminação, sem prejuízos ao desempenho e características de carcaça. / Two experiments were conducted at ESALQ/USPs Animal Science Department to evaluate corn gluten feed and dry citrus pulp in substitution for fine ground corn in high concentrate diets for finishing feedlot cattle. In Experiment 1, 88 croosbred (½ Braunvieh ¼ Angus ¼ Nelore) bulls (BW = 407 kg) were kept in 24 pens for 57 days. The rations contained 12% sugarcane bagass and 88% concentrate. The treatments were: (1) fine ground corn (M); (2) fine ground corn and wet corn gluten feed (MFUG); (3) citrus pulp pellets (P); (4) citrus pulp pellets and wet corn gluten feed (PFUG). ADG and G:F ratio did not differ among treatments (P>0,05), but there was an energetic source effect on DMI, higher for corn based diets (P<0,05). No differences were observed for energy souce or corn gluten feed level for NEm and NEg on this experiment (P>0,05), but an interaction (P<0,05) was observed for PFUG wich had higher energy value then the other treatments. In Experiment 2, 99 Nelore bulls (BW = 348 kg) were kept in 20 pens for 85 days. The treatments were: (1) fine ground corn (M); (2) fine ground corn and citrus pulp pellets (MPC); (3) fine ground corn and wet corn gluten feed (MFUG); (4) citrus pulp pellets and wet corn gluten feed (PFUG); (5) citrus pulp pellets and dry corn gluten feed (PFSG). The diets had 5 to 11% grass hay and 89 to 95% concentrate. No differences (P>0,05) were observed for DMI, ADG and G:F ratio among treatments. Diets energy value showed no differences among treatments (P>0,05). Observed/expected NEm and NEg values led to the conclusion that brazilian corn grain has lower energy value than what NRC (1996) tables show. Corn energy values (NEm and NEg was 2,24 and 1,55 Mcal/kg) predicted from fecal starch were similar to american cracked corn and higher than ground corn. Wet corn gluten feed and citrus pulp can be used in substitution for fine ground corn, alone or in combination, in high concentrate finishing feedlot diets, without depressing animal performance and carcass charateristics.

This study investigated the effects of Brevibacillus laterosporus and live yeast (LY) on rumen fermentation, nutrient digestibility and microbial protein synthesis. The basal diet was a total mixed ration formulated to fulfil the minimum nutrient requirement of early lactating 600 kg Holstein cow producing 40kg of milk with 3.5 % fat and 3.3 % protein using CPM-dairy software (NRC, 2001). Treatments were: T1 (Control: basal diet with no additive), T2 (Basal diet + Brevibacillus laterosporus), T3 (Basal diet + Live yeast), and T4 (Basal diet + Brevibacillus laterosporus + Live yeast). In situ degradation, in vitro batch fermentation were performed. Data obtained were subjected to analysis of variance (ANOVA) using PROC GLM (SAS Institute, 2009). The effective dry matter (DM) degradability evaluated at low (0.02) and medium (0.05) ruminal passage rate (ED1 and ED2) were higher (p<0.05) in T1 compared to T2 and T3, but did not differ (p>0.05) between T2, T3 and T4, and between T1 and T4. When evaluated at fast passage rate (0.08) the effective DM degradability (ED3) was higher (p<0.05) in T1 compared to T3 and T4, but did not differ (p>0.05) between T1 and T2. The difference in ammonia nitrogen production was observed only between T1 and T2, and was higher (p<0.05) in T1. The total VFA’s concentration was higher (p<0.05) in T3 compared to the control. All additives decreased the molar percentage of acetate (P<0.05). The concentration of acetate was lower (p<0.05) in T3 and T4 compared to control. Propionate concentration was higher (p<0.05) in T3 and T4 compared to other treatments and lower (p<0.05) in the control compared to the rest of treatments. Butyrate concentration was higher (p<0.05) in T2 and T4 compared to the rest of the treatments, and lower (p<0.05) in T3 than other treatments. The microbial protein synthesis measured as purine derivate done on residues was higher (p<0.05) for T3 compared to T1 and T2, but did not differ between T1, T2 and T4, and between T3 and T4. These results showed that the two additives have different individual effects on DM and CP degradability, but also associative effects in some fermentation parameters such as propionate production. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)