ABSTRACT. This study aimed to evaluate the intake and milk yield of crossbred cows (Holstein x Zebu), under two management strategies, based on 95% light interception and fixed days. Eight lactating cows with body weight of 466 kg (± 35 kg) and lactation stage of 137 days (± 107 days) were used, four animals were assigned to each treatment. Dry matter intake was estimated indirectly, using neutral detergent insoluble fiber as internal indicator and chromium oxide as external indicator. This was a completely randomized design, with four replications, two grazing strategies and three days of occupation. The animals under light management showed dry matter intake on the first day (11.42 kg) similar to the second day (9.57 kg), and this was similar to the third day (7.06 kg), but the intake on the first day was greater than on the third day. On the fixed days, intake did not differ between the first and second day (12.05 and 11.47 kg, respectively), and intake of the third day (6.70 kg) was lower than in the first two days. The dry matter intake in relation to the body weight of the animals presented similar results to the dry matter intake of forage in kilos, which can be explained by the small difference in weight between the mean of the groups. The individual milk yield showed a similar behavior among the grazing strategies for the days of occupation, which increased from the first to the second day (12.49 to 13.88 kg) and decreased from the second to the third day (12.20 kg). Grazing management strategies did not promote differences in the performance traits of lactating cows. The day of grazing during the period of occupation can be decisive for intake and production.

RESUMO Objetivou-se avaliar as características da conservação de silagens do bagaço de cultivares de sorgo sacarino. Conduziu-se o experimento na Fazenda Rio Manso, unidade experimental da Universidade Federal dos Vales do Jequitinhonha e Mucuri. Utilizaram-se 25 cultivares de sorgo sacarino, com três repetições, no delineamento inteiramente casualizado. Extraiu-se o caldo do corpo da planta através de uma moenda elétrica, gerando o bagaço, que logo foi moído em máquina ensiladora estacionária, adicionados de suas panículas, e depois introduzido com um bastão em silos experimentais. As silagens das cultivares: BR505; CMSXS629; CMSXS635; CMSXS639; CMSXS643; CMSXS646; V82391 e V82392 apresentaram menor taxa de Recuperação Total de Matéria Seca e consequentemente maiores perdas por gases. Os teores médios de Matéria Seca do bagaço e da silagem foram de 32,80 e 28,55% respectivamente. As cultivares BR501; XBSW80147; BR505; CMSXS629; CMSXS633; CMSXS634; CMSXS635; CMSXS639, CMSXS643; CMSXS644, CMSXS648; BRS601; Sugargraze; V82391; V82392 e V82393 apresentaram maiores teores de proteína bruta. Registrou-se média de 3,49 para o pH e de 0,96 para atividade da água. As cultivares BR501 e BRS601 apresentaram maiores valores de condutividade elétrica: 0,93 e 0,95 S/cm respectivamente. Apenas nas cultivares BR501; CMSXS629; CMSXS636; CMSXS648 e V82392 notaram-se maiores teores de nitrogênio amoniacal. De acordo com as variáveis avaliadas neste estudo, as silagens do bagaço de cultivares de sorgo sacarino apresentaram uma adequada conservação do material dentro dos silos.

SUMARY The aim of this study was to evaluate conservation characteristics of sweet sorghum bagasse silages. The experiment was carried out at Fazenda Rio Manso, an experimental unit of the Federal University of the Jequitinhonha and Mucuri Valleys. Twenty-five sorghum cultivars with three replicates were used in a completely randomized design. The juice was extracted from the plant through an electric mill, generating bagasse, which was ground in a stationary silage machine, added of its panicles, and then introduced into experimental silos. Silages of the varieties BR505; CMSXS629; CMSXS635; CMSXS639; CMSXS643; CMSXS646; V82391 and V82392 presented lower rate of total dry matter recovery and, consequently, higher gas losses. The means of dry matter contents of bagasse and silage were 32.80 and 28.55%, respectively. The cultivars BR501; XBSW80147; BR505; CMSXS629; CMSXS633; CMSXS634; CMSXS635; CMSXS639; CMSXS643; CMSXS644; CMSXS648; BRS601; Sugargraze; V82391; V82392 and V82393 showed higher crude protein levels. The cultivar CMSXS642 presented lower neutral and acid detergent fiber content: 39.23 and 19.23%, respectively. The cultivar XBSW80147 showed lower acid detergent fiber content. Means of 3.49 for pH and 0.96 for water activity were recorded. The cultivars BR501 and BRS601 showed higher values of electrical conductivity: 0.93 and 0.95 S/cm, respectively. Higher levels of ammoniacal nitrogen were only observed in cultivars BR501; CMSXS629; CMSXS636; CMSXS648 and V82392. Sorghum bagasse silages presented adequate conservation inside the silos, according to the evaluated variables.

RESUMO. Avaliou-se o crescimento de três leguminosas forrageiras tropicais em dois sistemas de cultivo: sistema silvipastoril (SSP) e pleno sol. Foi adotado um delineamento inteiramente casualizado, em arranjo fatorial com três leguminosas (estilosanthes cv. Campo Grande (Stylosanthes macrocephala x Stylozanthes capitata), kudzu tropical (Pueraria Phaseoloides) e macrotiloma Macrotyloma axillare)) x dois sistemas de cultivo, com quatro repetições. Foi utilizado um SSP de eucalipto já implantado, com arranjo espacial de 12 x 2 m entre árvores. As leguminosas foram plantadas em janeiro de 2014, sendo feito um corte de uniformização em maio de 2014. O corte de avaliação foi realizado 125 dias após o corte de uniformização. Observou-se diferença para produção de massa de matéria seca de leguminosa (PMMSL) entre os sistemas de cultivo, sendo evidenciada maior produtividade no cultivo a pleno sol. O macrotiloma apresentou maior PMSL (5,29 kg de MS ha-1 corte-1), enquanto o kudzu obteve a menor produtividade (3,42 kg MS ha-1 corte-1) no cultivo a sol pleno. O cultivo de leguminosas no SSP incrementou os teores de matéria mineral, proteína bruta e fibra em detergente neutro. O sombreamento proporcionado pelo SSP acarretou redução na produção de massa de matéria seca, como também, alterou a composição bromatológica das leguminosas estudadas.

ABSTRACT. Growth was evaluated three tropical forage legumes in two cropping systems: silvopastoral system (SSP) and full sun. A completely randomized design was adopted in factorial three legumes (estilosanthes cv. Campo Grande (Stylozanthes macrocephala x Stylozanthes capitata), tropical kudzu (Pueraria phaseoloides (Roxb.) Benth) and macrotiloma (Macrotyloma axillare cv. Java)) x two farming systems, with 4 repetitions. A eucalyptus SSP already deployed, with spatial arrangement of 12 x 2 m between trees was used. Legumes were planted in January 2014 a uniform cut being made in May 2014. The court assessment was carried out 125 days after the uniformity cut. There was difference for mass production of dry legumes (PMMSL) between cultivation systems, evidencing increased productivity in the farming full sun. The macrotiloma showed higher PMSL (5.29 kg DM ha-1 cut-1), while the kudzu obtained the lowest yield (3.42 kg DM ha-1 cut-1) in the sun growing full. The cultivation of legumes in SSP increased the levels of mineral matter, crude protein and neutral detergent fiber. The shade provided by the SSP caused a reduction in the mass of dry matter production, but also altered the chemical composition of the studied legumes.

RESUMO. Objetivou-se avaliar os efeitos da inclusão de concentrações do farelo de crambe (Crambe abyssinica Hochst.), com diferentes massas específicas, na ensilagem de capim-elefante (Penninsetum purpureum Schum.). Para tanto foram determinadas as composições bromatológica e microbiológica das silagens experimentais. Foram utilizados 48 minissilos distribuídos em delineamento inteiramente casualizado, arranjado em esquema fatorial 4 × 3, sendo quatro concentrações de inclusão do farelo de crambe (0; 10; 20 e 30%) e três massas específicas (400; 500 e 600 kg de MN m-3), com quatro repetições. Após 240 dias de fermentação os silos foram abertos. Foi observado efeito linear para os teores de MS, PB, FDNcp, FDAcp, HEM, LIG, CNF, CT e para a população de bactérias produtoras de ácido lático com a inclusão do farelo de crambe. Houve interação entre os fatores farelo de crambe e massas específicas sobre os valores de pH e N-NH3. Para as variáveis MM e contagem de leveduras houve efeito linear negativo em função da massa específica avaliada. A inclusão do farelo de crambe contribui para incrementar o perfil fermentativo e a composição bromatológica das silagens de capim-elefante estudadas, sendo os melhores resultados obtidos com a adição de 30% deste coproduto, com base na matéria natural.

ABSTRACT. This study aimed to evaluate the effects of inclusion of crambe bran concentrations (Crambe abyssinica Hochst.) with different specific masses in elephant grass silage (Penninsetum purpureum Schum.). For that, the bromatological and microbiological compositions of the experimental silages were determined. We used 48 mini silos distributed in a completely randomized design, arranged in a factorial 4 × 3, four levels of inclusion of crambe bran (0; 10; 20 and 30%) and three specific masses (400; 500 and 600 kg MN m-3), with four replications. After 240 days of fermentation the silos were opened. It was observed linear effect on DM, CP, NDFap, ADFap, HEM, LIG, NFC, TC and population of bacteria that produce lactic acid with the addition of crambe meal. There was interaction between the crambe bran factors and specific masses on the values of pH and N-NH3. For MM variables and yeast count there was a negative linear effect due to the evaluated specific mass. The inclusion of crambe bran helps to increase the fermentative profile and the bromatological composition of elephant grass silages studied, and the best results were obtained with the addition of 30% of this coproduct, based on the natural matter.

ABSTRACT The objective of this study was to simulate total dry matter intake and cost of diets optimized by nonlinear programming to meet the nutritional requirements of dairy does and growing doelings. The mathematical model was programmed in a Microsoft Excel(r) spreadsheet. Increasing values of body mass and average daily weight gain for growing doelings and increasing body mass values and milk yield for dairy does were used as inputs for optimizations. Three objective functions were considered: minimization of the dietary cost, dry matter intake maximization, and maximization of the efficiency of use of the ingested crude protein. To solve the proposed problems we used the Excel(r) Solver(r) algorithm. The Excel(r) Solver(r) was able to balance diets containing different objective functions and provided different spaces of feasible solutions. The best solutions are obtained by least-cost formulations; the other two objective functions, namely maximize dry matter intake and maximize crude protein use, do not produce favorable diets in terms of costs.

Objetivou-se avaliar a influência de diferentes arranjos espaciais de árvores ((3×2)×20 m, (2×2)×9 m e 9×2 m) e locais de amostragem (centro e lateral da entrelinha) na quantidade e qualidade de luz no sub-bosque de sistemas silvipastoris e seus efeitos na produção e composição bromatológica da pastagem. O delineamento utilizado foi blocos casualizados em parcelas subdivididas, com três repetições. O local de amostragem influenciou a irradiância absoluta, a radiação fotossinteticamente ativa incidente (RFAi), interceptação luminosa (IL) e relação vermelho/vermelho distante, sendo determinados maiores valores no centro das entrelinhas. Observou-se correlações altas e positivas entre IL/índice de área foliar (IAF), IL/produção de massa seca (PMS) e IAF/PMS no centro e IL/IAF e RFAi/PMS na lateral das entrelinhas. O arranjos espaciais (3×2)×20 m apresentaram maiores valores para altura da planta (AP), PMS e teor de fibra em detergente neutro, enquanto o (2×2)×9 m apresentou maiores valores para relação folha:colmo e teor de proteína bruta. Quanto ao local de amostragem, os maiores valores de AP e PMS foram observados no centro. A composição da forragem não foi influenciada pelos locais de amostragem. A maior PMS foi obtida no arranjo (3×2)×20 m e melhorias na composição da forragem foram observados nos arranjos mais adensados.

The aim was to evaluate the influence of different spatial arrangements of trees [(3×2)×20 m, (2×2)×9 m and 2×9 m] and sampling sites (center of row spacing and side of tree rows) with regard to the amount and quality of light in the understory of silvopastoral systems and their effects on the production and chemical composition of pasture. The experimental design was a randomized block in a split plot, with three replications. The sampling site affected absolute irradiance, photosynthetic active radiation (PAR), light interception (LI) and red/far red ratio, with higher rates in the center of spacing. There were high and positive correlations between LI/leaf area index (LAI), LI/dry mater (DM) and LAI/DM in the center and LI/LAI and FAR/DM in the side of tree rows. Spatial arrangement (3×2)×20 m had higher rates for plant height (PH), DM and neutral detergent fiber rate, while (2×2)×9 m had high leaf/stem ratio and crude protein rate. In the case of the sampling site, higher rates of PH and DM were reported in the center. Forage composition was not affected by sampling sites. Highest production of DM was obtained in the (3×2)×20 m arrangement and improvements in forage composition were observed in denser arrangements.

O experimento foi conduzido no setor de forragicultura e pastagens do Departamento de Nutrição Animal e Pastagens, no Instituto de Zootecnia da Universidade Federal Rural do Rio de Janeiro, em Seropédica, RJ, para avaliar a produção de matéria seca (PMS) e a composição químico-bromatológica de três leguminosas forrageiras tropicais: kudzu tropical (Pueraria phaseoloides), macrotiloma (Macrotyloma axillare) e soja perene (Neonotonia wightii) em dois sistemas de cultivo (SC) (tutorado e livre). Utilizou-se um delineamento em blocos ao acaso, em um esquema fatorial (3 (espécies) x 2 (SC) x 4 (Repetições), em parcelas de 20m². A PMS foi significativamente diferente (P<0,05) entre os SC, sendo que, para todas as espécies avaliadas, o SC tutorado apresentou maior produtividade. Não foi observado efeito significativo (P>0,05) para os valores referentes a proteína bruta (PB) e fibra em detergente ácido (FDA) das leguminosas em cada sistema de cultivo. Já para os valores de fibra em detergente neutro (FDN), houve diferença significativa (P<0,05) entre as espécies estudadas sendo que a espécie que apresentou maiores valores foi o kudzu tropical, seguido pela soja perene e o macrotiloma. Com relação à matéria mineral (MM), a interação (leguminosa x SC) apresentou efeito significativo (P<0,05). O maior valor observado no SC tutorado foi para o kudzu tropical, que diferiu das demais espécies. No entanto, quanto ao SC livre, o maior valor foi observado para a soja perene, o qual não diferiu para o kudzu tropical, porém diferiu para o macrotiloma.

The experiment was conducted in the forage crops and pastures section of DNAP/IZ/UFRRJ, Seropédica, Rio de Janeiro, to evaluate the dry matter production (DMP) and chemical composition of three tropical forage legumes: puero (Pueraria phaseoloides), archer (Macrotyloma axillare) and perennial soybean (Neonotonia wightii) in two cultivate systems (CS) (supported and free). A randomized block design, in a factorial arrangement was used: (3 species X 2 (CS) X 4 (Repetition), in plots measuring 20m². DMP was significantly different (P<0.05) among CS, where for all of the evaluated species the CS supported presented the largest productions. A significant effect was not observed (P>0.05) for the values regarding CP and ADF of the legumes in each cultivate system. For the values of NDF there was significant difference (P<0.05) among the studied species, and the species that presented larger values was the puero followed by the perennial soybean and the archer. There was significance (P<0,05) of mineral matter from the interaction between legume and cultivation system. The greater value observed in supported system was that of puero, that was different of other species. However, free system showed the highest value to perennial soybean, which was the same to puero but different of archer.