ABSTRACT The objective of this study was to analyze the economic result of feedlot operation for three genetic groups of cattle (Nellore, Nellore crossing with other Zebuine breeds, and Dairy crossbred) as a function of the overprice on the purchase price of cattle to be feedlot-finished. The study involved data of 57,589 animals divided into 709 lots originating from operation cycles from March to December 2016. Lots were considered replicates, and gross margin per animal was considered the economic result. Data pertaining to each lot, overprice, and gross margin were analyzed by regression, with mathematical models developed for each genetic group. After significance tests were applied, simple linear models were adopted for all studied groups. To check the equality or lack thereof of the three regression models generated, we used a model-identity test, which revealed that the model for Nellore animals was different from that used for Dairy crossbreds. The model generated for Nellore crossing with other Zebuine breeds did not differ from the models for Nellore or Dairy crossbreds, i.e., Nellore crossing with other Zebuine breeds may be grouped as a single model together with the Nellore group or with the Dairy-crossbred group. The estimates generated from the three individualized models suggest that the purchase of the feeder (unfinished) cattle for the Dairy crossbred, Nellore crossing with other Zebuine breeds, and Nellore groups, with an overprice starting at 1.19, 1.21, and 1.27, respectively, will result in negative gross margins. Thus, the overprice at purchase may compromise the economic result of feedlot operation, and more-efficient animals may allow for a greater overprice on the purchase in the operation, with a positive gross margin.

RESUMO Neste trabalho, foram avaliadas as características fermentativas e químico-bromatológicas da silagem de capim-elefante (CE) com diferentes níveis de inclusão, durante a ensilagem, do coproduto da extração da polpa do abacaxi, a casca de abacaxi (CA), nas proporções de 0,0; 12,5; 25,0; 37,5 e 50,0%, da matéria natural do capim-elefante. O material foi ensilado em silos laboratoriais e, após 180 dias, os silos foram abertos e coletaram-se amostras para a determinação dos teores de matéria seca (MS); carboidratos solúveis (CHOS); potencial hidrogeniônico (pH); nitrogênio amoniacal em percentagem do nitrogênio total (NNH3/NT); extrato etéreo (EE); proteína bruta (PB); proteína insolúvel em detergente neutro em percentagem do nitrogênio total (PIDN/NT); proteína insolúvel em detergente ácido em percentagem do nitrogênio total (PIDA/NT); fibra em detergente neutro (FDN); fibra em detergente ácido (FDA); celulose (CEL); lignina (LIG); nitrogênio insolúvel em detergente neutro (NIDN); nitrogênio insolúvel em detergente ácido (NIDA) e digestibilidade in vitro da matéria seca (DIVMS). Para a avaliação do efeito dos tratamentos, utilizou-se delineamento experimental inteiramente casualizado, com quatro repetições, executando-se o estudo de regressão para cada variável analisada (P < 0,05). De acordo com as equações de regressão, para as características fermentativas, as silagens podem ser consideradas de muito boa qualidade. Quanto às frações fibrosas da silagem, a inclusão de níveis crescentes deste coproduto contribuiu para diminuí-las, o que pode ser confirmado pelos resultados encontrados para a DIVMS. A inclusão da CA durante a ensilagem do capim-elefante favorece a fermentação e melhora o valor nutritivo das silagens, sendo recomendada em todos os níveis de inclusão avaliados.

ABSTRACT We evaluated the qualitative, fermentative, and chemical characteristics of elephant grass silage containing different levels of inclusion of coproduct of the pineapple pulp extraction, pineapple peel - (0.0%, 12.5%, 25.0%, 37.5%, and 50.0%) in relation to natural field of elephant grass during ensiling. The material was ensiled in laboratory silos and after 180 days, the silos were opened and samples were collected for determination of dry matter, soluble carbohydrates, pH, ammonia nitrogen in percentage of total nitrogen, ether extract, crude protein, neutral detergent insoluble protein as a percentage of total nitrogen, acid detergent insoluble protein as a percentage of total nitrogen, neutral detergent fiber, acid detergent fiber, cellulose, lignin, neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen, and in vitro digestibility of dry matter. To assess the effect of the treatments, we used a completely randomized design with four replications, running the regression analysis for each variable analyzed (P<0.05). According to the regression equations for the fermentative characteristics, the silages can be considered of very good quality. As for fiber digestibility of silage, the increasing levels of this coproduct contributed to its decrease, which can be confirmed by the results found for in vitro digestibility of dry matter. The inclusion of the pineapple peel during the elephant grass silage fermentation promotes and improves the nutritive value of silages being recommended at all levels of inclusion evaluated.

The objective of this study was to evaluate the performance of F1 (Holstein × Zebu) cows in lactation according to different levels of substitution of soybean meal for a protein equivalent non-protein nitrogen originated from slow-release urea (SRU). Eight F1 (Holstein × Zebu) cows in the first third of lactation, with an average milk yield of 12.7 kg (±3.1 kg)/day and a live weight of 552 kg (±30 kg), were used. The experimental design was composed of two simultaneous 4 × 4 Latin squares, with the following treatments: 100% soybean meal and 0% SRU; 66% soybean meal and 34% SRU; 34% soybean meal and 66% SRU; and 0% soybean meal and 100% SRU. Sorghum silage, used as roughage, was supplied together with the concentrate. Feed intake and digestibility as well as milk yield and milk composition were measured. The obtained data were subjected to analysis of variance, adopting a 5% probability level. No intake variable showed significant differences among the treatments, and the mean values for the intakes of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) were 18.35 2.62 and 5.85 kg/day, respectively. The results for apparent digestibility also did not show differences among treatments, with DM, CP and NDF averaging 58.16, 58.64 and 36.21%, respectively. Milk yield and composition were similar among the treatments. The average 4%-fat-corrected milk yield was 13.39 kg/animal day. Intake, digestibility and milk yield and composition variables are not changed according to the substitution of the soy protein for slow-release urea. Thus, for average-milk-yield crossbred.animals, this substitution depends on economic variables only.

<p>Objetivou-se com este trabalho avaliar a cinética da taxa de passagem ruminal de partículas das silagens oriundas dos consórcios: milho e capim-braquiária; milho, capim-braquiária e calopogônio; milho, capim-braquiária e macrotiloma; e milho, capim-braquiária e estilosantes. Foram usados quatro bovinos mestiços holandês-zebu, fistulados no rúmen. As fezes foram coletadas nos tempos zero (imediatamente após a administração da fibra complexada com cromo), 1, 2, 4, 6, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 56, 64, 72, 80, 88, 96, 120, 132, 144 e 192 horas. As estimativas dos parâmetros dos perfis de taxa de passagem foram ajustadas de acordo com procedimentos de regressão robusta. O tempo médio de retenção de partículas no <italic>raft</italic> (<italic>TMR1</italic>); o tempo médio de retenção de partículas na fase líquida ruminal (<italic>TMR2</italic>) e o tempo médio de retenção ruminal total (<italic>TMRR</italic>) foram ajustados para a cinética de passagem e estimados com o procedimento NLIN do SAS. A partir dos resultados observados, pode-se sugerir que a taxa de transferência <italic>λ</italic> possui comportamento inverso à taxa de escape<italic>κ</italic>; os valores médios de <italic>τ</italic>, os tempos médios de retenção e os tempos médios de retenção de partículas na fase líquida ruminal (<italic>TMR2</italic>) não diferiram estatisticamente. As características cinéticas dos alimentos, após escaparem do <italic>raft</italic>e chegarem à fase líquida, foram equivalentes. Os <italic>TMRR</italic> das fibras das diferentes silagens não diferiram entre si (<italic>p<0,05</italic>). Observaram-se pequenas diferenças numéricas dos <italic>TMRR</italic> nos diferentes alimentos. As fibras das silagens em estudo tiveram taxas semelhantes de <italic>λ</italic>, k, TMR1,TMR2 e TMRR. Portanto, a cinética da taxa de passagem ruminal de partículas das silagens dos consórcios é semelhante. Assim, a tomada de decisão pelo tipo de consórcio a ser utilizado deve ser baseada em outros fatores, tais como viabilidade do manejo de culturas e custo da silagem.</p>

<p>The purpose of this study was to evaluate the kinetics of ruminal passage rate of particles from the subsequent associations: corn and signal grass; corn, signal grass and Calopogônio; corn, signal grass and Macrotiloma; and corn, signal grass and Estilosantes. It was used four crossbred holstein-zebu cattle with the rumen tubed in order to determine the the kinetics of ruminal passage rate of particles. The feces were collected at the times zero (immediately after addition of fibers complexed with chromium), 1, 2, 4, 6, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 56 , 64, 72, 80, 88, 96, 120, 132, 144 and 192 hours. The profile parameters of passage rate estimative were adjusted according to robust regression procedures. The average time of particles retention in the raft (ATPR1); the average time in the rumen liquid phase (ATRLP2) and the average time of total ruminal retention (ATTRR) were adjusted for the passage kinetics and estimated with the NLIN procedure of SAS. From the observed results, may be suggested that the transference rate <italic>λ</italic> has an inverse behavior to the escape rate <italic>κ</italic>, the <italic>τ</italic> average values, the average retention time and average particles retention time in the rumen liquid phase (ATRLP2) were not statistically different. The feed characteristics after the raft escape and reach to ATRLP2, were very similar; (ATTRR), related to treatments, were not statistically different (P<0,05). There were observed small TMRR numerical differences in different foods. The corn and signal grass; corn, signal grass and calopogônio; corn, signal grass and macrotiloma, corn, signal grass and estilosantes silage fibers had similar rates of<italic>λ</italic>, k, ATPR1, ATRLP2 and ATTRR. Therefore, the the kinetics of ruminal passage rate of particles is similar. Thus, the choice of the system should be based on other factors, such as viability of the management ease and silage cost.</p>

The objective was to evaluate intake and digestibility of nutrients, as well as milk production and composition of the milk from F1 Holstein × Gyr cows kept on pasture, supplemented with sugarcane and concentrate (28% CP). Five cows with 150±14 lactation days and average milk production of 7.1±2.1 kg/day were distributed in a 5 × 5 Latin square design. The treatments were: soybean meal-based concentrate; soy bean-based concentrate; ground soybean-based concentrate; roasted soybean-based concentrate; and ground, roasted soybean-based concentrate. Dry matter (DM), organic matter, crude protein (CP), neutral detergent fiber (NDF), total carbohydrates and total digestible nutrients intakes were not affected by the diet, but ether extract intake was higher for the animals fed soy bean-based diets than those fed soybean meal. The digestibility of DM, NDF and CP did not differ. The corrected milk yield differed between treatments; animals on the treatment with soy bean-based concentrate had the lowest production in relation to the others, which did not differ from each other. There was no difference between treatments for milk composition. Thus, soybean meal can be replaced by ground soy beans or roasted soy beans (ground or whole) in diets for low-yield cows reared on Brachiaria decumbens pastures with no harm to milkproduction or composition. Therefore, the use of these alternative raw materials is recommended whenever their inclusion represents lower feeding costs.

The objective of the present study was to evaluate the parameters related to the digestion of the fiber from silages of four corn hybrids (BX1280, SHS4070, 2B433, and DKB390) developed for silage production. Four rumen-cannulated castrated Holstein × Zebu crossbred cattle with approximate initial weight of 400 kg were distributed in a Latin square design. To determine the fiber passage rate and degradability, the techniques of chromium-mordant and in situ incubation of the neutral detergent fiber of the silages in nylon bags were used. The profiles of concentration of the marker in the feces were described by the generalized two-compartment model. Corn hybrid DKB390 is the most indicated for production of better-quality silages, because its fiber is more degradable in the rumen as compared with the other hybrids tested.

Objetivou-se com o presente trabalho avaliar os efeitos de uma mistura comercial de óleos essenciais (capsaicina, eugenol, cinamaldeído e carvacrol) microencapsulados com inclusões crescentes (0; 1,5; 3,0 e 4,0g/dia) sobre o consumo, digestibilidade, desempenho e a composição do leite de 20 vacas Holandesas primíparas confinadas em baias com cama de areia. Não houve interação entre os tratamentos e os períodos avaliados, e o efeito dos tratamentos não foi significativo (P>0,05) para as variáveis consumo de matéria seca, expresso em % PV e em kg/dia, proteína bruta (% PV), extrato etéreo (% PV), fibra em detergente neutro (% PV), fibra em detergente ácido (% PV); digestibilidade da matéria seca (%), proteína bruta (%), extrato etéreo (%), fibra em detergente neutro (%); produção de leite (kg) e seus componentes gordura (%), proteína (%), lactose (%), sólidos totais (%), extrato seco desengordurado (%), contagem de células somáticas (log) e nitrogênio ureico (mg/dL). No entanto, avaliando separadamente os períodos testados, encontrou-se diminuição significativa (P<0,05) na produção de leite e aumento nas concentrações de sólidos totais (%). Não houve diferença (P>0,05) para os teores de extrato seco desengordurado (%) e contagem de células somáticas (log). Pôde-se concluir que a utilização de óleos essenciais contendo capsaicina, eugenol, cinamaldeído e carvacrol não influencia o consumo, digestibilidade, produção e composição do leite de vacas Holandesas primíparas.

The objective with the current study was to evaluate the effects of a commercial mixture of essential oils (capsaicin, eugenol, cinnamaldehyde, and carvacrol) microencapsulated with increasing inclusions (0, 1.5, 3.0 and 4.0g/day) on intake, digestibility, performance and milk composition of 20 primiparous Holstein cows confined in sand-bedded stalls. There was no interaction between treatment and observation periods, and the effect of treatments was not significant (P>0,05) for dry matter intake, expressed as % body weight (BW) and kg/day; crude protein (% BW); ether extract (% BW); neutral detergent fiber; acid detergent fiber (% BW); dry matter digestibility (%); crude protein (%); ether extract (%); neutral detergent fiber (%); milk production (kg); milk fat (%); milk protein (%); lactose (%); total solids (%); nonfat dry extract (%); somatic cell count (log); and urea nitrogen (mg/dL). However, evaluating each period, a significant decrease (P<0,05) on milk production, and an increase in total solids concentrations (%) were observed. There was no difference (P>0,05) for total solids levels (%) and somatic cell count (log). We concluded that the use of essential oils containing capsaicin, eugenol, cinnamaldehyde and carvacrol does not affect intake, digestibility, and milk production and composition of primiparous Holstein cows.

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.

The objective of this study was to determine the kinetics of in situ degradability parameters of the dry matter (DM) and neutral detergent fiber (NDF) and the passage of materials originating from the ensilage of the waste from pineapple cultivation (aerial parts). The four treatments utilized were silage of pineapple waste compacted at 600, 700, 900 and 1000 kg/m³. After ensiling the material from the pineapple cultivation, the particle-transit and rumen-degradation kinetics were analyzed. For the analysis of particle transit, chromium was utilized as a marker to mark the fiber. Passage rates were determined by retrieving the markers in the feces of the animals. In the degradation assay, samples were incubated in nylon bags for 0, 6, 18, 48 and 96 hours. The behavior observed in the regression curves of the variables analyzed describes high correlation between them, i.e., the time during which the silage is retained in the rumen influences its digestibility and its degradation rate. Although the silage compacted at 900 kg/m³ shows a larger potentially digestible fraction, it is recommended that it be ensiled at a compaction density of approximately 750 kg/m³ due to the lower cost and shorter mean retention time in the rumen-reticulum and rumen fill, thereby increasing the ruminal degradation and passage dynamics.

The present study was carried out with the objective to evaluate the productive and qualitative characteristics of forages produced in systems of intercropping of corn, brachiaria grass and different leguminous plants. Productivity, bromatological composition and the fermentative profile of the silages from the following treatments were evaluated: corn in exclusive cultivation (CEC); intercropping of corn with brachiaria grass (CB); intercropping of corn, brachiaria grass and Calopogonium mucunoides (CBCal); intercropping of corn, brachiaria grass and Macrotyloma axillare (CBMac); and intercropping of corn, brachiaria grass and Stylozanthes capitata (CBSty). The experimental design utilized was completely randomized. For each type of cultivation, five plots or replications of three linear meters were harvested, and the material was separated. The variables assessed were: dry matter productivity per area; dry matter productivity of corn per area; crude protein production per area and productivity of total digestible nutrients per area. The material originated from the cultures was ensiled, with dry matter between 28 and 32%. After, the material was placed and compacted appropriately in bucket silos. A sample was collected from each replication for determination of the contents of DM, crude protein (CP), ether extract (EE), lignin, neutral and acid detergent fibers (NDF and ADF) and TDN. A fraction of the sample of silages from each treatment was compressed for extraction of the juice and determination of the silage quality. There was difference between the forms of cultivation for the dry matter production per hectare. The CEC with production of 11920.1 kg DM/ha did not differ from CB (8997.41 kg DM/ha) or CBCal (10452.10 kg DM/ha); however, it was superior to CBMac (8429.75 kg DM/ha) and to CBSty (8164.83 kg DM/ha). The contents of DM, CP, NDF, ADF, lignin and TDN did not differ between the silages from the different treatments. All the silages presented good quality with good fermentation patterns.

The objective of this research was to identify the potential of maize hybrids for the production of silage. Hybrids 1671B, 2B433, 20A78, SHS4070, BX1280 and DKB390 were tested in a randomized block design with three replications. The hybrids yields were evaluated (average plant height, height of ear insertion, number of broken and lodged plants/ha, leaf:stem and ear:plant ratio and production of of DM, CP and TDN/ha). There was no difference between hybrids for the variables studied, except for the height of ear insertion. With respect to chemical characteristics, N-NH3/NT organic acids, and pH, there was also no difference between cultivars and hybrid silages are rated as of very good quality.