-The objective of this study was to evaluate live weight and carcass traits, from birth to slaughter, and meat quality of Nellore (NEL), Curraleiro Pé-Duro (CPD), and crossbred (F1) products in the state of Piauí, Brazil. Progenies from CPD, NEL, and their F1 crossbred (½ NEL + ½ CPD), a total of 252, males and females, from birth to 24 months of age, were evaluated in a comparative study in growth performance. The steers were sent to slaughter at 28 months of age and carcasses and meat quality were analyzed. After slaughter, carcass weight, dressing percentage and Longissimus dorsi area (rib eye area) were evaluated; an index was created by the relationship between these measures per hundred kg of chilled carcass produced.To assess meat quality, the shear force, water-holding capacity, color, brightness, pH, and cooking loss were investigated. Results obtained showed that month and year of birth were significant on growth, indicating influence of climatic variables. Nellore offspring was heavier than F 1 and this was heavier than CPD throughout the study period, including the hot and cold carcass. No differences were found in dressing percentage among NEL and F 1 , but CPD and F 1 showed a rib eye area and index significantly higher than NEL. The meat from CPD group presented a stronger red coloration than the others, but there was no significant difference in the remaining meat qualitative variables among the three groups. Curraleiro Pé-Duro and F 1 crossbred produce more meat per 100 kg of carcass than Nellore in natural pasture of Piauí State.

Objetivou-se avaliar os efeitos de variedades, da irrigação e da adubação sobre a produção e composição química da cana-de-açúcar com fins forrageiros em Parnaíba, Piauí. O delineamento experimental foi em blocos casualizados, em esquema fatorial 2 x 5 x 4, com quatro repetições. Os tratamentos consistiram em duas lâminas de irrigação (reposição de 50% e 100% da evapotranspiração de referência -ETo), cinco variedades de cana-de-açúcar (RB962962, RB867515, RB92579, RB863129 e RB98710) e quatro níveis de adubação (70 + 63; 140 + 126; 210 + 189 e 280 + 252 kg de N + K 2 O/ha/ano, respectivamente). O plantio foi realizado em julho de 2015 e a colheita em julho de 2016. As variedades de cana-de-açúcar RB962962 e RB867515 se sobressaíram das demais, apresentando elevada produtividade de biomassa e maiores percentuais de colmos, conciliada a satisfatórios teores de sólidos solúveis (açúcares). Para as condições do norte do Piauí, considerando-se a produtividade, melhoria da composição química e a possibilidade de economia de água, a lâmina de água aplicada (lâmina de irrigação + 1.696 mm de precipitação pluviométrica), associada à aplicação de 70 kg de N e 63 kg de K 2 O/ha/ano, pode ser utilizada na produção de biomassa da cana-de-açúcar com fins forrageiros.

ABSTRACT In intercropping systems, a high plant density can delay the biomass accumulation and affect the water availability to plants. This study aimed to evaluate the soil water dynamics and the crop yield performance in maize and Brachiaria ruziziensis intercropping under different sowing densities of the forage grass. The experiment was conducted in a randomized block design, with treatments associated to the sowing densities (2 kg ha-1, 4 kg ha-1, 6 kg ha-1 and 8 kg ha-1) and the single cropping for both species as controls. The maize plants were evaluated for grain yield and B. ruziziensis for number of plants per hectare and shoot fresh and dry matter. The intercropping performance was evaluated using the land-use efficiency index. The soil water dynamics was monitored in two soil depths (0-0.3 m and 0.3-0.6 m) by using the time domain reflectometry method. The evaluation of soil water storage was carried out from plots with four of the crop systems (single maize or B. ruziziensis, and intercropping with the extreme sowing densities), at four different times. The increase in the sowing density of B. ruziziensis decreased the grain yield of the intercropped maize by 30.8 %. The intercropping system using 2 kg ha-1 of the grass seeds resulted in the best land-use efficiency (23 %). In addition, the intercropping treatments promoted a higher extraction of water from the soil, mainly at the maize growth stages with higher hydric demand (e.g., flowering and grain filling). These systems stimulate the extraction of water from deeper soil layers, when compared to maize in single cropping.

A trial was carried out with objective of identifying economical sources of alimentary supplementation for cows milk in exclusive feeding regime of elephant-grass pasture (Pennisetum purpureum cv. Napier), submitted to the fertilization and irrigation. The experimental design was completely randomized with three treatments: T1 = cows grazing exclusively in elephant-grass pasture; T2 = T1 + bank of leucena protein and T3 = T1 + concentrated ration, supplied in the amount of 1 kg for each 3 kg of milk produced above 5 kg. The largest production milk was obtained of the animals of T3 (11.11 kg of milk/cow/day and 3,594.08 kg of milk/cow/lactation), followed by T2 (9.19 kg of milk/cow/day and 2,740.15 kg of milk/cow/lactation) and T1 (8.54 milk/cow/day kg and 2,520.36 milk/cow/lactation kg). The lower profitability was obtained with cows grazing elephant-grass supplemented with concentrates.

Avaliou-se os efeitos de diferentes lâminas de irrigação e doses de nitrogênio (N) sobre as características morfogênicas e estruturais do capim-Marandu (Brachiaria brizantha cv. Marandu). O estudo foi conduzido na área experimental da EMBRAPA Meio-Norte, em Parnaíba, Piauí, Brasil. Em delineamento em blocos casualizado, esquema fatorial 2 x 4, foram testadas lâminas de irrigação (equivalente a reposição de 50% e 80% da Evaporação do Tanque Classe “A”) x doses de nitrogênio (16,7; 33,3; 50,0 e66,7 kg de N/corte), com três repetições. Os cortes foram realizados a cada 30 dias, totalizando quatro cortes. A redução da lâmina de irrigação proporcionou decréscimos nas taxas de alongamento da folha, aparecimento de folha, comprimento final da folha e número de folhas vivas, enquanto que a taxa de senescência aumentou. A adubação nitrogenada incrementou as taxas de alongamento e aparecimento de folha, e o comprimento final da folha, no entanto, provocou redução do número de folhas vivas e a ampliação da taxa de senescência.

Objective was to determine the frequency and intensity of defoliation more appropriate for management pasture ofBrachiaria Brizantha in ecological conditions of Porto Velho, Rondônia. The experimental design was randomized blocks with split plots and three replications. The defoliation frequencies (21, 28, 35 and 42 days) represented the main plots and defoliation intensity (20 and 40 cm) the subplots. The highest forage yield were observed when the grass was cut every 35 and 42 days. The defoliation frequency ​​every 21 days, regardless of defoliation intensity, provided higher crude protein (CP), however the highest CP yields were obtained with defoliations every 28, 35 or 42 days and 40 cm above the ground. The highest concentrations of phosphorus, calcium and potassium, irrespective of the defoliation intensity, were recorded with frequency defoliation every 21 days. Aiming to combine the production and quality of forage, the results indicate that better management of B. brizantha cv. Marandu consists of defoliation frequency every 42 days, regardless of defoliation intensity, or cutting at 35 days and 40 cm above the ground.

Resumo: Estudou-se o retorno ao estro de 60 pós-parto ovelhas da raça Santa Inês distribuídas em quatro lotes experimentais, cujos critérios foram a oferta ou não de suplementação alimentar para as matrizes e amamentação continua ou controlada para as crias. As ovelhas permaneceram, nos meses de junho a novembro de 2004 e 2005, na Fazenda Experimental da Embrapa Meio-Norte, em Campo Maior-PI, localizada a 4° 46' 59" S e 42° 07' 20" W, a 120 m acima do nível do mar, pluviosidade média anual de 1.200 mm, distribuídos de janeiro a início de maio, temperatura média anual de 27 ºC e umidade relativa média de 70,34%. Usou-se o delineamento experimental inteiramente casualizado em arranjo fatorial 2x2, com avaliações dos fatores sem suplementação x com suplementação alimentar e amamentação contínua x controlada. As médias e respectivos desvios-padrão foram comparadas pelo teste Ducan a 5%. O período do parto ao primeiro estro pós-parto foi menor (p<0,05) tanto nas ovelhas que receberam suplementação alimentar como naquelas em que as crias tiveram amamentação controlada. Portanto, ovelhas da raça Santa Inês mantidas em pastagem nativa, suplementadas no pós-parto e com crias submetidas à amamentação controlada apresentam o primeiro estro pós-parto mais precoce.

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