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Phosphorus (P) is one of the most limiting mineral elements for biomass and grain production in tropical soils. This study was undertaken to assess the influence of P on herbage accumulation (DM) and the nutritive value of forage sorghum (Sorghum bicolor) and black oat (Avena strigosa) in succession. Evaluated treatments were P fertilization levels of 0, 50, 100, 150 and 200 kg of P2O5 ha-1 distributed in a randomized complete block design with three replicates. The treatments were applied at sorghum seeding in the summer 2010/2011 and 2011/2012. Black oat was seeded following sorghum in 2011 with no additional P fertilization. Herbage production and its nutritive value were assessed by successive cuts. The greatest sorghum DM yields were obtained at the highest phosphate level tested (200 kg P2O5 ha-1), with residual response in subsequent black oat. There was no effect of P fertilization levels on the nutritive values of both crops, considering crude protein (CP) levels, in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF) and acid detergent fiber (ADF), what demonstrates that P addition has no effect in forage nutritive value, especially when the soil P levels are classified as medium or high. The plant P recovery efficiency decreased when increasing P fertilization levels for both sorghum and black oat. The level of 50 kg P2O5 ha-1 year-1 presented the greatest P recovery by plants, which supports the idea of less fertilizer use with more efficiency.

We carried out this study to evaluate the productive performance and carcass yield of different strains and sexing of broilers. We evaluated 576 birds of Cobb, Ross, and Hubbard strains, arranged in male, female or mixed sexing, slaughtered at 45 days of age. We used a completely randomized design (CRD), in a 3 X 3 factorial (strain X sex), with four replicates per treatment. Body weight, weight gain, feed intake, and feed conversion showed significant differences in the course of the phases evaluated; however, they were similar at the end of the study period. Males showed superior results compared to females and mixed sexing. Carcass yield showed no significant differences among strains and sexing of birds; however, in some prime cuts, Cobb presented the best results. Keywords: consumer market; genetics; poultry; technology.

Realizou-se este trabalho com o objetivo de avaliar o desempenho produtivo e o rendimento de carcaça de diferentes linhagens e sexagens de frangos de corte. Foram avaliadas 576 aves das linhagens Cobb, Ross e Hubbard, dispostas nas sexagem macho, fêmea ou misto, abatidas aos 45 dias de idade. Utilizou-se o delineamento inteiramente casualizado (DIC), num bifatorial 3 x 3 (linhagens x sexagem), com quatro repetições e 16 aves em cada tratamento. O peso vivo, ganho de peso, consumo de ração e conversão alimentar apresentaram diferenças significativas no decorrer das fases avaliadas, porém, mostraram-se semelhantes ao final do período avaliado. O desempenho dos machos apresentou superioridade em comparação com as fêmeas e os mistos. No rendimento de carcaça, não foi possível observar diferenças significativas entre as linhagens e sexagens das aves; no entanto, em alguns cortes nobres a linhagens Cobb apresentou melhores resultados. Palavras-chave: avicultura; genética; mercado consumidor; tecnologia.

Alternative production of forages in periods of scarcity, especially during the winter, is expressively important for grazing of beef and dairy cattle in Brazil. The current work aimed to evaluate the influence of nitrogen fertilization on the production and nutritional value of ryegrass forage (cv. Barjumbo). The experiment was carried out on the winter seasons of 2009 and 2010, at the experimental area of UTFPR, Dois Vizinhos - PR, Brazil. The design consisted of randomized blocks with four N rates (0; 40; 80 and 120 kg ha-1) and three replicates. Each plot measured 5x5 m, with 20 cm row spacing and 2.5 cm between plants, totaling 20 kg ha-1 of viable seeds. It was determined the dry matter production, crude protein level, total accumulation of crude protein and neutral detergent fiber, during the whole growth cycle of ryegrass in two crop seasons. Nitrogen fertilization promotes a significant and linear increase in dry matter yield and in accumulation of crude protein, with the best results with the highest rate evaluated (120 kg N ha-1). Nitrogen levels are not capable to promote significant effects in forage neutral detergent fiber content.

Alternative production of forages in periods of scarcity, especially during the winter, is expressively important for grazing of beef and dairy cattle in Brazil. The current work aimed to evaluate the influence of nitrogen fertilization on the production and nutritional value of ryegrass forage (cv. Barjumbo). The experiment was carried out on the winter seasons of 2009 and 2010, at the experimental area of UTFPR, Dois Vizinhos - PR, Brazil. The design consisted of randomized blocks with four N rates (0; 40; 80 and 120 kg ha-1) and three replicates. Each plot measured 5x5 m, with 20 cm row spacing and 2.5 cm between plants, totaling 20 kg ha-1 of viable seeds. It was determined the dry matter production, crude protein level, total accumulation of crude protein and neutral detergent fiber, during the whole growth cycle of ryegrass in two crop seasons. Nitrogen fertilization promotes a significant and linear increase in dry matter yield and in accumulation of crude protein, with the best results with the highest rate evaluated (120 kg N ha-1). Nitrogen levels are not capable to promote significant effects in forage neutral detergent fiber content.