Abstract This study evaluates the economic viability of sheep finishing systems on irrigated Tamani grass pasture under continuous stocking, using castor bean cake. Four production systems were simulated: sheep supplemented with soybean meal on pasture fertilized with urea (SMUR), sheep supplemented with detoxified castor bean cake on pasture fertilized with urea (CCdUR), sheep supplemented with soybean meal on pasture fertilized with in natura castor bean cake (SMCC) and sheep supplemented with detoxified castor bean cake on pasture fertilized with in natura castor bean cake (CCdCC). A minimum unit of 3 hectares and an average slaughter weight of 28 kg were considered. A minimum selling price, at which the least profitable system would become profitable, was stablished: US$ 2.38 and US$ 4.45/kg per kilogram of body weight and carcass weight equivalent, adopting a minimum rate of return of 3.5% per year, based on the Selic rate. The costs for organic fertilization were 46.01% higher than in systems using chemical fertilization. The selling of live animals was not attractive in any of the systems evaluated, and the opposite was observed for the selling of carcasses and non-carcass components. System SMUR proved to be more profitable, with a gain of US$ 0.53 per kg carcass.

Resumo Objetivou-se avaliar a economicidade de sistemas de terminação de ovinos em pastagem irrigada de capim-tamani sob lotação contínua, utilizando torta de mamona. Foram simulados quatro sistemas de produção: ovinos suplementados com farelo de soja e o pasto adubado com ureia (FSUR), ovinos suplementados com torta de mamona destoxificada e o pasto adubado com ureia (TMdUR), ovinos suplementados com farelo de soja e o pasto adubado com torta de mamona in natura (FSTM) e ovinos suplementados com torta de mamona destoxificada e o pasto adubado com torta de mamona in natura (TMdTM). Foi considerada a unidade mínima de 3 hectares e determinado um peso médio ao abate de 28 kg de peso corporal. Estabeleceu-se um preço de venda mínimo, no qual o sistema de criação menos lucrativo se tornasse rentável de 2,38 e 4,45 dólares por quilograma de peso corporal e por equivalente de peso da carcaça, dotando uma taxa mínima de atratividade de 3,5% ao ano, com base na taxa Selic. Os custos com adubação orgânica, em média, são 46,01% superiores aos sistemas que utilizam adubação química. A venda de animais vivos não é atrativa em nenhum dos sistemas avaliados, sendo o contrário observado para a comercialização de carcaças e dos não componentes da carcaça de ovinos. O sistema de produção FSUR se mostrou mais lucrativo, com ganho de US$ 0.53 centavos por kg de carcaça.

ABSTRACT The application of organic composts derived from animal husbandry or agro-industry is a promising option to improve nutrient cycling and supply of soils and, consequently, forage production. The objective of this study was to evaluate the soil chemical properties and the nutritional state of elephant grass in response to rates of organic fertilizer composted from the waste of small ruminant production and slaughter systems. The experiment was conducted on a Fluvisol of a forage field with elephant grass var. Cameroon, and was arranged in a randomized block design with split-plots with repeated measures over time. Six rates of organic compost (0, 13.3, 26.6, 39.9, 52.3, and 79.8 t ha-1, in plots) and an additional treatment with mineral fertilizers were evaluated in four growth periods (60, 120, 180, and 240 days, in subplots) with four replications, resulting in a total of 28 plots. Soil fertility was evaluated after the fourth growth period, while leaf analysis was determined in every 60-day period. The increasing rates of organic compost increased the concentrations of OM, NH4+, NO3–, NH4+ + NO3–, P and base saturation, while the H+Al values decreased and the N and P contents increased in the plants. Compared with mineral fertilization, soil inorganic nitrogen and phosphorus increased by 34 and 97 % in response to the application of organic compost. In response to the application of organic compost, the leaf contents of all studied nutrients remained adequate in all studied periods, except for the macronutrient N and micronutrient Mn.

RESUMO Avaliou-se o fluxo de biomassa do Pennisetum purpureum cv. Cameroon irrigado submetido a doses de composto orgânico proveniente de resíduos da produção e abate da ovinocaprinocultura. O experimento foi realizado em capineira de capim-elefante, durante quatro ciclos de 60 dias. Os tratamentos foram doses do composto orgânico (0; 13,3; 26,6; 39,9; 53,2; 79,8) toneladas·ha-1, além de um tratamento mineral (nitrogênio e potássio) equivalente a 720 e 900 kg ha-1 ano-1, respectivamente. Foi utilizado um delineamento em blocos casualizados em esquema de parcelas subdivididas, com medidas repetidas no tempo, sendo as parcelas as doses e as subparcelas os ciclos. As características morfogênicas do capim elefante foram influenciadas pelas doses do composto. A taxa de produção de forragem apresentou efeito linear crescente com as doses do composto para todos os ciclos avaliados, enquanto a taxa de acúmulo de forragem respondeu de forma quadrática nos ciclos 1 e 2 às doses do composto. A análise de contraste entre a adubação orgânica x mineral, revelou em todos os ciclos, exceto no primeiro, superioridade dos índices morfogênicos para a adubação mineral. Conclui-se que o capim-elefante foi responsivo ao composto orgânico sugerindo-se uma dose de 70,63 toneladas ha-1.

ABSTRACT This study evaluated the biomass flow of irrigated Pennisetum purpureum cv. Cameroon fertilized with different levels of organic compost made from waste derived from production and slaughter of sheep and goat farming. The experiment was conducted in a cut and carry of elephant grass for four 60 day-cycles. The treatments consisted of levels of organic compost (0; 13.3; 26.6; 39.9; 53.2; 79.8) ton ha-1, besides a mineral treatment with nitrogen and potassium of 720 and 900 kg ha-1 yr-1, respectively. This was a split plot randomized block design with repeated measures over time, in which levels were assigned to plots, and cycles, to subplots. Morphogenetic characteristics of elephant grass were influenced by levels of the compost. Forage production rate had increased linearly with levels of the compost in all cycles, while the forage accumulation rate responded quadratically to doses of compost in cycles 1 and 2. The contrast analysis between organic x mineral fertilization revealed, for all cycles, except the first, superiority of morphogenetic indices for mineral fertilizer. It can be concluded that the elephant grass responded to the organic compost and it is recommended the use of 70.63 ton ha-1.

Este trabalho foi desenvolvido com o objetivo de observar a influência de quatro níveis de substituição (0; 50; 75 ou 100%) do farelo de soja pelo farelo de mamona destoxificado em rações para ovinos mestiços 1/2 Morada Nova x 1/2 SPRD (sem padrão racial definido) sobre o seu comportamento ingestivo. O delineamento utilizado foi o inteiramente casualizado com quatro tratamentos e cinco repetições. Os ovinos eram machos, inteiros, com peso corporal 18,01 ± 1,41 kg e idade média de 7 meses. Foram avaliadas atividades contínuas (tempo de alimentação, ruminação, outras atividades e ócio) e pontuais (consumo de sal, ingestão de água, micção e defecação), como também a eficiência de alimentação (EAL), eficiência de ruminação (ERU), tempo de alimentação (TAL), tempo de ruminação (TRU), tempo de mastigação total (TMT), número de bolos ruminais (BOL), tempo de mastigações merícicas por bolo ruminal (MMtb) e número de mastigações merícicas por bolo ruminal (MMnb). As variáveis tempo de alimentação, ruminação, outras atividades, ócio, consumo de sal e ingestão de água foram afetadas (P<0,05), especialmente o MMnb, que foi inferior para os animais alimentados com as rações com 100% de substituição, possivelmente pelo seu menor teor de fibra (oriundo da forragem), sendo possível a substituição total do farelo de soja pelo farelo de mamona destoxificado.

The aim of this work was to evaluate the effect of the replacement of four levels of a soybean meal by detoxified castor meal in rations fed to seven month-old 1/2 Morada Nova x 1/2 WDB (without defined breed) crossbred lambs, average 18 kg BW, on their ingestive behavior. The experiment was conducted in a completely randomized design with four treatments and five replicates. Continuous (feeding time, rumination, other activities and idleness) and punctual (salt consumption, water ingestion, urination and defecation) activities, as well as eating efficiency, rumination efficiency, eating time, rumination time, total chewing time, number of ruminal bolus, time of jaw movements per ruminal bolus and number of jaw movements per ruminal bolus were evaluated. The variables feeding time, rumination, other activities, idleness, salt consumption and water ingestion were influenced (P<0.05) by the replacement, especially the number of jaw movements per ruminal bolus, which was lower for animals fed diets with 100% replacement, possibly due to its lower fiber content. The results showed that it is possible the total replacement of the soybean meal by detoxified castor meal.