ABSTRACT: In Brazil, urea is the most used nitrogen (N) fertilizer to improve forage production. However, their excessive use can cause environmental impacts through N losses, such as ammonia (NH3) volatilization. Therefore, the current study adjusted and estimated the NH3 volatilization from urea applied on tropical pastures in three rainfall conditions using mathematical models. Data were collected from Marandu grass (Brachiaria brizantha) fertilized with 50 kg N ha-1 during wet, intermediate, and dry conditions. Ammonia volatilization was measured in five semi-open chambers for 21 days. The linear, quadratic, exponential, Gompertz, Groot, and Richards models were tested for fitting and estimating the NH3 volatilization. The Gompertz, Groot, and Richards models generated predictions similar to the observed data, with a high determination coefficient, indicating a better fit of these equations to data, with precision and accuracy. However, the Groot model was selected due to the lowest root mean square error of prediction (0.29 % total N lost as NH3). The greatest N loss as NH3 volatilization occurred in the wet, followed by intermediate and dry conditions (20.2, 17.0, and 11.3 % total N lost as NH3, respectively). Therefore, nitrogen losses as NH3 volatilization after application of 50 kg N ha-1, as urea source, are altered according to the weather conditions, reaching 20% of N added in the wet rainfall period. The Groot model is recommended for fitting and estimating the NH3 volatilization from urea applied on Marandu grass pastures in the wet and dry rainfall conditions.

RESUMO: No Brasil, a ureia é o fertilizante nitrogenado mais utilizado para melhorar a produção de forragem. No entanto, seu uso excessivo pode causar impactos ambientais por meio de perdas de nitrogênio (N), como a volatilização da amônia (NH3). Portanto, o objetivo do presente estudo foi ajustar a volatilização de NH3 da ureia aplicada em pastos tropicais em três condições de chuva utilizando modelos matemáticos. Dados foram coletados de pastos de capim-marandu (Brachiaria brizantha) adubado com 50 kg N ha-1 em condições úmidas, intermediárias e secas. A volatilização da NH3 foi medida em cinco câmaras semiabertas durante 21 dias. Os modelos, linear, quadrático, exponencial, Gompertz, Groot e Richards foram testados para ajuste e estimativa da volatilização do NH3. Os modelos de Gompertz, Groot e Richards geraram predições semelhantes aos dados observados, com alto coeficiente de determinação, indicando um melhor ajuste dessas equações aos dados, com acurácia e precisão. No entanto, o modelo Groot foi selecionado devido ao menor erro quadrático médio das predições (0,29% de N total perdido como NH3). A maior volatilização de NH3 ocorreu em condições climáticas úmida, seguido por intermediária e seca (20,2; 17,0 e 11,3% de N total perdido como NH3, respectivamente). Portanto, as perdas de N como volatilização de NH3 após a aplicação de 50 kg N ha-1, como fonte de ureia, são alteradas de acordo com as condições climáticas, atingindo a 20% do N adicionado nas condições úmidas. O modelo Groot é recomendado para ajuste e estimativa da volatilização de NH3 da ureia aplicada em pastos de capim Marandu em condições úmidas e secas.

Abstract Sheep production systems face numerous challenges, which make decision-making a process fraught with risks and uncertainties. Modelling is a helpful tool in this respect, as it allows decision-makers to evaluate the behaviour of variables and their interrelationships, in addition to using previous or related information to predict results and simulate different scenarios. The advent of prediction models has made it possible to monitor the weight of an animal and determine the best time for its sale. Additionally, it allows producers to estimate the weights of the carcass and major marketable cuts before slaughter. All this information is directly associated with the profitability and success of the production activity. Therefore, in view of the different applications of mathematical models in production systems, this literature review examines concepts in modelling studies and the importance of using prediction models in meat sheep production. Furthermore, it addresses the practical application of modelling studies in predicting dry matter intake and carcass traits of meat sheep through correlated variables.

Resumen Los sistemas de producción ovina se enfrentan a numerosos desafíos, que hacen de la toma de decisiones un proceso lleno de riesgos e incertidumbres. En este sentido, la modelación es una herramienta útil, ya que permite a los tomadores de decisiones evaluar el comportamiento de las variables y sus interrelaciones, además de utilizar información previa o relacionada para predecir resultados y simular diferentes escenarios. El advenimiento de los modelos de predicción ha permitido monitorear el peso de un animal y determinar el mejor momento para su venta. Además, permite a los productores estimar los pesos de la canal y los principales cortes comercializables antes del sacrificio. Toda esta información está directamente asociada a la rentabilidad y el éxito de la actividad productiva. Por lo tanto, en vista de las diferentes aplicaciones de los modelos matemáticos en los sistemas de producción, esta revisión de la literatura examina los conceptos en los estudios de modelación y la importancia de utilizar modelos de predicción en la producción de ovinos de carne. Además, aborda la aplicación práctica de los estudios de modelación en la predicción de la ingesta de materia seca y los rasgos de la canal de ovinos de carne a través de variables correlacionadas.

ABSTRACT The effects of diets containing oilseeds were measured to evaluate the productive and economic parameters in the finishing of young, feedlot Nellore bulls. Twenty-four young Nellore bulls were used, with an initial body weight (BW) of 311.46±0.37 kg and 24 months of age, distributed into individual stalls ( 4 × 20 m) in a completely randomized design, totaling four treatments with six repetitions per treatment. Four diets (control, based on corn and soybean meal, and three diets containing cottonseed, soybean, and sunflower) were evaluated. Feed and orts were measured daily to calculate intake and costs. The dry matter intake of the control group was higher than soybean (10.64 kg/day), cotton (9.88 kg/day), and sunflower (9.30 kg/day) treatments, respectively. The cottonseed treatment showed the highest average neutral detergent fiber intake. There was a dietary effect of diets on average daily gain, total weight gain, and final weight. The soybean treatment showed the highest performance, total gain (232.55 kg), and final weight (544.38 kg). Oilseed intake can modify the fatty acids profile in the meat, decreasing its saturated fatty acid content. Whole soybean seed favors performance, improves feed efficiency, fatty acid profile, and fat distribution in the carcass, and can reduce production costs.

Abstract We hypothesize that lambs fed diets with different lipids sources from oilseeds would similar performance but fatty acids profile of meat superior to those fed with conventional diets. We evaluated the effects of inclusion of oilseeds on the ingestive behaviour, performance, carcass trait and meat quality in feedlot lambs. Three isonitrogenous (18.31% crude protein) diets were evaluated, where one diet was the standard (control), and the others two diets contained soybean and cottonseed. Fifteen Texel lambs, weighting 28.5 ± 1.65 kg were distributed in a completely randomized design by 56 days. Animals fed soybean diet demonstrated greater final body weight when compared to animals fed cottonseed diet and standard diet. The inclusion of cottonseed provided lower average daily gain and total weight gain. Ingestive behaviour of the animals fed diets with grains resulted in greater rumination time. Lambs fed cottonseed diet spent greater time during rumination and presented greater number of chews/day. The hot carcass and cold carcass weight presented lower values in animals fed cottonseeds diet. There was no significant difference in meat for marbling, maturity, fat texture and shear force. Meat from animals fed soybean diet had highest fat content. There was a diet effect for fatty acids composition in the meat. Meat of lambs treated with soybean have greater amounts for fatty acids mostly the unsaturated ones, related to the decrease in cholesterol levels, and lower risk of cardiovascular diseases, thus, lambs fed soybean enrich meat produced with fatty acids that benefit human health.

Abstract The aim of this study was to evaluate the influence of dietary oilseed grains on physico-chemical and sensory parameters of the meat of Nellore steers. The animals were distributed in a completely randomized design in four treatments that consisted of four diets: one without the addition of lipids (control diet) and others containing cottonseed, soybean, sunflower seed. The meat from animals fed with soybean scored highest for succulence and tenderness. The inclusion of oilseed grains modified the composition of fatty acids in the meat, but did not influence the lipid indexes or the cholesterol content in the meat. We suggest the inclusion of soybean in the diet of young cattle because increase the meat acceptability by consumers.

Abstract Our hypothesis was that different sources of unsaturated fatty acids from oilseeds (sunflower, soybeans, and cottonseed) could alter milk yield, fatty acid profile, and the amount of unsaturated fatty acids yielded in milk. It aimed to evaluate the effects of lipid sources on yield and composition and fatty acids in milk of primiparous Girolando cows. Five cows in lactation (35 ± 8 days), with 410 ± 7.15 kg BW were randomly distributed in a 5 x 5 Latin square. Five experimental diets, namely a control diet without an additional source of lipid and four diets with different lipid sources: cottonseed, sunflower seed, whole soybean, or soybean oil, as lipid source, to reach 70 g/kg of ethereal extract dry matter basis were used. Cottonseed and soybean oil addition reduced daily yield by 15 and 22%. Oilseed can alter fatty acid profile in milk. Whole soybean provided greater daily milk and fatty acids yields.

ABSTRACT This study examined the effect of different supplementation strategies for ewes in the last third of gestation, kept on a deferred Brachiaria brizantha cv. Marandu pasture, on their performance and the growth curve of their lambs. A total of 54 ewes, of no defined breed, with an average weight of 41.10±3.10 kg, were used in a completely randomized design, divided into three groups (18 ewes per treatment). In total, 61 lambs were born, 28 females and 33 males, with 3.70±0.55 and 3.68±0.69 kg birth weight, respectively. Treatments were as follows: multiple mixture ad libitum, concentrate supplement at 0.4% live weight (LW), and concentrate supplement at 0.8% LW. Average daily weight gain (ADG, g/animal/day) and total weight gain (TWG, kg/animal) were evaluated in ewes and lambs. Reproductive efficiency indices were measured in the ewes and biometric variables in the lambs. The ADG and TWG of ewes in the last third of gestation were higher in animals supplemented at 0.8% LW. Reproductive efficiency results were superior in ewes supplemented at 0.4% LW. The effect of ewe supplementation on lamb growth curve as estimated by the Gompertz model did not reveal differences between the curves of lambs born to ewes that received supplementation at 0.4 and 0.8% LW. However, supplementing ewes with a multiple mixture induced a reduction in the growth curve parameters of their lambs. The use of concentrated supplementation, at levels of 0.4 and 0.8% of LW, provides greater productive and reproductive performance for ewes and lambs.

Resumen Se planteó la hipótesis de que es posible que el inóculo de diferentes especies de rumiantes con capacidades digestivas diferentes que se alimentan de un determinado forraje puede mostrar diferentes utilizaciones de alimento en comparación con otras especies de rumiantes. Se evaluaron cinco gramíneas Brachiaria: B. decumbens cv. Basilisk, B. decumbens acceso D70, B. humidicola cv. Tupi, B. humidicola cv. Común, y B. ruziziensis acceso R124, en dos edades de rebrote (21 y 42 d). Se analizó la producción, el contenido bromatológico, la digestibilidad de materia seca in vitro (DMSiv) y la digestibilidad de la fibra detergente neutro in vitro (DFDNiv) utilizando inóculos bovinos u ovinos. El experimento utilizó un diseño factorial de 5 × 2 × 2 y encontró efectos significativos para la variedad de gramínea y la edad de rebrote. Además, se encontraron interacciones significativas de gramínea × edad en la materia seca, la proteína cruda, la fibra detergente neutro y la fibra detergente ácido de la muestra total y lamina de la hoja. Hubo un efecto significativo de la variedad de gramínea y la edad de la gramínea en la masa del forraje, la relación lámina de la hoja/tallo, lámina de la hoja, tallo, material senescente y crecimiento. En los ensayos de la digestibilidad in vitro, el origen del inóculo mostró un efecto significativo en algunas variedades. Debido a las diferencias en los ensayos in vitro, se recomendó el uso de inóculos específicos de las especies para las evaluaciones de alimentos según el animal al que se destina. Asimismo, B. decumbens cv. Basilisk presentó la mejor digestibilidad in vitro (DMSiv y DFDNiv) en inóculo bovino, mientras que B. humidicola cv. Tupi tuvo mejor digestibilidad in vitro (DMSiv y DFDNiv) en inóculo ovino.

Abstract It was hypothesized that it is possible that inoculum from different ruminant species with different digestive abilities feeding from a certain forage may show different feed utilizations comparing to other ruminant species. Five Brachiaria grasses were evaluated: B. decumbens cv. Basilisk, B. decumbens access D70, B. humidicola cv. Tupi, B. humidicola cv. Common, and B. ruziziensis access R124, at two regrowth ages (21 and 42 d). Production, bromatological content, in vitro dry matter digestibility (ivDMD) and in vitro neutral detergent fiber digestibility (ivNDFD) were analyzed using bovine or ovine inoculums. The experiment used a 5 × 2 × 2 factorial design and found significant effects for grass variety and regrowth age. In addition, significant interactions from grass × age on dry matter, crude protein, neutral detergent fiber and acid detergent fiber of total sample and leaf blade were found. There were significant effect of grass variety and grass age on forage mass, leaf blade/stem ratio, leaf blade, stem, senescent material and growth. In vitro digestibility assays of inoculum source showed significant effect in some varieties. Due to differences in in vitro assays, it was recommended the use of species-specific inoculums for feed evaluations according to the animal it is intended for. Also, B. decumbens cv. Basilisk presented the best in vitro digestibility (ivDMD and ivNDFD) in bovine inoculum, whereas B. humidicola cv. Tupi had better in vitro digestibility (ivDMD and ivNDFD) in ovine inoculum.

RESUMO: Objetivou-se avaliar os modelos matemáticos Gompertz, Groot, monomolecular, Richards e logístico bicompartimental para estudar a cinética de produção de gás in vitro de dietas compostas de combinações de feno ou silagem de Gliricídia. Além disso, avaliou-se os efeitos da inclusão de feno ou silagem de Gliricídia sobre a produção cumulativa de gás in vitro destas dietas. A cinética de fermentação ruminal foi avaliada pela metodologia de produção cumulativa de gás in vitro. Os parâmetros dos modelos foram estimados usando o método de Gauss Newton, com exceção do modelo de Richards, que foi usado algoritmo de Marquardt. O ajuste dos modelos foi avaliado por meio do coeficiente de determinação, teste F para a identidade dos parâmetros, coeficiente de correlação e concordância, raiz quadrada do quadrado médio do erro da predição e a decomposição do quadrado médio do erro da predição em erro médio, vício sistemático e erro aleatório. Os modelos foram comparados quanto à acurácia (quadrado médio da predição pareado) e quanto à sua precisão (critério de informação delta de Akaike). Todas as estatísticas de avaliação e comparação dos modelos foram calculadas usando o software Model Evaluation System versão 3.2.2. Os modelos de Groot e Richards não diferiram entre si (P>0.05) e foram os mais precisos e acurados (P<0.05). Portanto, modelo de Groot foi selecionado devido apresentar melhor acurácia e precisão e apresentar maior facilidade na obtenção dos parâmetros. A inclusão da silagem de Gliricídia na dieta, resultou em elevação no tempo para obtenção da máxima taxa de degradação e no tempo após a incubação em que metade do nível assintótico foi atingido. Recomenda-se a utilização do modelo de Groot para estimativa da curva média. A inclusão da silagem de Gliricídia altera a curva de produção de gás devido o maior tempo necessário para que a dieta atingisse a máxima taxa de degradação, isso pode elevar o tempo de permanência da dieta no rúmen e promover redução no consumo.

ABSTRACT: This study examined the use of the Gompertz, Groot, monomolecular, Richards and two-compartment-logistic mathematical models to investigate the kinetics of in vitro gas production of diets composed of combinations of Gliricidia hay or silage. In addition, the effects of Gliricidia hay or silage inclusion on the in vitro cumulative gas production of these diets were evaluated. Rumen fermentation kinetics were analyzed by the in vitro cumulative gas production methodology. The model parameters were estimated using the Gauss Newton method, with the exception of the Richards model, which was used by Marquardt’s algorithm. Model fit was assessed using the determination coefficient, F test for parameters identity, concordance correlation coefficient, root mean square error of prediction, and decomposition of mean square error of prediction into mean error, systematic bias and random error. The models were compared for accuracy (pairwise mean square error of prediction) and precision (delta Akaike’s information criterion). All model evaluation and comparison statistics were calculated using Model Evaluation System software version 3.2.2. The Groot and Richards models did not differ from each other (P>0.05) and were the most precise and accurate (P<0.05). Therefore, the Groot model was selected due to its better accuracy and precision and easier access to the parameters. The inclusion of Gliricidia silage in the diet resulted in an increase in the time to obtain the maximum rate of degradation and in the time after incubation when half of the asymptotic level was reached. The Groot model is recommended to estimate the average curve. Dietary inclusion of Gliricidia silage alters the gas production curve due to the longer time required for the diet to reach the maximum rate of degradation, this can increase the time the diet remains in rumen and promote a reduction in the consumption.

RESUMO Objetivou-se avaliar o efeito de dois teores de proteína bruta no suplemento mineralnitrogenado para terminação de novilhos Nelore. Foram utilizados 90 animais, com peso médio inicial de 382,35±32,95 kg, submetidos a dois tratamentos: suplemento com 30% de proteína bruta (75% de milho, 8,91% ureia e 16,09% mineral) e 40% de proteína bruta (66,67% de milho, 11,90 % ureia e 21,43% mineral). Os animais foram mantidos em dois piquetes de Uruchloa brizantha cv. MG-5 (sin. Brachiaria brizantha). Foram realizadas pesagens ao início, aos 45 e aos 94 dias de experimento, quando foram abatidos com 451,1±35,38 kg. Foi avaliado o consumo de suplemento, o ganho de peso e variáveis econômicas. Houve efeito do tratamento sobre o consumo de suplemento (P<0,05), com médias de 0,69±0,21 (40% PB) e 2,26±0,52 (30% PB) kg/dia. A média de ganho de peso total foi superior (P<0,01) para os animais que receberam suplemento com 30 % PB (71,46 vs 64,33 kg/animal). Foi obtido maior peso de abate nos animais do tratamento com 30% PB (456,66 vs. 443,84 kg). Em ambos tratamentos, o desempenho e as caracteristicas de carcaça foram satisfatórios. Sob o ponto de vista econômico, recomenda-se a suplementação com 40 % PB na terminação de novilhos em pastagens, porém o sucesso para redução dos custos de produção no campo depende das variações entre as cotações nas diferentes regiões do país e mercado de oportunidades.

SUMMARY The objective of this study was to evaluate the effects of two protein levels in mineral-protein-energy supplements on the productivity and economic performance of Nellore steers. Ninety animals weighing 382.35±32.95 kg on average, were treated with mineral-nitrogen supplements containing 30% crude proteins (CP; 75% ground maize, 8.91 % urea and 16.09% mineral) and 40% CP (66.67 % ground maize, 11.90% urea, and 21.43% mineral). The animals were housed in two paddocks of Uruchloa brizantha ‘MG-5’ (syn. Brachiaria brizantha) and were weighed at the beginning, at 45 days, and at 94 days of the experiment, when they were slaughtered at an average weight of 451±35.38 kg. We evaluated supplement intake, weight gain and economic aspects. The 40 and 30% CP treatments significantly affected supplement intake (P<0.05), with averages of 0.69 and 2.26 kg/day, respectively. The average total weight gain was higher (P<0.01) in animals receiving the supplement containing 30 % CP (71.46 kg / animal) than in animals receiving 40% CP (64.33 kg/animal). Greater slaughter weight was attained in the animals treated with 30% CP (456.66 vs. 443.84 kg). The mineral-nitrogen supplementation in both CP levels provided satisfactory animal performance and carcass characteristics. Owing to economic considerations, it is recommended to use 40% CP mineral-nitrogen supplements on finishing steers on pasture, although success in reducing production costs of livestock ultimately depends on the variations in prices between the different regions of the country and market opportunities.

ABSTRACT The addition of levels of ethanol extract of brown propolis was evaluated by assessing diet degradation in rumen fluid and predicting cumulative in vitro gas production by nonlinear (dual pool logistic and exponential) models. A total of 35 g of crude propolis were extracted in 65 mL of cereal alcohol (95% ethanol). In a completely randomized factorial design, the experimental diets combined four concentrations of extracted propolis diluted in cereal alcohol (0, 50, 70, and 100% of propolis extract) and supplementation doses (4, 8, 12, 16, and 20 mL/kg dry matter), tested in triplicate. Diet (400 g/kg Tifton hay and 600 g/kg concentrate) was incubated for 96 h carried out three times in three different weeks. There was significant interaction between extract concentration and dose on the dry matter (DM) degradability. Dry matter degradability of diet decreased exponentially as a function of the increase in dose (y = 678.55×dose–0.271). Pure alcohol treatment showed a negative exponential effect, with degradability of 303.61 g/kg when administered at a dose of 20 mL/kg DM. Treatment 100% ethanol extract reached the greatest degradability, estimated at 18.93 mL/kg DM. The treatment with 70% extract showed 6.35 mL/kg DM and the 50% extract, 7.65 mL/kg DM of minimum degradability. The reduction potential of pure ethanol was –0.32 mL gas/mL. Estimates of maximum gas production by dual pool logistic and exponential models were 13.10 mL and 12.07 mL for 100% extract, respectively. The 100% extract produced the highest gas production estimates, above 30 mL gas/100 mg DM of fermented diet. The degradation and fermentation of ruminant diet can be improved using 13 mL/DM kg of ethanol extract of propolis.

RESUMO: A ingestão das favas de Enterolobium contortisiliquum causa distúrbios digestivos, fotossensibilização hepatógena e abortos em ruminantes. Para caracterizar a intoxicação aguda, favas de E. contortisiliquum foram administradas a ovinos por meio de cânula ruminal. No Experimento 1, uma dose única de 12g/kg de peso corporal (pc) foi administrada a três ovinos. Um dos ovinos morreu e os outros dois se recuperaram após mostrar sinais clínicos. No experimento 2, 10g/kg/pc foram administradas diariamente a 15 ovinos, por três dias consecutivos ou até o parecimento dos sinais clínicos. Catorze ovinos mostraram sinais clínicos leves a acentuados após ingestão de 1-3 doses. Dois ovinos morreram e os outros se recuperaram. Observou-se nos ovinos dos experimentos 1 e 2, diarreia, anorexia, atonia ruminal, apatia, desidratação e taquipneia. Os principais achados macroscópicos incluíram conteúdo ruminal espumoso e alaranjado em meio ao qual se observavam fragmentos das favas de E. contortisiliquum, e conteúdo intestinal líquido. Histologicamente, havia degeneração balonosa e desprendimento do epitélio de revestimento dos pré-estomagos. A avaliação do conteúdo ruminal revelou acidose ruminal láctica aguda (ARLA). Análise bromatológica das favas de E. contortisiliquum revelou 537.8g/kg de matéria seca de carboidratos não fibrosos, quantidade suficiente para causar ARLA. Um ovino do Experimento 2 teve insuficiência hepática aguda, caracterizada por icterícia, elevação da atividade sérica das enzimas hepáticas e alterações histológicas observadas em biópsia hepática. Concluiu-se que a administração de favas de E. contortisiliquum na alimentação de ovinos, nas doses de 10g/kg pc ou maiores, pode causar ARLA. A ocorrência de insuficiência hepática num dos ovinos deste experimento sugere que a lesão hepática pode se desenvolver em ovinos que não apresentam ARLA.

ABSTRACT: Ingestion of Enterolobium contortisiliquum pods causes digestive disturbances, secondary hepatogenous photosensitization and abortions in ruminants. Pods were administered to sheep via a ruminal cannula to characterize acute poisoning. In Experiment 1, a single dose of 12g/kg of body weight (BW) was administered to three sheep in one experiment. One sheep died, and the other two recovered after presenting clinical signs. In Experiment 2, 10g/kg BW were administered daily to 15 sheep until the onset of clinical signs or for three consecutive days. Fourteen sheep showed mild to severe signs after the ingestion of 1-3 doses. Two sheep died, and the others recovered. Clinical signs in both experiments were diarrhea, anorexia, rumen atony, apathy, dehydration and tachypnea. The main macroscopic findings were an orange, frothy ruminal content witch contained pods fragments. The intestinal content was liquid. Detachment of the mucosa from the submucosa and ballooning degeneration of mucosal cells were observed histologically in the forestomachs. Evaluation of ruminal contents revealed acute lactic ruminal acidosis (ALRA). Bromatological analysis of E. contortisiliquum pods revealed 537.8g/kg DM (dry matter) of non-fibrous carbohydrates, which is sufficient to cause ALRA. Only one sheep in Experiment 2 had liver failure, characterized by jaundice, elevated serum activity of liver enzymes and histological lesions in liver biopsies. It is concluded that the administration of E. contortisiliquum pods in forage-fed sheep at doses of 10g/kg BW or higher may cause ALRA. The induction of liver failure in one sheep suggests that liver damage may occur in those sheep that do not develop acidosis.

RESUMO Objetivou-se avaliar fontes de nitrogênio não-proteico (NNP) combinadas para suplementação de novilhos Nelore na recria mantidos em pastagens diferidas. Após o deferimento de quatro piquetes de Brachiaria brizantha cv. MG4 por 60 dias (20 ha cada) 80 novilhos Nelore castrados, com peso corporal médio de 280,40±19,59kg, foram avaliados durante 120 dias. O manejo adotado foi pastejo rotacionado, com mudanças de piquetes a cada 15 dias. Foram avaliados quatro tratamentos com diferentes combinações de fontes de NNP: Ureia + Ureia extrusada + Ureia revestida; Ureia + Ureia revestida; Ureia + Ureia extrusada; Ureia extrusada. Em todos os tratamentos foram fornecidos suplemento proteico-energético-mineral ad libitum, com 30% de proteína bruta e 40% de nutrientes digestíveis totais.Quando avaliadas individualmente, as fontes de NNP apresentaram solubilidades distintas em água e solução tampão, sendo o menor valor observado para ureia revestida (P<0,05). Os animais dos tratamentos Ureia + Ureia extrusada + Ureia revestida e Ureia extrusa da apresentaram ganho médio diário superior (0,4kg/dia; P<0,05) aos animais dos tratamentos Ureia + Ureia extrusada (0,34kg/dia). Os animais do tratamento Ureia extrusada apresentaram maior ganho de carcaça (1,71 @/animal) em relação aos demais (P<0,05). A margem líquida do tratamento Ureia extrusada (R$ 158,20/animal) foi superior em 10,8%, 8,2% e 35,8% aos tratamentos Ureia + Ureia extrusada + Ureia revestida, Ureia + Ureia revestida e Ureia + Ureia extrusada, respectivamente. Recomenda-se a utilização de ureia extrusada como fonte de nitrogênio não proteico em suplementos para novilhos Nelore em pastagem diferida.

SUMMARY The objective of evaluating sources of non-protein nitrogen (NPN) combined for supplementation of Nelore steers in deferred pasture. After the deferral of four pickets of Brachiaria brizantha cv. MG4 (20 ha each) of 60 days, 80 Nellore steers, with average body weight 280.40 ± 19.59 kg, were evaluated for 120 days. The management adopted was rotational grazing, with pickets changes every 15 days. We evaluated four treatments with different combinations of NNP sources: Urea +Urea extruded + Urea coated; Urea + Urea coated; Urea + Urea extruded and Urea extruded. In all treatments were provided protein supplement-mineral energy ad libitum, with 30% of crude protein and 40% of total digestibility nutrient. When evaluated individually, the NPN sources presented different solubility in water and buffer, and lowest value observed for coated urea (P<0.05).The animals of the treatments Urea + Ureaextruded + Urea coated and Urea extruded showed average daily gain (0.4 kg/day; P<0.05) of animals treatments Urea + Urea extrudedthe animals(0.34 kg/day).The animals of the Urea extruded treatment higher carcass gain (1.71 @/animal) compared to other (P<0.05).The net margin of the Urea extruded treatment (R $ 158,20/animal) was superior in 10.8%, 8.2% and 35.8% to treatments Urea + Urea + Urea coated, Urea + Ureaextruded and Urea + Ureacoated, respectively. It is recommended to use extruded urea as source of non-protein nitrogen (NPN) in supplements of Nellore steers in deferred pasture.

RESUMO Objetivou-se avaliar o efeito dos resíduos da extração hidroalcoólica de própolis dos tipos verde e marrom sobre o desenvolvimento de bactérias Gram-positivas e Gram-negativas. As própolis brutas foram adquiridas da apicultura “Companhia da Abelha”, instalada em Contagem, Minas Gerais. A própolis verde foi derivada de “alecrim-do-campo” (Baccharis dracunculifolia), e a própolis marrom foi derivada de “alecrim-do-campo” (B. dracunculifolia) e “assa-peixe” (Vernonia polyanthes). Foram usados cinco níveis de inclusão (0; 0,625; 0,125; 0,25; 0,5g) dos resíduos, além do controle para o inóculo (CI), e seis amostras bacterianas, sendo duas delas Gram-positivas e quatro Gram-negativas. O método utilizado foi o de contagem de unidades formadoras de colônias em placas de petri (pour plate). Entre as bactérias Gram-positivas, o maior efeito inibidor foi detectado para amostras de Staphylococcus aureus, e maior susceptibilidade foi para a Escherichia coli dentre as Gram-negativas. Houve efeito antimicrobiano do resíduo da extração da própolis verde sobre as bactérias S. aureus e S. intermedius. O resíduo da extração da própolis marrom apresentou maior inibição para S. intermedius somente nos tratamentos com 0,5 e 0,25g de resíduo. Não houve efeito do resíduo da extração de própolis verde ou marrom sobre o crescimento de bactérias gênero Pseudomonas. Os resíduos da extração hidroalcoólica de própolis verde e marrom atuaram como inibidores de crescimento das bactérias Staphylococcus aureus, Staphylococcus intermedius e Escherichia coli, e em menor grau para Salmonella e Klebsiella. O resíduo tem maior efeito inibidor em bactérias Gram-positivas.

SUMMARY This study aimed to evaluate the effect of residues extraction hydroalcoholic of propolis, green and brown, on the development of Gram-positive and Gram-negative bacteria. The crude propolis was obtained from “Companhia da Abelha” in Contagem, Minas Gerais. The green propolis derived from “alecrim-do-campo” (Baccharis dracunculifolia), and the brown propolis derived from “alecrim-do-campo” (B. dracunculifolia) and “assa-peixe” (Vernonia polyanthes). We used five levels of inclusion (0; 0.625; 0.125; 0.25; 0.5g) of the residue, and control for the inoculum (CI) and six bacterial strains, two of which are Gram-positive and four Gram-negative. The method used was to count colony-forming units in petri dishes (pour plate). Among the Gram-positive bacteria, the greatest inhibitory effect was detected for Staphylococcus aureus strains, and increased susceptibility was observed for Escherichia coli among Gram-negative bacteria. There was antimicrobial effect of the residue of the propolis extract on S. aureus and S. intermedius. The residue of brown propolis extract showed greater inhibition for S. intermedius only in 0.5 and 0.25g of residue inclusion levels. There was no effect of residues extraction hydroalcoholic of propolis, green and brown on the growth of Pseudomonas. The residues of the extraction of propolis green and brown acted as inhibitors of growth of Staphylococcus aureus, Staphylococcus intermedius and Escherichia coli, and to a lesser extent Salmonella and Klebsiella. The residue has greater inhibitory effect on Gram-positive bacteria.

RESUMO Objetivou-se avaliar a terminação de novilhos Nelore, castrados e não castrados, em confinamento recebendo dieta alto grão, por meio do consumo de nutrientes, desempenho produtivo e viabilidade econômica da dieta. Foram utilizados 180 animais da raça Nelore, distribuídos em dois tratamentos (castrados e não castrados), com 90 animais por tratamento, com peso médio inicial de 415,64kg, recebendo dieta alto grão, constituída de 85% de milho grão e 15% de núcleo mineral-proteico-energético. O período experimental foi de 63 dias, sendo 15 dias para adaptação as dietas e 48 dias de confinamento. Houve efeito significativo para os consumos de nutrientes (P<0,05), apresentando médias de consumos de matéria seca de 7,60 e 7,96kg para animais castrados e não castrados. Houve efeito para as variáveis de desempenho produtivo em função da classe sexual (castrado e não castrado). Os animais não castrados apresentaram maiores (P<0,05) peso de abate, ganho de peso, peso de carcaça quente, rendimento de carcaça e melhor conversão alimentar quando comparados aos animais castrados terminados em confinamento recebendo dieta alto grão. Os animais castrados apresentaram maior espessura de gordura que os animais não castrados, de 4,80 e 3,40mm, respectivamente. Os animais não castrados apresentaram margem de lucro/animal de R$ 256,00 e os castrados de R$ 202,80. Recomenda-se a terminação de novilhos Nelore em confinamento recebendo dieta alto grão. Os animais não castrados apresentaram maior ganho de peso e lucro no sistema de terminação em confinamento recebendo dieta alto grão.

SUMMARY This study aimed to evaluate the finishing Nellore steers castrated and no-castrated in feedlot receiving high-grain diet through the nutrients intake, productive performance and economic viability of the diet. 180 Nellore animals were divided into two treatments (castrated and no-castrated), with 90 animals per treatments, with an average initial weight of 415.64kg, receiving high-grain diet with 85% corn grain and 15% supplement mineral-protein-energy. The experimental period was 63 days with 15 days for adaptation diets and 48 days of feedlot. Was no significant effect on intake of nutrients (P<0.05), presenting a mean intake of dry matter (DM) of 7.60 and 7.96kg for castrated and no-castrated. Effects were observed for productive performance as a function of sex condition (castrated and no-castrated). The not castrated animals had higher (P<0.05) slaughter weight, total weight gain, hot carcass weight, carcass yield and better feed conversion when compared to castrated animals finished in feedlot receiving high-grain diet. Castrated animals have a higher fat thickness that animals no-castrated, 4.80 and 3.40mm, respectively. The no-castrated animals showed profit margin lucre/animal of R$ 256.00 and R$ 202.80 for castrated. Receiving the termination of Nellore steers in a feedlot is recommended high-grain diet. The no-castrated animals showed greater weight gain and profit in the feedlot finishing system receiving high-grain diet.