Dynamics of nitrogen concentration on intercropped ryegrass.

The dynamics of nitrogen (N) in ryegrass intercropped with different forage species with regard to dry matter (DM) accumulation within an agroecological transition system was evaluated. Annual ryegrass was intercropped with black oats (RY + BO), white clover (RY + WC) and forage peanut (RY + FP). The experimental design was completely randomized, with three replications. The study applied the N dilution model for plant tissue which comparatively uses modifiable factors of the environment at optimal levels. The model shows decline in N concentration due to the DM accumulation of temperate grass pastures. Data were compared to model by the root mean square deviation analysis. Dilution coefficient (β), used in all pasture samples, was lower than -0.60. Highest N concentration decline in plant tissues, due to DM accumulation, occurred in RY + WC pastures (β = -0.94), followed by RY + FP (β = - 0.86) and RY + BO (β = - 0.67), respectively. Ryegrass intercropped with white clover showed the highest N content in plant tissue, with a nitrogen nutrition index close to the proposed model

FERTILIZATION RESPONSE AND NITROGEN NUTRITION DIAGNOSIS OF A NATURAL GRASSLAND IN SOUTHERN BRAZIL

Natural grasslands found in Campos Biome in Southern Brazil are the main forage source for production approximately 13 million cattle and 5 million sheep. The forage yield is often limited by the soil fertility, which is naturally low. This study aimed to test the response of natural grassland to fertilization and to assess the level of N nutrition index (NNI) achieved with fertilization by using a dilution curve model. The experimental design was a factorial arrangement in sub-divided plots, where the landscape was considered the main plot and fertilization the subplots, with three replicates. In the fertilized treatment were applied 310 kg ha–1 of N, 160 kg ha–1 of P2O5, 160 kg ha–1 of K2O, and 3 Mg ha–1 of dolomitic lime. No fertilization was applied in the non-fertilized treatment (natural soil fertility). Herbage mass was evaluated over 224 days of growth by harvesting all the aboveground plant biomass in a 0.25 m2 quadrat. Herbage mass was higher in the fertilized treatment from 180 to 224 days of growth. At 180 days of growth, herbage mass was 7.8 Mg ha–1 in the fertilized treatment and 3.0 Mg ha–1 in the non-fertilized treatment. Generally, herbage mass accumulation from 83 to 180 days of growth was 3.2 times as high in the fertilized (62 kg ha–1 day–1) than in the non-fertilized treatment (20 kg ha–1 day–1). The N dilution curve model was successfully tested under high and low soil fertility conditions. At 83, 109, and 136 days of growth in the fertilized treatment, the nitrogen nutrition index (NNI) was 95, 103 and 92, respectively; while in the non-fertilized treatment, the NNI was always lower than 52. Therefore, the level of nitrogen nutrition index (NNI) estimated by the N dilution curve model was a good indicator of N availability to the natural grassland, and can be used for assessing the N nutrition status during the growth of natural grassland in Southern Brazil.

Bioelectrical impedance analysis (BIA) in animal production: Review

El análisis de impedancia bioeléctrica (AIB) es un método basado en los diferentes niveles de oposición al flujo de una corriente iónica a través de los diversos tejidos corporales. Los resultados se expresan mediante medidas primarias de resistencia (Rs) y reactancia (Xs). A partir de estas medidas, se aplican ecuaciones para determinar el ángulo de fase (AF) y la impedancia (Z). El análisis de bioimpedancia ha sido indicado como un método fiable y preciso para determinar la composición corporal y el estado nutricional en los seres humanos. El AIB se ha adaptado recientemente para ser aplicado en la producción animal. Por lo tanto, el objetivo de esta revisión es proporcionar un análisis sobre el uso potencial de la impedancia bioeléctrica en la producción zootécnica. A través del AIB se pueden establecer correlaciones entre las medidas bioeléctricas y la composición de los tejidos de los cadáveres de los cerdos, los bovinos, los ovinos, los bufalinos y los peces. En este sentido, entre el número creciente de demandas destaca la de contar con métodos más precisos y rentables para evaluar la composición corporal en el sector zootécnico, entre los que el análisis de la impedancia bioeléctrica demostró ser una tecnología prometedora y mínimamente invasiva para reemplazar los métodos tradicionales.Bioelectrical impedance analysis (BIA) is a method based on the different levels of opposition to the flow of an ionic current through the different body tissues. Results are expressed by primary measures of resistance (Rs) and reactance (Xs). From such measures, equations are applied to determine the phase angle (PA) and impedance (Z). Bioimpedance analysis has been indicated as a reliable and precise method to determine the body composition and nutritional status in humans. BIA has recently been adapted to be applied on animal production. Therefore, the aim of this review is to provide an analysis on the potential use of bioelectrical impedance on zootechnical production. Through BIA, correlations among bioelectrical measures and tissue composition of swine, bovine, ovine, bubaline and fish carcasses can be established. In this regard, a growing number of demands were led by more precise and cost-effective methods to evaluate the body composition in the zootechnical sector, in which the analysis of bioelectrical impedance proved to be a promising and minimally invasive technology to replace traditional methods.

Phytogenic additive on the diet of dairy heifers: Hematological parameters Parâmetros hematológicos de novilhas leiteiras submetidas a dietas com aditivos fitogênicos

With objective to evaluate the effects of utilization of herbal extracts on supplementation of dairy heifers was conducted an experiment utilizing 12 Jersey’s heifers, with mean age and weight at start of trial of eight months old and 112 kg, respectively. The animals were separated in two groups, with same number of replications, considered a Control group (without addition of herbal extracts) and a Treatment group (with inclusion of 500 grams of herbal extracts per ton. of ration). The herbal extracts utilized were a mixture of garlic, onion, cinnamon, clove and linseed. The animals received, daily, divided in two feeding, 2 kg. of ration and, approximately, 3 kg. of alfalfa hay and 10 kg. of chopped fresh black oat and ryegrass. The hematological parameters evaluated were red blood cell count (106 units/ L), hemoglobin and plasmatic protein (g/ dL), hematocrit (%), leukocytes, lymphocytes, neutrophils, and monocytes (units/ L). There were observed significantly differences to red blood cell count and monocytes count (P &lt; 0.10), lymphocytes count (P &lt; 0.05) and leukocytes count (P &lt; 0.01). It is concluded what herbal extracts act above hematological parameters of dairy heifers receiving this supplement.<br>Com o objetivo de avaliar os efeitos da utilização de extratos vegetais na suplementação de novilhas leiteiras, foi conduzido um experimento com 12 novilhas Jersey, com idade e peso médio de 8 meses e 112kg, respectivamente. Os animais foram separados em dois grupos, com o mesmo número de repetições, um chamado grupo-controle (sem a adição de extratos vegetais) e um grupo-tratamento (com a inclusão de 500 gramas de extratos vegetais por tonelada de ração). Os extratos vegetais utilizados foram uma mistura comercial de alho, cebola, canela, cravo e linhaça. Os animais receberam, diariamente, divididos em duas refeições, 2kg de ração, 3kg de feno de alfafa e 10kg de aveia e azevém fresco. Os parâmetros hematológicos avaliados foram hemácias (106 unidades/L), hemoglobina e proteína plasmática (g/dL), hematócrito (%), leucócitos, linfócitos, neutrófilos e monócitos (unidades/L). Foram observadas diferenças significantes na contagem de hemácias e monócitos, contagem de linfócitos e de leucócitos. Os autores concluíram que os extratos vegetais atuam nos parâmetros hematológicos de novilhas leiteiras recebendo esse suplemento

Análise econômica de sistemas de produção com bovinocultura de leite da depressão central do Rio Grande do Sul Economic analysis of production systems of dairy cattle farms in central Rio Grande do Sul, Brazil

O presente trabalho foi desenvolvido junto às unidades de produção familiar (UPFs) associadas à Cooperativa dos Produtores de Leite de Santa Maria (COOPROL) RS, com o objetivo de identificar o desempenho econômico e os sistemas de produção existentes entre as mesmas. Foram coletadas as informações de 53 propriedades, sendo identificados os seguintes sistemas de produção: a) leite e arroz com tração animal (TA) e superfície agrícola útil (SAU) média de 30ha; b) leite e arroz com tração mecanizada (TM) e SAU média de 54ha; c) leite e hortigranjeiros com TA e SAU média de 20ha; d) leite e hortigranjeiros com TM e SAU média de 50ha; e) leite e bovinos de corte com TA e SAU média de 40ha; f) leite e bovinos de corte com TA e SAU média de 308ha; g) leite e bovinos de corte com TM e SAU média de 80ha; h) leite estreme com TA e SAU média de 2 ha; i) leite estreme com TM e SAU média de 45ha. Os sistemas A, B, C, F, H e I apresentam um desempenho econômico por unidade de trabalho homem (UTH) superior ao salário mínimo regional, enquanto os sistemas D, E e G apresentam desempenho abaixo deste indicador.<br>This work was developed in family production units (UPFs), associated to a co-operative society, the Cooperativa dos Produtores de Leite de Santa Maria (COOPROL) RS. The goal was to identify the economical performance and the different systems of production used by the UPFs. The information was obtained from 53 farms, and among them the following production systems were identified: a) Milk associated to rice crops, with animal traction (AT) and an average of 30ha of tillable area (TA); b) Milk associated to rice crops with mechanical traction (MT) and TA=54ha; c) Milk associated to olericulture with AT and TA= 20ha; d) Milk associated to olericulture with MT and TA= 50ha; e) Milk associated to beef cattle with AT and TA= 40ha; f) Milk associated to beef cattle with AT and TA= 308ha; g) Milk associated to beef cattle with MT and TA= 80 ha; h) Milk with AT and TA= 20ha; i) Milk with MT and TA= 45ha. It was observed that the systems a, b, c, f, h and i showed an economic performance per worker labour unit (WLU) superior to the regional minimum wages, while the systems d, e, f presented a performance below the minimum wages