Nitrogen efficiency in marandupalisadegrass pastures under increasing nitrogen levels / Eficiência do nitrogênio em pastagens de capim-marandu adubadas com doses crescentes de nitrogênio

The use of nitrogen (N) in pastoral ecosystems leads to increased productivity, as it allows the plant to elongate its leaves and, therefore, grazing herbivores harvest the green leaves. However, there are very volatile N sources, which can be replaced by ammonium nitrate, which is less volatile and less dependent on the application in rainy days. The treatments are compound of Marandu palisade grass pastures managed under continuous stocking at a canopy height of 25 cm, with different levels of N fertilizer: 0, 75, and 150 kg ha-1year-1, as ammonium nitrate (32% of N), with four replicates (pastures) in a completely randomized design. Nitrogen uptake (54.9, 96.5, 113.8 kg N ha-1) and N nutrition index (0.67, 0.98, 1.15) were different between N level, respectively, 0, 75 and 150 kg ha-1 year-1. The N recovery (58.3, 40.9 %) differed between 75 and 150 kg ha-1 year-1, respectively. The dose of 75 kg N kg ha-1 year-1 results in better N utilization, while the dose of 150 kg N ha-1 year-1 enables greater stocking rate; therefore, requiring less grazing area.

O uso de nitrogênio (N) em ecossistemas pastoris leva ao aumento da produtividade, pois permite que a planta alongue suas folhas e, portanto, os herbívoros colham as folhas verdes. Porém, existem fontes de nitrogênio muito voláteis, que devem ser substituídas por nitrato de amônio, que é menos volátil e menos dependente da aplicação em dias chuvosos. Os tratamentos foram compostos por pastagens de capim-marandu, manejadas sob lotação contínua, na altura do dossel a 25 cm, com diferentes doses de N: 0, 75 e 150 kg ha-1 ano-1, na forma de nitrato de amônio (32% de N), com quatro repetições (piquetes), em delineamento inteiramente casualizado. A absorção de nitrogênio (54,9; 96,5; 113,8 kg N ha-1) e o índice nutricional de N (0,67; 0,98; 1,15) foram diferentes entre as doses de N, respectivamente, 0, 75 e 150 kg ha-1 ano-1. A recuperação de N (58,3; 40,9%) diferiu entre 75 e 150 kg ha-1 ano-1, respectivamente. A dose de 75 kg N kg ha-1 ano-1 resultou em melhor aproveitamento do N, enquanto a dose de 150 kg N ha-1 ano-1 possibilita maior taxa de lotação; portanto, exigindo menos área de pastagem.

Is just considering texture enough to define compaction on the basis of soil density? / Considerar apenas a textura é suficiente para definir a compactação a patir da densidade do solo?

The bulk density values indicative of compaction in clayey soils correspond to a wide range of values (1.30-1.47 Mg m-3), due to the diverse types of soil management. Our hypothesis is that if we consider bulk density values within similar management groups (those that fall to the ground and those that do not fall), the values will be more accurate within each management group. Our objective in this work was to analyze using the concepts of (Yates & Cochran, 1938; Whitehead, 2002) what is a suitable statistical way of grouping these results to reach a consensus regarding a tested hypothesis, the greatest number of density values surveyed between 1977 and 2021, considered for the study of compaction in clayey Oxisols under different managements, to verify whether our hypothesis will be confirmed. We selected 1,521 studies with bulk densities in the literature, corresponding to 44 years (1977 and 2021), which were analyzed by a statistical technique that integrates the results of two or more independent studies on the same subject and combines them into a summary measure (portion forestry). From the data collected in the literature, it was possible to separate two groups of bulk density and management in clayey soils indicative of compaction: the managements that perform little or no manipulation of the soil, such as pasture and no-tillage, densities between 1.41-1.45 Mg.m-3 (average 1.43 Mg m-3), and for the others, such as conventional plowing and minimum tillage, soil densities between 1.31-1.38 Mg.m-3 (average 1.35 Mg m-3). Finally, we conclude that compaction must be analyzed considering the texture and type of soil management.(AU)

Os valores de densidade do solo indicativos de compactação em solos argilosos correspondem a uma ampla faixa de valores (1,30-1,47 Mg m-3), devido aos diversos tipos de manejo do solo. Nossa hipótese é que se considerarmos os valores de densidade do solo dentro de grupos de manejo semelhantes (os que caem no chão e os que não caem), os valores serão mais precisos dentro de cada grupo de manejo. Nosso objetivo neste trabalho foi analisar usando os conceitos de (Yates & Cochran, 1938; Whitehead, 2002) qual é uma forma estatística adequada de agrupar esses resultados para chegar a um consenso sobre uma hipótese testada, o maior número dos valores de densidade levantados entre 1977 e 2021, considerados para o estudo da compactação em Latossolos argilosos sob diferentes manejos, para verificar se nossa hipótese será confirmada. Selecionamos 1.521 estudos com densidades do solo na literatura, correspondentes a 44 anos (1977 e 2021), que foram analisados por uma técnica estatística que integra os resultados de dois ou mais estudos independentes sobre o mesmo assunto e os combina em uma medida resumida (forest plot). A partir dos dados levantados na literatura, foi possível separar dois grupos de densidade do solo e manejo em solos argilosos indicativos de compactação: os manejos que realizam pouca ou nenhuma manipulação do solo, como pastagem e plantio direto, densidades entre 1,41 -1,45 Mg.m-3 (média 1,43 Mg m-3), e para as demais, como aração convencional e preparo mínimo, densidades de solo entre 1,31-1,38 Mg.m-3 (média 1,35 Mg m-3). Por fim, concluímos que a compactação deve ser analisada considerando a textura e o tipo de manejo do solo.(AU)

Effect of solar radiation on Holstein heifers' physiological variables and grazing behavior

The objective was to assess the physiological and behavioral variables of pasture-raised Holstein heifers on the basis of their coat color. Eight heifers were used, four with black coat, and four with white coat. In the morning and afternoon periods, their physiological variables were measured, namely respiratory rate (RR, mov min. -1), rectal temperature (TR, ºC), and coat surface temperature (TS, ºC). The behavior analysis considered the site (sun or shade), position (standing or lying down), and activities (idleness, rumination, grazing, and others). The data of the physiological variables were assessed through analysis of variance, and significance, through Tukey's test at 5%, while behavioral data were assessed using the Chi-squared test (SAS Software). There was a difference for all of the heifers' physiological variables as a function of coat color (p < 0.0001) and period (p < 0.0001), with black ones showing greater results than white ones as to all physiological variables in the afternoon period (p < 0.0001). Grazing behavior is reduced during the hottest hours of the day. We conclude that solar radiation changes the physiological variables and grazing behavior of pasture-raised Holstein heifers.(AU)

Morpho-physiological and anatomical characteristics of Urochloa brizantha cv. Marandu in silvopastoral and monoculture systems

To gain insights into the forage morphological and anatomical characteristics in a silvopastoral system (SPS) with Bolsa de Pastor (Zeyheria tuberculosa) and palisadegrass 'Marandu' (Urochloa brizantha) monoculture (MONO). The SPS was established through natural regeneration of the tree species. Treatments were a SPS and MONO distributed in a completely randomized design with six replicates and repeated measures were the harvest periods. Response variables were morpho-physiological and anatomical characteristicss: green: dead material ratio, leaf blade: stem+sheath ratio, leaf area index, chlorophyll and carotenoid concentrations, proportions of non-lignified and achlorophyllous areas, lignified areas in stems, proportions of non-lignified and achlorophyllous areas, lignified and chlorophyllous areas in leaves, as well as cell length in longitudinal section of stem. Morpho-physiological patterns were altered (p < 0.05) under natural shading conditions due to higher photosynthetic efficiency in the SPS. There was no effect (p > 0.05) of the systems on anatomical patterns, proportions of non-lignified and achlorophyllous, lignified and chlorophyllous tissues, these proportions were influenced only by the periods of the year, both for stems and leaves. Cells of the internodes of the grasses of the studied systems had the same length. The SPS alters morpho-physiological characteristics of palisadegrass and increases the concentration of chlorophyll a and b.(AU)

Influence of inclusion of low doses of tannin blends in beef cattle dietary supplements on in vitro and in situ digestibility of nutrients in some feedstuffs / Influência da inclusão de baixas doses de taninos em suplementos para bovinos de corte sobre a digestibilidade in vitro e in situ dos nutrientes de alguns alimentos

The objective of this study was to evaluate the effects of the daily supplementation with a low dosage of a blend of condensed and hydrolysable tannins on the in vitro and in situ digestibility of protein and fibrous feedstuffs. In situ ruminal incubation assays were conducted on seven protein and five roughage feedstuffs with and without tannin supplementation (1 g kg-1 DM intake). From these same cattle, rumen Mundim, A. T. et al.1146Semina: Ciênc. Agrár. Londrina, v. 44, n. 3, p. 1145-1166, maio/jun. 2023fluid was collected for in vitro incubations of the same feedstuffs. In vitro assays we evaluated the gas production (GP) up to 24 h and, sequentially, digestibility of dry matter (IVDMD), crude protein (IVCPD), fiber (IVNDFD), and ammonia nitrogen (NH3-N). For in situ assays, the disappearance curves were modeled and then the potentially degradable (B), digestion rate (kd), and undegradable (U) fractions were estimated. Of all the variables studied, only IVCPD of soybean meal showed effect (P<0.05) with the addition of dose of tannins. The supplementation of tannin affected only B of the DM and CP of the cottonseed meal. The kd of DM and CP increased with the supplementation of the tannin blend only for Marandu (dry season), soybean and cottonseed meal. Additionally, the kd of the DM of corn silage was reduced. The U of CP was affected by the increase of tannin supplementation for soybean and cottonseed meal. Daily supplementation with a low dose of tannin blend for grazing cattle affects for grazing cattle affects the ruminal digestibility of some of the evaluated feedstuffs, which are soybean and cottonseed meal.(AU)

O objetivo com este estudo foi avaliar os efeitos da inclusão de uma mistura de taninos condensados e hidrolisáveis em suplementos sobre a digestibilidade in vitro e in situ de alguns alimentos proteicos e volumosos. Sete alimentos proteicos e cinco volumosos foram avaliados in situ no rúmen de bovinos de corte em pastejo recebendo suplementos com e sem taninos (dose de taninos = 1g kg-1 MS). Destes mesmos animais, foi coletado líquido ruminal para incubação in vitro dos alimentos. Nos ensaios in vitro avaliou-se a produção de gás (PG) até 24 h e, sequencialmente, a digestibilidade da matéria seca (DMS), proteína bruta (DPB), fibra (DFDN) e nitrogênio amoniacal (N-NH3). Para os ensaios in situ, as curvas de desaparecimento foram modeladas e, em seguida, as frações potencialmente degradáveis (B), taxa de digestão (kd) e indigestível (U) foram estimadas. De todas as variáveis estudadas, apenas a DPB do farelo de soja apresentou efeito (P<0,05) com a adição de taninos. A suplementação com taninos afetou apenas a fração B da MS e PB do farelo de algodão. O kd da MS e PB aumentaram com a inclusão de taninos para o capim Marandu (estação seca), farelo de soja e farelo de algodão. Adicionalmente, o kd da MS da silagem de milho foi reduzido. A fração indisgestível (U) da PB do farelo de soja e farelo de algodão foram afetadas pela suplementação com taninos. A inclusão de baixas doses de um blend de taninos em suplementos para bovinos em pasto afeta a digestibilidade ruminal de alguns dos alimentos avaliados, notadamente em farelo de soja e farelo de algodão.(AU)

Bacterial diversity and detection of resistance genes to broad-spectrum betalactams in dairy family farm soils / Diversidade bacteriana e detecção de genes de resistência a betalactâmicos de amplo espectro em solos de propriedade familiar leiteira

Bovine mastitis is a complex disease that brings great losses to the dairy producer. The microbial diversity of the soils, as well as the presence of resistance genes in the environment directly influence the maintenance of mastitis in the farm. The objective of this work was to analyze the bacterial diversity in pasture soils of a dairy family farm, detecting enterobacteria that may be involved in the etiology of bovine mastitis, and to detect genes that encode broad-spectrum betalactamases in these soils. Twelve soil samples, representative of different areas of the farm located in the municipality of Barra do Piraí, Rio de Janeiro, were collected at different times of the year. Total DNA was extracted from the samples, gene amplified by Nested-PCR and then the amplification products were separated by DGGE (Denaturing Gradient Gel Electrophoresis). With the DGGE it was possible to construct dendograms that effectively represented the bacterial diversity of these soils. Eight of the soil samples were used to amplify the genes encoding the betalactamase enzymes TEM (blaTEM gene), SHV (blaSHV gene) and CTX (blaCTXM gene). In three of the eight soil samples, the blaSHV gene was found to be present. The blaTEM and blaCTX-M genes were not detected in any of the samples. The detection of genes encoding broad-spectrum betalactamases in dairy cattle pasture soils is of concern, because the transfer of gene material between pathogenic and non-pathogenic bacteria in this environment is a reality

A mastite bovina é uma doença complexa que traz grandes prejuízos ao produtor de leite. A diversidade micro-biana dos solos, bem como a presença de genes de resistência no ambiente, influencia diretamente a manutenção da mastite na fazenda. O objetivo deste trabalho foi analisar a diversidade bacteriana em solos de pastagem de uma propriedade familiar leiteira, detectando enterobactérias que possam estar envolvidas na etiologia da mastite bovina, e detectar genes que codificam betalactamases de amplo espectro nesses solos. Doze amostras de solo, representativas de diferentes áreas da fazenda localizada no município de Barra do Piraí, Rio de Janeiro, foram coletadas em diferentes épocas do ano. O DNA total foi extraído das amostras, o gene foi amplificado por Nested-PCR e, em seguida, os produtos de amplificação foram separados por DGGE (Denaturing Gradient Gel Electrophoresis). Com a DGGE, foi possível construir dendogramas que representavam efetivamente a diversidade bacteriana desses solos. Oito das amostras de solo foram usadas para amplificar os genes que codificam as enzimas betalactamase TEM (gene blaTEM), SHV (gene blaSHV) e CTX (gene blaCTXM). Em três das oito amostras de solo, foi constatada a presença do gene blaSHV. Os genes blaTEM e blaCTX-M não foram detectados em nenhuma das amostras. A detecção de genes que codificam betalactamases de amplo espectro em solos de pastagens de gado leiteiro é preocupante, pois a transferência de material genético entre bactérias patogênicas e não patogênicas nesse ambiente é uma realidade

Influence of irrigation and supplementation on performance and ingestive behavior of beef cattle on mixed grass pastures

The purpose of this study was to evaluate the performance of beef cattle with two levels of energy-protein supplementation of low-consumption on African Bermudagrass pasture, overseeded in winter with oat and ryegrass, with or without irrigation. Twenty-four castrated Angus steers (11 months old and had an initial average of 220 kg body weight (BW)) were used in experimental area of 3.6 ha. The experiment was completely randomized in a 2×2 factorial design, with three replicates. The evaluation period was 249 days (July/2019 to March/2020). The treatments were: irrigated pasture with supplementation of 1 g/kg BW or 2.7 g/kg BW and non-irrigated pasture with 1 g/kg BW of supplement or 2.7 g/kg BW. The grazing method was continuous with a variable stocking rate. Irrigation provided pastures with better chemical composition in winter and spring. Irrigation increased the daily accumulation rate in winter (84.6 vs. 45.9 kg DM/ha/day), providing a greater stocking rate (1,702 vs. 1,385 kg/ha) and, consequently, body weight gain per hectare. Supplementation of 2.7 g/kg BW provided a greater stocking rate in winter (1,652 vs. 1,435 kg/ha) and spring (3,096 vs. 2,811 kg/ha), not changing in summer. The association of irrigation and supplementation of 2.7 vs. 1.0 g/kg BW improves the intake pattern by the animal in summer without changing productivity parameters. Irrigation increases productivity and the nutritional value of pasture with higher livestock production per area in periods of water deficit. The supply of 2.7 vs. 1.0 g/kg BW provides a greater stocking rate and body weight gain per hectare.(AU)

The economic value of sustainability of the integrated crop-livestock system in relation to conventional systems

The objective of this study was to evaluate the potential of improving the economic value of integrated crop-livestock systems (ICLS) compared to conventional systems specialized in monoculture. The experimental area was 16.02 ha, divided into 18 paddocks of 0.89 ha each, organized in a randomized block design, with three replicates and six models of production systems: crop system [corn ( Zea mays ) grain production], livestock system (beef cattle under grazing conditions), and four ICLS, identified as: ICLS-1, corn integrated with Marandu palisadegrass [ Urochloa brizantha (Hoechst. ex A. Rich.) R.D. Webster cv. Marandu (syn. Brachiaria brizantha cv. Marandu] sown simultaneously without herbicide; ICLS-2, corn and Marandu palisadegrass sown simultaneously with herbicide; ICLS-3, corn and Marandu palisadegrass with lagged sowing; and ICLS-4, corn and Marandu palisadegrass sown simultaneously, with herbicide in rows and between-rows of corn. We demonstrated the economic impact analysis combined with the risk optimization and discounted cash flow techniques based on Monte Carlo simulation, considering price and productivity uncertainties. The indicators of added value and return on investment of ICLS had an economic advantage compared with conventional systems. It was also found that ICLS needed a smaller operational area than conventional systems for the economic break-even point. Integrated systems provide lower financial and operational risk levels and greater economic value per hectare compared with conventional systems specialized in monoculture.(AU)

Legume inclusion or nitrogen fertilization on Aruana grass overseeded with temperate grasses: Performance, carcass characteristics, and fatty acid profile of the meat of beef steers

The objective of our study was to evaluate the effect of the use of legume (Arachis pintoi) or nitrogen fertilization on animal performance, characteristics of carcass and meat, and fatty acids profile of crossbred steers on Megathyrsus maximus cv. Aruana pasture, overseeded with temperate grasses. The experimental design was completely randomized, with three treatments and three replicates. The experiment was carried out from June to October (127 d). The treatments were: Low-N: 100 kg of N/ha; Medium-N: 200 kg of N/ha; and Legume: Arachis pintoi + 100 kg of N/ha. The pasture with higher nitrogen fertilization (N200) showed a more significant forage mass yield. The mixed grass with legumes presented a higher concentration of saturated fatty acids and saturated:unsaturated ratio in the meat. However, the grass pastures resulted in a higher content of unsaturated fatty acids in the meat. The other pasture variables, and characteristics of carcass and meat were not influenced by the treatments. The increase in nitrogen fertilization, from 100 to 200 kg/ha, and Arachis pintoi mixed with Aruana grass pasture overseeded with black oat and ryegrass does not affect the daily weight gain and the carcass and meat characteristics of the steers. The grass-legume mixture decreases the total concentration of unsaturated fatty acids in meat without influencing the concentration of polyunsaturated fatty acids.(AU)

Seasonality effect on the physiological and productive responses of crossbred dairy cows to the equatorial Amazon climate / Efeito da sazonalidade sobre as respostas fisiológicas e produtivas de vacas leiteiras mestiças ao clima amazônico equatorial

The objective of this study was to evaluate the seasonal effect of months of the year upon the physiological and productive responses of crossbred dairy cows raised in an Amazonian climate. Twenty lactating cows were evaluated, fed on Brachiaria decumbens pasture, with free access to water and mineral supplementation. Data from climate variables air temperature (AT), relative humidity (RH), rainfall (RA) and temperature and humidity index (THI) were recorded dur ing the months of January to April 2019. The physiological data collected were: respiratory rate (RR, mov/min), heart rate (HR, beats/min), rectal temperature (RT, ºC), udder surface temperature (UST, ºC), body surface temperature (BST, ºC), dorsum surface temperature (DST, ºC), front surface temperature (FST, ºC) and rear shin temperature (RST). Milk production (MP) was also measured. There was a significant difference (P<0.05) of RST and RR with values ranging from 34.8 to 35.5°C and 32.0 to 36.2 mov/min, respectively. There were no significant difference (P>0.05) for BST, and the values for MP and THI were 3.8; 3.8; 4.6; 4.1 kg and 77.7; 79.7; 80.6; 80.1, respectively. It was concluded that there was a seasonal effect of the months of the year evaluated on the respiratory rate of animals, however, it did not change the MP and the THI. The Amazon environment is conducive to causing thermal stress in lactating cows raised on pasture, requiring the use of shading to facilitate the ability of these animals to dissipate heat.(AU)

O objetivo desse estudo foi avaliar os efeitos sazonais dos meses do ano sobre as respostas fisiológicas e produtivas de vacas leiteiras mestiças criadas em clima amazônico. Foram avaliadas 20 vacas lactantes, alimentadas com pasto de Brachiaria decumbens, com acesso livre a água e suplementação mineral. Foram registrados dados das variáveis climáticas temperatura do ar (TA), umidade relativa do ar (UR), precipitação pluviométrica (PP) e índice de temperatura e Umidade (ITU) durante os meses de janeiro a abril de 2019. Os dados fisiológicos coletados foram: frequência respiratória (FR, mov/min), frequência cardíaca (FC, bat./min), temperatura retal (TR, ºC), temperatura superficial do úbere (TSU, ºC), temperatura superfície corporal (TSC, ºC), temperatura superficial do dorso (TSD, ºC), temperatura superficial da fronte (TSF, ºC) e temperatura superficial da canela (TSCA, °C). Também foi mensurada a produção de leite (PL, kg). Houve diferença significativa (P<0,05) da TSCA e FR com valores variando de 34,8 a 35,5°C e 32,0 a 36,2 mov/min, respectivamente. Não houve diferença significativa (P>0,05) para TSC e os valores observados para PL e ITU foram 3,8; 3,8; 4,6; 4,1 kg e 77,7; 79,7; 80,6; 80,1, respectivamente. Houve efeito sazonal dos meses avaliados sobre a taxa respiratória dos animais, no entanto, isso não alterou a PL nem o ITU. O ambiente amazônico é propício a causar estresse térmico em vacas lactantes mantidas a pasto, sendo necessário o uso de sombreamento para facilitar a capacidade de dissipação de calor corporal desses animais.(AU)

Strategic diagnosis of a property specialized in breeding, rearing and finishing beef cattle in the southern region of Piauí

This study aimed to perform a strategic diagnosis on a property specialized in breeding, rearing and finishing beef cattle in the southern region of Piauí. It was conducted at Agropecuária Alvorada, located in the countryside, municipality of Bom Jesus, PI, Brazil. The farm develops the full cycle of beef cattle production, which is divided into breeding, rearing and finishing. A SWOT analysis (which stands for Strengths, Weaknesses, Opportunities and Threats) was carried out, consisting of an assessment of the property's internal and external environments. To evaluate the internal environment, an interview was held for data collection by means of questionnaires. The evaluation included: breeding management, sanitary management, nutritional management, infrastructure, workforce, technologies used in pasture formation, conservation and recovery, pasture management and zootechnical indices. To analyze the external environment, a group of people (experts) with deep knowledge of the subject addressed during the study was used as source of information. A matrix was generated with all the information from the SWOT analysis, strengths, weaknesses, opportunities and threats, culminating with the establishment of strategies to increase the productive efficiency of the cattle raising activity.(AU)

Yield, chemical composition, and efficiency of utilization of applied nitrogen from BRS Kurumi pastures / Produção, composição química e eficiência da utilização de nitogênio aplicado de pastagens de BRS Kurumi

The objective was to evaluate the effect of nitrogen fertilization levels on productivity, and nutritional value of BRS Kurumi managed at different residue heights during rainy and dry periods of the year. The pasture was managed in three residue heights (20, 35, and 50 cm) and three nitrogen fertilization levels (0, 100, and 200 kg N/ha/year) during the rainy and dry seasons. When the height of the grass of each plot reached 80 cm, the Kurumi was cut manually at the pre-established residue heights. Around 89% of the dry matter (DM) production was observed during the rainy season. The residue height of 35 cm together with doses of 100 or 200 kg N/ha/year, and the residue height of 20 cm, with a dose of 100 kg N/ha/year were the treatments that had the highest DM production during the rainy period. No differences in DM production were observed between tested treatments during the dry period. The Kurumi cultivated during the dry period had the highest content of neutral detergent fiber and lowest digestibility. The Kurumi managed with residue heights of 20 and 35 cm and fertilized with 100 kg N/ha had the highest values of efficiency of utilization applied nitrogen. The use of 20 or 35 cm of residue height and 100 kg of N/ha/year is recommended to obtain greater biomass production and nutrients, nutritional quality, and nitrogen use efficiency.

O objetivo foi avaliar o efeito dos níveis de fertilização nitrogenada na produtividade e no valor nutritivo do BRS Kurumi quando manejado em diferentes alturas de resíduos durante os períodos seco e chuvoso do ano. O capim foi manejado em três alturas de resíduos (20, 35 e 50 cm) em associação com três níveis de fertilização com nitrogênio (0, 100 e 200 kg N/ha/ ano), durante o período seco e chuvoso do ano. Quando a altura do capim de cada parcela atingiu 80 cm, o Kurumi foi cortado nas alturas de resíduos pré-estabelecidas. Cerca de 89% da produção de MS foi observada durante o período chuvoso. A altura do resíduo de 35 cm juntamente com doses de 100 ou 200 kg N/ ha/ ano, e a altura do resíduo de 20 cm, com dose de 100 kg N/ha/ ano foram os tratamentos que apresentaram maior produção de MS durante o período chuvoso. Não foram observadas diferenças na produção de MS entre os tratamentos testados durante o período da seca. O Kurumi cultivado no período da seca apresentou maior teor de fibra em detergente neutro e menor digestibilidade. O Kurumi manejado com alturas de resíduo de 20 e 35 cm e fertilizado com 100 kg N/ha apresentou os maiores valores de eficiência de utilização do nitrogênio aplicado. Recomenda-se a utilização de 20 ou 35 cm de altura do resíduo e 100 kg de N/ha/ ano para obter maior produção de biomassa e nutrientes, qualidade nutricional e eficiência no uso do nitrogênio.

Airborne cameras for natural grassland classification in the Pampa biome / Câmeras aerotransportadas para classificação da vegetação em pastagem natural no bioma Pampa

The extension of the area occupied by the inter tussock stratum and tussock stratum in natural pastures is essential for the productive performance of grazing animals. Images obtained from unmanned remote sensors can provide useful information, especially because they have a high spatial resolution. Thus, this study evaluated the performance of the supervised adaptive classification applied to aerial images obtained from an onboard drone camera to map the area covered by tussocks in a natural pasture of the Pampa biome. The study was carried out in a natural pasture area managed since 1986 under different forage allowances, considering treatments of 8, 12, and 16 kg of dry matter per 100 kg live weight (% LW). An aerial image from September 2017, obtained with a Canon S100 camera onboard a drone at an altitude of 120 m, with a spatial resolution of 5 cm, was used. The random forest and support vector machine classifiers were tested associated with specific classification rules. False-color images showed considerable visual similarity in the large patterns of the vegetation distribution and the validation performed with independent samples when compared to the classified images. The tested classifiers were able to measure the area covered by the tussock stratum, which could be an indicator of the quality vegetation in a natural grassland of the Pampa biome.

A quantidade de área ocupada por estrato inferior e superior em pastagens naturais tem grande importância sobre o desempenho produtivo dos animais em pastejo. Imagens obtidas de sensores remotos não tripulados podem fornecer informações úteis, especialmente por possuírem alta resolução espacial. O objetivo deste trabalho foi avaliar o desempenho de classificação supervisionada adaptativa aplicada a imagem aérea obtida por câmera a bordo de drone, no mapeamento da área coberta por touceiras em pastagem natural do bioma Pampa. O estudo foi realizado em área de pastagem natural, manejada desde 1986 sob diferentes ofertas de forragem, tendo sido considerados os tratamentos 8, 12 e 16 kg de matéria seca por 100 kg de peso vivo (% PV). Foi utilizada uma imagem aérea, de setembro de 2017, obtida com uma câmera Canon S100, a bordo de um drone a 120 m de altitude, correspondendo a resolução espacial de 5 cm. Foram testados dois classificadores, Random Forest e Support Vector Machine associados a regras específicas de classificação. As imagens de falsa cor, quando comparadas às imagens classificadas, apresentaram considerável semelhança visual nos grandes padrões de distribuição da vegetação, bem como na validação feita com amostras independentes. Os classificadores testados foram capazes de mensurar a área coberta por estrato superior, podendo ser um indicador da qualidade da vegetação, em pastagem natural do bioma Pampa.

Canopeo and GreenSeeker applications as tools to support tropical pasture management / Aplicativos Canopeo e GreenSeeker como ferramentas de apoio ao manejo de pastagens tropicais

This study determined whether Canopeo and GreenSeeker measurements in Megathyrsus maximus can estimate plant height, dry matter mass, morphological components, and content of crude protein and neutral detergent fiber at different days of growth. Five plots of 5 × 25m M. maximus grass were defined: subplots of 1×1m were evaluated every three days, in which the pasture shows 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days of regrowth. The subplot was evaluated for canopy height and mass accumulation. The canopeo index (CI) obtained at a higher height was lower than those obtained at a smaller height. Higher measurement height increased the normalized difference vegetation index (NDVI) relative to 0.10 m. The highest indexes were observed since 18 d of regrowth. Except for the CI evaluated at 0.10 m of height, the indexes were not correlated to the chemical composition of the forage. The CI and NDVI were positively correlated to plant height, dry matter mass, and leaf index, whereas both were negatively correlated with stalk index. Thus, lower evaluation heights for CI and NDVI can be a good predictor of forage height. Values of 0.83 and 85.8 for NDVI and CI, respectively, indicated an appropriate time to start the grazing of M. maximus.

O presente estudo teve como objetivo avaliar se os índices obtidos com Canopeo e GreenSeeker (NDVI) em Megathyrsus maximum são capazes de estimar altura de plantas, massa de matéria seca, componentes morfológicos e teor de proteína bruta e fibra em detergente neutro em diferentes dias de crescimento. Cinco parcelas de 5 × 25 m de capim M.maximum foram definidas: sub parcelas de 1 × 1 m foram avaliadas a cada três dias, nas quais a pastagem apresenta 3, 6, 9, 12, 15, 18, 21, 24, 27 e 30 dias de rebrota. A sub parcela foi avaliada quanto à altura do dossel e acúmulo de massa. O índice do Canopeo (IC) obtido em maior altura foi menor do que o obtido em menor altura. A maior altura de medição aumentou o NDVI em relação a 0,10 m. Os maiores índices foram observados desde 18 dias de rebrota. Exceto para o IC avaliado a 0,10 m de altura, os índices não foram correlacionados com a composição química da forragem. IC e NDVI correlacionaram-se positivamente com a altura da planta, massa de MS e índice foliar, e negativamente com o índice de colmos. Assim, menores alturas de avaliação para IC e NDVI podem ser um bom preditor da altura da forragem. Valores de 0,83 e 85,8 para NDVI e IC, respectivamente, indicam um momento adequado para o início do pastejo de Megathyrsus maximum.

Bioeconomic evaluation of pasture sheep finishing using castor bean cake / Avaliação bioeconômica da terminação de ovinos sob pastejo utilizando torta de mamona

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.

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.

Methods for estimating forage mass in marandu palisade grass canopies / Métodos para a estimativa da massa de forragem em dosséis de capim-marandu

This study compared three methods for estimating forage mass and its morphological components in canopies of Urochloa brizantha cv. Marandu (marandu palisadegrass). Two experiments were carried out, the fi rst simulating deferment and the second, continuous stocking. In the fi rst experiment, three methods for estimating forage mass (square, row, and tiller methods) were evaluated in different canopies with three initial heights (15, 30, and 45 cm). In the second experiment, two methods for estimating forage mass (square and tiller methods) were evaluated in canopies with three average heights (15, 30, and 45 cm) in summer. The experiments were conducted in a completely randomized design, in a split-plot scheme, with four replications. The plots were canopy heights and the subplots, the forage mass estimation methods. In general, taller canopies have greater forage mass. The tiller method resulted in lower total forage and senescent forage masses than the other methods. The tiller method underestimates total forage and senescent forage masses. The square and line methods are suitable to estimate the pasture total and senescent forage masses.(AU)

Este estudo comparou três métodos para a estimativa das massas de forragem e dos seus componentes morfológicos em dosséis de Urochloa brizantha cv. Marandu (capim-marandu). Dois experimentos foram realizados, sendo o primeiro simulando o diferimento e o segundo, a lotação contínua. No primeiro experimento, foram avaliados três métodos para estimativa de massa de forragem (métodos do quadrado, da linha e do perfilho) em dosséis diferidos com três alturas iniciais (15, 30 e 45 cm). No segundo experimento, foram avaliados dois métodos para estimativa de massa de forragem (métodos do quadrado e do perfilho) em dosséis com três alturas médias (15, 30 e 45 cm) no verão. Os experimentos foram conduzidos em delineamento inteiramente casualizado, em esquema de parcelas subdivididas, com quatro repetições. As parcelas foram as alturas dos dosséis e as subparcela, os métodos de estimativa da massa de forragem. Em geral, os dosséis mais altos apresentam maior massa de forragem. O método do perfilho resultou em massas de forragem total e de forragem senescente inferiores ao demais métodos. O método do perfilho subestima as massas de forragem total e de forragem senescente. Para estimar as massas de forragem total e de forragem senescente do pasto, os métodos do quadrado e da linha são adequados.(AU)

Automatic cattle weighing on pastures with behavioral analysis during drinking

t Livestock body weight (BW) and average daily weight gain (ADG) are primary indicators of beef cattle productivity. The conventional method of weighing involves moving the cattle to a weighing location, which is labor-intensive, stressful for the animals and has a negative impact on their growth. An alternative approach is to use special weighing platforms attached to the drinkers to weigh the animals. This method enables daily monitoring of BW and ADG without incurring additional labor costs or stress. In this study, an experimental weighing platform, previously developed at KazATU and named after S. Seifullin, was employed to measure livestock's partial body weight (PBW). The weighing platform recorded the weights of the animals on the front legs at one-second intervals, allowing for subsequent calculation of the animals' total weight. However, due to significant weight fluctuations observed when the animals were on the platform, the accuracy of calculating the weight based on a simple average of the one-second measurements was questionable. Hence, an algorithm was developed to determine live weight by analyzing the primary data from the scales and identifying moments of animal immobility during drinking. The calculated results were compared with both mean and median values and data from Kazakhstan's information base of selection and breeding work (IBSBW). The experimental method exhibited a stronger correlation (r = 0.925) with the actual IBSBW data compared to the mean method (r = 0.887) or the median method (r = 0.921).(AU)

Forage production, morphogenetic and structural components, and nutritional value of tropical grasses in the semiarid condition / Produção de forragem, componentes morfogênicos e estruturais e valor nutricional de gramíneas tropicais em condição semiárida

The objective of this study was to evaluate the forage mass, morphogenetic and structural characteristics, and nutritional value of tropical forage grasses in semiarid conditions. Nine grasses were evaluated, namely, three cultivars of Urochloa brizantha (Marandu, MG4, and Piatã); Urochloa decumbens cv. Basilisk; Urochloa humidicola cv. Llanero; Urochloa ruziziensis cv. Kennedy; and three cultivars of Megathyrsus maximum (Massai, Mombaça, and Tanzania). The experiment was laid out in a randomized complete block design in a split-plot arrangement in which the main factor were the grass cultivars and the secondary factor the seasons, with five replications per treatment. The statistical model included the fixed effect of treatment (grass), whereas the season was included as a random effect within treatments. Urochloa brizantha cvs. Marandu, MG4, and Piatã and Urochloa decumbens cv. Basilisk produced on average 858 kg ha-1 more forage mass than cvs. Kennedy and Basilisk. Megathyrsus maximum cv. Mombaça produced 40% more forage mass than the other cultivars of M. maximum (4205 vs. 3001 kg ha-1). Urochloa ruziziensis cv. Kennedy showed the lowest water use efficiency (36%). Urochloa ruziziensis cv. Kennedy exhibited the lowest leaf weight among the Urochloa cultivars (740 vs. 1319 kg ha-1). There was no treatment effect for leaf weight in the M. maximum cultivars. Urochloa ruziziensis cv. Kennedy showed the highest values of total digestible nutrients and dry matter digestibility (1.84 and 2.34%, respectively) among the other Urochloa cultivars. The M. maximum cultivars showed little differences in nutritional values. Cultivars Marandu, Piatã, and Massai exhibited better productive responses in the edaphoclimatic conditions of this study. However, future studies must be conducted evaluating the adaptation of the forage grass under semiarid conditions. Considering the settings of this study, the grasses Urochloa brizantha cvs. MG4, Marandu, and Piatã, as well as Megathyrsus maximum cvs. Massai and Mombaça, can be used in the semiarid condition.

O objetivo deste estudo foi avaliar a produtividade, características morfogênicas e estruturais e valor nutritivo de gramíneas forrageiras tropicais em condições semiáridas. Nove gramíneas foram avaliadas: Três cultivares de Urochloa brizantha (Marandu, MG4 e Piatã), Urochloa decumbens cv. Basilisk, Urochloa humidicola cv. Llanero, Urochloa ruziziensis cv. Kennedy e três cultivares de Megathyrsus maximum (Massai, capim-Mombaça e Tanzânia). O experimento foi conduzido em blocos completos casualizados em esquema de parcelas subdivididas com o fator principal (cultivar) e o fator secundário (estação) com cinco repetições por tratamento. O modelo estatístico incluiu o efeito fixo de tratamento (cultivar), e a estação do ano foi incluída como efeito aleatório dentro do tratamento. Urochloa brizantha cv. Marandu, MG4 e Piatã e Urochloa decumbens cv Basilisk produziram em média 858 kg ha-1 de massa de forragem a mais que a cv. Kennedy e Llanero. Megathyrsus cv. Mombaça produziu 40% (4205 vs. 3001 kg ha-1) a mais de massa de forragem do que as demais cultivares de Megathyrsus maximum. Urochloa ruziziensis cv. Kennedy apresentou a menor (36%) eficiência no uso da água (EUA). Urochloa ruziziensis cv. Kennedy produziu menor quantidade de folhas (740 vs. 1319 kg ha-1) para as demais cultivares de Urochloa. Não houve efeito do tratamento na produtividade de folhas para as cultivares Megathyrsus maximum. Urochloa ruziziensis cv. Kennedy apresentou os maiores valores de nutrientes digestíveis totais (NDT) e digestibilidade da matéria seca (DMS) (+1,84 e 2,34%, respectivamente) em relação à outra cultivar de Urochloa. As cultivares Megathyrsus maximum tiveram pouco efeito sobre os valores nutritivos. As cultivares Marandu, Piatã e Massai apresentaram melhores respostas produtivas nas condições edafoclimáticas deste estudo. No entanto, estudos futuros devem ser realizados avaliando a adaptação da forrageira em condições semiáridas. Nesta condição de estudo, as gramíneas Urochloa brizantha cv. MG4, Marandu e Piatã, assim como o Megathyrsus maximum cv. Massai e Mombaça podem ser usados em condições semiáridas.

Nutritional and metabolic parameters of sheep on deferred pasture with different strategy changes during the dry season / [Parâmetros nutricionais e metabólicos de ovinos em pasto diferido com diferentes estratégias mudam ao longo do período seco]

To verify if strategies to reduce the height of Marandu grass pasture at beginning of the deferral period change intake and metabolic parameters in sheep during the dry season, 18 crossbred females, ½ Dorper + ½ Santa Inês were used, distributed in 9 Marandu grass paddock handles to 3 drawdown strategies at the beginning of deferral period: 1) maintenance of grass with 15cm for 5 months before deferral start (15/15cm); 2) maintenance of marandu grass with 25 cm for 5 months, but at the beginning of deferral it was reduced to 15cm (25/15cm); 3) maintenance of 35 cm grass for 5 months, but at the beginning of deferral it was reduced to 15cm (35/15cm). The experiment was conducted in a completely randomized design (CRD), with 6 repetitions and repeated measures over time. Strategies to reduce the height of Marandu grass pasture, at the beginning of the deferral period, do not change nutrient intake and energy and protein metabolism. However, changes occurring in the pasture during the dry season alter these variables, and deferral is an interesting strategy to be used for forage production in winter, however, to optimize its use, it is necessary to use supplementation with concentrated rich in fermentable carbohydrates.

Para verificar se estratégias de redução da altura do pasto de capim-marandu, no início do período de diferimento, alteram consumo e parâmetros metabólicos em ovinos durante o período seco, foram utilizadas 18 fêmeas, mestiças, ½ Dorper + ½ Santa Inês, que foram distribuídas em nove piquetes de capim-marandu, com três estratégias de rebaixamento no início do período de diferimento: 1) manutenção do capim com 15cm, por cinco meses, antes do início do diferimento (15/15cm); 2) manutenção do capim-marandu com 25cm, por cinco meses, rebaixado, no início do diferimento, para 15cm (25/15cm); e 3) manutenção do capim com 35cm durante cinco meses, rebaixado, no início do diferimento, para 15cm (35/15cm). O experimento foi conduzido em delineamento inteiramente ao acaso (DIC), com seis repetições e medidas repetidas no tempo. Estratégias de redução da altura do pasto, no início do período de diferimento, não alteram o consumo de nutrientes e metabolismo energético e proteico. Porém, as mudanças no pasto durante o período seco alteram essas variáveis, sendo o diferimento uma estratégia interessante para utilizar na produção de forragem no inverno. Para otimizar seu uso, faz-se necessária, entretanto, a utilização da suplementação com concentrados ricos em carboidratos rapidamente fermentáveis.

Land use and land cover modification and its impact on biodiversity and the ecosystem services in District Kurram, Pakistan / Uso del suelo y modificación de la cobertura terrestre y su impacto en la biodiversidad y los servicios de los ecosistemas en el distrito de Kurram, Pakistán

Modifications of land use and vegetation cover are proceeding faster than ever before in human history, with a considerable reduction in forest cover in biodiversity hotspots. We investigated the land use and vegetation cover changes, their impact on biodiversity in the Kurram District, Pakistan, for 27 years (1989 to 2015). Temporal satellite imagery was processed using a supervised maximum likelihood classification algorithm in ARCGIS 10.1 to elucidate information regarding land use/land cover changes,with conducted structured interviews to obtain the inhabitants' perspectives on their dependence on ecosystems in Kurram, and how their environment is changing. We found that the land under forest cover and rangeland showed a remarkable decrease over the study period. This decline in rangeland and forest cover was a result of the increased of farmland, barren land. The study area is part of a biodiversity, with important medicinal, rare and unique plant species.

Las modificaciones del uso de la tierra y la cobertura vegetal están avanzando más rápido que nunca en la historia de la humanidad, con una reducción considerable de la cobertura forestal en los puntos críticos de biodiversidad. Investigamos el uso de la tierra y los cambios en la cobertura vegetal, su impacto en la biodiversidad en el distrito de Kurram, Pakistán, durante 27 años (1989 a 2015). Las imágenes satelitales temporales se procesaron utilizando un algoritmo de clasificación de máxima verosimilitud supervisada en ARCGIS 10.1 para dilucidar información sobre los cambios en el uso del suelo/cobertura del suelo, con entrevistas estructuradas realizadas para obtener las perspectivas de los habitantes sobre su dependencia de los ecosistemas en Kurram y cómo está cambiando su entorno. Descubrimos que la tierra cubierta por bosques y pastizales mostró una disminución notable durante el período de estudio. Esta disminución en los pastizales y la cubierta forestal fue el resultado del aumento de las tierras de cultivo, tierras estériles. El área de estudio es parte de una biodiversidad, con importantes especies de plantas medicinales, raras y únicas.