Correlações entre características morfogênicas e estruturais em pastos de capim-braquiária

The analysis of both morphogenetic and structural characteristics of pasture allows us to understand the response patterns of the plant to the environment. Thus, this study was conducted to evaluate the associations between the morphogenetic and structural characteristics of Brachiaria decumbens under continuous grazing by cattle. The development of individual tillers in pastures was evaluated under two grazing management strategies during three seasons (winter, spring and summer). Pearson correlations between variables were estimated. The lengths of leaf and stem, number of tillers and leaves per tiller, rates of leaf appearance and elongation of leaf and stem of B. decumbens were positively correlated. There was a negative relationship between appearance and lifespan of leaves (r = -0.89). However, positive correlations between leaf appearance rate and number of tillers (r = 0.64) and between length of stem and leaf senescence rate (r = 0.63) were determined. The B. decumbens modifies its morphogenesis to better adapt to climate and grazing management.

Efeito de três espécies de gramíneas forrageiras sobre a estrutura da pastagem e distribuição vertical de larvas infectantes de nematódeos gastrintestinais de ovinos

The knowledge of interaction between infective larvae setting and the type of grass is important to epidemiological studies and the control of gastrointestinal nematodes in sheep. The objective of this work was to evaluate the effects of three species of forage grasses on pasture characteristics and the vertical distribution of infective larvae (L3) of gastrointestinal nematodes of woolless sheep on the grasses during the rainy season. Sixty non-periparturients ewes were used, naturally infected, equally distributed on 2ha paddocks sowed with Tanzania, star, and gamba grasses, managed under continuous grazing system, from October 2003 to March 2004, at Santa Bárbara farm, Barreiras-Bahia-Brazil. Data of three samples between December 2003 and March 2004 were analyzed by SAS, using split-plot design, with 10 replications. Infective larvae of Haemonchus spp. and Trichostrongylus spp. were observed on forage in all stratus of vertical layer of the grasses without a defined pattern. Pastures with different characteristics under continuous grazing system had good conditions for developing infective larvae of sheep.

Mastigação simulada e digestão ácido-enzimática de sementes de leguminosas forrageiras tropicais

This study aimed to evaluate the effect of simulated chewing in the laboratory on the survival of seeds of four tropical forage legumes (butterfly pea, Clitorea ternatea; estilosantes, Stylosanthes capitata/S. macrocephala 'Campo Grande; archer, Macrotyloma axillare and perennial soybean, Neonotonia wightii) submitted to different periods of acid enzymatic digestion in vitro. Three trials were conducted to observe the percentage of destroyed seeds by the mastication; to compare the germination of the seeds (intact seeds, simulated mastication, scarification with sandpaper, mastication and scarification with sandpaper). And, finally the seeds were incubated at 39oC with hydrochloric acid and pepsin for: 0, 2, 4, 8, 12 and 24 hours. The percentages of not destroyed seeds in mastication (archer, 91,5; perennial soybean, 88.0; butterfly pea, 82.1, and estilo, 81.1), associated with the beneficial effects of scarification on germination (64.7, 60.0, 92.0 e 87.3%, respectively) and the effects of time of acid-enzymatic digestion (75% higher if they stay 24 hours in HCl + pepsin) associated to the hard and not permeable coats of legume seeds, allow a high potential for resistance, and to pass intact through the digestive tract of cattle, being able to germinate when defecated in the pastures. However, estilo should not be included in the feeding of cattle for this purpose, because it do not resists the acid-enzyme digestion.

Uso de sig e fotografias aéreas na determinação de conflitos na rede de drenagem na bacia experimental do Rio Pardo

This study aimed to detect and evaluate potential conflicts in the land use along the Rio Pardo's tributaries and sub-tributaries from its source which is in Pardinho, SP to the water capture system by the Basic Sanitation Company located in Botucatu, SP. It was used 2005 colored aerial photos, taking as a tool for assessing the Geographical Information System - IDRISI Andes. The results showed that the riparian forests were substituted predominantly by pastures, which is called conflict. In other words, the 1590.82ha of environmental preservation areas (PPA's) that should be protected by riparian forests and meadows (41.51%) in 2005, were used as pastures, being in conflict with the legislation. The aerial pictures associated to SIG-Idrisi proved to be efficient tools in mapping the area and monitoring the environmental impacts.

Uso do solo e monitoramento dos recursos hídricos no córrego do Ipê, Ilha Solteira, SP

Brazil has great potential of water resources, however, with deficiency in terms of qualitative and quantitative monitoring and knowledge of the influences of land use. So, this study had the purpose of presenting the qualitative and quantitative monitoring of water for irrigation and the influences caused by the use and occupation of land in the watershed of Ipê stream, in the municipality of Ilha Solteira, São Paulo. The qualitative monitoring was conducted from 2006 to 2011 and the quantitative monitoring from 2009 to 2011. In order to evaluate the influences, the Pearson correlation analysis was used. It was found that the watershed is mostly made up by the crop of sugar cane and the use in conflict with areas of permanent preservation are the fallow areas and pasture. The watershed is characterized with high concentrations of iron and coliforms, originating from degraded pastures and irregular use of urban and rural occupation. The small permanent preservation areas, bad soil conservation and expansion of urban areas imply in the deterioration of the quality and availability of water, generating socio-economic and environmental impact in the area.

Identificação de microrganismos resistentes ao herbicida ácido 2,4-diclorofenóxiacético (2,4-D) em solos de Rondônia, Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of bovine somatotropin administration on growth, physiological, and reproductive responses of replacement beef heifers

This experiment compared growth, body composition, plasma IGF-I and leptin, and reproductive development of beef heifers receiving or not recombinant bovine ST (BST) beginning after weaning until the first breeding season. Fifty Angus × Hereford heifers (initial BW = 219 ± 2 kg; initial age = 208 ± 2 d), weaned at approximately 6 mo of age, were assigned to the experiment (d 0 to 210). On d 0, heifers were ranked by initial BW and age and assigned to 1) treatment with BST or 2) saline control. Heifers assigned to the BST treatment received subcutaneous (s.c.) injections containing 250 mg of sometribove zinc whereas control heifers received a 5-mL s.c. injection of 0.9% saline every 14 d. Treatments were initiated on d 14 and last administered on d 196. Heifers were maintained on separate pastures harvested for hay the previous summer according to treatment and received grass and alfalfa hay at a rate to provide a daily amount of 7.0 and 1.0 kg of DM per heifer, respectively. Heifer shrunk BW was collected on d 1 and 211 for heifer ADG calculation. Blood samples were collected weekly from d 0 to 210 for determination of plasma progesterone to estimate puberty attainment as well as plasma concentrations of IGF-I and leptin in selected samples. On d 0, 63, 133, and 189, heifers were evaluated for intramuscular marbling, LM depth, and backfat thickness via real-time ultrasonography. No treatment effects were detected (P = 0.27) for heifer ADG (0.49 vs. 0.51 kg/d for control and BST heifers, respectively; SEM = 0.02). Mean backfat thickness was lesser (P < 0.01) in BST heifers compared with control cohorts (3.56 vs. 3.92 mm, respectively; SEM = 0.08). Heifers receiving BST had greater plasma IGF-I concentrations compared with control cohorts 7 d after treatment administration (treatment × day interaction; P < 0.01). Mean plasma leptin concentrations were lesser (P = 0.05) in BST heifers compared with control cohorts (1.82 vs. 2.03 ng/mL, respectively; SEM = 0.07). Onset of puberty was hastened in BST heifers compared with control cohorts (treatment x day interaction; P = 0.04). In summary, a greater proportion of BST heifers reached puberty during the experiment compared with control cohorts, despite lesser plasma leptin concentrations, backfat thickness, and similar ADG. Hence, circulating IGF-I was positively associated with hastened puberty attainment independently of growth rate, circulating leptin concentrations, and body fat content of replacement beef heifers. © 2013 American Society of Animal Science. All rights reserved.

Teor de ácido cianídrico e taxa de crescimento do híbrido de sorgo x capim sudão durante o outono

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Características morfogênicas e estruturais do capim-xaraés submetido a intesidades de pastejo

The aim of this study was to evaluate the effects of residual leaf area index (rLAI), years of evaluation and grazing cycles on the morphogenetic and structural characteristics of xaraés palisadegrass subjected to grazing intensities in two summers (years of evaluation). The experiment was carried out at the Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP, Campus de Jaboticabal, São Paulo, Brasil and the intensities of grazing were defined by four rLAI: 0.8, 1.3, 1.8 and 2.3. When the canopy intercepted 95% of incident light, the animals were placed on the pasture for grazing and kept until the rLAI target has been reached. Pastures were grazed by non-lactating Holstein cows (Bos Taurus Taurus L.), using the technique of mob-stocking. The morphogenetic and structural characteristics of xaraés palisadegrass respond effectively to weather conditions. There is variability in morphogenetic and structural characteristics in response to years and grazing cycles within years.

Resistance of beef cattle of two genetic groups to ectoparasites and gastrointestinal nematodes in the state of São Paulo, Brazil

The resistance to infestations by ectoparasites and infections by gastrointestinal nematodes was studied in 45 animals (males and females) of two genetic groups: purebred Nelore (NI, n=28) and Three-Cross (1/2 Angus+1/4 Canchim+1/4 Nelore - TC, n=17). The animals were monitored for 24months, during which they were left to graze in tropical pastures without receiving treatment for parasites. Each month the animals were examined for infestations by external parasites, to count the numbers of cattle ticks Rhipicephalus microplus with diameter greater than 4.5mm present on the left side, horn flies (Haematobia irritans) present in the lumbar region and botfly larvae (Dermatobia hominis) present on the entire body. The H. irritans counts were performed with the aid of digital photographs. At the time of examination, fecal samples were collected to count the eggs per gram (EPG) and to perform coprocultures, and peripheral blood samples were drawn to determine the packed cell volume (PCV) and to count the eosinophils. For statistical analysis, the count data were transformed into log10 (n+1), where n is the number of parasites. For PCV, significant effects (P<0.05) were found for collection month (CO), genetic group (GG) and gender (SX), with means and respective standard errors of 41.5±0.65% for the NI animals, 39.3±0.83% for the TC, 41.5±0.72% for the females and 39.3±0.77% for the males. Regarding the eosinophil counts, only the effect of sex was significant (P<0.01), with means and respective standard errors of 926.0±46.2/μL, for males and 1088.0±43.8/μL of blood, for females. The NI animals presented lower mean counts for all the external parasites compared to the TC animals (P<0.01). For ticks, the transformed means followed by standard errors for the NI and TC animals were 0.06±0.01 and 0.34±0.02, while for horn flies these were 0.92±0.05 and 1.36±0.06 and for botfly larvae they were 0.05±0.03 and 0.45±0.05, respectively. The average EPG values were only influenced by CO (P<0.01). The coprocultures revealed the presence of the following endoparasites: Haemonchus spp., Cooperia spp., Oesophagostomum spp. and Trichostrongylus spp., the last in smaller proportion. There were no significant differences between the genetic groups for the endoparasite loads, except for Cooperia spp., which were present in greater number (P<0.05) in the NI group. The results obtained in this experiment confirm previous findings of greater susceptibility of the Nelore breed to Cooperia spp. and high resistance to ectoparasites. © 2013 Elsevier B.V.

Detecção da doença mela-das-sementes da braquiária em gramíneas forrageiras através de técnicas de sensoriamento remoto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Carbono orgânico em função do uso do solo

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Variabilidade espacial de propriedades físicas e químicas da camada orgânica superficial do solo em um ecótono cerrado-pastagem na microbacia do Rio Pântano (Selviria-MS)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A comunidade de borboletas frugívoras de áreas em processo de restauração, fragmentos de floresta estacional semidecidual e pastagens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A cultura da soja implantada em diferentes coberturas e manejos do solo em área de pastagem degradada

Pós-graduação em Agronomia (Energia na Agricultura) - FCA