Pastos e manejo do pastejo de áreas dependentes de chuva.

Sistemas pecuários de produção em condições de sequeiro. Manipulação da vegetação da caatinga para exploração pecuária. Caatinga rebaixada. Caatinga raleada. Caatinga rebaixada-raleada. Caatinga enriquecida. Caatinga desmatada. Sugestões de modelos de exploração e de tecnologias com potencial para manter a sustentabilidade da produção agropecuária. Sistemas sem uso da caatinga e com espécies forrageiras cultivadas. Sistemas com uso da caatinga para produção animal. Sistemas com uso da caatinga para produção animal. Espécies de forrageiras apropriadas para exploração em áreas de sequeiro

Breeding Small Grains as a Forage, Silage and Cover Crop for the Southern Coastal Plain (USA) in a Changing Climatic Environment

Forage breeding of small grains in the southern Coastal Plains region of the U.S. mimic many other countries experiencing climate changes and breeding strategies should be similar for improving small grains grown for forage, silage or as cover crops. Significant focus on improvements in stress-adaptation has encouraged members of the SunGrains cooperative to cross, evaluate and develop experimental lines with inherent adaptation to climatic conditions including heat stress, drought tolerance, short-day and long-day forage production periods, and flooded conditions for events with storm-related, short-term durations. Many new cultivars, grown throughout the southeastern U.S. have resulted from breeding selection under abiotic and biotic stresses, adapted to climate change and related concerns, such as disease and insect pests

Weed Management Affects Pasture Productivity and Animal Performance

Weed can be defined as any plant growing in undesirable locations. Weeds are considered one of the main challenges in agricultural fields. Weeds affect pasture productivity mainly because of the competition for limited resources such as nutrients, water, and light with forage plants. Weeds encroach pastures spontaneously and spread quickly through the farm and neighboring areas, making their control difficult. In addition, weeds can affect forage nutritive value, grazing behaviour, voluntary forage intake, animal health, and consequently animal performance. The low efficiency of mechanical weeding and the global concern about indiscriminate use of herbicides impose challenges for producers in grazing systems. These factors justify the importance of proper weed management to minimize financial losses and environmental impacts and drive the research effort in this area. Currently, some strategies including grazing management, grass and legumes integration, and site-specific weed spraying have demonstrated potential to improve the efficiency of weed supression and increase the productivity and profitability of livestock systems. This review aims to discuss about the main effects of weed encroachment in grasslands regarding pasture productivity and animal performance, as well as emphasize potential strategies for weed management

Herbage Responses and Performance of Mature Horses Grazing Warm-Season Perennial Grass-Legume Mixed Pastures

Legume-grass mixtures may be a useful alternative to nitrogen-fertilized grass monocultures, but pasture and animal responses have not been assessed for pastures grazed by horses in Florida. This 2-yr study compared pasture and horse responses of continuously stocked, mixed pastures of rhizoma peanut (RP, Arachis glabrata Benth) and bahiagrass (BG, Paspalum notatum Flüggé) receiving 30 kg nitrogen (N)/ha (RP-BG) compared with BG pastures fertilized with 120 kg/N ha (BG-N) or with no N (BG-No N). Herbage mass was similar among treatments in 2020 and for most evaluation days in 2019. In 2019, stocking rate (AU/ha) was greater in BG-N (3.9) than in RP-BG (3.7) and BG-No N (3.1). In 2020, BG-No N (2.6) had the lesser stocking rate compared with BG-N (2.9) and RP-BG (2.9), with RP-BG not differing from BG-N. Herbage crude protein (CP) and digestible energy were similar across treatments in 2020, but they were greater for BG-N and RP-BG than BG-No N at some evaluation days in 2019. Except for CP, treatment did not affect nutrient digestibility by horses. Digestibility of CP was greatest for RP-BG in the late season. In the RP-BG treatment, proportion of RP in the pasture (~29%) was not affected by sampling date, and RP comprised 18.4% of the diet. Nonetheless, no differences were observed among treatments for body weight and condition score. The results indicate that intercropping legumes into warm-season perennial pastures can improve some measures of nutritive value and maintain horses’ body condition with similar stocking rate as N-fertilized bahiagrass pastures, while contributing to development of sustainable grazing systems for horses with reduced off-farm nitrogen inputs

Diurnal Variation in Forage Nutrient Composition and Metabolic Parameters of Horses Grazing Warm-Season, Perennial Grass-Legume Mixed Pastures

Although warm-season, grass-legume mixed pastures have improved nutritive value and may reduce negative environmental impacts relative to nitrogen-fertilized grass monocultures, no study has been done to evaluate their effect on diurnal variation of non-structural carbohydrates (NSC) and other nutrients, and on the metabolic responses observed in horses’ blood and fecal samples. This 2-yr study aimed to investigate the circadian variation in nutrient composition and the fecal and blood metabolic responses in horses grazing these pastures. Forage, fecal, and blood samples were collected every 28 days at 0600, 1200, 1800, and 0000 h, in two years, for measurement of diurnal variation in forage nutrient composition and fecal and blood metabolites. Forage nutrient composition was affected by time of the day, with digestible energy (DE) and NSC increasing at 1800 h, crude protein decreasing after 1200 h and the fiber components increasing at 1200 h. Fecal lactate and blood insulin were also affected by time of the day. Fecal lactate increased from 0600 to 1200 h. Insulin levels were greater at 1800 than at 0600 h. The increased insulin level followed the increased concentration of NSC in the forage. In conclusion, warm-season, grass-legume mixed pastures show a diurnal pattern in forage nutrient composition, with increased NSC later in the afternoon. However, the metabolic responses observed in this study were not sufficient to predispose horses to metabolic dysregulation. The results also indicate that restricting grazing to the morning may reduce the forage nutritive value, with decreased concentration of DE and increased concentrations of the fiber components, which may decrease diet digestibility

Chapter 17 - Economics of adaptation

This chapter assesses the literature on the economics of climate change adaptation, building on the Fourth Assessment Report (AR4) and the increasing role that economic considerations are playing in adaptation decisionmaking and policy. AR4 provided a limited assessment of the costs and benefits of adaptation, based on narrow and fragmented sectoral and regional literature (Adger et al, 2007). Substantial advances have been made in the economics of climate change adaptation after AR4

Use of Limpograss as an Alternative Feed During the Fall Forage Gap in Beef and Dairy Systems in Central and North Florida

In central and North Florida, the use of limpograss [Hemarthria altissima (Poir.) Stapf & C. E. Hubb.] for beef and dairy operations is limited and its potential use is not well documented. Two on-farm projects have been conducted in Central and North Florida to explore the use of limpograss as an alternative conserved forage during late fall and winter. The potential use of this forage as baleage for dairy farmers and as stockpiling for livestock producers would offer another alternative to reduce feed costs and fill the forage gap in the area when typical warm-season forages go dormant. In addition, the on-farm limpograss establishment would serve as dissemination for the limpograss planting material. Four dairy farms in Central and North Florida were enrolled in the study to evaluate two cultivars of limpograss for their potential when conserved as baleage. Four 0.2 ha strips were planted per farm, two for each variety (‘Kenhy’ and ‘Gibtuck’). The strips were arranged in a randomized complete block design, with two replicates in each location. Before wrapping the harvested forage for baleage, samples were taken to evaluate crude protein (CP) and in vitro digestible organic matter concentration (IVDOM). In addition, samples of fresh baleage at 60 and 90 d were analyzed for fermentation profile (pH, organic acids, and ammonia). Four beef cattle farms in North Florida allowed us to plant 1 ha of ‘Gibtuck’ for stockpiling evaluating the nutritive value at 30, 60, 90, and 120 days. Each plot was replicated four times and allocated in a randomized complete block design. The fermentation profile from the bales does not show differences between cultivars (P \u3e 0.05) and the pH is lower than 5 indicating that the fermentation process was successful. The CP and IVDOM of the stockpiling limpograss were different among the treatments (P \u3c 0.001)

Legume and Nitrogen Fertilization Affect Animal Performance and Enteric Methane Emission of Nellore Heifers

Methane emission from livestock operation is an important source of greenhouse gas and contributes to global warming. Forage legume secondary compounds may mitigate methane emissions by reducing methanogenic population in the rumen. This study evaluated animal performance and methane emission from beef cattle grazing either a mixed pasture [Brachiaria brizantha cv. Marandu (palisadegrass) and Arachis pintoi (forage peanut) cv. BRS Mandobi] or a palisadegrass monoculture with or without nitrogen (N) fertilisation. A 2.5-yr continuous stocking experiment was carried out in southeast Brazil, on a randomized complete block design with three treatments and four replicates. Two Nellore heifers were used as tester animals and additional put-and-takes were used to keep canopy height at 20-25 cm. The treatments comprised three pasture types: 1) palisadegrass-forage peanut mixed pasture (GRASS+LEGUME); 2) palisadegrass + 150 kg N/ha/year (GRASS+N); 3) palisadegrass without N fertilization (GRASS). Response variables included average daily gain (ADG), forage intake, and methane emission. Methane emission was estimated by the sulphur hexafluoride (SF6) tracer technique. There was no difference between grazing systems for the ADG (P = 0.439) and DMI (P = 0.394; averages of 0.433 kg/d and 2.10 %BW/d, respectively). In the GRASS+LEGUME, there was a decrease of 11.7% in methane emission per animal (148 vs. 170 and 165 g/day for GRASS+N and GRASS, respectively; P = 0.001). Grazing systems including legume reduced methane emission per unit of ADG (365 vs. 428 and 398 g/kg for GRASS and GRASS+N, respectively; P = 0.061) and per carcass gain (656 vs. 800 g of methane/kg carcass for GRASS; P = 0.022). Intake of condensed tannins was greater for GRASS+LEGUME (0.61 vs. 0.17 %BW/d, P \u3c 0.001). Forage peanut decreased enteric methane emission intensity, reducing carbon footprint of livestock systems in Southeast Brazil