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Objective: To evaluate two methods to estimate dry matter availability in mixed pastures in the Amazon region, Peru. Materials and Methods: The traditional method and the electronic capacitance method with Grass Master Pro equipment were used. A complete randomized block design was used, with two sources of variation: five pastures, three evaluation periods (20, 40 and 60 days) and the average of 15 observation units per pasture. A variance analysis and multiple comparisons of means were performed using Tukey's test: 5 % probability to compare the existence of significant differences among means. Linear and polynomial regression were also used to estimate the relationship between the two methods. For data processing and analysis, the statistical program R was used. Results: Actual dry matter values were obtained using the quadrat method. The traditional method and the electronic capacitance method showed significant differences (p < 0,05). Dry matter availability by the traditional method was 3 530,3 kg DM/ha and by the capacitance method 3 942,4 kg DM/ha. With the linear regression, a determination coefficient of R² = 0,87 was obtained and with the polynomial regression, of R² = 0,93. Conclusions: The electronic capacitance method reported average dry matter measurements in the pasture, significantly higher than the traditional method, and showed desirable and concordant characteristics for its use in animal husbandry activity. [ABSTRACT FROM AUTHOR]

Objective: To characterize the plant community of the pastureland in a dairy farm under commercial conditions in Matanzas province, Cuba. Materials and Methods: A study was conducted of the pastureland community on a Ferralitic Red soil, in a typical dairy farm of 120 animals and an area of 72,4 ha. From them, 57,8 dedicated to grazing, distributed in 29 paddocks of 1,9 ha each as average. The variables pasture availability, floristic composition of the pastureland, stocking rate and forage balance, were analyzed. Results: The natural pastures predominated in the system, with a contribution of more than 60,0 % in the dry season and close to 70,0 % in the rainy season. The species Paspalum notatum Alain ex Flügé, Dichanthium annulatum (Forssk.) Stapf and Dichanthium caricosum (L.) A. Camus prevailed. The highest pasture yield was obtained in the rainy season (2,86 t/ha) and the lowest value, in the dry season (1,79 t/ha). Nevertheless, the dry matter supply throughout the year did not exceed 16 kg DM/animal/day. The effective stocking rate values (1,3 LAU/ha) exceeded the established optimum value. The forage balance showed a dry matter deficit higher than 3,0 kg /LAU/day in both seasons. Conclusions: The low pasture yield throughout the year was linked to the high predominance of natural species and weeds present in the pastureland. The highest availability was reached in the rainy season. The stocking rate values are over the optimum value. [ABSTRACT FROM AUTHOR]

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the semi-arid region of central Argentina, a part of which is included in La Pampa province, most of the land is dedicated to livestock activity, mainly cattle breeding on grasslands as the primary source of fodder. Stocking rate in these environments does not always keep an adequate relationship with carrying capacity to prevent degradation of these ecological systems. Rainfall levels play a key role for both, the geographical layout of plant communities and variability in forage production and availability between and within years. Rangeland carrying capacity for livestock in such a region would be closely related to rainfall and land background of use, major determinants of the state of condition and forage production of plant communities. The present work was aimed to: (a) assess how forage availability and carrying capacity of different types of plant community units and micro-regions of La Pampa relates to rainfall; and (b) construct maps showing data for those three variables in sites of La Pampa under different conditions of ecosystems. There were considered all the plant community units that make up the target region, two rangeland condition states (good and fair) and three climatic scenarios of different rainfall levels (good, higher than 120% of annual mean value; normal, within mean value ± 20%; and poor, lower than 80% of mean value). Estimation of carrying capacity was based on pre-existing data of forage availability for each site. It was noted that both forage availability by plant community unit and carrying capacity by micro-region are strongly explained by rainfall level. Besides, a close relationship was observed between actual stocking rate and the estimated carrying capacity when rangeland condition was fair with years of normal and good rainfall. In years of poor rainfall, regardless of the rangeland condition state, forage availability is not enough to sustain the stock of cattle at the historical level for the province. In order to assure the conservation of natural resources and achieve a sustainable livestock production, it is imperative to follow models that consider both the productive capacity and variability for each region of the province, attributes that are instead strongly influenced by ecological characteristics. [ABSTRACT FROM AUTHOR]

In Campeche state, 122 Wildlife Conservation and Management Units have been recently conformed. In these units, eventhough the white tailed deer Odocoileus virginianus thomasi is a game species, no studies on its diet have been undertaken. The objectives of this work were to estimate the botanical composition of the diet and its seasonal change, to determine forage availability, carrying capacity and stocking rate of O. virginianus thomasi. The study was conducted in the experimental unit of Colegio de Postgraduados in Campeche, Mexico, from October 2010 to May 2012. The diet was determined through microhistological analyses of the white tailed deer feces by the use of reference material. Forage availability was determined through the Adelaide's method; the stocking rate, using the grazing pressure factor; and carrying capacity considering forage availability and 35% of utilization efficiency. In this experimental unit, the deer diet included 40 species belonging to15 families. The highest species richness ocurred during the rainy season with 29 species. However, deers preferred shrubs during all seasons, and herbaceous species during the rainy season. The diet composition, forage availability, carrying capacity and stocking rate varied throughout the year. Carrying capacity ranged from 0.04 to 1.08deer/ha. Additional studies are required to detail about the composition of the diet, habitat availability and use throughout its geographical range, and to detail on nutritional and health aspects. [ABSTRACT FROM AUTHOR]

Outdoor pig production offers advantages with respect to investment costs, animal welfare, and reduced environmental impact. However, these systems, if not operated judiciously, can damage the environment. Environmental Impact Indicators are useful to identify, interpret and prevent such damage. Nitrate leaching and loss of vegetative cover are among the factors associated with mismanagement of the stocking rate that can affect the ecological sustainability of these systems. In Argentina little pertinent information is available. Thus, the aim of this study was to analyze the evolution of ecological sustainability, from the dynamics of vegetation and soil chemical characteristics, using standardized indicators. In the Swine Production Module of the Faculty of Agricultural Sciences (UNR), on a pasture implanted to fescue grass, the animals were divided among the treatments T1: low stocking rate during the growth phase; T2: high stocking rate during the growth phase; T3 low stocking rate during finishing; and T4: high stocking rate during finishing. The variables evaluated were vegetative characteristics (abundance, cover, biomass) and soil characteristics (nitrate and available phosphorus contents and pH). Normalization of the indicators was performed using ELANEM methodology. The indicators are represented in radial figures. Already by 5 Mo into the experiment T4 was observed to have caused displacement most distant from the ideal condition. Further studies are needed to determine the recommendable stocking rate and evaluate the indicators that best explain the environmental degradation. The radial figures proved useful to show how each indicator interacts and influences others. [ABSTRACT FROM AUTHOR]

In the humid tropic of Veracruz state the productive response of a native pasture under intensive rotational grazing was estimated, using Zebu Brahman cattle, during the period of June 1994 to May 1997, with variable grazing (1-3 days) and recovery (10-151 days) periods. Six paddocks, (3.0 ± 0.5 ha/division) were sampled. The standing DM before and after grazing for the dry season (March-June; 2,135 and 1402 kg/ha) were lower than those of the northern wind (November-February; 2,846 and 1,909 kg/ha) and rainy (July-October; 2,844 and 1,864 kg/ha) seasons, which did not differ between them. The live weight of the calf differed between seasons: 71 (dry), 142 (rainy) and 161 (northern wind) kg/ head. The stocking rate in the dry season (2.0 animal units [AU = 450 kg of LW]/ha) was lower than those of northern wind (2.4 UA/ha) or rainy (2.3 UA/ha) seasons, which did not differ among them. The season did not affect crude protein of the standing DM before grazing (9.3 ± 1.7%), days of recovery per division (50 ± 26), live weight of the cow (397 ± 11 kg/head), absolute crop growth rate (41 ± 33 kg DM/ha/ day), available DM (5.8 ± 2.6 kg DM/100 kg LW), dry matter intake (2.3 ± 1.5 kg DM/100 kg LW), and degree of use of available DM (40 ± 22%). The mean stocking rate of the present study was twice the traditional (1.0 AU/ha), suggesting a higher productive potential for native grass pastures in this region. [ABSTRACT FROM AUTHOR]