Livestock production plays a key role in tropical Latin America in a changing economic environment. This study focuses on documenting the transformations of extensive production systems by using superior forage germplasm supplied by regional research systems. The adoption of improved Brachiaria grasses was evaluated from 1990 to 2003 to estimate its impact in terms of animal productivity and income in Central America and Mexico. Information on seed sales in the local market made it possible to estimate the areas planted and the value of additional milk and beef production attributable to adoption. Mexico presents the highest volume of marketed seed and of area established with improved pastures. Among Central America countries, Costa Rica was outstanding in terms of the high volume of seed sold and the area planted, followed by Honduras, Nicaragua, and Panama. The annual growth rate of seed sales was very high during the study period, reaching 32% in Mexico, 62% in Honduras, 45% in Nicaragua, 39% in Costa Rica, and 54% in Panama. The area planted with Brachiaria species during this period totaled 6.5% of the total surface of permanent grasses in Mexico, 12.5% in Honduras, 1.0% in Nicaragua, 18.7% in Costa Rica, and 0.1% in Panama. Excluding Nicaragua and Panama, where adoption is low, Brachiaria grasses account for 24%-55% of total annual milk production and for 5%-18% that of beef. These figures clearly demonstrate that those adopting new Brachiaria cultivars are farmers mainly oriented toward milk production and, to a lesser extent, beef. In monetary terms, the value of additional production attributable to the adoption of Brachiaria grasses in the selected study countries was estimated at US$1084 million per year, 78% corresponding to milk and 22% to beef. Due to the magnitude of the livestock sector in Mexico, adoption generates slightly more than 80% of production profits. Study results indicate that the investment of public funds in Central America and Mexico to support the International Network for Evaluation Tropical Pastures (RIEPT, its acronym in Spanish) paid off in terms of adoption of improved grasses and significant increases in the supply of milk and beef, fundamental items in the diet of consumers from all income levels in the region.

Extensive comparisons of the effects of tropical shrub legumes rich in condensed tannins (CT) require well-conserved material. It is, however, unclear if the application of even gentle methods like freeze drying (lyophilization) affects the results in comparison to fresh material. Therefore, an experiment with the gas-pressure transducer technique, simulating ruminal fermentation dynamics in vitro, was conducted to investigate the effect of freeze drying on the ruminal nutrient degradability of three tropical multipurpose shrub legumes. Leaves of the CT shrubs Calliandra calothyrsus and Flemingia macrophylla and of the CT-free shrub Cratylia argentea were tested either in fresh form or lyophilized. In order to simulate practical feeding conditions, the legume leaves were incubated together with Brachiaria humidicola (1:2) for 144 h. Additionally, incubations were carried out either with or without polyethylene glycol (PEG) to be able to separate effects either dependent or independent of the CT. Only few differences were found between fresh and lyophilized leaves. These included that the proportion of apparently undegraded nitrogenous compounds was higher in fresh than in lyophilized leaves of Flemingia macrophylla, and freeze drying had a limited influence on volatile fatty acid production in Calliandra calothyrsus. The variables related to degradation dynamics (i.e., total gas production, the time until the point of inflection, apparent dry matter degradability), however, were not influenced. There was also no difference between CT and non-CT plants in that respect, as is also obvious from the lack of interactions of state of the plant material and PEG addition. This indicates that effects of freeze drying of shrub leaves on overall ruminal nutrient degradation in mixed grass-legume diets were minor.

A pot experiment was conducted to assess the fertiliser value of faeces from sheep fed with a diet supplemented with legumes free of or containing condensed tannins. Ten animals received the same five diets in different experimental runs of a double Latin Square design, all consisting of a low quality tropical grass ration, supplemented with 450g/kg legumes. Legume treatments were either solely Vigna unguiculata (a tannin free herbaceous legume) or mixtures of V. unguiculata with either Calliandra calothyrsus or Flemingia macrophylla (both shrub legumes rich in condensed tannins) in ratios of 2:1 and 1:2. Faeces from animals receiving the same diets were pooled and applied at two levels (20 and 80 mg N/kg soil) to pots with seedlings from the cultivar Mulato II, a Brachiaria grass hybrid. An acidic infertile tropical soil was used. Aerial biomass yield and plant N content were evaluated. The results seem to indicate that the N fertiliser value of faeces from sheep receiving a diet supplemented with tanniniferous legumes is not substantially reduced compared to diets free of condensed tannins. However, the data also indicate that nitrogen was not the most limiting element in the soil used since mineral fertilisation without extra nitrogen was efficient, too.

The early adoption of the legume Arachis pintoi was studied in the State of Caquetá, located in Colombia’s Amazon region. Data came from 174 farmers randomly surveyed within the area of influence of Nestlé, a multinational milk-processing company. In addition, 52 farmers who had already adopted Arachis were surveyed separately to study their experiences, difficulties, and prospects with the legume. Results indicated that livestock activity is undergoing dynamic intensification. Since 1986, milk production per lactation has increased by 31%, cow fertility by 5%, herd size by 18%, and the area sown to improved pastures by 165%. Current adoption rate of Arachis is about 9.2%, with an estimated 3000 ha already planted. Two-thirds of farmers who had adopted Arachis said they would double, in the next year, the average area sown (9.6 ha/farm). Adopters tended to have larger farms and to have invested twice the capital than did non-adopters. The cost of seed for both grass and legume accounted for 40-52% of total establishment costs, making seed quality decisive in guaranteeing success. To promote Arachis, more information on the plant and its management in association with grasses must be disseminated. Mechanisms should also be sought to reduce establishment costs.

Livestock production plays a key role in tropical Latin America in a changing economic environment. This study focuses on documenting the transformations of extensive production systems by using superior forage germplasm supplied by regional research systems. The adoption of improved Brachiaria grasses was evaluated from 1990 to 2003 to estimate its impact in terms of animal productivity and income in Central America and Mexico. Information on seed sales in the local market made it possible to estimate the areas planted and the value of additional milk and beef production attributable to adoption. Mexico presents the highest volume of marketed seed and of area established with improved pastures. Among Central America countries, Costa Rica was outstanding in terms of the high volume of seed sold and the area planted, followed by Honduras, Nicaragua, and Panama. The annual growth rate of seed sales was very high during the study period, reaching 32% in Mexico, 62% in Honduras, 45% in Nicaragua, 39% in Costa Rica, and 54% in Panama. The area planted with Brachiaria species during this period totaled 6.5% of the total surface of permanent grasses in Mexico, 12.5% in Honduras, 1.0% in Nicaragua, 18.7% in Costa Rica, and 0.1% in Panama. Excluding Nicaragua and Panama, where adoption is low, Brachiaria grasses account for 24%-55% of total annual milk production and for 5%-18% that of beef. These figures clearly demonstrate that those adopting new Brachiaria cultivars are farmers mainly oriented toward milk production and, to a lesser extent, beef. In monetary terms, the value of additional production attributable to the adoption of Brachiaria grasses in the selected study countries was estimated at US$1084 million per year, 78% corresponding to milk and 22% to beef. Due to the magnitude of the livestock sector in Mexico, adoption generates slightly more than 80% of production profits. Study results indicate that the investment of public funds in Central America and Mexico to support the International Network for Evaluation Tropical Pastures (RIEPT, its acronym in Spanish) paid off in terms of adoption of improved grasses and significant increases in the supply of milk and beef, fundamental items in the diet of consumers from all income levels in the region.

Objectives of this study were to compare costs and expected benefits of feed supplementation in cattle with alternative shrub legumes during the dry season using as a case study the hillsides of Central Nicaragua. The information used was gathered in a survey of 32 farms in the states of Boaco and Chontales in Central Nicaragua. The survey was designed to determine herd structure, land use patterns, milk and beef production, and use of inputs for animal nutrition, in order to estimate production, reproductive parameters and employment of family/contracted labor, as well as indicators of profitability of the alternatives under study. To calculate the economic return to the investment in alternative forages, a simulation model that applies optimization techniques through linear programming, implemented as a spreadsheet, was used to perform an ex ante evaluation of the costs and benefits of different land use alternatives and of interactions between technological components and biological productivity. The model compares the costs and benefits of the traditional feeding system versus an improved feeding system. The traditional system consists of grazing naturalized pastures (Hyparrhenia rufa) during the rainy season. In the dry season producers supplement the herd with small areas of king grass (Pennisetum spp.). The improved feeding system consists of establishing forage legumes for dry season feeding as a supplement to replace king grass during the dry season. Supplements to evaluate are the shrub legume Calliandra calothyrsus as partial replacement of the herbaceous high quality legume Vigna unguiculata, commonly known as Cowpea. Under the new feeding system, herd size can be increased by 60% due in part to the increase in stocking rate as well as to the increase in the quality of the diet offered with higher protein content. This increase in herd size raises both milk and beef output that generates an increase in farm income by 1.8 times more (i.e., from $1,314/farm/yr to $2,386). The economic return to family labor is increased by 20% to $ 5.26/day equivalent to 2.3 times higher than the local wage rate. The adoption of Vigna (Cowpea) after the harvest of maize/beans and a shrub legume as Calliandra to replace king grass seem to have the potential to significantly improve the productivity in smallholder farms. with the resulting increase in the economic return to family labor.

Surveys were made of rural artisan cheese factories located in the region of Olancho, Catacamas, and Juticalpa in Honduras (n=10) and in Esquipulas and Muy-Muy in Nicaragua (n=13). The objective was to analyze the milk market of small rural artisan cheese factories in livestock watersheds of Honduras and Nicaragua to determine if: there is a market for higher milk production how much additional milk can the market absorb in each season of the year there is a market for milk of higher hygienic quality. The main buyer of the milk from small and medium scale farmers in Honduras and Nicaragua is the rural artisan cheese industry, which absorbs almost 80% of the milk produced in both countries. Total milk production during the rainy season is about twice that during the dry season, causing an over-supply and scarcity of milk, respectively. The shortage of fluid milk during the dry season leads to an unsatisfied market. The artisan cheese factories in Honduras and Nicaragua would be willing to buy 76% and 55% more milk during the dry season, but this supply is not available due low milk productivity. This fact suggests that an aggressive program for the promotion of shrub legumes with sugarcane to supplement the herd during the dry season would have more impact that the promotion of grasses or legumes for the rainy season when there is little market for additional milk produced. In addition, rural artisan cheese factories in Honduras and Nicaragua, that consider the milk they collect is of bad quality, would be willing to pay a higher price if the option to collect milk of better hygienic quality exists. In Honduras this price would be about 9% higher during the dry season and 11% higher during the rainy season. In Nicaragua the cheese factories would be willing to pay a milk price which is 17% higher, but only during the rainy season. As a result, large incentives exist in both countries to increase milk production during the dry season and to improve the hygienic quality of milk in the studied areas.

After regaining independence the agricultural production in Estonia has undergone a drastic decline. Due to the inadequate application of fertilizers and pesticides, the yield of field crops and grasslands has decreased 1-7 % per year. The balance of nitrogen in the arable soils is negative, particularly respecting fodder crops. At present, in Estonia most of grasslands are practically not fertilized, or they are fertilized in the last order. The amount of nitrogen removed with the yield of fodder crops, cereals and potato are by 45, 20 and 17 kg ha*[-1) higher, respectively, compared with the amounts of N applied to the soil with organic and mineral fertilizers, available for those crops. The effectiveness of nitrogen fertilizers depends largely on weather conditions during the vegetation period and is the lower, the higher is soil humus content. On gleyic and gley soils, whose humus content is higher, the efficiency of nitrogen fertilizers is 2-3 times lower and the agroecological and economic fertilization risks are higher. On sown grasslands, the efficiency of nitrogen fertilizers depends not so much on soil fertility as on soil water supply, humus content and grass sward type. With proper application of fertilizers, use of suitable plant species and varieties, it is possible to increase significantly not only the yield per unit area but also its nutritive value.

One of the main preconditions for an economical milk production is a balanced cow feeding that contains high quality grass forage. Chemical composition of cocksfoot forage during vegetation was investigated at the Research Centre "Sigra" in the Biochemical laboratory of the Latvia University of Agriculture. Changes in the content of crude protein, NEL MJ kg*[-1) of DM, NDF, ADF and DM digestibility were determined. The chemical composition of grass forage depends on many factors, the most significant of which is the harwesting time. The feeding value of the cocksfoot grass decreases during its growing stages as the content of fibre increases and becomes lignified.