The role and contributions of animals in alternative agricultural systems
Livestock are important components of agricultural systems. In the U.S., one-half of total agricultural receipts come from the sale of livestock. They are the harvestors of range plants, forages, and crop residues; they level out the effects of the seasonally and variability of rainfall; they cushion disruptions in the trade and marketing of feed grains; they counteract declining soil fertility and soil erosion; and they contribute to the efficient year-round use of farm labor. Unfortunately, farmers are often not inclined to adopt alternative animal agriculture systems despite the advantages they may offer. Constraints that may be encountered include possibilities of reduced short-term profits, difficulties in adapting available technology to alternative farming systems, difficulties in shifting from specialized crop or livestock farms to crop/livestock farms, and the increased needs for labor and management. Some actions needed in the U.S. to improve livestock production in alternative farming systems are: the establishment of government policies to promote the shift of marginal lands to soil and water conserving crops and the incorporation of pastures and forages in crop rotations; research to improve the utilization by ruminants of ligno-cellulosic feeds (pastures, forages, crop residues); and programs to improve range and forest management and to lead to the development of systems that optimize the use of forages for the production of nutritionally desirable lean beef.
The Relationships and Roles of Animals in Sustainable Agriculture and on Sustainable Farms1
Abstract Sustainability of individual farms involves primarily resource-based, economic, environmental, and social issues of the farm families. Sustainability of the total agriculture and food system from the farm producers to ultimate consumers includes economic, environmental, ecologic, societal, and cultural aspects for communities and larger regions. Animals and their products are important in the American diet as sources of nutrients and on individual farms as major sources of income in more than 80% of the states. In the agroecosystems of farms there is competition for and synergism in the use of basic resources of land, water, energy, air, labor, technology, capital, and management. Ideally, a stable biotic community or balance among plants and animals is established. Livestock-based farming systems can have an important role in coping with environmental problems such as declining soil fertility, soil erosion, and water contamination. Economically, animals represent a value-adding phase of livestock-crop systems. Animals also play a major role in cushioning or buffering trade and market disruptions of total agriculture. Diversifications of enterprises on a farm is a consideration in risk control. Animal productive efficiency is important in sustainability of individual farms and agriculture in total. Sustainability of livestock-based systems may be significantly influenced by the use of energy or the type of energy used. Constraints to shifting future livestock production to more sustainable systems are: a) current agricultural policies and production practices, b) current technology developed for systems now in use, c) management skills and labor availability based on systems now in use, and d) risk control and financial practices oriented to the systems in use and to the short term rather than long term. Public concerns about animal-based systems are: a) diet and health concerns, b) land and resource availability, c) animal welfare, d) use of biotechnology and other scientific interventions, and 3) environmental impacts.
New Sweet-Tasting C21-Pregnane Glycosides from Pericarps of Myriopteron extensum.
Ten novel C21 pregnane glycosides, extensumside C-L (1-10), were isolated as highly sweet-tasting substances from the edible pericarps of Myriopteron extensum (Wight) K. Schum by sensory-guided fractionation and purification. Their structures were determined through 1D and 2D NMR, such as HSQC, HMBC, 1H-1H COSY, HSQC-TOCSY, and ROESY, as well as other spectroscopic analysis combined with chemical evidence. These compounds shared the same aglycone, 3β,16α-dihydroxy-pregn-5-en-20-one, and contained the deoxysugar chain and the glucose chain which were linked to C-3 and C-16 of the aglycone, respectively. The sweetness potency was evaluated by a human sensory panel test and preliminary structure-taste relationship was discussed. The sweetness intensities of these compounds are between 50 and 400 times greater than that of sucrose. Furthermore, quantitation analyses of compounds 1, 3, 4, and 6 in different parts of M. extensum indicated that the concentrations of these sweet components in the pericarps are obviously higher than those in stems and roots.