Thông tin tài liệu
Farm Animal Welfare: Philosophical Aspects Paul B Thompson Michigan State University, East Lansing, Michigan, U.S.A INTRODUCTION Traditionally thought of as part of the art of husbandry, the welfare of farm animals has become a critical area of livestock production and animal science The notion of welfare is derived from economics and utilitarian philosophy Its application to animal production reflects that heritage Developing and applying measures of welfare continue to require philosophically based assumptions, working principles, and judgments WELFARE ETHICS AND ANIMAL AGRICULTURE Welfare is a normative or evaluative term indicating how well or poorly a creature does (e.g., fares) in a given situation or setting The term became especially important in the British utilitarian tradition of ethics and social thought made famous by Jeremy Bentham (1748 1832) and John Stuart Mill (1806 1873), by which conduct was evaluated in light of its impact on human welfare Many approaches in ethics hold that human conduct must abide by predetermined constraints In contrast, utilitarian ethics claim that actions or policies are justified only if they have the best possible impact on the happiness or satisfaction (e.g., welfare) of affected parties, without regard to whether conduct conforms to legal, religious, and customary rules and codes As early as 1789, Bentham argued that the concept of welfare applied to both human beings and nonhuman animals capable of suffering For a utilitarian, ethics demands that one anticipate the benefits and harms to everyone affected for each of one’s options, and then choose the option producing the greatest good for the greatest number Utilitarianism gave rise to the field of welfare economics, which developed economic tools for evaluating the costs and benefits of alternative social policies, especially those intended to secure the well-being of indigent people (hence the popular meaning of the word welfare) Welfare Economics Attempts to measure or quantify welfare are subject to a number of difficult conceptual and methodological prob356 lems, even when the problem is confined to human beings Economists have argued that market prices provide a measure of the relative value that human beings place on goods (such as food, automobiles, or entertainment) that are easily bought and sold, but concede that other goods (such as health, environmental quality, or community) resist the mechanisms of ordinary economic exchange Providing such goods may require a degree of cooperative effort that borders on coercion Furthermore, some people may be effectively excluded from participating in market exchange (either by inequities in law or poverty), and the impact that an activity or good has on their welfare will not be reflected in the market price Goods having an impact on welfare that is not reflected by market price are referred to as externalities in welfare economics The identification, conceptualization, and quantification of health, environmental, or social externalities can be confusing, contentious, and inherently philosophical Additional philosophical difficulties arise when one attempts to sum or compare impacts on welfare accruing to different parties Kenneth Arrow (b 1921) proved an impossibility theorem, showing that it is mathematically impossible to derive an optimal social welfare function (that is, a calculation of the greatest good for society as a whole) from measurements of the welfare of individuals.[1] For these reasons, welfare economics remains one of the most philosophical areas of modern economic theory.[2] Many of these issues carry over to any attempt to understand the welfare of animals Application to Farm Animals The externality model applies to the welfare of farm animals Historically, farm animals have been held as chattel by producers Concern for the welfare of farm animals has traditionally been understood as a personal ethical responsibility of individual owners However, as the livestock industries have become highly competitive, producers are under increasing pressure to utilize the most cost-effective methods for raising and handling animals Although some adverse effects on livestock affect producer profitability, those that not affect profitability represent costs that are borne by animals, rather than being internalized in those production costs that are eventually passed on to consumers These external costs costs Encyclopedia of Animal Science DOI: 10.1081/E EAS 120019596 Copyright D 2005 by Marcel Dekker, Inc All rights reserved Farm Animal Welfare: Philosophical Aspects above and beyond those reflected in the normal profitability of livestock farming represent the basic problem of farm animal welfare How should these external costs be understood, and what responses are appropriate? The model for answering these questions that has been most widely adopted in the animal sciences has been to utilize a blend of standard veterinary health indicators, physiological stress measures, behavioral studies, and cognitive performance measures to form an estimate of how animals are faring in a given setting This approach to animal welfare has been applied to develop comparative estimates of farm animal welfare relative to alternative housing and production methods, including cage and pen size, water and feed mechanisms, gestation stalls, and the use of methods for production practices such as beak trimming, milking, and molting (see Animal Welfare Science) Once such measures were available, one would then use them to reflect costs borne by animals in a given production system, and these costs could, in principle, be compared to costs and benefits that would be borne by humans in the form of higher production cost and increased food prices.[3,4] This general model follows the basic outline of utilitarian ethics in that each production option is evaluated in terms of its expected impact on the welfare of affected parties (human and animal), and then the option producing the greatest good is the one seen as ethically justified Philosophical Difficulties Historically, animal welfare scientists have not always agreed on how to prioritize the indicators listed earlier The use of multiple indicators to determine welfare also leads to an analogue of Arrow’s impossibility theorem: Since improvements in one parameter can be correlated with declining measurements in another, there may be no way to create a consistent cardinal ordering of animal welfare under a variety of different production regimes Another problem associated with comparing production systems is that situational features such as climate and especially husbandry practices may have more impact on the welfare of animals than the production systems that have been tested empirically Hence, whereas animal welfare science provides a basis for understanding how animals fare in production settings, well-known problems are associated with summing and comparing individual welfare measurements As such, like welfare economics, animal welfare is likely to remain dependent on philosophical value judgments The classic utilitarian response to externalities has been regulations that require producers to mitigate harm to others This allows the cost of mitigation to be inter- 357 nalized and reflected in the cost of producing goods However, many animal producers continue to see animal welfare as a personal ethical responsibility and see government intervention in their operations as a form of interference It may thus be necessary to interpret farm animal welfare as one among several elements that would need to be addressed in a complete approach to animal ethics Ethical responsibilities associated with traditional notions of stewardship of animals might provide a useful complement to welfare-based approaches to animal ethics.[5,6] Advocacy groups have often argued that a rights approach, stressing constraints on producer behavior, might be required Animal Rights Some would argue that if the problem consists in the fact that animal interests are external to decision making in animal agriculture, the most direct legal response is to provide an actionable basis for advocates to intervene in policy and production practices Recognizing animal rights as the basis for human’s ethical responsibility to animals provides philosophical support for legal action on behalf of animals Animal rights philosophy has been advocated by Tom Regan (b 1938), who argues that the utilitarian arguments in Peter Singer’s (b 1946) widely read book[7] not provide a strong enough basis for protecting animal interests.[8] Effective legal rights allow affected parties (or their representatives) recourse against harms or costs that are inflicted on them by others Once such rights are in place, affected parties may enter into negotiations for compensation, allowing formerly external costs to be reflected in normal economic activity Animal rights may thus represent an alternative response to the problem of external costs to animal welfare This intervention might take the form of government regulation of animal production, or the creation of new legal standing that would allow court cases to be brought on animals’ behalf.[9] It is not clear how such an approach would be operationalized as a response to problems in farm animal welfare One question concerns who would be entitled to represent the interests in a legal or regulatory proceeding If animal advocates were to take on this role, there would be a considerable shift in the property rights traditionally held by producers, and the economic repercussions of this shift might be considerable Furthermore, the rhetorical use of animal rights as a catch-phrase representing an extreme position on the human use of animals may serve as an additional political barrier to any use of rights reform as a strategy for addressing farm animal welfare As such, an animal rights approach represents at best one among many possible responses to resolving the problem 358 Farm Animal Welfare: Philosophical Aspects of farm animal welfare, rather than a clear alternative to utilitarianism may result in innovative approaches to problems in measuring animal welfare CONCLUSION REFERENCES Animal welfare can be understood as an external cost borne by animals and not reflected in the prices paid by food consumers in the industrial food system Animal scientists have developed a utilitarian approach to this problem by utilizing animal welfare science to quantify the costs to animals, whereas some animal advocates prefer a rights approach However, neither of these approaches escapes the need for judgment and assumptions about how to frame problems and interpret values At present there is no widely accepted or noncontroversial philosophical approach to augmenting scientific studies of animal welfare, nor is there a clear way to resolve conflicts between utilitarian and rights-based approaches Pragmatic ethics calls for systematic articulation, discussion, and debate over uneliminable subjective, interpretive, and judgmental assumptions Articulation of assumptions and opportunity to challenge and debate them at least offer the possibility of consensus solutions and Arrow, K Social Choice and Individual Values Wiley and Co: New York, 1951 Sen, A.K On Ethics and Economics Oxford U Press: Oxford, 1987 Rollin, B.E Farm Animal Welfare Iowa State U Press: Ames, 1995 Appleby, M.C What Should We Do About Animal Welfare? Blackwell Science: Oxford, UK, 1999 Fraser, D Animal ethics and animal welfare science: Bridging the two cultures Appl Anim Behav Sci 1999, 65, 171 189 Thompson, P.B Getting Pragmatic About Farm Animal Welfare In Animal Pragmatism: Rethinking Human Nonhuman Relationships McKenna, E., Light, A., Eds.; Indiana U Press: Bloomington, IN, 2004 Forthcoming Singer, P Animal Liberation Avon Books: New York, 1977 Regan, T The Case for Animal Rights U California Press: Berkeley, 1986 Wise, S.M Rattling the Cage: Toward Legal Rights for Animals Perseus Press: Cambridge, MA, 2000 Feed Quality: External Flow Markers Alexander N Hristov University of Idaho, Moscow, Idaho, U.S.A INTRODUCTION Tracers or markers are used to study digestion, intake, or pool sizes and kinetics of digesta fractions in specific organs or the entire digestive tract of farm animals Digesta kinetic analyses are integral parts of animal nutrition research Nutrients (and symbiotic microbial mass) are associated and leave digestive compartments with the fluid or the solid digesta phases Thus, the rate of flow of digesta dictates, in the large part, nutrient availability for growth and production This entry will briefly discuss the most common external markers used in animal nutrition research with particular emphasis on ruminant nutrition FLUID AND PARTICULATE EXTERNAL MARKERS In general terms, a tracer is a detectable substance added to a chemical, biological, or physical system to follow its process or to study distribution of the substance in the system.[1] An external marker is a substance that is either not present or present in minute concentration in the diet An ideal marker must: (a) not be absorbed throughout the digestive tract; (b) not affect or be affected by digestive processes, including microbial fermentation; (c) follow the kinetics of and not separate from the material/digesta phase it is to mark; and (d) have a specific and sensitive method of analysis.[2] Detailed reviews on marker use in animal nutrition have been published.[2–5] Passage rate and residence time of digesta can be determined from a given meal to which a unique marker has been applied Therefore, external markers and pulse dosing are the techniques of choice when digesta flow characteristics are studied most common approach is fractionation into fluid and solid phases The fluid phase includes not only solutes, but also small feed particles, which are densely populated with microbial cells and obey the kinetics of the fluid Fluid markers should behave as ideal solutes and have a molecular weight high enough not to be absorbed throughout the digestive tract A number of fluid markers have been proposed and employed with varying success Polyethylene glycol (PEG) with a molecular weight of 1000 Da or greater (usually 4000 Da) has been extensively, and relatively successfully, used as a solute marker Studies with rabbits and sheep, however, showed incomplete (95%) recovery in digesta and feces Reports also indicated that PEG was not completely associated with water in beet pulp tissues, can be precipitated by dietary tannins, and binds to particulate matter if digesta is frozen PEG is assayed by turbidimetry Complexes of cobalt (Co) and chromium (Cr) with ethylenediamine tetraacetic acid (EDTA)[6,7] occupy larger fluid space in the rumen and have practically replaced PEG as fluid markers Similar to PEG, both chelates are slightly absorbed (at approximately 5%) through the rumen wall Adsorption of Cr EDTA to particulate matter has been reported at low concentrations and is affected by osmotic pressure in the rumen, which could lead to overestimation of water flow Co EDTA is prepared as the sodium or lithium (Li) salt of the monovalent Co EDTA anion Both compounds are readily soluble in water, relatively easy to prepare with a yield of approximately 90% (the Li salt in the case of Co EDTA), and are stable on drying A common practice is to use Li/ Co EDTA as a fluid and Cr-mordanted fiber as a solid marker (see the following discussion) Cobalt and Cr are routinely analyzed by atomic absorption spectrophotometry, neutron activation, or plasma emission spectroscopy Particulate Markers Fluid Markers Digesta, particularly ruminal contents, is not a homogenous entity Digesta phases have different composition and flow characteristics, which necessitates a compartmental approach and the use of separate markers for as many digesta pools as can be reliably distinguished by physical or chemical means With ruminal contents, the Encyclopedia of Animal Science DOI: 10.1081/E EAS 120027391 Copyright D 2005 by Marcel Dekker, Inc All rights reserved Compared to solute markers, particulate digesta markers are considerably less reliable Problems related to recovery, migration, representativeness of labeled fraction kinetics, and effect on digestion and the ruminal ecosystem make the choice of particulate marker a difficult one Stained feed particles and synthetic organic materials such as plastic and rubber pieces, cotton knots, 359 360 charcoal, and others have been used as solid markers in the past Lack of reliable quantitative assays, different physical properties (specific gravity and size) than those of the particulate digesta fractions in the case of nonfeed materials, and uncertainty as to what extent particle kinetics represent the kinetics of the fraction they are intended to label have rendered these techniques of little value in animal nutrition research A variety of heavy metals and rare earth elements, particularly those forming strong bonds with feed/digesta particles, have been successfully employed as particulate markers An important prerequisite is that these elements are either not present or present in minimal concentration in soil and plants Metal oxides (Cr and titanium) have been proposed as digestibility markers Chromium sesquioxide (Cr2O3) is one of the most commonly used digestibility markers, but it is an unreliable passage marker because its physical properties and flow kinetics have little resemblance to the flow characteristics of any digesta fraction.[2] Chromium forms strong ligands with plant cell wall constituents, and Cr-mordanted fiber is used as a particulate flow marker.[7] Nonfiber substances are removed before binding in order to improve retention of Cr on the cell wall matrix Concentration of Cr, however, dramatically increases the density and reduces digestibility of the labeled particles It is recommended that the Cr concentration be reduced to 10 g/kg hay (or 23 g/kg feed pellets) in order to minimize the effect of the heavy metal on particle density.[4] Particle size of the Crmordanted fiber can also significantly affect the rate of passage Other metals such as ruthenium (Ru) and hafnium (Hf) have been proposed as particulate markers Ruthenium is usually used in the form of Ru phenanthroline (Ru phe or 103 Ru phe) in low concentration, which reportedly does not adversely affect microbial fermentation in the rumen.[8] Ruthenium has a strong affinity for particulate matter, but no specific affinity for binding to fiber fractions, and a very high rate of recovery in the digestive tract Hafnium has strong binding properties, is resistant to displacement at low pH,[9] and can be a suitable particulate flow marker (specifically for the more acidic segments of the gastrointestinal tract) if applied at low concentrations in order to minimize the effect on particle density and digestibility Various rare earth elements (cerium, europium, ytterbium, terbium, samarium, lutetium, lanthanum, samarium, neodymium, dysprosium, erbium) have been used as particulate markers These elements are inert, indigestible, and, if feed/digesta samples are properly labeled (and within the normal pH range for ruminal digesta), are relatively resistant to displacement from the treated material.[5] Dissociation in the acidic, postruminal Feed Quality: External Flow Markers sites is of little importance in digesta flow studies The number of acid-resistant binding sites for rare earths on feedstuffs is low (2 to 30 mg rare earth/g DM) and should not be exceeded.[9] Relatively large amounts of feed have to be labeled in order to achieve sufficiently high marker concentrations in digesta.[5] The strength of binding will depend on the application method used Simple spraying will saturate both strong and weak binding sites and will result in significant marker migration in the rumen A strong relationship between gastrointestinal mean residence time of La, Yb, and Tb and potentially indigestible fiber was established for cottonseed-based diets.[10] The most commonly used rare earths give similar digesta kinetic estimates and can be used to label different particles[11] or dietary ingredients Ytterbium is perhaps the element of choice since it is relatively inexpensive, has a low analytical detection limit, and forms strong complexes with feed particles Rare earths can be assayed by neutron activation analysis, plasma emission spectroscopy, and flameless atomic absorption spectroscopy Even-chain n-alkanes occur in low concentrations in plants and were used as particulate phase markers delivered by various techniques (in most cases, with cellulose as a carrier), i.e., gelatin capsules, impregnated filter paper, or grass particles, or by being sprayed onto the forage Recovery in the feces of the most commonly used external alkane marker (dotriacontane, C32) was around 87%.[4] Internal markers flow with undigested feed residues and not affect particle digestion kinetics, but they are not unique to a given meal and can be used as flow markers only with rumen evacuation or slaughter techniques Indigestible fractions of plant cell walls can be intrinsically labeled with stable or radioactive isotopes of carbon (C)[12] or with 15N (ADF-15N)[13] and used as particulate flow markers Both C and N are incorporated in indigestible as well as digestible fractions, and care must be taken to remove potentially digestible C or N before analysis CONCLUSIONS Flow kinetics of the digesta fluid phase can be reliably determined using EDTA complexes of Cr or Co A number of solid external markers have been utilized with variable success in animal nutrition research Mordanting fiber with heavy metals can potentially affect digestion and flow characteristics of the labeled material When properly used, rare earth elements are the particulate marker of choice Intrinsic labeling of forage plant cell Feed Quality: External Flow Markers walls with stable isotopes, particularly 15N, provides the advantage of being unique to a given meal without the negative impact on particle density and digestion associated with the most common external markers 361 REFERENCES Tracer Encyclopædia Britannica; Encyclopædia Bri tannica Premium Service, Dec 20, 2003 Owens, F.N.; Hanson, C.F External and internal markers for appraising the site and extent of digestion in ruminants J Dairy Sci 1992, 75 (9), 2605 2617 Kotb, A.R.; Luckey, T.D Markers in nutrition Nutr Abstr Rev 1972, 42 (3), 813 845 Marais, J.P Use of Markers In Farm Animal Metabolism and Nutrition; D’Mello, J.P.F., Ed.; CABI Publishing: Wallingford, UK, 2000; 255 277 Ellis, W.C.; Matis, J.H.; Hill, T.M.; Murphy, M.R Methodology for Estimating Digestion and Passage Kinetics of Forages In Forage Quality, Evaluation and Utilization; Fahey, G.C., Jr., Collins, M., Mertens, D.R., Moser, L.E., Eds.; American Society of Agronomy: Madison, WI, USA, 1994; 682 756 Downes, A.M.; McDonald, I.W The chromium 51 com plex of ethylenediamine tetraacetic acid as a solute rumen marker Brit J Nutr 1964, 18 (1), 153 162 10 11 12 13 Uden, P.; Colucci, P.E.; Van Soest, P.J Investigation of chromium, cerium and cobalt as markers in digesta Rate of passage studies J Sci Food Agric 1980, 31 (7), 625 632 Tan, T.N.; Weston, H.; Hogan, J.P Use of 103Ru labelled tris (1,10 phenanthroline) ruthenium (II) chloride as a marker in digestion studies with sheep Int J Appl Radiat Isot 1971, 22 (5), 301 308 Worley, R.; Clearfield, A.; Ellis, W.C Binding affinity and capacities for ytterbium (3 + ) and hafnium (4 + ) by chemical entities of plant tissue fragments J Anim Sci 2002, 80 (12), 3307 3314 Ellis, W.C.; Wylie, M.J.; Matis, J.H Validity of specifi cally applied rare earth elements and compartmental models for estimating flux of undigested plant tissue residues through the gastrointestinal tract of ruminants J Anim Sci 2002, 80 (10), 2753 2758 Hristov, A.N.; Ahvenjarvi, S.; Huhtanen, P.; McAllister, T.A Composition and digestive tract retention time of ruminal particles with functional specific gravity greater or less than 1.02 J Anim Sci 2003, 81 (10), 2639 2648 Smith, L.W A review of the use of intrinsically 14C and rare earth labeled neutral detergent fiber to estimate particle digestion and passage J Anim Sci 1989, 67 (8), 2123 2128 Huhtanen, P.; Hristov, A.N Estimating passage kinetics using fiber bound 15N as an internal marker Anim Feed Sci Technol 2001, 94 (1 2), 29 41 Feed Quality: Natural Plant Markers—Alkanes Hugh Dove CSIRO Plant Industry, Canberra, Australia Robert W Mayes Macaulay Institute Aberdeen, U.K INTRODUCTION The measurement of diet composition and total intake of grazing animals has always been difficult and errorprone, mainly because of limitations in the available techniques A relatively recent development has been the use of plant wax compounds, especially the saturated hydrocarbons (alkanes), as fecal marker compounds that can be measured in dietary components and feces, and that permit more accurate estimates of diet composition and intake THE CONCEPT OF FECAL MARKERS Fecal markers can be defined as substances of dietary origin found in the feces (often referred to as internal markers) or substances that are absent from the diet (or present in very small amounts), but which are given by oral dosing (external markers) An ideal marker is one that: 1) is completely recovered in the feces; 2) is chemically discrete and accurately quantifiable; 3) is inert, with no effect on digestion or passage through the gut and no toxic effect; and 4) is physically similar to the contents of the digestive tract.[1,2] To date, no ideal marker has been found; the suitability of existing markers depends on the purpose to which they are put Main Uses of Fecal Markers The fecal output (FO) of an animal depends on its intake (I) and the proportion of this that remains undigested This proportion can be calculated as (1 À D), where D is the digestibility of the diet (D) In mathematical terms: FO ¼ I Â ð1 À DÞ Rearranging this relationship provides the major approach to estimating intake: twice daily, or in the form of a controlled-release device, which is dosed once and then resides in the digestive tract, releasing a known daily dose of marker The FO is estimated from the dilution of the marker dose in feces Indigestible substances in the diet can also be used as fecal markers In this case, they are functioning as internal markers The increase in the fecal concentration of marker relative to the concentration in the diet provides an estimate of digestibility (D), which, in the previous equation, also allows the estimation of intake Many dietary substances have been evaluated as digestibility markers, and none has proved wholly successful Consequently, digestibility has routinely been determined using laboratory procedures imitating the process of digestion (in vitro digestibility) ALKANES AS NATURAL PLANT MARKERS Plant wax compounds offer major advantages as possible fecal markers They are a readily analyzed, normal part of the diet, and are relatively inert, with no adverse effects at normal intakes Moreover, the patterns of the different plant-wax compounds differ between plant species, providing a means of identifying the species composition of the diet Previous fecal markers have not permitted this Plant Wax Components Almost all higher plants have, on their outer surfaces, a layer of epicuticular wax containing a complex mixture of aliphatic lipids The major components of plant wax are listed in Table 1; most classes of compounds are present as mixtures of individual compounds with differing carbon chain length Only the alkanes, wax esters, and the long-chain fatty acids and alcohols will be discussed in detail I ẳ FO=1 Dị Hydrocarbons External markers have been used for many years to determine FO They are given as an oral dose once or Hydrocarbons are present in the cuticular wax of most plants, mainly as mixtures of n-alkanes, but are rarely the 362 Encyclopedia of Animal Science DOI: 10.1081/E EAS 120027390 Copyright D 2005 by Marcel Dekker, Inc All rights reserved Feed Quality: Natural Plant Markers—Alkanes 363 Table Major components of plant epicuticular wax Component Remarks Hydrocarbons Saturated straight chain hydrocarbons (n alkanes) and branched chain alkanes; unsaturated hydrocarbons (alkenes) Predominantly odd numbered carbon chains Esters of long chain fatty acids and fatty alcohols (mainly even numbered carbon chains C32 C64) Predominantly even numbered carbon chains Predominantly even numbered carbon chains Quantitative analytical procedure not yet established Quantitative analytical procedure not yet established Potentially difficult to separate from alcohols Wax esters Free long chain fatty alcohols Free long chain fatty acids Long chain fatty aldehydes and ketones b diketones Sterolsa a Not part of plant wax, but extracted together with plant wax components major component of plant wax Their carbon chain lengths range from C21 to C37, with over 90% by weight having odd-numbered carbon chains In pasture plants, C29, C31, and C33 predominate Alkanes are easily analyzed and relatively inert, and thus have received the most attention as potential fecal markers of fatty acids and alcohols, plus their wide variation in pattern between plants species means that the compounds have great potential to complement n-alkanes as diet composition markers USING n -ALKANES TO ESTIMATE DIET COMPOSITION Wax Esters, Fatty Acids, and Alcohols Wax esters arise from linkages between long-chain fatty acids and alcohols, and are usually the main components of cuticular wax Free (unesterified) long-chain fatty acids and alcohols are also usually present Existing procedures for analyzing plant wax markers hydrolyze wax esters into their component fatty acids and alcohols, and thus quantify total fatty acids and alcohols The esters, free fatty acids, and alcohols have therefore not yet been evaluated as markers The relatively high fecal recoveries Cuticular wax alkane patterns differ markedly between plant species (Table 2) The fecal alkane pattern will therefore closely reflect the combination of plant species consumed by the animal and can be used to estimate this, with one proviso: While the fecal recovery of alkanes is high, it is not complete and generally increases with increasing carbon chain length.[3] Before relating fecal alkane patterns to those in the dietary components, it is therefore necessary to correct for differential recoveries of individual alkanes.[1,3] Table Patterns of the major n alkanes in a selection of pasture and browse species consumed by livestock Alkane (mg/kg dry matter) Plant species Grasses Perennial ryegrass (Lolium perenne) Cocksfoot (Dactylis glomerata) Deschampia cespitosa Legumes White clover (Trifolium repens) Subterranean clover (T subterraneum) Alfalfa (Medicago sativa) Browse species Mulga (Acacia aneura) Willow (Salix sp.) Juniper (Juniperus communis) C25 C27 C29 C31 C33 25 20 43 122 38 384 208 58 657 117 21 95 29 16 36 92 250 202 67 74 324 10 21 226 38 119 162 126 74 23 1197 63 73 1646 19 477 17 364 Several mathematical packages are available for calculating diet composition from alkane patterns in feces and the plant species on offer In general, these return very similar results.[1] In controlled comparisons with relatively simple mixtures (< species), alkane-based diet compositions have shown excellent agreement with known diet compositions.[1,3] However, as the number of species to be separated approaches the number of available alkanes, it becomes increasingly difficult to reliably estimate diet composition; the number of dietary components cannot exceed the number of available markers The use of long-chain alcohols and fatty acids, in addition to nalkanes, will probably help to overcome this limitation and allow more species to be discriminated A point to note is that many supplementary feeds also contain alkanes, or can be labeled with them The proportion of supplement in the total intake can thus be estimated by treating it as one of the species in the diet.[1] USING n-ALKANES TO ESTIMATE DIGESTIBILITY AND INTAKE Together with diet composition and the nutrient content of the dietary components, the total intake of the animal and whole-diet digestibility determine the intake of nutrients and are thus key determinants of the productivity of grazing livestock To determine digestibility, fecal and dietary concentrations of a natural alkane (e.g., C31 or C33) can be used as an internal marker, as described earlier; corrections for incomplete fecal recovery would be necessary If the animals are also dosed with an evenchain alkane (e.g., C32) as an external marker to determine fecal output, intake can also be estimated As with the digestibility marker, the fecal output estimate would be biased unless a fecal recovery correction were applied However, the conceptual leap that permitted the use of alkanes to estimate intake was the realization that if the fecal recoveries of the dosed and natural alkane are the same, unbiased estimates of intake can be obtained without fecal recovery corrections;[4] the biases in the digestibility and fecal output estimates will cancel out Furthermore, it is not necessary for the dosed alkane to be absent from the diet Comparative studies indoors have demonstrated that dosed C32 alkane and natural C33 alkane had very similar fecal recoveries, resulting in very close agreement between actual intake and that estimated using these alkanes.[1,3] The combination of dosed (evenchain) alkanes and natural (odd-chain) alkanes has now Feed Quality: Natural Plant Markers—Alkanes become a standard method for estimating intake, and a single-dose device providing an accurate daily dose of alkane is commercially available for ruminant livestock OTHER USES OF ALKANE MARKERS Natural alkanes are part of the plant material and remain attached to it during transit through the digestive tract This means they could be used as markers for estimating the flow of digesta in different parts of the tract The passage rate of material through the gut could also be determined from the levels of radioactively labeled alkanes, in a series of feces samples taken after a single feed of labeled plant material CONCLUSION Experiments have shown that plant wax alkanes permit an accurate estimate of total diet digestibility and intake, plus an estimate of the species composition of the diet It thus becomes possible to define the nutrient intake of the grazing animal with much greater accuracy, and also to define those parts of the plant biomass preferred by the animals This has ramifications for the sustainability of the system, by identifying plants at risk of overgrazing, and also for plant breeding, by indicating which plants the animals prefer Similarly, since the proportion of supplement in the total intake can be defined, the interaction between supplement and herbage can be quantified much better, with major ramifications for the management of supplementary feeding, one of the largest discretionary costs in grazing systems REFERENCES Mayes, R.W.; Dove, H Measurement of dietary nutrient intake in free ranging mammalian herbivores Nutr Res Rev 2000, 13 (1), 107 138 Kotb, A.R.; Luckey, T.D Markers in nutrition Nutr Abs Rev 1972, 42 (3), 813 845 Dove, H.; Mayes, R.W Plant wax components: A new approach to estimating intake and diet composition in herbivores J Nutr 1996, 126 (1), 13 26 Mayes, R.W.; Lamb, C.S.; Colgrove, P.M The use of dosed and herbage n alkanes as markers for the determination of herbage intake J Agric Sci., Camb 1986, 107 (1), 161 170 Feed Quality: Natural Plant Markers—Indigestible Fiber William C Ellis J H Matis Texas A&M University, College Station, Texas, U.S.A H Lippke Texas Agricultural Experiment Station, Uvade, Texas, U.S.A INTRODUCTION Plant fiber (NDF) is the major source of potentially digested nutrients for ruminants, and variations in NDF digestibility are a major factor determining feed quality, especially that of foragers The NDF consists of two conceptual entities: potentially digestible NDF (PDF) and indigestible NDF (IDF) Being indigestible, the level of IDF in the feed is an important predictor of feed quality, albeit negative Thus, digestibility of PDF determines the digestibility of NDF Additionally, IDF is nutritionally important as an indigestible natural plant marker intrinsic to the feed that can be used to estimate digestibility of PDF and other analytically definable feed entities Because of the dynamic physical and chemical interactions involved in ruminal microbial digestion (hydrolysis) of PDF, one must distinguish between conceptual and analytically definable entities of PDF and IDF in their application to ruminant nutrition INDIGESTIBLE FIBER (IDF) Fiber is commonly determined as the dry matter (DM), or preferably the organic matter (OM), insoluble after extraction with a neutral detergent solvent The NDF consists of the structural carbohydrates cellulose and hemicelluloses and potentially indigestible entities such as lignin and lignified structural carbohydrates Conceptually, NDF can be divided into PDF and IDF Analytically, IDF is estimated by fitting kinetic models[1,2] that describe the disappearance of NDF over digestion time The IDF is estimated as the undigested NDF remaining when no further disappearance of NDF is detectable by the kinetic model Alternatively, IDF is analytically defined as the undigested NDF remaining after exposure to agents of digestion for a sufficient time (6 10 days) to approximate complete digestion of PDF.[3] The PDF is analytically defined as the difference between NDF and IDF Thus, by Encyclopedia of Animal Science DOI: 10.1081/E EAS 120019601 Copyright D 2005 by Marcel Dekker, Inc All rights reserved difference, the quantitative estimation and utility of both IDF and PDF are inseparable CHEMICAL AND PHYSICAL DIGESTION OF NDF Chemical digestion (hydrolysis) of PDF is achieved by enzymes associated with the microbial cells of fibrolytic microbes These enzymes physically attach to and hydrolyze specific plant tissue surfaces of PDF.[4] Digestion of PDF is via erosion from the surface attachment site Therefore, rate and extent of digestion of PDF are functions of 1) the microbially accessible surface area of plant tissue fragments;[5] 2) the abundance of PDF on such surfaces; 3) the rate of exposure of new surface levels of PDF by ruminative mastication;[6] and 4) an adequate ruminal flux of ruminal degraded protein (RDP) for growth of the fibrolytics Newly ingested fragments have intrinsic buoyancy due to the structure of large fragments of ingestive mastication Intrinsic buoyancy of vascular tissues within the relatively large fragments of ingestive mastication is the initial force that positions younger fragments of ingestive mastication into flow paths involving ruminative mastication With microbial colonization and residence time in the lag-rumination pool, aging fragments undergo agedependent changes in their masticated size, rate of exposure of new surfaces of microbially accessible PDF (maPDF), and fermentation-based buoyancy Collective changes of ruminative mastication, fermentation-based buoyancy, and mass action competition among fragments of similar buoyancy constrain ruminal escape of individual fragments until fragments’ surface level maPDF is extensively digested (mean of 90± 5%) (Fig 1A) and fragments are physically masticated to relatively small fragments We propose[7,8] that the fractional rate of digestion of maPDF provides the fermentation-based buoyancy gradients that constrain the fractional rate of escape of IDF from the rumen (Fig 1B) 365 430 Fur and Mink Fig Modern mink farms raise their animals in clean, airy, and well lit sheds (View this art in color at www.dekker.com.) number of kits per litter, and freedom from disease To speed up selection, farmers sometimes start by concentrating on one trait, such as color, before proceeding to the next Many farmers also use what is called the index method to aid selection This allows them to combine several traits, perhaps with different weightings, into a single index figure that is then used to rank the animals In early spring, cages are fitted with nest boxes filled with warm bedding such as shredded paper or grass straw, and breeding cards, containing information from the selection process, are over the cages Prior to mating, males and females are often kept in separate parts of the shed, and females are generally restricted in their feed for a few weeks to keep them in active condition The males are then introduced to their chosen mates, with a mature male typically servicing 10 females and a kit male servicing It is particularly important to ensure the males are fertile, and this may be done by extracting fluid from a female’s vagina right after mating and examining it to determine the number of live, active sperm DIET AND NUTRITION Feed represents the single largest expense in mink production, so the feeding program is crucial to a farm’s profitability Because of significant differences in the nutritional needs of mink from those of other domesticated animals, mink farmers have been unable to rely on information gathered for other species in developing diet formulations, and have had to a lot of work for themselves As carnivores, mink require a diet derived primarily from animal sources, be they meat, fish, poultry, or dairy Many mink farms base their feed programs on expired produce originally intended for humans, or on by-products collected from packing plants The food producers also benefit because the amount of waste they must dispose of is reduced Diet formulations are dictated to a great extent by the length of the mink’s digestive tract, the shortest of any domesticated species Food can pass through a mink in as little as 2.5 hours, compared with about 72 hours for cattle, which means their diet must be highly digestible The major nutritional needs of mink, like other species, are protein and energy, but the quantities and form in which they are ingested demand special attention A mink’s protein needs are high because, in addition to providing for growth and maintenance of body tissues, it must also provide for fur production Accordingly, proteins fed to mink should be of high biological value, supplying a good mix of the essential amino acids Muscle tissues require considerable lysine and methionine, while fur production needs methionine, arginine, and cystine Quality protein can be derived from eggs, fish and meat products, and dairy products such as cheese Conventional mink diets contain such protein sources in a fresh state, often purchased in bulk and placed in cold storage until they are needed Most farm animals obtain their energy from carbohydrates, but mink use them to a much lesser extent, deriving most of their energy from dietary fats and oils Such feedstuffs, however, must be stored correctly or they will Fur and Mink Fig The color and quality of a mink’s pelt are good indicators of its health and diet The pelt at left shows graying and banding of the fur, indicating the presence of avidin in the diet The pelt at center has been parted to show a condition known as ‘‘cotton fur,’’ a deficiency in melanin formation absent in normal mink (right) (View this art in color at www.dekker.com.) oxidize and turn rancid Vegetable oils are not too problematic because they usually contain sufficient vitamin E, an antioxidant, to retard the onset of rancidity Fish oils, however, are high in unsaturated fatty acids, which are easily oxidized, and lack the protective levels of vitamin E Supplementary minerals and vitamins can be supplied naturally as components of a mink’s diet, or added in synthetic form Minerals such as calcium and phosphorus, for example, can be derived either from bone-in products, such as whole fish, or by adding dicalcium phosphate to the feed Most of the vitamin requirements, meanwhile, can be met by using so-called ‘‘protective feeds.’’ One of the most popular of these is liver, usually from beef cattle or chickens, and many farmers include liver in amounts of 5% or even 10% of the diet as a safety measure Mink farmers usually calculate dietary requirements for chemical nutrients based on the published works of animal nutritionists.[2,3] They then set about gathering appropriate raw materials at the best prices, often showing great ingenuity in formulating diets from a wide range of feeds and by-products Sometimes farmers form feed cooperatives to achieve economies of scale, and take delivery every other day or so of however much feed they need 431 In the quest for diet formulations that are both nutritious and economical, inevitably some diet-related problems have been identified in mink (Fig 2) One example is ‘‘cotton fur,’’ a bleached-out and consequently worthless fur condition, which has been linked to the presence in the diet of a substance that interferes with iron metabolism Found in some fish such as hake, this substance prevents the formation of melanin, a dark fur pigment Another is ‘‘fur graying’’ caused by the presence in the diet of avidin, found particularly in turkey eggs, which creates a deficiency of the B vitamin biotin The U.S fur industry has formed the Mink Farmers’ Research Foundation, which sponsors research to solve and advise on such problems In recent years, considerable effort has been expended on developing dry feeds for mink that meet the requirements for both growth and furring The incentive here is to reduce the cold storage costs associated with fresh feed, and many farms now use dried, pelleted feeds at some time of the year CONCLUSION Mink farming differs in major ways from other kinds of livestock production due to the distinct needs of these carnivores and also the nature of the end product Raising an animal for its fur involves considerations not shared by producers of meat, milk, or eggs Yet successful mink farmers also follow rules common to all livestock producers The finest furs come about only by selecting animals with the best genes, and then providing proper nutrition and high standards of animal welfare REFERENCES Ness, N.; Einarson, E.; Lohi, O Beautiful Fur Animals and their Colour Genetics; SCIENTIFUR: Hillerod, Denmark, 1988 Ensminger, M.; Oldfield, J.; Heineman, W Feeds and Nutrition, 2nd Ed.; Ensminger Publishing: Clovis, CA, 1990; 1145 1168 Nutrient Requirements of Mink and Foxes, 2nd Revised Ed.; National Research Council, National Academy of Sciences: Washington, DC, 1982; 72 Future of Animal Agriculture: Demand for Animal Products Christopher L Delgado International Food Policy Research Institute (IFPRI), Washington, D.C., U.S.A International Livestock Research Institute (ILRI), Nairobi, Kenya INTRODUCTION From the beginning of the 1970s to the mid-1990s, meat consumption in developing countries increased by 70 million metric tons (mmt), almost triple the increase in developed countries, and consumption of milk by 105 mmt of liquid milk equivalents (LME), more than twice the increase that occurred in developed countries The market value of that increase in meat and milk consumption totaled approximately $155 billion (1990 US$), more than twice the market value of increased cereals consumption under the better-known Green Revolution in wheat, rice, and maize The population growth, urbanization, and income growth that fueled the increase in meat and milk consumption are expected to continue well into the new millennium THE LIVESTOCK REVOLUTION These changes create a veritable Livestock Revolution propelled by demand.[1] People in developing countries are increasing their consumption from the very low levels of the past, and they have a long way to go before coming near developed country averages In developing countries, people consumed an annual average in 1996 1998 of 25 kg/capita meat and 44 kg/capita milk, one-third the meat and one-fifth the milk consumed by people in developed countries Nevertheless, the caloric contribution per capita of meat, milk, and eggs in developing countries in the late 1990s was still only a quarter that of the same absolute figure for developed countries and, at 10%, accounted for only half the share of calories from animal sources observed in the developed countries.[1] For present purposes, developed countries include Western Europe and Scandinavia, North America, Eastern Europe and the former Soviet Union, Japan, Malta, Israel, and South Africa All others are classified as developing countries Per capita consumption is rising fastest in regions where urbanization and rapid income growth result in people adding variety to their diets Across countries, per capita consumption is significantly determined by average per capita income, and aggregate consumption grows 432 fastest where rapid population growth augments income and urban growth.[2] Since the early 1980s, total meat and milk consumption grew at and 4% per year, respectively, throughout the developing world (Table 1) In East and Southeast Asia where income grew at 8% per year between the early 1980s and 1998, population at 3% per year, and urbanization at 6% per year meat consumption grew between and 8% per year.[1] China plays a dominant role on the meat side The share of the world’s milk consumption rose from 34 to 44% Pork and poultry accounted for 76% of the large net consumption increase of meat in developing countries from 1982 1984 to 1996 1998 Conversely, both per capita and aggregate milk and meat consumption stagnated in the developed world, where saturation levels of consumption have been reached and population growth is small Whether these trends will continue was explored in 1998 with the International Food Policy Research Institute’s (IFPRI) International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT), a global food model.[4,5] RISING CONSUMPTION OF MEAT AND MILK TO 2020 The IMPACT model projects developing countries aggregate consumption growth rates of meat and milk separately to be 3.0 and 2.9% per year, respectively, over the 1996/1998 to 2020 period, compared to 0.8 and 0.6%, respectively, in the developed countries Aggregate meat consumption in developing countries is projected to grow by 106 mmt between the late 1990s and 2020, whereas the corresponding figure for developed countries is 19 mmt (Table 2) Similarly, additional milk consumption of 32 mmt of liquid milk equivalents (LME) in the developed countries will be dwarfed by the additional consumption of 177 mmt in developing countries In the developing countries, 71% of the additions to meat consumption are from pork and poultry; in the developed countries, the comparable figure is 74% Poultry consumption in developing countries is projected to grow at 3.9% per annum through 2020, followed by Encyclopedia of Animal Science DOI: 10.1081/E EAS 120019628 Copyright D 2005 by Marcel Dekker, Inc All rights reserved Future of Animal Agriculture: Demand for Animal Products 433 Table Per capita meat and milk consumptiona by region, 1983 and 1997 Meatb 1983d Milkc 1997 Region China Other East Asia India Other South Asia Southeast Asia Latin America WANAf Sub Saharan Africa Developing world Developed world United States World 1983 1997 15 46 47 10 93 86 32 35 195 237 76 19 62 63 12 112 73 30 43 194 257 77 (kg) 16e 22 11 40 20 10 14 74 107 30 43 31 18 54 21 10 25 75 120 36 a Consumption is direct use as food, uncooked weight, bone in Beef, pigmeat, sheep and goat meat, and poultry c Includes cow and buffalo milk and milk products used as human food, in liquid milk equivalents d Dates are three year moving averages centered on the year shown e Values are three year moving averages centered on the year shown, calculated from data in FAO 2002 f Western Asia and North Africa (From Ref 3.) beef at 2.9% and pork at 2.4% In the developed countries, poultry consumption is projected to grow at 1.5% per annum through 2020, with other meats growing at 0.5% or less (Table 2) As the growth rates in Table suggest, high growth in consumption is spread throughout the developing world and is in no way limited to China, India, and Brazil, although the sheer size and vigor of those countries will mean that they will continue to increase their dominance of world markets for livestock products Real beef prices fell by a factor of three from 1970/ 1972 to 1996/1998 IMPACT projects the expected change in real prices to 2020, relative to 1996/1998 The overall picture for 2020 is a noticeable decline for wheat and rice (8 and 11%, respectively), a similar decline for milk (8%), more modest decreases for meats (3%), and stability or slight increases for feedgrains (+ 11 and À 4% for maize and soybeans, respectively).[1] The Livestock Revolution will also cushion, if not prevent, the further fall in real global livestock prices b CONCLUSIONS The demand-driven future of animal agriculture includes both opportunities and perils The principal conclusion of the most recent projections is to confirm the view that the Table Food consumption trends of various livestock products projected to the year 2020a,b Per capita consumption Total consumption Region Developed world Beef Pork Poultry Meat Milk Developing world Beef Pork Poultry Meat Milk a Projected growth of consumption 1997 2020 (%/year) 1997c 0.5 0.4 1.5 0.8 0.6 30 36 28 98 251 34 39 39 117 286 40 33 36 35 43 23 28 22 75 194 25 29 29 87 210 2.9 2.4 3.9 3.0 2.9 27 47 29 111 194 52 81 70 217 375 61 67 64 65 57 10 25 43 13 11 36 62 2020 (million mt) % of world total 2020 (%) 1997c 2020 (kg) See notes to Table for definitions The 2020 projections are from the July 2002 version of the IMPACT model c Total and per capita consumption for 1997 are calculated from FAO 2002 and are three year moving averages centered on 1997 (From Refs and 5.) b 434 Future of Animal Agriculture: Demand for Animal Products Table Projected food consumption trends of meat and milk, 1997 2020a,b Total consumption in 2020 Projected annual growth 1997c 2020 Meatd Region China India Other East Asia Other South Asia Southeast Asia All of Latin America Brazil alone WANAe Sub Saharan Africa Developing world Developed world World Milk Meat (%/year) 3.1 3.5 3.2 3.5 3.4 2.5 2.4 2.7 3.2 3.0 0.8 2.1 Milk Per capita consumption in 2020 Meat (million mt) 3.8 3.5 2.5 3.1 3.0 1.9 1.8 2.3 3.3 2.9 0.6 1.7 107 10 19 46 20 13 11 217 117 334 Milk (kg) 24 133 42 12 85 30 42 35 375 286 660 73 54 13 30 70 94 26 12 36 86 45 16 105 29 82 19 130 145 82 37 62 210 89 a See Table for product definitions Projections are from the July 2002 version of IMPACT c 1997 is the average of 1996 1998 d Total and per capita meat consumption for 1997 are annual averages of 1996 to 1998 values e Western Asia and North Africa (From Refs and 5.) b Livestock Revolution in developing countries will continue at least until 2020 and will increasingly drive world markets for meat, milk, and feed grains Whether it is a good thing is not the issue; it is a phenomenon that will occur Meat and milk production increases in developing countries will largely match the big consumption increases, and meat exports from Latin America to Asia will soar Even so, for the large majority of people in developing countries, consumption levels will remain very low, at 36 kg of meat per capita on average in 2020 (compared to 87 kg per capita in the developed countries as a whole) Average consumption in poor rural areas will surely be much lower than this, and especially for poor people Protein and micronutrient deficiencies, which tend to disappear with increased consumption of livestock products, will likely remain widespread in developing countries The rapidly growing demand for livestock products in developing countries is a rare opportunity for smallholder farmers to benefit from a rapidly growing market, and for their families to have a viable source of much-needed micronutrients and dense calories The worst thing that agencies targeted to poverty reduction and rural development can is to cease public investments that facilitate sustainable small-operator forms of market-oriented livestock production Lack of action will not stop the Livestock Revolution, but by abandoning the field to big industrial farming operations concentrated around large cities, it will help ensure that the form it takes is less favorable for poverty alleviation, better nutrition, and health ACKNOWLEDGMENTS This article draws on fruitful collaboration over several years with Mark Rosegrant of IFPRI, creator of the IMPACT global food model Greater detail on the results of that collaboration can be found in Refs and 6, and in the IMPACT model.[4,5] REFERENCES Delgado, C A food revolution: Rising consumption of meat and milk in developing countries J Nutri 2003, Nov., 133 (11 Supplement II) Cranfield, J.A.L.; Hertel, T.W.; Eales, J.S.; Preckel, P.V Future of Animal Agriculture: Demand for Animal Products Changes in the structure of global food demand Am J Agric Econ 1998, 80, 1042 1050 Food and Agriculture Organization of the United Nations FAOSTAT Statistical Database; FAO http://faostat.fao.org/ default.htm (accessed various months, 2002) Rosegrant, M.W.; Praisner, M.; Meijer, S.; Witcover, J Global Food Projections to 2020: Emerging Trends and Alternative Futures; International Food Policy Research Institute: Washington, DC, 2001 Rosegrant, M.; Meijer, S.; Cline, S International Model 435 for Policy Analysis of Agricultural Commodities and Trade (IMPACT): Model Description; International Food Policy Research Institute: Washington, D.C., 2002 http://www ifpri.org/themes/impact/impactmodel.pdf Accessed June 2003 Delgado, C.; Rosegrant, M.; Steinfeld, H.; Ehui, S.; Courbois, C Livestock to 2020: The Next Food Revo lution In Food, Agriculture, and the Environment Dis cussion Paper 28; International Food Policy Research Institute: Washington, DC, 1999 Future of Animal Agriculture: Market Strategies Wayne D Purcell Virginia Tech, Blacksburg, Virginia, U.S.A INTRODUCTION Animal agriculture is moving from commodity products to consumer-driven product lines As part of the transformation, the historical price-driven systems are being replaced by contracts, vertical alliances, and other forms of nonprice coordination and quality control It is likely that the moves away from a price-driven marketplace will continue Market strategies will have to change The objective here is to explain why the transformation is occurring and to suggest strategies for the future ECONOMIC SETTING OF ANIMAL AGRICULTURE Animal agriculture is a textbook illustration of an atomistic economic setting There are many small producers at the farm level in cattle, hogs, and sheep The individual producer is a price taker and has no ability to command a price that ensures costs will be covered In recent research, the average per-head profit for cattle feeding activities during the 1990s was estimated at À $4.27.[1] Profits at the cow-calf level are variable, ranging in recent decades from $80 per cow in 1990 1991 to À $75 in 1996.[2] Returns to producers will be variable as cycles run their course, even if demand is constant Since the late 1970s, demand has not been constant Demand for beef declined each year from 1980 through 1998, and demand for pork declined through 1995 (demand indices at www.aaec vt.edu/rilp) Most researchers attribute the declines to a divergence between the fresh product offering and changing consumer preferences.[3] Price signals to prompt changes in what producers offer have not worked Important product attributes such as tenderness in beef have not been incorporated into the quality grades The pricing system cannot motivate needed genetic and management changes at the producer level when important product attributes are not identified The beef and pork sectors produced commodity product during the 1980s and into the 1990s and demand languished Conversely, the poultry sector grew during the 1980s and 1990s as investments were attracted by profit 436 opportunities The reduction in per-capita consumption of beef from 94.5 lb in 1976 to 67.4 lb in 2002 was more than offset by chicken, where per-capita consumption increased from 46.9 lb in 1980 to 93.8 lb in 2002 Cattle and hog producers were forced out of business The beef cow inventory declined from 45.7 million head in 1975 to 32.4 million head in 1990 and was 32.9 million on January 1, 2003 The breeding herd in hogs was 9.6 million head in 1978 and declined to 6.0 million head as of December 1, 2002 Significant increases in production per breeding animal in beef and pork were not enough to maintain market share If the demand problems had continued, the beef and pork sectors would have been even smaller in 2003 Fortunately, the demand declines have been halted by moving to a new business model Processors have made massive investments in product and market development since the mid-1990s Following the demand lows in 1995 for pork and in 1998 for beef, the cumulative increases in demand have been 9.78% and 8.26% for beef and pork, respectively Tables and show demand indices for beef and pork The transformation of the supply chain away from commodity products and its related demand improvement have improved the economic outlook for every participant and especially the livestock producer Producers suffer the most when processors see no reason to make investments in new product offerings Check-off programs are too small to prompt change on the scale needed It is the transformation from a commodity orientation to a consumer orientation that will be the primary determinant of the economic future of the animal industry TRANSFORMATION TO MARKET DRIVEN As Table shows, the demand problems were especially acute in beef Figure provides another perspective, showing per-capita consumption of beef and inflationadjusted retail prices of Choice beef from 1975 through 2002 During the 1970s, 1980s, and into the 1990s, the trend in both series was down, and there are consecutive years in which both the price and consumption declined If price and per-capita consumption are both declining, Encyclopedia of Animal Science DOI: 10.1081/E EAS 120019631 Copyright D 2005 by Marcel Dekker, Inc All rights reserved Future of Animal Agriculture: Market Strategies 437 Table Demand index for beef, 1980 2002 Year Per-capita consumption Deflated price (cents/lb) Constant demand price Index (1980 = 100) Index (1998 = 100)a 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 76.6 78.3 77.1 78.6 78.5 79.3 78.9 73.9 72.7 69.0 67.8 66.6 66.2 64.6 66.3 66.6 67.2 65.7 66.7 67.5 67.6 66.2 67.5 283.5 258.2 247.0 235.0 227.3 212.7 206.9 209.8 211.6 214.2 214.5 212.0 203.3 203.1 190.9 186.6 178.6 174.2 170.0 173.4 178.1 190.7 184.3 274.13 280.71 272.40 271.82 268.59 270.78 298.35 304.99 325.38 332.04 338.71 340.94 349.69 340.41 338.78 335.40 343.79 338.17 333.85 333.08 340.96 333.82 100.00 94.19 87.99 86.27 83.26 79.19 76.41 70.32 69.38 65.83 64.60 62.59 59.63 58.08 56.08 55.08 53.25 50.67 50.27 51.94 53.47 55.93 55.21 198.89 187.40 175.00 171.57 165.62 157.56 152.02 139.92 138.00 130.95 128.53 124.50 118.65 115.52 111.59 109.58 105.95 100.81 100.00 103.33 106.35 111.29 109.78 a By rescaling the index to 1998 100, the 9.78% improvement since the demand bottom in 1998 can be read directly from the 2002 index value Table Demand index for pork, 1980 2002 Year Per-capita consumption Deflated price (cents/lb) Constant demand price Index (1980 = 100) Index (1995 = 100)a 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 57.3 54.7 49.1 51.7 51.5 51.9 49.0 49.2 52.5 52.0 49.8 50.2 52.8 51.9 52.5 51.8 48.4 47.9 51.5 52.7 51.2 50.2 51.4 1.79 1.77 1.92 1.80 1.65 1.59 1.72 1.75 1.64 1.56 1.72 1.65 1.50 1.45 1.41 1.35 1.49 1.53 1.49 1.45 1.50 1.52 1.48 1.79 1.91 2.17 2.05 2.06 2.04 2.18 2.16 2.02 2.04 2.15 2.12 2.01 2.05 2.01 2.04 2.21 2.24 2.06 2.00 2.07 2.12 2.07 100.00 92.78 88.53 87.90 80.18 78.01 79.06 80.92 81.34 76.46 80.08 77.66 74.77 70.83 70.16 66.04 67.51 68.45 72.21 72.49 72.31 71.67 71.50 151.43 140.50 134.07 133.11 121.42 118.13 119.72 122.54 123.17 115.78 121.27 117.60 113.22 107.26 106.24 100.00 102.23 103.66 109.35 109.78 109.51 108.53 108.26 a By rescaling the index to 1995 100, the 8.26% improvement since the demand bottom in 1995 can be read directly from the 2002 index value 438 Future of Animal Agriculture: Market Strategies Fig Inflation adjusted retail price (CPI, 1982 1984 = 100) and per capita consumption for beef, 1975 2002 (From: Livestock Marketing Information Center (LMIC), www.lmic.info.) (View this art in color at www.dekker.com.) demand is decreasing The situation was similar if less dramatic in pork, but was significantly different for chicken A comparable plot for chicken would show consecutive years in which both price and per-capita consumption were increasing.[4] Changes to move toward a consumer-friendly product offering for beef and pork were essential Investments in the product offering had lagged for nearly two decades in the face of a commodity orientation and the continued absence of the levels of coordination and quality control that processors and retailers needed to offer branded fresh beef and pork Investments in new products have surged since the mid-1990s, but the moves to contracts, vertical alliances, and vertical integration to get the coordination and quality control necessary to prompt those investments have been controversial The historical price-driven system used price signals to coordinate production with consumer preferences Adversarial relationships between participants along the supply chain constrained the level of coordination achieved, however Packers who can only buy slaughter cattle or slaughter hogs of variable quality not see reasons to invest in new products The quality control needed for branded product lines looked impossible to achieve and the animal industry drifted for two decades In the 1990s, processors discovered that consumers would pay significant premiums for branded and qualityassured product offerings Major pork processors such as Smithfield Foods, Inc., moved to common genetics in company-owned and contract production facilities Taking advantage of a level of quality control that had not been possible when buying slaughter hogs in the traditional open market, Smithfield has introduced an array of branded products and is active in the qualityconscious Japanese market Larger producers who started vertical beef or pork alliances to avoid selling at average prices approve of the new nonprice systems But independent livestock producers sometimes feel they are being denied access to the marketplace and they wonder about the competitiveness of bids for cattle or hogs The U.S Department of Agriculture was petitioned for rule changes that would have banned most types of contract buying in livestock.[5] In 2002, an amendment to farm bill legislation would have prevented packers from owning, producing, or controlling the production of livestock Legislation calling for a similar set of regulations was introduced in the 2003 Congressional session As we look back, the price-driven system had little chance to survive as a coordinating mechanism The quality grades in beef and pork were never changed to allow effective price signals that communicate needed changes and incentives for those changes to the producer Producers of uniformly fed cattle or slaughter hogs using outdated genetics face the unwelcome specter of having cattle or hogs that are uniformly wrong compared to the needs of new branded and quality-assured product lines LOOKING AHEAD TO NEW MARKET STRATEGIES The transformation away from the historical price-driven system is likely to continue The economic reasons to move toward a consumer-friendly product offering are grounded in significant profit opportunities Nonprice Future of Animal Agriculture: Market Strategies types of coordination that provide the raw material needed to support branded consumer product lines are growing in popularity with retailers, processors, and some producers The research literature shows that when a participant in an organized group effort such as a vertical alliance makes investments in technology that is use-specific, the traditional pricing system may not be adequate as a governance system.[6] Investments in genetics, scanning technology, and technology to inject tenderness are clearly investments in use-specific technologies In the presence of such new investments, governance systems will change and market strategies will have to change as well 439 premiums through alliances or price grids in contracts with buyers Investments in technology will be made within governance systems that specify performance standards for everyone involved Packers will seek arrangements to eliminate the quantity and quality variations in the historical price-driven systems in efforts to reduce their costs of operation and to ensure access to the livestock that support consumer-driven product lines Selling most slaughter cattle, regardless of quality, at essentially the same price during a brief marketing window each week will disappear Producers’ marketing strategies will focus on market access, on valuations that reflect the true value of their livestock, and on sharing in the profits that can be earned when consumers are well served CONCLUSIONS The marketing strategies of the future in animal agriculture will be different Consumers will demand that their needs be met in terms of product form, product offerings, consistency, quality, and convenience in preparation, and they will be willing to pay premiums for the right products Quality-controlled, quality-assured, and branded fresh meat lines will continue to replace commodity products, and the new products will be mainstays of the animal industry of the future If nonprice means of coordination such as contract, vertical alliances, and vertical integration are required to prompt the needed investments, those nonprice means of coordination are likely to grow in importance Consumers will be helped by revised product offerings consistent with changed lifestyles, and profits are always more likely at the producer level when the consumer is well served In the new market strategies, genetic selection will focus on livestock to meet the needs of a consumer-driven supply chain Producers of superior livestock will earn REFERENCES Purcell, W.D.; Hudson, W.T Risk sharing and compensa tion guides for managers and members of vertical beef alliances Rev Agric Econ 2003, 25 (1), 44 65 Livestock Marketing Information Center (LMIC) www lmic.info, (accessed June 23, 2003) Schroeder, T.C.; Marsh, T.L.; Mintert, J Beef Demand Determinants Report Prepared for the Joint Evaluation Advisory Committee, National Cattlemen’s Beef Associa tion; Kansas State University, 2000; 61 pp Purcell, W.D Measures of changes in demand for beef, pork, and chicken, 1975 2000 Res Inst Livest Pricing Res Bull 2000, 4, 32 pp Petition for Rulemaking: Packer Livestock Procurement Practices; GIPSA, USDA, October 12, 1996 Boehlje, J.; Schrader, L.F The Industrialization of Agricul ture: Questions of Coordination In The Industrialization of Agriculture; Royer, J.S., Rogers, R.C., Eds.; The Ipswich Book Company: U.K., 1988; 26 Future of Animal Agriculture: Urban/Rural Agriculture Ecosystems Maurice Lenuel Eastridge The Ohio State University, Columbus, Ohio, U.S.A INTRODUCTION The age of the agrarian society in the United States has long passed, but the volume of food needed to feed the world population continues to increase Less than 2% of the U.S population is presently engaged in food production; thus, the number of farms has decreased, the size (acres or number of animals) per farm has increased, and the performance of each productive unit (land, crop, or animal) continues to make improvement This advancement in productive capacity is made possible by advancement in genetics, new technology in production and harvesting, and more specialized management skills The economics of this food production continues to be challenged, resulting in globalization of the food production system and increased size of operations to increase total profitability The increased size of operations is driven by limited margins per production unit, thus causing farm owners to increase the number of producing units to achieve a targeted income In the midst of these changes in agriculture, the increase in spendable income and the desire to work in an urban setting and live in a rural setting have resulted in movement of people from cities even from the suburban areas to residential developments in more rural locations with increased area of land per resident The interface issues between urban and rural sometimes occur between cities and commercial agriculture, but the issues are more common between rural residential developments and commercial agriculture These residential developments occur with zoning regulations set by townships instead of by city zoning boards and are usually established with fewer restrictions Agriculture in some areas is exempt from zoning, but increased focus on environmental preservation is beginning to change this The future of animal agriculture is being affected by the issues that arise between the commercial food operation and community residents common boundary is being shared by two or more groups with different identities The urban and rural interface would imply that the boundary is being shared between a city, which has the purpose of sustaining commercial businesses, governmental offices, and high-density residential housing, and the dwellers in the country who have taken on the responsibility of food production for the population And although this interface sometimes occurs, the more frequent interface is rural-to-rural residents, with the identity differences being those in commercial food production versus those with public jobs who live in the country in low-density housing (Fig 1) In some cases the interface is rural-to-rural, in that the identity difference is small- versus large-scale food production operations The primary issues that surface in the urban and rural interface are environmental effects and quality of life Water quality and availability are the primary environmental issues The concern with water quality is caused by the risk of contamination from manure storage and the land application of manure The availability of water is a concern related to the amount of water consumed by the livestock and the water used for cleaning the facilities or product (e.g., egg washing) The level of risk for impacts to the water supply depends on the specific site The odor from food animal operations is viewed by some as both an environmental and a quality of life issue: There are environmental risks from airborne particles, and the quality of life is affected by the repulsive nature of the odor These aspects have also led to concerns about property values in proximity to animal operations Other quality of life issues include road damage due to heavy equipment, mud on roads from farm equipment, slowmoving equipment on the local roads, loud noises (e.g., from tractors or drying equipment) during all hours of the day from farm operations, and dust from crop harvesting or animal operations URBAN AND RURAL INTERFACE FOOD PRODUCTION AND LAND USE The term urban and rural interface is frequently uttered in communities today The idea of an interface is that a Location of food production in the world is affected by people and land resources The suitability of the land for 440 Encyclopedia of Animal Science DOI: 10.1081/E EAS 120019636 Copyright D 2005 by Marcel Dekker, Inc All rights reserved Future of Animal Agriculture: Urban/Rural Agriculture Ecosystems 441 Fig Urban and rural interface: the coexistence of the human population and commercial food animal production (View this art in color at www.dekker.com.) food production is very important, and the availability of technology to people in developed countries is key to production of food for the population in the country and for export Public policies and cultural traditions also impact the food production system Over 50% of the land area is used for agricultural production in Argentina, Australia, China, New Zealand, and the United Kingdom, but land area per person ranges from 0.7 ha/person (China) to 40 ha/person (Australia), with each having a population growth of about 1.0 to 1.2% (Table 1) In contrast, Canada and Japan have 7.5 and 13.8% of the land in agricultural production, with population densities of 32.1 and 0.3 ha/person, respectively Yet the reasons for the percentage of land in agricultural production differ Much of Canada’s land is not productive because it is in the extreme northern climate, and much of Japan’s land is used for housing in that densely populated country However, the Netherlands and the United Kingdom have a similar human population per land area to that of Japan, yet the Netherlands and the United Kingdom have more Table Human population, total land area, and agricultural land area in selected countries for 2001 Country Argentina Australia Brazil Canada China Japan Netherlands New Zealand United Kingdom United States a From Ref From Ref b Populationa ( Â 1000) Populationa growth (%) Land areab ( Â 1000 ha) Land area (ha/person) Agricultural land areab ( Â 1000 ha) Agricultural land area (% of land area) 37,488 19,338 172,559 31,015 1,284,972 127,335 15,930 3,808 59,542 285,926 1.3 1.2 1.4 1.0 1.0 0.3 0.6 1.1 0.3 1.0 278,040 774,122 854,740 997,061 959,805 37,780 4,153 27,053 24,291 962,909 7.4 40.0 5.0 32.1 0.7 0.3 0.3 7.1 0.4 3.4 177,000 455,500 263,465 74,880 555,276 5,199 1,931 117,235 16,954 411,259 63.7 58.9 30.8 7.5 57.9 13.8 46.5 63.7 69.8 42.7 50,669 30,500 176,000 13,700 106,175 4,564 4,050 9,633 10,343 96,700 Country Argentina Australia Brazil Canada China Japan Netherlands New Zealand United Kingdom United States 2,300 2,120 15,600 1,084 5,134 1,219 1,486 3,749 2,222 9,135 Dairy cows 14,000 113,000 15,000 994 136,972 11 1,300 43,142 35,832 6,685 Sheep 3,550 310 9,800 30 161,492 35 215 183 – 1,250 Goats 4,250 2,912 30,000 14,367 464,695 9,612 13,000 358 5,588 59,074 Pigs 110,500 93,000 1,050,000 160,000 3,923,600 283,102 98,000 13,000 155,800 1,940,000 Chickens 2,350 540 3,500 1,150 661,250 – 1,020 170 4,000 6,650 Ducks 135 – – 300 215,000 – – 65 100 – Geese 2,850 1,400 13,000 5,900 250 1,523 70 8,500 88,000 Turkeys 3,650 220 5,900 385 8,262 20 122 78 184 5,300 Horses 64,519 53,154 225,345 19,990 306,874 10,384 9,589 21,793 21,916 148,654 Animal unitsa (AU) 2.74 8.57 1.17 3.75 1.81 0.50 0.20 5.38 0.77 2.77 ALA/AU Calculated based on estimated dry matter excreted per day using the beef animal as the base, with body weight (kg) and the coefficient for each species, respectively, being: cattle (less dairy cows), 500 and 000; dairy cows, 545 and 310; sheep, 45 and 160; pigs, 70 and 170; chickens, 1 and 009; ducks, and 014; geese, and 040; turkeys, and 024; and horses, 455 and 700, respectively (From Ref ) a All cattle Table Population (Â 1000) of primary food animals, animal units (AU; Â 1000), and hectares of agricultural land area (ALA) per AU in selected countries for 2002 442 Future of Animal Agriculture: Urban/Rural Agriculture Ecosystems Future of Animal Agriculture: Urban/Rural Agriculture Ecosystems land devoted to agricultural production than Japan Increased environmental regulations in both countries and animal welfare guidelines in the United Kingdom are having major impacts on food animal production These changes are driven somewhat by cultural views and the limited land base to support the presence of food animals, with the Netherlands and the United Kingdom having less than one hectare of agricultural land per animal unit (Table 2) Sufficient land base is needed for food animal production, not only directly for the animals but also for growing the crops to feed the animals and to which manure can be applied for fertilizer Alternative uses of manure, instead of providing nutrients for crop production, include energy generation from methane production and composting for use in agronomic or ornamental horticulture, although these systems are in various stages of development and acceptance Countries with high concentrations of animals per hectare of agricultural land are going to be faced with continued pressure from the urban and rural interface Yet the concentration of animals within a country is not the only factor that gives rise to these pressures For example, the United States has 2.77 per animal unit, and many hectares of agricultural land have been idled in recent years by governmental programs to control production of grain Consequently, a lot of available land for agriculture has not been in use The concern over food animal production varies by state within the United States due to the availability of water resources, the human population of the state, the cultural acceptance of agriculture, and the accepted meaning of a family farm Within a state, these aspects can vary even within a community In some areas, animal density is actually much lower than 20 years ago, but urban rural pressures are intense Therefore, the interface oftentimes becomes a local community issue because of the concentration of animals within a community and the demand for resources Who was there first the animal production facility or the resident community? Was the new animal production unit begun by someone from the local community or by someone outside the local community (e.g., from another state or country) ‘‘Can they be trusted?’’ If the animal operation already in existence is expanding, ‘‘Are they accepted in the community?’’ BEING A GOOD NEIGHBOR Minimizing the challenges of the urban and rural interface can be aided if the individuals sharing this common boundary agree to be good neighbors.[3–5] This attitude is 443 needed by both the farmers and the rural residents Each party needs to make efforts to get to know each other, to keep their properties neat and clean (i.e., take pride in an attractive community), to accept that they are a community, and to develop respect for each other The farmer needs to take the responsibility for sharing good will in the community, promptly cleaning up spills on the roads, using management practices to minimize environmental risks, and providing opportunities for the residents to understand their production enterprise and the food production system Rural residents need to take the responsibility to ask questions about the agricultural enterprise, to not trespass on the farmer’s property, and to know the proper manner in which to file complaints about an animal operation Realtors and communities are working together in some areas to educate people about country living before they purchase a house in a rural community.[6] CONCLUSION Food production is essential to the world’s population of people, and where food animal production occurs it will continue to be determined by the economic viability in the area and the production efficiency that can be attained We have focused for many years on these two aspects as the foundation for the future of animal agriculture However, with increased concentration of animals per operation to attain economic viability, environmental risks have increased This has given rise to increased environmental standards for food animal production in order to preserve the environment Sustaining the environment is critical for the future of food animal production An ever-arising force affecting the future of animal agriculture is social acceptance Increased social pressure arises from the environmental risks, perceived concerns with quality of life in the community, the notion that a large-scale operation is not a family farm, and the perception that animal well-being is less in a large-scale operation Social pressure has been intense, even in some areas that have fewer animals per land area than 20 years ago Although the population may prefer that food be produced locally and at low cost,[7] the reality of the economic forces resulting in larger animal operations may not even enter their mind as a trade-off Fewer people have agrarian backgrounds, yet more of them desire to live in the country The increased presence of low-density housing in rural areas and the increased size of animal production operations will continue to cause challenges in the urban and rural interface In some communities, it is the social acceptance of animal agriculture that will determine the continued presence of animal agriculture, 444 even if the land and economics are not limiting These social issues also will direct some of the changes in public policy that affect land use,[8] from preserving open space in rural areas to bringing agricultural enterprises more in line with what is expected from other commercial businesses Future of Animal Agriculture: Urban/Rural Agriculture Ecosystems REFERENCES UNICEF 2003 http://www.unicef.org/statistics Food and Agriculture Organization of the United Nations FAOSTAT, agriculture data 2003 http://faostat.fao.org Ohio Livestock Environmental Assurance Program Build ing Positive Neighbor Relations; Ohio Livestock Coalition: Columbus, OH The Code of Country Living: A Look at the Realities of Living in the Countryside of Rural Illinois; Illinois Farm Bureau: Bloomington, IL, 1999 Good Neighbor Relations: Advice and Tips from Farmers; The Pennsylvania State University: University Park, PA, 1997 If You Are Thinking About Moving to The Country You May Want to Consider This; Ottawa County Planning Department: West Olive, MI, 2003 Davis, G.; Smith, M.B.; Tucker, M Ohioans’ Perceptions of Agricultural Land Use and the Environment; Department of Human and Community Resource Development, The Ohio State University: Columbus, 2002 http://www.ag.ohio state.edu/~hcrd/staff/AgEnPollReport.pdf Libby, L.W Rural Land Use Problems and Policy Options: Overview from a U.S Perspective; The Ohio State University: Columbus, 2002 http://aede.osu.edu/programs/ Swank/pdfs/rural land.pdf ... rate differences that reflect the importance of net flux of nutrients from the rumen and specific constraints of miIDF upon the intake rate of NDF and the rate of and efficiency of digestion of maPDF... non-in vitro methods for estimating the rate of digestion of maPDF Mean in vivo rate of digestion of PDF (inclusive of effects of ruminative rumination) consistently exceeds (1. 3- to 4.4-fold)... extent of digestion of PDF are functions of 1) the microbially accessible surface area of plant tissue fragments;[5] 2) the abundance of PDF on such surfaces; 3) the rate of exposure of new surface
Ngày đăng: 02/07/2014, 00:20
Xem thêm: Encyclopedia Of Animal Science - F ppt, Encyclopedia Of Animal Science - F ppt
