September 1997
RICHARD D. REYNNELLS
BASIL R. EASTWOOD
US Department of Agriculture
Cooperative State Research, Education and Extension Service
Plant and Animal Production, Protection and Processing
There are many confusing nuances within the concepts of animal welfare, animal well-being, animal rights, and related terms. County and state Cooperative Extension personnel often are asked to comment or provide advice to clientele relative to a particular event or piece of information touching on animal welfare. To address the information requirements of county and state Extension personnel, we have enlisted the assistance of a number of authors and co-authors, as well as numerous reviewers to produce the 14 discussion papers in this compendium.
Authors were chosen for their expertise in commodity areas, and knowledge of animal welfare issues. We requested individuals from many points within the ideological spectrum of animal welfare/rights to review the papers.
Because of the controversial nature of this topic, and to ensure an adequate review of these papers, a double review was conducted. The authors retained the right to make final corrections and decisions regarding the content of their articles. Persons on the review committee were only responsible for review and editing the document. Their views were seriously considered but may or may not be reflected in the final document. The authors are responsible for the final product.
The papers are not intended to be all inclusive or the final word on these issues. Readers are encouraged to use the references provided with most papers as further resources, and to reach their own conclusion on these emotion laden and often difficult to understand issues. We hope these papers are of assistance in this process.
Facilitators for this series are: Richard D. Reynnells and Basil R. Eastwood, USDA/CSREES/PAPPP.
Jack L. Albright
Professor of Animal Sciences and Veterinary Medicine
Lilly Hall, Purdue University
West Lafayette, Indiana 47907
Animals have contributed to human welfare since prehistoric times. The domestication of plants and animals for food, fiber, and other purposes was an integral part of the development of agriculture (Council for Agricultural Science and Technology [CAST] 1981).
During the years in which humans and animals have interacted since animal domestication, changes have been made in both the animals and their husbandry. The act of male castration, possibly the first surgery, was practiced first on humans without anesthesia (CAST, 1981). Later, large animal species were castrated as part of the domestication process. Without the widespread use of this incidental surgery early in the animal's life, control of cattle for the development of settled agriculture would have been delayed. Use of oxen (castrated male bovine) as the first nonhuman power source made possible the production of enough grain to release some of the people from the responsibility of food production (CAST, 1981). This, in turn, permitted the development of civilization with decreasing agricultural orientation.
Today, people use animals to ride; to provide power; to serve as guards; to assist with specific types of jobs; and to become subjects for research. Many people also find satisfaction in companionship from pets, as well as from the use of dogs for hunting, horses for riding, and various animals as participants in competitive events. However, the primary importance of domestic animals for people in the United States is as a source of milk, eggs, meat, wool, hair, leather, pharmaceuticals, and other byproducts.
Mench and Van Tienhoven (1986) report that remarkable increases in the efficiency of poultry and livestock production have occurred during the last half-century. In the United Sates, for example, the number of eggs a hen lays annually has doubled during this period, while the amount of feed consumed for each egg produced has decreased by 50 percent. Because of these improvements in egg production and feed efficiency, the cost of eggs to the consumer since 1925 has risen by only 40 percent, which is considerably less than the cost increases of most other consumer goods. Similar trends are apparent in beef, pork, poultry meat, and dairy production (CAST 1980).
Many factors have contributed to these improvements. Major roles in increasing efficiency and improving animal health have been played by sophisticated techniques of artificial selection; advances in the detection, treatment, and prevention of disease; mechanization of farm labor; and the development of nutritionally balanced animal feeds. In addition, the increasing use of light- and temperature-controlled housing provides protection from extremes of weather and predation and permits the control of the photoperiod necessary to stimulate growth and reproduction (Mench and Van Tienhoven 1986).
Farmers and consumers have benefitted greatly from the modernization of animal agriculture. However, since the publication of "Animal Machines -- The New Factory Farming Industry," by Ruth Harrison (1964), public concern about the treatment of farm animals has risen steadily. Harrison found most of her examples in the farming and veterinary press. With a foreword by Rachel Carson, of "Silent Spring" fame, Harrison's book was especially critical of (1) the use and misuse of hormones, antibiotics, and additives to animal feeds and (2) the care and handling of farm animals, especially hens kept in cages and veal calves housed in crates.
This book landed like a bomb in England. Within a year the Brambell Report (1965) to Parliament, which inquired into farm animal welfare, was published. The investigation was followed by the release of various Codes of Recommendations for the Welfare of Livestock in the U.K. (1971) including chickens, turkeys, pigs, cattle, sheep, rabbits, and ducks. The codes are advisory; failure to observe them is not in itself an offense. They have legal standing, however, and a person cannot claim ignorance of them as a defense.
The passage of legislation regulating animal production in England and the European Economic Community is complex and analyses of it can be found elsewhere (Ewbank, 1988). Similar legislation has been proposed by animal welfare groups in the United States.
A growing number of U.S. agricultural commodity groups have guidelines and codes of practice on animal welfare in place. Guides that have been produced voluntarily by industry provide good examples of the ethical placement of priority on animal care and handling, as well as the self-policing nature of industry (See Supplemental Reading -- General Guidelines). A useful starting point for U.S. guidelines on farm animals is the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (Consortium, 1988). Chapters 5 through 11 include separate guidelines for husbandry for beef cattle, dairy cattle, horses, poultry, sheep and goats, swine, and veal calves. The guide was prepared by animal scientists, veterinarians, industry representatives, and agricultural engineers.
Certain commercial husbandry procedures that may cause some temporary discomfort or pain are done to sustain the long-term welfare of animals. These special agricultural practices are widely accepted as standard operating procedures if they are:
Husbandry procedures and production methods should be revised as research at agricultural research stations and elsewhere suggests improvements. Research on improved methods and procedures is encouraged (Consortium 1988).
Cruelty is defined as having or showing indifference to, or pleasure in, another's pain or suffering. Producer-originated animal suffering has been categorized in three areas:
Most humane societies can identify animal suffering and follow through with legal prosecution. There should be no place in any industry for those who mistreat animals.
Cases of deprivation are difficult to resolve, as they involve the denial of certain, perhaps less vital, needs of the animal's environment. In some cases, these needs have not been definitely established. The veal industry is an example. Earlier introduced as HR2859 and HR84, the Veal Calf Protection Act (1989) assumed that close quarters and lack of physical contact among veal calves caused behavioral and social deprivation. The counter-argument is that placing the animals in individual stalls helps prevent spread of disease. This issue and related ones concerning rigid diet, iron status, additives, and government regulation, as well as the need for further research, have been carefully stated. They remain unresolved (Schwartz 1990).
That farm animals can suffer and have "behavioral needs" was expressed in the Brambell Report (1965) from England. Since that time, many English and other European animal welfare advocates, administrators, and scientists have accepted "behavioral needs" as doctrine. In the United States, issues related to animal behavior, physiology, the external appearance of animals, ways of expressing emotion, learning processes, and "behavioral needs" are still being discussed. Research and interpretation concerning farm animal perception and cognition are needed (Curtis and Stricklin 1991).
A scientific assessment of animal welfare was compiled earlier by Fox (1984), who studied welfare determinants; cognitive ethology; animal sentience, sapience, and self-awareness; and animal consciousness, feeling, and suffering. Duncan and Petherick (1991) have distinguished between needs and desires, sensing or detecting, feeling and perceiving, memory and learning (expectation or anticipation), recall, and awareness. More recently, the idea has emerged that welfare is mainly (Dawkins 1990) or solely (Duncan 1993; Duncan and Petherick 1991) dependent on what the animal feels. Stanley Curtis has stated that farm animal regulations are inevitable in the future only if producers fail to police themselves properly. Expressing concern about the impact of animal activists on legislation, Curtis says:
As activists push for farm animal regulations, it's vital that those regulations be based on research about how animals think and feel. I'm very concerned about letting naive people decide what's best for animals, because we all tend to anthropomorphize -- when we look at an animal, we imagine ourselves in the animal's place. But what the animal itself thinks and feels is more important than what we imagine. That's really the crux of the issue (Martz, 1991).
Narveson (1986) is critical of Regan's (1983) statement that animals have "concepts" and that "perception, memory, desire, belief, self-consciousness, intention, a sense of the future" are among the leading attributes of the mental life of normal mammalian animals aged one year or more.
In the animal welfare movement, there is concern over the consciousness of suffering (Harrison 1964; Singer 1975, 1990; Mason and Singer 1980, 1990; Dawkins 1980; Fox 1980, 1984). Animal welfare activists suppose that animals may be conscious of suffering if either the structure of their nervous systems or their reactions to stimuli resemble those of humans. The reactions of farm animals to stimuli of pain or fear, which we at once recognize as resembling our own, are of three kinds (Baker 1948):
Barbara Orlans (1993) modified a chart by Katherine Morgan (1986) that provides an overview of classification categories of animal-related organizations. These preliminary classifications use attitudes toward animals, from exploitation to liberation, to label various types of organizations. The Orlans model, which uses five categories, is included. The Morgan model lists six categories of organizations, including the additional "animal control" designation.
The elusive nature of defining the concept of animal "welfare" has been summarized by Ewbank (1988) as follows:
Many attempts have been made to define the term welfare as applied to animals. Two recent and widely used definitions are: 'Welfare on a general level is a state of complete mental and physical health where the animal is in harmony with its environment' (Hughes 1976), and 'The welfare of an individual is its state as regards its attempts to cope with its environment' (Broom 1986).
Both definitions refer in a general way to the balance which exists between the animal and its surroundings. They are not immediately helpful at the practical level in determining whether an animal is in fact enjoying a correct balance. For practical purposes, there is merit in simply replacing the word 'welfare' by the terms 'health' and 'well-being', both of which have strong positive components. Health is more than the mere absence of disease and well-being is more than the absence of discomfort and distress. This positive approach is to be welcomed because it inherently encourages high standards and it also plays into the natural pride of the good stockman in having contented, thriving and productive animals.
In the past, farm animal welfare has been considered primarily in relation to maximization of productivity. Fox (1984) states that there are no clear-cut correlations between productivity and animal well-being. He claims, however, that neglecting the welfare side of farm animal science by making productivity the sole criterion of sound husbandry practices can be counterproductive. When greater attention is given to the animals' physiological, emotional, and behavioral well-being, he states, the animal will be healthier and more productive. Fox apologizes for not offering a "variety of easily adoptable, tried and true, humane and more profitable alternatives." Still, he says, "These will come when all of us who are involved begin to think less in terms of productivity, short-term costs, and other narrow self-interests, and more in terms of the animals, their well-being, our treatment of them and our moral humane obligations toward them, science and ethics notwithstanding."
In addition to productivity, criteria that should be considered in assessing welfare or well-being are animal behavior, health, musculoskeletal soundness (lameness), reproduction, immune status, and physiological endpoints (Albright 1987 and Zimbelman 1991). It is vital both for the health and well-being of the animals involved and for the financial future of the farming industry that an increasing critical interest should be taken in the mixture of economic, scientific, ethical, aesthetic, and practical concepts that make up the complex subject of animal welfare, and that action should be taken on the new knowledge and ideas thus gained (Ewbank 1988).
What is the distinction between animal welfare and animal rights? Animal welfare reflects people's concern for the humane treatment of animals and is regarded as more representative of the societal mainstream. It appears to have growing support from society at large. In contrast, proponents of animal rights hold that animals must not be exploited in any manner. In other words, the only interactions humans should have with animals are those that occur by happenstance or those that are initiated by an animal. Animal rights advocates believe that animals have basic rights -- many say, the same as people -- to be free from confinement, pain, suffering, use in experiments, and death for reason of consumption by other animals (including humans). Thus, animal rights advocates oppose the use of animals for food, for clothing, for entertainment, for medical research, for product testing, for seeing-eye dogs, and as pets. Currently, animal rights doctrine is essentially philosophical, anti-vivisectionist, vegetarian, pro-activist, moralistic, and urban-based (Albright 1986). The animal rights proponents believe that humans have evolved to a point where they can live without any animal products -- meat, milk, eggs, honey, leather, wool, fur, silk, byproducts, etc. These advocates offer a long list of concerns in support of the conclusion that neither medical researchers nor the cosmetic industry has the right to experiment on animals. They also conclude that the animal kingdom is exploited by hunters, zoos, circuses, rodeos, horse racing, horseback riding, the use of simians (small primates) to assist quadraplegics in wheelchairs, and by the keeping of animals as pets.
Kim Bartlett, editor of "The Animal's Agenda," a magazine published by the Animal Rights Network, Inc. in 1991, states:
It is indeed true that there is a fundamental theoretical difference between animal 'rights' and animal 'welfare,' as commonly defined: the animal 'rights' advocate would argue that animals have certain inalienable moral rights which humans should not violate; the animal 'welfarist,' however, accepts the notion that humans have a right to use animals, as long as suffering is reduced or eliminated. In theory, the animal 'welfarist' would work exclusively for the reform of cruel or abusive situations to alleviate animal suffering, while the animal 'rights' activist would focus on the abolition of cruel or abusive situations to eliminate animal suffering."
Animal rights advocates often express concern for welfare problems, but the eventual or hidden animal rights agenda is that of a purist. In one example, the goal is not larger cages/pens but the elimination of cages/pens. The concept of not using animals for any reason at all eliminates choices or discussion. Thus, the debate over how best to promote animal welfare shifts to a debate on animal rights versus human rights (Mathis 1991).
The case for animal rights has yet to be fully argued as a test case in a court of law. Under English common law, animals are considered to be personal property, and the animals themselves have no rights. In a U.S. case, the court decided that a dog "is something else" -- not just a thing, but occupying a special place somewhere between a person and a piece of personal property. The court ruled that the plaintiff had suffered mental anguish and despondency due to the defendant's wrongful destruction of the remains of her dog for whom she had planned an elaborate funeral; she was awarded damages beyond the market value of the dog (Kay Corso, Plaintiff, vs. Crawford Dog and Cat Hospital, Inc. Defendant. 97 Misc. 2nd 530: 415 N.Y.S. and 2nd 182 Civil Court of the City of New York, Queens County, March 22, 1979).
Salt (1892) preceded Singer (1975) by many years with a discussion of the rights of animals and possible lines of reform. However, sensitivity to issues involving animal rights intensified into a movement in the mid-1970s. The modern movement gained momentum with the publication of "Animal Liberation" by philosopher-vegetarian Peter Singer in 1975. The philosophy of Peter Singer, who many consider the "father" of the modern-day animal rights movement, is not a "rights" philosophy at all. "Animal Liberation," a seminal work, calls for humans to consider the "interests" of all sentient beings (Bartlett 1991).
Since 1975, many other departments of philosophy and religion have picked up the battle cry. Early Christian churches professed that animals do not have souls. Gradually, however, societies have admitted that, because animals experience pain, it is not too far-fetched to believe that they also have feelings. Until recently, human language, upright locomotion, use of the thumb, and the ability to solve complex problems were attributes humans cited to "keep animals in their place" (Albright 1986).
In his book, Singer denounced animal pain and suffering while supporting freedom for animals. He also defined a new form of prejudice called "speciesism." He defined speciesism as a prejudice or an attitude of bias toward the interests of members of one's own species and against the members of other species. To avoid speciesism and cruelty to animals, Singer espouses vegetarianism as a form of boycott as well as a lifestyle. The preface to the second edition of "Animal Liberation" (Singer 1990) states, "The strength of the case for Animal Liberation is its ethical commitment; we occupy the high moral ground and to abandon it is to play into the hands of those who oppose us." The book has had an enormous impact as a forceful call to arms for the general reader, especially on the subjects of "factory farming," the use of animals in medical research, and vegetarianism as morally and socially necessary. The question of animal rights and total abolition of the use of animals in science, animal agriculture, and commercial and sport hunting and trapping also have been the subject of published works by many other philosophers (Albright 1986).
Another proponent of animal rights is philosopher Tom Regan (Regan 1983, 1989; Regan and Singer 1976). Regan's book, "The Case for Animal Rights ," could very well be called "The Case for Mammal Rights," because his use of the term "animal" seems to refer to "a mentally normal mammal a year or more in age." Regan explores the implications of the use of animals for food, the hunting and trapping of animals, and the use of animals in science:
On this view, animal agriculture, as we know it, is unjust because it fails to treat farm animals with the respect they are due, treating them instead as renewable resources having value only relative to human interests. Animal agriculture, as we know it, is wrong, not only when farm animals are raised in close confinement in factory farms, but also when they are raised 'humanely,' since even in this case their lives are routinely brought to an untimely end because of human interests....The rights view will not be satisfied with anything less than the total dissolution of the animal industry as we know it.
In the last chapter, Regan sets forth his reasons for believing that vegetarianism is morally obligatory.
Elsewhere (1989), Regan has written: "I regard myself as an advocate of animal rights -- as a part of the animal rights movement. That movement, as I conceive it, is committed to a number of goals, including:
In a moralistic style of writing that Regan himself terms "disciplined passion," he concludes this article by stating that "the fate of animals is in our hands. God grant that we are equal to the task." Earlier (Regan and Singer 1976), Regan sowed seeds of doubt and suspicion about agricultural animal systems: "For the fact is that in ever-increasing numbers farm animals are being raised in incredibly crowded, unnatural environments according to what are called "intensive rearing methods." Some of the details and consequences of these methods are presented in Peter Singer's 1976 essay "Down on the Factory Farm." Singer reveals that animals raised by these methods lead lives characterized by "extreme deprivation, pain and frustration."
At a 1991 animal protection symposium put on by the National Alliance for Animals, a call for the animal rights movement to distance itself from animal "welfare" was voiced by two prominent animal rights speakers: Regan, of North Carolina State University, and Gary Francione of Rutgers University Law School. Though the style and substance of their oratory was markedly different, both Francione and Regan characterized animal welfare as the "enemy" of animal rights; argued that the animal rights movement is being co-opted by proponents of animal welfare; and encouraged listeners to return to a belief in the fundamental principles of the animal rights doctrine, as articulated by Regan.
To Francione and Regan, the goals of animal "welfare" not only differ from animal "rights," they contradict them. In the words of Francione, "What you do when you merely ameliorate the conditions of enslavement is that you perpetuate the enslavement. And that is totally inimical to the goal of abolition." Regan stated that "people who work to improve the corrupt system of exploitation fail to understand this truth, a simple truth: to make injustice seem better is to prolong injustice" (Bartlett 1991).
In an attempt to consider differing points of view, the book "Animal Rights: Opposing Viewpoints" (Rohr 1989) is recommended. It presents 32 articles debating the use of animals and whether they have rights. This book considers and debates five questions:
A helpful periodical bibliography and list of critical thinking activities (especially for students) are included with each chapter. The activities help students distinguish between fact and opinion, develop the ability to empathize, recognize deceptive arguments, recognize statements that are provable, and evaluate sources of information.
Drs. Rowan and Tannenbaum (1986) from Tufts University take a more moderate animal rights view. "We believe that animals have some rights and that we have important moral obligations regarding animals, but we also believe that at least some use of animals for human ends is legitimate." They conclude "...it would be most unfortunate if the concept (of animal rights) became equated with one particular political movement -- such as those seeking to abolish any humane use of animals. The concept of rights is both powerful and subtle and must be used with care and precision to explore our relationship with and responsibility to animals."
"The philosophical animal rights debate is a question of absolutes -- either you use animals or you don't," says Curtis. "The vast majority of people in the world today have decided to use animals because they want meat and other products of animal origin. It's an issue that's already been decided in our society. The more complex issue that remains open for discussion is animal welfare, and that isn't a matter of absolutes. Animal welfare concerns our moral responsibility to support the well-being of animals. This concern always sparks angry debates, because each and every human being is going to have a different opinion about where to draw the line" (Martz 1991).
Thompson (1992) has presented an overview of animal welfare and animal rights as they relate to biotechnology. First, criticisms of the use of animals in scientific research have led to reforms, as well as constraints, and increased costs on research practices in all areas of biological sciences. Second, some potential political allies for opposition to biotechnology may lead animal activists to target the products of recombinant DNA research. Third, the potential for using recombinant DNA techniques to develop new animal genomes (i.e. transgenic animals) may raise special questions for animal well-being. Finally, the public's perception of a lack of compassion for animal interests on the part of the research community may be a component of a vague, but extremely significant, antipathy toward science in general. Opposition to biotechnology may be cited, along with the perception of scientific dishonesty that has led to public disenchantment with science and scientists. If so, a willingness to understand and take seriously the issues of animal well-being and of public attitudes toward animals will be a component of responsible science in the coming decades.
A discussion of ethical issues on the care and use of animals commonly presumes a distinction between animal welfare and animal rights, but the distinction itself has become the source of much confusion. There are at least three ways to draw the distinction. Thompson (1992) refers to political, conceptual, and philosophical objectives. He includes an ethical analysis of each.
Vegetarianism is not new. The word "vegetarian" was invented in 19th century gland. Early Greek thinkers advocated a vegetarian diet in reaction to over-indulgence in animal flesh and wine. Excesses finally gave birth to the vegetarian movement in both Greece and Rome. Pythagoras (6th century B.C.) argued for vegetarianism on the basis of transmigration of souls between humans and animals. Plato (5th-4th centuries B.C.) drew sharp distinction between the rational soul of humans and appetitive soul of animals and claimed that superior rational humans naturally rule over inferior appetitive animals. He characterized animal existence as "beastly", sexually wanton, lawless, murderous, and warlike, but was sympathetic to vegetarianism as an ideal. Aristotle (4th century B.C.) claimed that animals with a lower type (sensitive) soul are meant to serve the purposes of humans, who have a higher type (rational) soul. This idea has heavily influenced to the present day a Western anthropocentric view of animals (Magel 1989).
The idea that it is morally wrong to eat animals also held sway for about 1,000 years among some of the most prominent ancient Greek philosophers. The idea died out in the Western world for almost 1,700 years. Since the 1970's, however, there has been a resurgence of interest in vegetarianism, marked by lively debates and the emergence of a substantial literature in the form of scholarly books and articles (Dombrowski 1984).
The Vegetarian Information Service, Inc. (formed in 1976) has stated that major training, mobilization, planning conferences, and animal rights actions are being held. Their major objective is to promote vegetarianism and animal rights.
Alex Hershaft (1982), founder of the Farm Animal Reform Movement, president of the Vegetarian Information Services, and former editor of the "Vegetarian Times," has written about the emerging structure of the vegetarian and animal rights movement in the United States as follows:
...Where 1970 had begun the shift of public consciousness toward life-enhancing ideologies and 1975 sparked an explosive growth of the vegetarian and animal rights movements, 1980 was the year for reassessment and consolidation. At the same time, animal rights loomed as a prime candidate to become the major cause of the 1980's, just as civil rights and women's rights had been in the 1960's and 1970's. In fact, most animal rights advocates were graduates of those movements and viewed animal rights as a logical extension of those ideologies. Most importantly, ethical vegetarians and animal rights advocates discovered that, despite their diverse origins, their ideologies were one and that they had much more in common with each other than with the traditional wings of their respective movements. The fresh idealism and excitement of animal rights advocates provided a fitting complement to the experience, resources, and credibility of ethical vegetarians. Clearly, the time had come for the two movements to merge and to make a major impact on the social and economic fabric of American society. It was precisely with this goal in mind that, in the summer of 1980, we formed Action for Life -- a framework for arranging conferences and seminars to train and mobilize animal rights and vegetarian activists.
Lehman and Hurnik (1980), Department of Philosophy and Department of Animal and Poultry Science, respectively, at the University of Guelph, Ontario, Canada, prepared a paper entitled "On an Alleged Moral Basis of Vegetarianism." They formulated the argument (called the vegetarian argument) for the conclusion that it is wrong to kill animals for food. If this argument is acceptable, they said, then so is a parallel argument that it is wrong to kill plants for food. The parallel argument is not acceptable, and thus the vegetarian argument is not acceptable. Other basic premises of the vegetarian argument are discussed and challenged in their guest editorial.
Kathryn George (1990), Department of Philosophy at the University of Idaho, argued that the vegetarian ideal as a social goal for all would be wrong because it fails to consider the individual nutritional needs of humans. These needs vary throughout the stages of life with biological differences between the sexes and the eugenic effect of limiting the adaptability of the human species. She identified seven classes of individuals, comprising most of the earth's population, not required to be or become vegetarians.
There are many kinds of vegetarians. Hershaft has already alluded to ethical vegetarians. Does that mean that they are vegans and consume only plant sources? Some draw the line as lacto-ovo vegetarians (dairy products and eggs, respectively). There are pesco-vegetarians (fish), fruitarians ("nuterers") who consume only those plant sources that are ripe or mature (i.e. fruits, grains, and nuts).
Morris (1990) states eloquently that:
We humans, as evolved carnivores, have the right to live by our natural diet. Mankind is irreversibly adapted to a diet that contains meat as a major constituent and is no longer suited to a predominantly vegetable diet. Proof of this comes from those struggling peasant populations where meat is in short supply. Populations forced to suffer a low-protein, high-carbohydrate diet for prolonged periods eventually succumb to cirrhosis of the liver, pellagra, beriberi, kwashiorkor, and other serious deficiency diseases.
George Bernard Shaw, one of history's most famous vegetarians, is often cited as an example of a man who lived actively into his nineties through his special diet, but the truth is that he survived despite it, not because of it. Serious anemia, caused by his vegetarianism, was threatening to kill him at one stage and he could only be saved by accepting medication that included liver extracts. This made the leaders of the vegetarian movement furious and they savagely attacked the elderly playwright, apparently caring more for principles than for Shaw's continued survival. Shaw wrote a withering reply, in which he made the crucial point that the value of vegetarianism is greatly diminished by the fact that it is so difficult and expensive to do well, ending with the comment: 'The so-called simple life is beyond the means of the poor.'
For those who have not studied the problem this may be difficult to understand. Vegetables are cheaper than meat, but the problem is one of balancing the intake of vegetables in order to produce, by human cunning, the amino-acid balance so amply offered by every piece of meat. Different vegetables possess different essential amino acids, but not in the right combination: without the perfect combination of all of them, none of them works properly in the human digestive system. This means that, to produce a safe vegetarian meal, a delicate balance based on biochemical knowledge has to be achieved, employing just the right mixture of botanical elements. This requires patience and expertise and explains why it is that, in ignorant peasant communities, the unavoidable vegetable diet causes so many serious deficiency diseases. As things are at present, an efficient vegetarian diet is essentially a phenomenon of the affluent middle classes. By contrast, a crudely applied vegetarian diet for the masses remains a killer.
Vegetarians are quick to point out that this need not always be so: if advanced nutritional knowledge were applied on a global scale so that a carefully balanced plant diet could be mass-produced in starvation areas, there is hope that the terrible deficiencies caused by the absence of sufficient meat could be avoided. This is clearly a prospect for the future and an important one, since it seems that in any case there will never be enough meat for everyone.
There are additional difficulties, however, because certain crucial vitamins and minerals are missing from a purely botanical diet, even the most expertly balanced one. Clearly the vegetarian movement, despite its good intentions, is fighting against nature, and its unequal struggle will continue until that far-off day when our biochemists have eventually succeeded in creating a complete synthetic diet from basic chemicals for us all to eat.
If meat is necessary for nutritional reasons, it must be admitted that its consumption makes hypocrites of many of us. Modern citizens love their joints of meat and their steaks, but how many of them would be prepared to carry out the killing, the degutting and the butchering themselves? Isolation from farming and from hunting has made us squeamish. We live in an age of specialization, when matters of life and death are kept discreetly at a distance. If we had to do the killing, many more of us would resort to the vegetarian or vegan solution than do so already. Those who market our food are well aware of this, which is why so much meat today is displayed in shapeless cellophane packets which give no hint of its natural animal origins. It is abstract food for a generation that prefers not to associate the meat it eats with the animals from which it comes.
There is nothing shameful about killing animals solely as a source of food. What is shameful, however, is the manner in which we treat many of them before we kill them. We all have to die, both humans and non-humans, but neither we nor they need to live miserable lives. There is no excuse for inflicting pain, frustration or deprivation on any of our food animals at any stage in their lives. Death may be inevitable but cruelty is not. If we must eat meat, then we must ensure that the animals we kill for our food live the best possible lives before they die. Anything less is a betrayal of the Animal Contract.
Further scrutiny and scientific answers are needed in response to welfare questions being raised about such issues as antibiotics in animal feeds; hormone implants; pesticides in food production; the diet-health and nutrition controversy; food safety; feeding grain to farm animals versus hungry people; environmental issues (livestock grazing, methane production, manure management, deforestation, public lands, energy use, water use, etc.); genetic engineering and biotechnology (bovine and porcine somatotropin). Responses such as "Animal Agriculture: Myths and Facts" (Animal Industry Foundation, P. O. Box 9522, Arlington, VA 22209) and "Myths and Facts About Beef Production" (National Cattlemen's Foundation, P.O. Box 3469, Englewood, CO 80155) have been formulated and distributed to interested persons.
Animal rights and animal welfare have biological, cultural, economic, social, philosophical, emotional, political, legal, and policy dimensions. Hundreds of organizations are active in some aspect of these issues. Viewpoints range in a continuum from animal rights advocates to livestock producers (Getz and Baker 1990).
The animal welfare issue is not going to go away. Continuing to cloud the issue is the subject of animal rights along with humane care and treatment, especially of laboratory (research) animals. The present-day animal rights movement has civil disobedience precedents, starting with Thoreau and continuing through Gandhi, Martin Luther King, Viet Nam protesters, and anti-abortion activists. Similar to the environmental movement, widely divergent differences about animal care and well-being seem to be headed toward regulations and legislation (Albright 1986).
Before 1991, 12 States had enacted legislation prohibiting individuals from entering an animal facility with intent to destroy property or injure animals. Since that time, other states have passed similar bills. States with legislation include Arkansas, Arizona, Colorado, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Minnesota, Missouri, Montana, Nebraska, New York, North Carolina, North Dakota, Oklahoma, Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington and Wisconsin. Although each State's bill is somewhat different and legislation in some States does not include agricultural facilities, it is interesting to see how the momentum has shifted toward such legislation. Only a few years ago such action would have been viewed as unnecessary.
Legislative activity is not limited only to States. The Animal Enterprise Protection Act of 1992 was signed on August 26, 1992, by President George Bush. Congressman Stenholm (D-TX) said in his introductory remarks: "Criminal terrorist activities will continue unless the full power of the legal system is used." The bill was sponsored in the Senate by Senator Heflin (D-AL). Need for such national legislation was brought to light when it was revealed that more than 100 acts of terrorism, vandalism (including animal liberation), and other illegal acts had been reported in the United States in recent years, yet only one conviction had resulted. Current laws do not adequately cover this type of illegal activity. (Johnson 1991, 1992, 1993; Kopperud 1991).
Geoffrey S. Becker, Specialist, Environmental and Natural Resources Policy Division, prepared a 43-page report for Representative Stenholm on State and Federal laws relating to the welfare of farm animals. In summary, the report states:
Animal protection activists in the United States are seeking modifications (or even curtailment) of many practices long considered acceptable and necessary to animal agriculture. Examples include rearing large numbers of cattle, hogs, and chickens in close confinement; performing surgical procedures such as castration, tail-docking, or beak-trimming; housing layer hens in cages; and isolating veal calves in crates.
Currently, no Federal law prescribes standards for on-farm handling and care of animals, although two statutes do address the humane transport and slaughter of livestock. All States have anti-cruelty laws, which can -- but do not always -- cover farm animals. Many States regulate the transport and slaughter of farm animals, but few if any address on-farm activities.
Recent surveys suggest that most people still support agricultural uses of animals (as do many animal protection groups), and they believe that farmers generally treat their animals humanely. However, many also appear to support some government regulation to insure humane treatment, the surveys suggest.
Animal agriculturists insist they are concerned about and understand their animals' welfare needs and would be economically foolish to ignore them. They express worry about misguided efforts by uninformed critics that could lead to the imposition of mandatory, unworkable regulations harmful to producers and animals alike. Producer education and voluntary guidelines are more effective ways of assuring animal welfare, they believe.
But many animal protection groups contend that producers' efforts fall short, in part because today's intensive farming systems perpetuate standard practices that may be harmful to animals' well-being. (The more radical animal 'rights' groups believe man has no right to use animals for any purpose.)
Conventional agricultural interests have always deployed strong scientific and economic arguments in defense of their industry. However, the 98 percent of the population no longer residing on farms holds an extremely wide range of moral and religious beliefs about man's relationship with other animals -- which ultimately could carry more weight in future policy decisions than traditional economic and scientific arguments (Becker 1992).
Abuse -- Obvious cruelty; striking or willfully harming an animal with a club or instrument of harm.
Ahimsa -- Doctrine of non-violence or non-killing (from Sanskrit a without, himsa injury); Hindu, Buddhist, and Jainist philosophy.
Animal husbandry -- The proper breeding, feeding and care of animals, especially farm animals. Some modern dictionaries substitute the word "science of" for "proper" in the definition. Unfortunately, the term "husbandry", fell from grace about 30 to 35 years ago. Universities substituted "science" for "husbandry" in the names of animal, dairy, and poultry departments. Position titles were changed to create "animal scientist." At the same time, an emphasis on basic research and an overt de-emphasis on husbandry-related issues were initiated. The trend continues.
Animal rights -- The concept that animals have rights that are equivalent to, or even supersede, those of humans; implies that animals should be used for no other purpose than for the benefit of the animals themselves.
Animal welfare -- The concept of using animals for human ends but minimizing pain, stress, suffering, and deprivation and enhancing the animals' well-being during their lifetimes.
Anthropomorphism -- Ascribing human traits to animals, gods, etc.
Confinement -- Imprisonment; restriction of freedom.
Cruel -- Having or showing indifference to or pleasure in another's suffering.
Deprivation -- Loss of desired thing; refers to implied cruelties such as limiting an animal's freedom or association with others of its kind.
Ethology -- The study of behavior of animals in the wild, under conditions of domestication, or in the laboratory for the purpose of confirming field observations. Emphasis is on the evolutionary perspective, particularly the adaptiveness and modification of behavior for the animal's natural environment, be it the wild, zoo, farm, laboratory, or home. This information aids in appraising animal health and welfare.
Liberation -- Setting free.
Neglect -- Denying a vital requirement such as food, water, or shelter to an animal under one's care.
Protect -- Keep safe, defend, or guard a person or thing from or against danger.
Speciesism -- A prejudice or bias toward the interests of members of one's own species and against the members of other species.
Vegetarian -- Persons who do not eat meat, poultry, and fish. Vegans are vegetarians who abstain from eating or using all animal products, including milk, cheese, other dairy items, eggs, wool, silk, or leather.
Vivisection -- Act of operating or experimenting on living animals for medical or scientific research.
Many of the above videos are available from:
Animal Welfare Information Center
USDA, National Agricultural Library
Document Delivery Services Branch, 6th Floor
10301 Baltimore Blvd.
Beltsville, MD 20705-2351.
Note: The five videos (8-12) above are the Dr. Jeff Goodwin Series of Educational Videos.
Thomas G. Hartsock
Department of Animal Avian Sciences
University of Maryland
College Park, Maryland 20742
J. David Barrett
Associate Director Field Operations
Virginia Cooperative Extension
117 Hutcheson Hall
Virginia Tech
Blacksburg, Virginia 24061-0402
Gary Davis
Department of Poultry Science
Box 7608
North Carolina State University
Raleigh, North Carolina 27695-7608
Cheryl Schwanke
Dairy Science Department
1675 Observatory Drive
University of Wisconsin
Madison, Wisconsin 53706-1284
Lowell W. Wilson
Department of Dairy and Animal Science
324 W. L. Henning Building
The Pennsylvania State University
University Park, Pennsylvania 16802-3503
Shows, fairs, and exhibitions have become annual traditions in many parts of the country. As the general population has shifted from rural to urban, with less than 2 percent of Americans now living on farms, the majority of spectators are now urban dwellers. It is extremely important to recognize that fairs, shows, and exhibitions represent the only direct contact that many urban dwellers have with farmers or farm animals.
Local, county, State, national, and international fairs, shows, and exhibitions have provided the format within which significant genetic selection decisions have been made for many domesticated animals. Judges who are experts in rating animals according to current industry or breed standards rank individual animals from "best" to "worst" in a series of classes. The economic value of breed and show champions, as well as their relatives and descendants, is enhanced by this process.
Although these gatherings have for the most part been open to the public, in years past a large proportion of the observers had a direct interest in the outcome of the animal judging competitions. This was particularly true of rural agricultural fairs where producers gathered information to make decisions on breeding stock purchases for the following year.
With the increasing use of performance testing and the availability of ultrasound and other noninvasive techniques for accurately determining body composition, the value of show ring evaluation as a genetic selection tool has diminished and will continue to do so. Due to decreased entries, some urban fairs have replaced traditional show ring competitions with live-animal educational exhibits and demonstrations. The tradition of culminating 4-H and FFA projects with live-animal exhibitions is likely to continue, but these exhibitions represent only the final stage of the educational process built into the youth projects. The opportunity for youth to demonstrate what they have learned and accomplished is probably more important than the genetic evaluation aspect of the exhibition.
A well-planned animal exhibition should be an educational experience for both participants and spectators. Animal care and management at the show site should reflect the best management practices routinely carried out at home. County Extension agents and State Extension specialists provide educational information about care and management of animals. They can also provide information about unique conditions encountered in show situations. It should always be remembered that fairs and other animal exhibitions are the windows through which urban dwellers and the general public view animal agriculture.
Training and preparation for the show and for the associated fitting and showing competitions yield great benefits in promoting direct contact and interaction between youth and their project animals. But the competitions may have been over-emphasized with respect to the overall goals of the youth projects. In some counties and States, the auction sales associated with the 4-H fairs and shows are big dollar events, with champions selling for 10 to 20 times their commercial market value.
The profits associated with show ring champions have spawned an industry devoted to producing potential champions. Some youth are able to purchase higher priced show steers, club lambs, club feeder pigs, dairy calves, etc. from breeders who produce animals that will catch the judges' eye. In addition, illegal or unethical chemical applications, surgical techniques, and physical training regimes to increase muscle size and definition are sometimes used to artificially enhance the appearance of show animals. Blood and/or urine testing of champion animals is now routine at some shows to discourage attempts to use unacceptable practices. Show rules must ensure that physical or chemical abuse of animals will result in immediate disqualification.
Although most exhibitors have received training on the farm or as part of their project and are good animal handlers, those involved in such things as sheep-shearing contests, herding animals for transport, and similar activities may appear to be handling animals in an unacceptable manner. Extension personnel and show officials who are involved should caution and offer instruction to exhibitors and competitors who might mishandle animals, and be prepared to intervene if animals are being abused. It is also important to take the time to explain to spectators proper handling and management techniques and the reasons for them.
If animals are injured in any way, they should be attended to immediately. Minor cuts or wounds should be treated by exhibitors. Animals with more serious injuries or illnesses should be treated promptly by a veterinarian. The show management should have a veterinarian on duty or on call at all times.
The management should regularly monitor livestock housing areas for possible overcrowding, frequency of stall cleaning, amount of bedding, and methods of livestock restraint, and should make sure all animals are regularly fed and watered. In addition, show management should be alert for any practices that are unacceptable or that could be perceived by the general public as being unacceptable.
Nearly all people who work with animals and show them are aware of the growing size and impact of the animal activist movement. Several national animal activist organizations have state and local affiliates, and many are well financed. They conduct extensive educational and public relations programs, employing famous people as spokespersons. They may have individual agendas and compete for financial support, but they often work together to influence legislatures, corporate boards, and other public policy decision makers.
While often thought of as a unified effort, in reality the animal activist movement is made up of many groups with widely differing philosophies. The more extreme groups are against the use of animals for any purpose; on the fringe are those who are against even the keeping of pets.
More moderate animal welfare or protectionist groups recognize that plants and animals serve each other's needs and that human use of plants and animals is justifiable and natural. However, most animal protectionist groups want humans to use fewer animals and keep animals in conditions that are less confining and more "natural." Their main goal is to make sure animals are raised, handled, and slaughtered or euthanized as humanely as possible. Farmers and others who work with animals have much in common with these organizations and should communicate with them more effectively.
Strategies of some of the more radical activist groups include acts of civil disobedience during public demonstrations, as well as illegal raids on animal facilities to destroy property and steal animals. Legislation passed in 1992 (Animal Enterprise Protection Act of 1992) gives Federal protection from such illegal acts against animal facilities, including those used for animal exhibitions.
Livestock shows and sales are easy and effective places to focus public attention. Show managers, FFA advisors, and 4-H leaders should prepare for upcoming fairs and shows by knowing what local animal activist groups advocate, how they operate, and how to proceed if demonstrations occur. Overall site security should be evaluated and increased if necessary.
If animal rights demonstrations are expected, show managers should designate an even-tempered, knowledgeable individual to take charge and to serve as a spokesperson. This lead person may be the show manager, livestock superintendent, member of the fair board, or other responsible person.
Other individuals should be assigned by the lead person to monitor demonstrators' activities while they are on or near the show grounds. Monitors should:
If trouble is anticipated, the lead person may find it useful to inform local police ahead of time so they can have units in the vicinity. Any communication with police must be coordinated with officials in charge of the show and the persons in charge of the facility where the activity is taking place.
Avoiding confrontations is of utmost importance. Animal activists who picket or demonstrate at livestock shows or sales are not there to try to change exhibitors' minds about raising livestock; they are there primarily to influence the attitudes of the general public. Anything that calls attention to their actions gives them publicity and could turn the activity into a media event. It is best for those involved with the show to avoid arguments and to give positive responses with facts. This is often best accomplished by directing demonstrator and media questions to a single spokesperson.
Remember that everyone has a legal right to express his or her opinion as long as they obey the law. However, no one may enter private property without permission or disrupt properly scheduled events staged in public areas.
Although group members should not confront demonstrators, the demonstrators might move from the demonstration area to confront individuals. If they disrupt ongoing activities, they should be asked to stop. Under no conditions should physical force be used against the demonstrators. If demonstrators are unlawfully disrupting planned activities, inform the lead person.
The lead person may find it useful to speak with the demonstrators to find out who their leaders are and what organizations they represent. It is important to use common sense and not get angry or call the police prematurely. A businesslike approach might allow the lead person to work out some "ground rules." It could also provide an opportunity to inform the demonstrators of the purpose of the group's activities and permit them to get to know the group. People who know and respect each other have a better chance of getting along, despite their differing philosophies.
Although radical activists receive much attention and press coverage because of their tactics, their numbers are actually very small. Of far greater significance is the much larger group of people who use animal products but who have legitimate consumer concerns about how those products are produced. Not everyone who asks probing questions will be an animal rights activist. Most contacts will be with people who are trying to find out more about how animals are raised and used. Take the time to answer their questions and explain what is being done and why.
One of the primary purposes of youth animal projects is to train today's young people to be tomorrow's responsible adults. 4-H and FFA members learn and practice the best ways to house, feed, manage, and care for animals. Project members work closely with small numbers of animals. This allows them to get to know animals as individuals, to gain a real appreciation for their needs and welfare, and to feel the loss associated with marketing an animal. Youth programs are probably society's best hope for producing future farmers who are aware of and sensitive to the needs of the animals under their care.
T.E. Schwedler
Aquaculture Health Specialist
Aquaculture, Fisheries, and Wildlife Department, G08 Lahotsky Hall
Clemson University
Clemson, South Carolina 29634
and
S. K. Johnson
Fish Disease Specialist
Wildlife and Fisheries Science
Texas A & M University
College Station, Texas 77841
currently:
Aquatic Animal Disease Specialist
Texas Medical Diagnostic Laboratory
Drawer 3040
Texas A & M University
College Station, Texas 77841-3040
Production agriculture has enabled the United States to become the best fed society in the world and is vital in domestic and international trade. An important segment of production agriculture, livestock production, has successfully provided consumers with a low-cost, wholesome protein source. Consumers have dictated low prices and high quality. Consequently, to maintain competitiveness, producers have set management objectives that maximize production while minimizing costs. In addition to public concerns about cost and wholesomeness of animal products, there is growing concern for the well-being of the animals while in the care of the producers. Most animal farming systems are designed to maximize production; however, proper care and good husbandry practices are linked not only with high productivity, but also with animal health and well-being. Producers must make a conscious effort to ensure the well-being of animals in their care. The argument is often made that attention to animal welfare can adversely affect profitability. In most systems, however, improved health and well-being translate into better animal performance. Both animal welfare and environmental quality protection are the responsibility of producers, and appropriate management inputs should be factored into production costs. If production costs increase significantly, the consumer will either have to pay higher prices or face limited supplies caused by producers being forced out of business.
Aquaculture, the raising of animals or plants in an aquatic environment, has received considerable attention during the past two decades as an alternative farming practice. Aquaculture has enabled society to enjoy fish for food, pets, and recreation and contributes to the preservation of certain threatened aquatic species. Concurrent with aquaculture development, concern for the welfare of the animals grown in aquatic systems has become an increasingly important issue with certain segments of society. The goals of the aquaculturist and concerns over animal welfare are not necessarily at odds. With careful planning and proper management, fish can be cultured to meet production and profit goals while maintaining aquatic animal health and well-being.
Both the general public and the producers must understand the needs and health status of the animals being produced. However, concern should be based on scientific facts about the animals' well-being and not solely on perceptions. It is generally easier to identify with the welfare needs of animals that are more closely related to humans, such as primates and other mammals. Understanding of the well-being and care of lower vertebrates, such as fish, is usually less. Assessment of animal well-being should be based on subtle behavioral and physiological changes as well as established environmental limits.
The number of aquatic species is vast and their needs vary greatly; this publication addresses primarily finfish. New species of fish from the approximately 20,000 species worldwide are being evaluated and adopted as candidates for aquaculture. The optimum health requirements for major farm-raised species are known. However, requirements for other species are being determined by ongoing research that aims at defining the unique limits of each. Consequently, the amount of information available concerning health requirements varies considerably depending on the species. An understanding of the health requirements for a species increases with the length of time it is commercially cultured and its economic importance. We know much more about how to evaluate the well-being of traditionally grown species, such as channel catfish, goldfish, fathead minnows, golden shiners, and rainbow trout than we do about newer aquaculture species.
This document describes some basic requirements of cultured finfish and suggests management strategies to help ensure their well-being. It describes aquaculture systems and discusses how fish sense and react to the external environment and respond to stressful conditions. Additionally, it presents management options that can effectively address both the goals of commercial production and the well-being of the fish being produced. It is intended to provide aquaculture producers and the general public with scientifically based information on which to base procedures for the care and husbandry of aquatic animals raised in commercial production systems.
Finfish aquaculture is commonly classified according to (1) consumer use of the farm-raised product or (2) the environmental requirements of the fish being produced.
Aquaculture classifications based on the environmental requirements of the fish being cultured commonly use the criteria of water temperature and salinity. Each classification has an optimal range of environmental conditions where a fish species thrives and a larger range where they survive.
While these classifications are somewhat arbitrary, they are helpful when discussing basic environmental requirements and the well-being of fish grown in different aquaculture settings.
Regardless of the type of aquaculture based on the previous classifications, fish can be cultured in many different systems. Each type of system can have different effects on cultured animals. To address the management inputs required to maintain the health and well-being of the fish within a system, it is important to understand the type of system in which the fish are grown. Each of these systems has specific sets of conditions that can be controlled by the producer, resulting in a graded level of management responsibility.
Pond systems may be classified by the level of intensification or the degree of management necessary to produce the quantity and quality of fish desired. The least intensive system offers the producer few control options, and management requirements are low. Management inputs include stocking and harvesting control to establish a balanced relationship between predator and prey species (i.e. a bass and bluegill sunfish pond). The major management strategy is to control the species ratios of the original stocking and to control subsequent harvests. The productivity of fish in the culture system depends on the natural fertility of the pond.
The next level of intensification involves the use of inorganic fertilizer, consisting of nitrogen, phosphorus, and potassium (NPK). Management efforts are similar to those described previously, but now the fertility and production of the pond are enhanced. The fertilizer increases production of plants (primary productivity) and of the small aquatic animal life that feeds on these plants. This increased food supply results in as much as a five-fold increase in fish production.
The productive capacity of the system can be further increased through supplemental feeding. By providing commercial feed, the number and weight of fish per unit volume of water can be greatly increased. The factor limiting production is usually dissolved oxygen. Oxygen supply usually limits the total weight of fish to about 1,500 pounds per acre per year. While the weight limit varies by species, the likelihood of oxygen depletion increases as the total weight of fish increases. It is common at this level of intensification and management to grow a single species of fish. Stocking, reproduction, and feeding rates are managed to ensure that overpopulation or excessive fish weight does not create high-risk conditions.
Management at the next intensification level includes greater control of dissolved oxygen, with the objective of obtaining even higher production rates. This type of system may accommodatae 5,000 to 10,000 pounds of fish per acre, depending on the species grown and the availability of water quality management equipment. Greater inputs of feed cause increased production of waste products by the fish. If the dissolved oxygen is managed effectively, nitrogenous waste products produced by the fish usually become the next production- limiting factor. If stocking and feeding rates are not carefully controlled, the concentration of un-ionized ammonia and nitrites can increase to undesirable or dangerous levels. Nitrogenous waste becomes a limiting factor because of the limited capacity of the pond biota (primarily algae and bacteria) to convert the waste products into less harmful byproducts. The amount of nitrogenous compounds that can be effectively processed and removed on a daily basis in this type of system is about 3 pounds of nitrogen per acre per day. This translates into about 100 pounds of 32-percent protein feed per acre per day. These values can change with different climates, environmental conditions, and fish species.
All of the systems described thus far are pond culture systems that require little or no water exchange. They rely on physical, microbial, and/or photosynthetic processes to remove waste products released by the fish.
Other aquaculture systems for commercial and research use require specific management practices and typically contain aquatic stocks of high density. These systems are referred to as intensive culture systems. Fish density is usually expressed in number of fish or weight of fish per cubic foot of water and/or by the flow rate. These intensive culture systems require the highest degree of management, which is aided by system design. Intensive culture systems include net pens or cages, raceways, and recirculating systems.
Net pen or cage culture systems involve the stocking of high numbers of fish per cubic foot into enclosures placed in large bodies of water. Water quality management within the cage is one of the primary tasks of the producer. For good water quality, water must flow through the cage at a rate sufficient to remove the water containing the fish wastes and replace it with cleaner water containing suitable concentrations of dissolved oxygen. The next management task is to ensure that the fish are stocked at the proper density. This provides for adequate lateral swimming space and limits aggressiveness resulting from dominance behavior. Under good management, certain fish species (i.e., catfish) can be grown at densities as high as 10 pounds per cubic foot of enclosure. Another important management strategy is making sure that the fish are fed a "complete" diet -- one that contains all the essential nutrients. The quality of the feed used in any intensive culture system is critical because the fish have limited access to natural food sources.
In raceway production, continuously flowing water provides fish with a high-quality environment. The water flows through the system and is discharged before the water quality degrades. Fish density of a raceway system is determined by the flow rate and quality of the incoming water. Stocking rates are high in these systems, and the lateral swimming space requirements for each species has to be known. Water flow velocities must be maintained below a critical level to avoid excessive exercise, which can cause stress. Trout, for example, are commonly grown at densities as high as 2 to 3 pounds per cubic foot of water and catfish at 10 to 15 pounds per cubic foot of water without any adverse effects, if suitable water quality is maintained. Supplemental aeration and oxygen injection are commonly used to enhance production in raceways. Because water quality is controlled more by physical factors than biological factors, problems that result from environmental stressors are usually limited. Generally, problems in raceway systems are caused by system failure (reduction or cessation of water flow) or the introduction of disease organisms into the facility.
Recirculating culture systems can be complex and are the most difficult aquaculture system to manage. The usual intent of this culture method is to limit new water inputs to about 5 to 10 percent replacement per day. Such control attempts either to control water temperature within a specific range or to limit water usage. The water that flows through the tank or trough is collected and filtered both mechanically and biologically to remove waste products before returning to the fish culture unit. Though the basic principle of this type of system is sound, backup systems are required to maintain water movement and quality within established critical limits. The most common problem with this type of system is biofilter overload or failure. Additionally, health management can be difficult because practical, legal applications of certain chemicals and drugs are constrained by unique functional features of the system.
Most compounds that will control disease agents also have a detrimental effect on the bacteria that are responsible for removing or converting waste products to nontoxic forms within this system.
The nervous system of fish is similar to that of birds, amphibians, reptiles, and mammals. Their central nervous system consists of a brain and spinal cord capable of receiving and reacting to external stimuli. The central nervous system receives information from the external environment via sensory organs and peripheral nerves. The information is processed in the brain or spinal cord, and the appropriate reactions to the stimuli are initiated. The nervous system transmits both voluntary and involuntary signals to control the action of muscles and glands. Upon stimulation, the nervous system and the endocrine glands integrate to control functions and processes such as feeding and digestion, reproduction, respiration, circulation, osmoregulation, growth, excretion, buoyancy regulation, avoidance behavior, disease resistance, and even body temperature.
While most of the endocrine and nervous system functions found in land animals are also found in fish species, there are important anatomical, physiological, and biochemical differences. A major difference between mammals and birds and most species of fish is that fish cannot control their body temperature. The temperature of a fish varies with the temperature of the water; thus also do its biochemical, physiological, and behavioral responses. While there is some variation, fish generally double their metabolic rate for each 10 oC rise in temperature, within their acceptable range. This becomes important when assessing the health of fish that appear listless, a common response to low temperatures.
An understanding of how fish perceive their environment is helpful when managing their care properly. Fish are finely attuned to their environment by the senses of taste, touch, sight, smell, hearing, and additional senses unique to fish. Sense organs of fish are adapted for life in an aquatic environment and have many sensory structures and functions that differ somewhat or completely from those of land animals.
Sensory functions of fish can be grouped according to the type of physical or chemical stimuli that are detected. The detection of chemical stimuli by the senses of smell and taste may overlap because water is very different from air as a means of transport for chemical substances. Some fish have taste buds on their body that detect the taste of food at a distance. The sensitivity of detection increases as the fish gets closer to the food source. This allows them to locate food even under conditions when it cannot be seen. Fish also have sensory organs called nares, which are similar in structure and function to those in nasal passages of land animals, but it is the water rather than the air that carries the smell.
The perception of physical disturbances by fish is also different from that of higher vertebrates because the density of water is greater than that of air. Orientation and pressure recognition, along with buoyancy control, are important parts of a fish's physical sensory capacity. Hearing in fish is different from land animals because sound waves are received in a liquid medium, and there is no need for specialized structures to translate sound waves from the air to liquid (the ear drum). There is also little need for the external structures that are used in land animals to concentrate sound waves from the air. A fish's lateral line system, which is a sensing system for low-frequency pressure waves, can be thought of as "touch at a distance." This system provides fish with important information about food or predators while some distance away. Additional sensory capabilities in some species can recognize and react to very low levels of electricity. The organs that receive the electrical impulses from the water help the fish to find their prey and avoid predators. This can be important when considering the possible effects of stray electrical currents that can occur in fish culture units.
Sight in fish is similar to vision in land animals. Lens shape varies considerably among species, but the eyes are functionally similar. In some fish species, the small pineal gland in the brain has sensory function in light perception. This function is thought to be responsible for circadian rhythms (biorhythms based on a 24-hour cycle) that control maturation and spawning activity. These senses may require the regulation of light intensities and daily light/darkness regimes to avoid stress in fish.
We do not know the extent to which fish perceive pain as a sensory function. We do know, however, that when fish are presented with conditions that cause pain in humans, they display an avoidance behavior. Pain, as defined in Webster's New World Dictionary, is "a sensation of hurting or strong discomfort, in some part of the body, caused by an injury, disease, or functional disorder, transmitted through the nervous system." The difficulty in assuming similarities between what fish experience and what humans experience is based on our inability to find structures in fish that are similar to those known to sense pain in humans. It is also impossible to ascribe to fish the process of conscious recognition of pain so well developed in humans. While evidence that fish have pain receptors identical to mammals is disputed (Nickum 1988), their ability to identify irritants appears to be well documented. Thus it appears important to avoid conditions that cause a violent response from fish or more subtle physiological changes that are indicative of stress.
It is impossible for humans to understand completely how fish perceive and respond to their environment. Some differences that are not part of our own experiences are how fish perceive acoustical and electrical stimuli and their ability to taste the environment with external taste buds. Possibly even more difficult to understand is how fish perceive touch. An important question to answer might be whether fish have the ability or need to discriminate between tactile stimuli that humans describe as "pleasurable" or "painful." This question is certainly important when considering the well-being of higher vertebrates that have the ability to display their pleasure or discomfort. Because we do not understand the fish's perception, a prudent policy would be to assume that conditions that cause pain in higher vertebrates should be avoided with fish whenever possible.
Fish, like other animals, have both generalized and specific responses to prolonged or repeated exposure to less than favorable environmental conditions. In a manner similar to other vertebrates, fish respond with a specific set of biochemical and physiological changes that help them survive adverse conditions. Some of the changes that occur when a fish is exposed to a stressor are similar regardless of the type of stressor. The types of stressors that can occur in aquaculture are chemical, physical, or behavioral. Because the net effect of a stressor is costly to the fish's energy, stressful environmental conditions become costly to the producer and may result in lower production efficiencies and a poor survival rate.
The overall effect of a stressor on an animal depends on the nature of the stressor and the degree and duration of exposure. Three recognizable stages are common in animals forced to tolerate sub-optimal conditions: a stage of adaptation, a stage of recovery, and/or a stage of exhaustion. The degree and duration of the stressor generally dictates the outcome of the "stress event." If the stress event is limited, fish are often able to adapt to the conditions and reestablish normal function under the new set of conditions. If the stress is removed, fish will generally go through a process of recovery, where they reestablish normal function over a period of time. If the stress is too great for the fish to compensate through adaptation, the fish will enter the stage of exhaustion and eventually die.
Even if fish recover from a stressful experience, important physiological and immunological changes can cause the animal to become more susceptible to disease organisms. The response pattern of fish is less understood than that of mammals and birds, but its key elements are similar. The basic response of fish to a stressor or adverse condition is to adopt an emergency survival status. While some of the responses that occur have obvious benefits to the fish, such as mobilization of energy reserves, other responses appear to have negative effects on long-range survival, such as decreased immune function. It appears that when fish are presented with a stressor, they sacrifice long-term survival strategies to concentrate their efforts on short-term survival.
The overall effect of a stressful environment to fish stocks is reduced performance. Reduced performance may be measured in poor survival, poor feed conversion rates, poor reproduction, and poor feeding and growth. Thus, raising fish in sub-optimal conditions is not to the advantage of the aquaculturist. Understanding the environmental requirements of the fish species and providing proper care and health maintenance to avoid stressful conditions are the keys to the success of the producer and the well-being of the fish.
The basic requirements for the well-being of fish that are raised in an aquaculture facility must be provided by the producer. While fish in the wild are capable of migrating and changing behavioral patterns to meet their needs, fish in an aquaculture facility often cannot seek out optimum or more suitable conditions. To provide fish with a healthy environment, it is important to have both a properly designed facility and a management plan that addresses the needs of the fish. Fish should be provided with their basic needs: sufficient lateral swimming space; good water quality; a nutritionally complete diet; limited physical disturbance; and careful, prudent handling. The producer should also have a health management program that focuses on both infectious and noninfectious diseases. The program should be based on sound information and a thorough understanding of environmental requirements of the fish species and the culture system.
Because there is so much diversity in culture species and culture systems, a responsible management strategy has to be developed for individual aquaculture operations. For example, the management inputs necessary for a less intensive pond system raising an environmentally tolerant species such as the common carp would be low. However, raising the more environmentally sensitive rainbow trout in a recirculating system would require a very high level of management input. Proper management is a requirement for achieving high fish performance in any culture system. A well-designed and properly managed aquaculture facility can produce fish consistent with production goals while maintaining the well-being of the fish.
The number of fish stocked in the culture unit is very important to production goals and the well-being of the fish. Enough fish must be stocked to meet production goals but not so many that management cannot maintain proper health. If stocking rates exceed the carrying capacity of the system, then management to maintain acceptable conditions may be impossible. The influence of stocking rate is expressed in two ways: (1) effects fish have on the environment, and (2) effects fish have on each other. Greater fish densities will result in greater release of waste products into the culture environment. To avoid water quality problems associated with stocking rates, the capacity of the system to remove waste products should be understood by the producer. The carrying capacity of the system is limited by reliable physical and biological processes that have the capacity to remove specific amounts of waste on a reliable basis. Stocking rates should match the quantity of fish to be produced with the carrying capacity of the system. Additionally, the producer should provide the equipment necessary to maintain a healthy environment, and the management necessary to ensure production goals and the well-being of the fish stock.
Assuming that the stocking rate is within the carrying capacity of the system, the next important consideration is fish interactions. Most fish species of commercial aquaculture are characteristically tolerant of the presence of other fish of their own species. This is important in the selection of a candidate species for aquaculture. The lateral swimming space of high fish densities is most important in culture systems such as raceways, tanks, or cages. Depending on the species, limited swimming space may or may not cause stress. For example, catfish have been grown in cages in excess of 10 pounds of fish per cubic foot without a reduction in performance (Davis et. al. 1991). There is evidence that intermediate stocking rates of catfish (below 4 fish per cubic foot) results in fighting and injury. Thus, catfish raised in intensive systems should be stocked at rates that do not exceed the carrying capacity of the system and are above the threshold where fighting commonly occurs. Studies on coldwater fish (salmonids) have demonstrated that an elevated cortisol level (an indicator of stress in fish) is more dependent on dominance factors and inter-specific fighting than on rate of stocking (Li and Brockman 1977).
A fish's natural behavior influences its density requirement. For example, adverse effects of crowding are often experienced with open-water pelagic species and predatory species, but occur infrequently with schooling or socially oriented fishes. Consequently, naturally tolerant species are ones often selected for aquaculture. It is recommended that producers carefully investigate stocking rates to establish criteria that minimize aggression among cultured fish and maintain good water quality.
Management of good water quality is necessary to maintain good production and the well-being of farm-raised fish. Two sets of water quality conditions must be managed. The first set consists of factors that are generally provided within an optimal range for the culture species. Examples are dissolved ions (sodium, chloride, calcium, and bicarbonate), temperature, pH, and dissolved oxygen. The second set consists of water quality factors which, in excess, are potentially harmful to the fish and should be maintained below a specific threshold. This set can be divided into (1) external or introduced toxicants, such as heavy metals, pesticides, and supersaturated gases and (2) natural substances, such as ammonia, nitrites, carbon dioxide, hydrogen sulfide, and suspended solids.
To maintain the health of the fish in the culture unit, it is important to select a water source that meets the requirements of the fish. A culture unit's water supply will often limit the range of species that can be grown. Not only does the ionic content of the water determine the aquatic environment where aquaculture can occur (i.e., saltwater, brackishwater, or freshwater), it can also affect management practices. For example, in freshwater aquaculture, calcium, sodium, and chlorides are very important ions to fish physiology. If they are not present in concentrations high enough for the fish to efficiently utilize them from the water, then a fish can have osmoregulatory (salt water balance) problems. The dissolved ion complex of bicarbonate/carbonate is very important in management because its buffering capacity (total alkalinity) helps control changes in water pH. While all of the important ions can be added to aquaculture water supplies, cost and logistics of such additions make certain water sources impractical for aquaculture.
Table 1. Preferred water temperature ranges for optimal growth for various fish species of different temperature classifications.
| TEMPERATURE CLASSIFICATION | FISH SPECIES | OPTIMAL TEMPERATURE RANGE (C) |
|---|---|---|
| Coldwater | Rainbow trout | 7-13 |
| Coolwater | Yellow perch | 24-27 |
| Warmwater | Channel catfish | 28-31 |
| Tropical | Tilapia | 27-32 |
Temperature of the source water is also very important in selection of production sites. As mentioned earlier, temperature is important in classifying aquaculture systems. Species-specific temperature requirements also make certain climates and water sources preferred for optimal growth (Table 1). While temperature of the water can be changed to meet the requirements of almost any fish species, the cost is often excessive. Rapid water temperature changes will also cause stress in fish. It is generally recommended to change the water temperature slowly at a rate of less than 3 oC per hour. This allows the fish to adapt to a new water quality condition.
The type and concentration of dissolved ions in water must be compatible with the species of fish that are grown within the system. Salinity is a measurement of the ionic concentration of water, primarily sodium and chloride. The salinity of the water greatly affects the physiology of the fish being cultured. Waters can be broadly classified into three basic categories: saltwater -- >20 parts per thousand (ppt); brackishwater -- 5 to 20 ppt; and freshwater -- <0.5 ppt. The strategy that different fish species have developed to maintain internal salt concentrations (osmoregulation) depends on the salt concentration of their natural environment. Saltwater fish have developed mechanisms that help to remove or exclude ions from internal tissues. Freshwater fish have developed mechanisms to concentrate or retain internal ions within their bodies. In fresh water, sodium and chloride should be maintained at a level of at least 10 parts per million (ppm) and calcium at 20 ppm for most fish species. Selection of a fish species that is compatible with the water source is necessary if fish are to be raised under healthy conditions.
The pH of the water in the culture unit should be maintained within a desired range (generally 5 to 9) for the health and well-being of the fish. The pH of the water is dependent on both the buffering capacity (usually total alkalinity) and the biological activity within the unit, including the fish. The buffering capacity of the water controls the degree of pH change in the water which is caused by photosynthesis and respiration. Photosynthesis by plants in the system removes carbon dioxide (the major source of acidity in most natural waters) from the water, causing the pH to rise. Respiration, on the other hand, adds carbon dioxide to the water, thus lowering the pH. The changes in pH that occur in the system are dynamic and can differ from hour to hour depending on conditions. As with other water quality conditions, maintenance of pH within the acceptable range must be considered during facility design and managed during production.
Possibly the most important management task of a producer is to maintain dissolved oxygen at acceptable levels (above 4-5 ppm). The level of management changes dramatically with the intensity of the culture system and is also affected by the fish species raised. There are two basic approaches to managing dissolved oxygen in aquaculture systems:
The passive management approach is to control stocking rates so that dissolved oxygen concentrations in the water do not reach critical levels (below 4-5 ppm). Oxygen can be managed by stocking and feeding fish at low levels, as with low intensive pond culture (feeding under 30 pounds per acre per day) or by designing a raceway system so adequate water replacement keeps dissolved oxygen at desired levels. The critical level depends on the species and their health status.
The active management approach is to introduce supplemental oxygen by mechanical or other means. There are many different designs and approaches, but all supply oxygen to the fish at a rate that will prevent stressful conditions. The two major strategies for supplying oxygen to the fish are, (1) aeration, where the diffusion of oxygen is mechanically enhanced, and (2) oxygenation, where pure oxygen is delivered into the water. Regardless of the method used, dissolved oxygen should be maintained at acceptable levels to ensure good production and the well-being of the fish.
Of the compounds that are directly toxic to fish, the types that come from sources outside of the system (external toxicants) are the most diverse. It is necessary to prevent the occurrence of these compounds in production systems by proper site selection, water source evaluation, selection of nontoxic materials, and avoidance of any harmful contaminants.
A second group of compounds that are toxic to fish are the compounds that are produced within the system. Some of these are released by the fish as metabolic byproducts (ammonia and carbon dioxide). Others are products of decomposition of the waste products, such as nitrites and hydrogen sulfide. A third group of compounds, produced by other organisms within the system, include bacterial and algal metabolites. Fish waste products are very soluble in water and quickly become incorporated into the water. Metabolites and their breakdown products become environmental problems for the fish if released in excess of a culture system's ability to convert them to harmless forms (Table 2). When more fish are raised per unit of water, the release of metabolic wastes also increases. Fish cultured at high densities without proper waste management can cause poor water quality. This increases the risk that the water will become degraded to the point where fish will experience discomfort. The metabolic byproducts of primary concern are the nitrogenous compounds; of these, ammonia and nitrites are the most important. Proper management of waste products requires careful design of the system to ensure that the waste produced by the