Pet Food & Nutrition: A Necessary Review For Veterinarians
M.E. Smart, C. Haggart, J.A. Mills
This paper reviews the current status of the pet food industry from a veterinarian's perspective. Summaries of market features, regulation and non-regulation are presented. In addition to a review of the industry, we also discuss the value of information currently provided to veterinarians and their clients, and some of its consequences.
2. The Pet Food Market
3. The Changing Attitudes of Pet Owners
5. Customer Information
6. A Conclusion
Two diametrically opposed views exist today on how capable or knowledgeable a veterinarian is in providing their clients with nutritional advice:
The first is commonly held by the pet food industry, government regulators, the veterinary professionals who work for them, and passively by most veterinarians. This predominant view is that because of the pet food industry's commitment to pet health and nutrition, it is providing the public and veterinary profession with regulatory standards, diets, and nutritional information based on the latest research and best knowledge available. Accepting this, the veterinary profession endorses their products without question.
The second view is supported by some veterinarians and a rising number of pet owners and small pet food producers. This view maintains that the pet food industry has wooed the veterinary profession through sponsorship, allowing this industry to frame the discussion on nutrition while gaining credibility from the profession as an unbiased provider of nutritional education. In this view, veterinarians are considered poorly trained in nutrition and yet are respected by the public as guardians of their pets' health and welfare. Veterinarians and veterinary associations actively market individual pet food products because they are controlled by the industry. Some proponents even go as far as claiming that a conspiracy exists between the two. In the meantime, the pet food industry has been able to convince the regulators that scientific nutrition is impossible to provide and that the current compromises are sufficient, while convincing the public that this compromise is in fact the best choice for them and their pets.
Both views vary to different extremes, with adherents to the first view pointing to evidence of increased longevity of canine and feline pets over the years as proof of the pet food industry's success, and with the second group pointing to the widespread health problems that may in fact be caused by diet. Unfortunately, the two sides of this argument leave the veterinarian in the middle, as the supposed holder of the truth and as the scapegoat.
The purpose of this review is to give veterinarians a clearer picture of the complex environment surrounding these issues. We do not intend to lay blame, but to bring to light assumptions and compromises that have been made and to stimulate a higher level of understanding and discussion.
Prevention is considered across disciplines to be the best kind of medicine, and diet is one of the most significant ways that a pet owner can ensure the health of their pets. Veterinarians must provide detailed and scientifically proven dietary advice. To accomplish this, veterinarians must understand both the current scientific, commercial, and regulatory environment surrounding nutritional claims. Armed with this information, practicing companion animal veterinarians will be able to give better advice to their clients and research veterinarians may be able to better identify the numerous gaps in our current knowledge and discern how we can move forward.
2. The Pet Food Market
The United States pet products industry is estimated to reach over US$38 billion in 2006, representing an almost 170% increase since 1998. This increase has been led by the growth in pet food, estimated at US$15 billion (1) in the U.S. These numbers represent a major increase for a developed market that was considered saturated, consolidated, and possibly stagnant as recently as 1990 (2). The global dog and cat food market has shown similar explosive growth, and at over $42 billion (3), it is considerably bigger than the worldwide baby food market.
This growth has attracted new market entrants, the expansion of niche products (vegetarian, therapeutic, "diet", "organic", "ultra premium"), and, perhaps most significantly, the simultaneous consolidation of the manufacturing of pet food. In 2005, the top two producers, Mars Inc and Nestlé SA, manufactured almost 50% of the world pet food market (4). The industry is in continual transition. With the spring 2006 announcements of the acquisition of Meow Mix Co by Del Monte and the Mars Inc. purchase of Doane Pet Care Co. (producer of the vast majority of private label pet food brands) (5), the output of five companies represents over 75% of the pet food sold in the world. One reason that these large conglomerates are so interested in acquiring pet food companies is the potential synergies that result. Animal feeds provide a practical outlet for plant and animal by-products not suitable for human consumption. The pet food industry serves as an extension of the human food and agriculture industries because corporations producing both human food products and pet food products are able to take what would otherwise be waste from the human product lines, and use them as convenient and affordable ingredients in pet foods (6).
Name Brand vs. Private Label Products
Private label pet foods are commissioned, marketed and owned by the retailer as opposed to a manufacturer. Originally, private label products were considered of inferior quality, but now the goals of private label are to produce high quality products at wholesale prices. These companies produce products based on nutrition, palatability, and quality standard equal to the leading Name Brand diets and in some instances they are the same product. In the pet food industry, private label accounts for 21% of the market share and has an annual growth rate of 11% (7). Doane Pet Care Company represents the majority of private label pet food sales worldwide selling to 650 customers worldwide, including Wal-Mart and Disney and offering a full range of pet food products (4). The "Manufactured For" notation on the label differentiates private label diets.
The price differential between the manufacturers of pet foods and the private label is about 40%, which gives one of the few clear indications available on the profit margins of pet food companies (8).
While private labels are reaping some of the benefits of the growth of the pet food industry, it is the activities of their brand name competition that have fuelled the rapid and sustained growth of the industry. A key example is Hill's Science Diet. In 1976, Colgate-Palmolive acquired a then-small pet food producer named Hill's Pet Products. Based on its experience with using dentists to promote its toothpastes (and similar successes in the pharmaceutical and tobacco industries), the company decided to have veterinarians endorse its Science Diet pet food line. Hill's Science Diet obtained these endorsements by providing free pet food to vet students, hundreds of thousands of dollars of research funding at each of the 27 U.S. veterinary colleges, and funding nutrition professorships at many veterinary schools. "The bulk of our expenditure goes to the veterinary community," said a former Colgate's senior vice president of global marketing and sales (8). The success of this strategy is clear: With a fraction of the marketing budget of it's competitors, Hill's has developed from a small company with US$40 million in sales in 1982 to fourth-largest producer of pet food in the world (as part of Colgate-Palmolive) (1) with US$1.5 billion in net sales and an operating profit of US$412 million (10). The success of Hill's led to the other major players in the industry to imitate its successful strategies, and they remain a standard today, though increased direct competition has led to a comparative increase in advertising from Hill's original low rates.
The advantages of veterinarian endorsement as a tactic becomes clear when the other sources of information available to the consumer are considered. The pet food industry spends around US$400 million on advertising in the U.S. alone (11). Additional money is spent on brochures, websites, and attractive packaging (spending on packaging often falls under the category of "Research & Development" in a company's ledgers). Instead of informing, in our experience this barrage of information tends to confuse, overwhelming pet owners' sensibilities towards their pets' nutrition and constituting a continual challenge to the companion animal veterinarian. Some of the reasons for this will be discussed later in this paper, when regulated consumer information is considered. As a result of this situation, pet owners often turn to their veterinarians for dietary advice, since virtually any governmental or commercial material on the subject suggests that owners do just that. But can a veterinarian actually provide positive factual unbiased advice in the face of this advertising and marketing onslaught? With hundreds of new diets and diet-related supplements released annually, each one promising to embrace the latest innovative concepts in pet nutrition, how can a veterinarian keep up and remain knowledgeable without becoming a victim to the same promotional advertising that the pet owner is questioning?
3. The Changing Attitudes of Pet Owners
Much of this industry growth has been driven by demographic conditions and a shift in the role of pets in North America and Western Europe. These changes will have significant consequences for the field of veterinary nutrition.
The Human-Pet Bond
Pet ownership per capita continues to increase. The reasons for this are difficult to discern, but the increasing loneliness of modern life and the newly proven health benefits of pet ownership are often cited. This latter point has been primarily encouraged and publicized through the efforts of the Delta Society and the Pet Food Institute, the lobbying organisation of the pet food industry (12). Delta Society, founded in 1977, is the nation's largest organization promoting the benefits to human health of service and therapy animals. When it was first founded in 1977, it was able to collect more than US$350,000 from pet food companies to conduct research and publish its scientific journal, Anthrozoös. 15 years later, pet food companies felt they had everything they needed and stopped funding, according to Linda Hines, former president and chief executive of the Society (13).
Increased Willingness to Spend
The increase in pet ownership is joined by the increased willingness of owners to spend money on their pets. "The success of premium dog foods in the US has been fuelled by the trend towards the "humanization" of pets. Pets are increasingly regarded as family members, and are often considered as equivalent to children in the level of attention and care they get from their owners" (14)(15). David Lummis, the lead pet market analyst for Packaged Facts, a partner of the American Pet Products Manufacturers Association (APPMA) (16), was quoted by the New York Times saying that "Businesses have tapped into a potent marketing tool by inciting a pet owner's sense of loyalty...This human-animal bond is just being fully exploited by marketers." Mr. Lummis continued: "A lot of it is trading people up to more expensive products, basically, and making people feel like, 'Hey, it's O.K. for me to spend $20 on a bag of dog treats instead of $2.99,' " he said. "These dog treats are going to be really good for my dog, and he's going to love them" (17). It is not surprising that pets are increasingly suffering from the same diet-related health problems as their owners: 34% percent of adult dogs were overweight or obese in the U.S. according to one study (18), with diabetes, hypertension, and heart disease looming larger, as well. One study even found a direct connection, with obese dogs much more likely to be "over humanised" than healthy dogs (19).
Humanization has inspired a growing interest and concern in pet health care, with the options for humans now available to house pets, such as less-invasive surgical techniques, CT and MRI diagnostics, pathology-specific diets, acupuncture, massage, and psychological therapy becoming common. The increased attention that owners are giving their pets will lead to increased scrutiny of nutritional and health claims that are made in the industry. Remember the smoking industry, where doctor testimonials and industry-funded research labs were relied on to determine product safety, or the recent diet pill scandals, where the closeness of industry and government led to approval of unsafe products that were clearly not backed by strong scientific research? The veterinary profession may in the future have to defend the claims and commitments it has made on behalf of the pet food industry.
Over the last decade, the trend has been to identify individual features of diets that are harmful. The written, researched, and legislated emphasis on the "bad" end of the scale for pet foods has left precious little information on what constitutes a "good" pet diet, or what makes one diet better than another in enhancing health or preventing diseases.
According to the Pet Food Institute (PFI), in its Pet Food Report for consumers, "Pet food is one of the most highly regulated of all food products." As we will examine in this section, there are indeed aspects in the industry that are highly regulated and others that remain in effect unregulated.
In Canada, the regulation of pet foods comes under three jurisdictions. Health Canada enforces legislation prohibiting unsubstantiated health claims in advertising and labelling. The Canadian Food Inspection Agency regulates the movement of inedible meat products and the certification of imported pet foods containing animal products. The Competition Bureau of Canada requires that all pre-packaged pet food destined for retail consumption have a bilingual product name, net quantity declaration (in metric) on the principal display panel as well as the dealer's name and address, and if applicable, declare "manufactured for" or "manufactured by", and the geographic origin.
In the United States, the regulation of animal feed comes under the jurisdiction of individual state legislation with the Food and Drug Administration (FDA) and its Center for Veterinary Medicine (CVM) playing a role in specific aspects of regulation.
Since between 85-90% of the pet food sold in Canada is manufactured by large U.S.-owned multinationals (20), and as much as 97% is controlled by US companies (21), the Canadian market is essentially regulated by the FDA and U.S. states in which the individual pet foods are produced.
Both the FDA and Health Canada (22) administer legislation prohibiting unsubstantiated health claims in the labelling of all food. In addition, the FDA is responsible for ensuring that food made and sold in the US is packaged under sanitary conditions, that the food and ingredients are not dangerous. Labelling plays an important role in FDA efforts to fulfill its regulatory mission, which calls for "maximizing the availability and clarity of information to consumers and patients concerning new products." (23). In addition to the Canadian label requirements the FDA requires an ingredient list with the ingredients listed in descending order of predominance by weight, and identified by their common or usual names, including artificial flavouring, colouring, and preservatives. Since pet foods have no requirement for pre-market approval, regulation is only undertaken in the face of complaints and an investigation (24). In other words, the product will most likely be in the consumer's home before an investigation takes place and the product is recalled.
The FDA and the CVM
Within the FDA, the CVM is technically responsible for applying these regulations to "animal food (feed) products." The CVM is busy. With 188 Scientific & Technical Staff and 240 Field Activities staff, the CVM claims to "regulate the activities of 6,600 feed manufacturers and related firms, nearly 300 animal drug manufacturers and other sponsors of animal drug applications and Type A Medicated articles, many thousands of livestock and poultry producers, and firms in a variety of specialized industry groups" (25). In addition to its seven activities for ensuring safe food and drugs, the CVM also lists 14 "Counterterrorism Projects" that it is currently undertaking (26).
In reality, the CVM limits its activities to the regulation of animal drugs, medicated feeds and food additives. Since animal foods that contain drugs or medication are generally limited to medicated feeds for the livestock industry, this leave additives as the only category of active regulation in the pet food industry. The CVM requires pre-market approval for food additives that are not generally recognized as safe (GRAS), but "has used regulatory discretion and not required food additive petitions for substances that do not raise any safety concerns." The applicant only needs to submit information so that it can be added to the list of the Official Publication of the Association of American Feed Control Officials (AAFCO). As a result, food additives are not actively regulated "to conserve agency resources, as food additive approval is time-consuming" (24). In our research, we repeatedly found evidence of regulatory bodies claiming, and then absolving themselves of, specific responsibilities due to resource constraints.
If scientific data are presented that show a health risk to animals of an ingredient or additive, CVM can act to prohibit or modify its use in pet food. Recent examples highlight the fact that the CVM requires scientific proof that a given ingredient is unsafe (as opposed to the opposite), and that a lack of scientific information means that potentially dangerous ingredients continue to be allowed. For example, propylene glycol was used as a humectant in soft-moist pet foods and affirmed Generally Recognized As Safe (GRAS) for use in human and animal food, although it was known for some time that propylene glycol caused Heinz Body formation in the red blood cells of cats (small clumps of proteins seen in the cells when viewed under the microscope), but it could not be shown to cause overt anaemia or other clinical effects. However, recent reports in the veterinary literature of scientifically sound studies have shown that propylene glycol reduces the red blood cell survival time, renders red blood cells more susceptible to oxidative damage, and has other adverse effects in cats consuming the substance at levels found in soft-moist food. In light of this new data, CVM finally amended the regulations to expressly prohibit the use of propylene glycol in cat foods (27).
Another pet food additive of some controversy is ethoxyquin, which was approved as a food additive over thirty-five years ago for use as an antioxidant chemical preservative in animal feeds. Approximately ten years ago, CVM began receiving reports from dog owners attributing the presence of ethoxyquin in the dog food with a myriad of adverse effects, such as allergic reactions, skin problems, major organ failure, behaviour problems, and cancer. However, lack of available scientific data to support these contentions, or to show other adverse effects in dogs at levels approved for use in dog foods means that more information on the utility of ethoxyquin is still needed in order for CVM to suspend or modify its use. While studies are being conducted to ascertain a more accurate minimum effective level of ethoxyquin in dog foods, CVM has asked the pet food industry to voluntarily lower the maximum level of use of ethoxyquin in dog foods from 150 ppm (0.015%) to 75 ppm. Regardless, most pet foods that contained ethoxyquin never exceeded the lower amount, even before this recommended change (27).
Advisors to Industry and Government
The National Research Council (NRC), Association of American Feed Control Officials (AAFCO) and the Canadian Veterinary Medical Association (CVMA), through its Pet Food Certification Program, contribute in establishing the minimum and maximum nutrient intakes required for growth, gestation/lactation, and maintenance in dogs and cats. None have any regulatory powers, but the relevant government departments often use the recommendations they produce when setting regulatory standards. The AAFCO recommendations are by far the most dominant in this respect, and enough states have adopted the AAFCO models to make an international impact.
This is a private advisory body whose members are representatives of individual state government agencies, the U.S Food and Drug Administration and other federal and foreign agencies that share responsibilities in the regulation of animal feed. An FDA representative serves on the AAFCO Board of Directors. Members of the FDA have also served on the AAFCO Pet Food Committee. CVM staff also serve AAFCO on committees and as investigators. We believe that continued partnership with AAFCO is vital to the effective regulation of pet food products because of the limited FDA enforcement resources outlined in this article. For this reason, an important role of CVM staff is to serve as scientific resources for U.S. State Department of Agriculture regulatory officials (28).
AAFCO's self-imposed mission is to develop uniform definitions covering all feed ingredients and their proper labelling. In 1993 AAFCO expanded their role to include the development and publication of the minimum nutrient requirements and testing procedures for pet food claims of "complete and balanced" nutrition.
In 1976, the Canadian Veterinary Medical Association, working with industry, instituted The CVMA Pet Food Certification Program. Their mission is to provide the consumer with an independent quality assurance program and a means of identifying nutritionally sound pet food for all life stages in the Canadian market place. This is accomplished by providing nutritional standards for the certified pet diets and through constant monitoring of the diets to ensure they continue to meet the standards for composition and digestibility. Initially the CVMA adopted the NRC 1974 nutrient requirements for dogs and cats but the CVMA standards "continue to evolve as new scientific information becomes available".
In 2003 the CVMA published the CVMA Veterinary Reference Manual on Nutrition. In this manual, the recommended nutrient profiles are compatible with AFFCO profiles except that the CVMA classification of "all life stages" is the same as the AAFCO profile for "growth and reproduction". Feeding trials are not part of the certification process. To date only pet foods manufactured by Canadian based producers have applied for and received certification.
In 1974, the first National Research Council (NRC) Nutrient Requirements of Dogs was released. An academic panel of animal nutritionists reviewed the relevant published research on the minimal requirements for growth and then supplemented these nutrient requirements with a 20% safety margin. Most of the reviewed literature was based on the minimum nutrient intake that was adequate for growth; biological function was ignored. These nutrient requirements were used by the pet food industry until the NRC released revised editions for dogs in 1985 and cats in 1986. Despite their greater depth and detail, these new requirements were judged inadequate by the pet food industry and never incorporated. The argument against them focused on the fact that the NRC requirements did not take into account the type of ingredients and technologies used to manufacture commercial pet foods, since they were generated from scientific research where purified diets of extremely high digestibility were fed under laboratory conditions (29).
To address the industry concerns, the American Association of Feed Control Officials (AAFCO) appointed a committee that in 1991 produced the AAFCO Nutrient Profiles for Dogs and Cats. Their mandate was to build on the 1974 NRC nutrient requirements and establish practical minimum and maximum limits nutrient levels in dog foods formulated from non purified, complex ingredients. The 1974 NRC values were modified "only where indicated based on the practical experience of the subcommittee members or by new data from the1985 NRC publication or elsewhere" (29). The values took into consideration the various known effects of ingredients and processing methods as well as in the potential for lower digestibility in some of the products (29). AAFCO recommendations also considered the bioavailability of the nutrient source and made allowances in the formulations for losses during processing and storage.
In the spring of 2006 NRC published a new "Nutrient Requirements of Dogs and Cats". The committee's mandate for this new publication was to address the deficiencies found in the 1985 requirements and to produce an updated estimate of requirements based on a comprehensive review. The project started in 2000 and the committee acquired input and data from public and private organizations. They combined this information with a critical review of the published scientific literature to date to produce recommendations "firmly grounded in science".
This publication, according to the Pet Food Institute, has fallen short of its goals of providing a research compendium that is useful to the pet owners, government agencies and in particular, the pet food industry (30). This reaction by the voice of the pet food industry likely means that this publication too will be disregarded like previous NRC recommendations since 1974.
5. Customer Information
"Your best source for finding the ideal pet food is to talk with an expert, your veterinarian. But the choice is ultimately up to you, so be an informed consumer" (31) This is a typical piece of advice for the modern pet food consumer. How does an informed consumer, or even veterinarian (who may have received limited training in nutrition) go about being informed? This section will look at the requirements for pet food products and the information that is provided about them.
The label and promotional materials, included by the pet food producers are terms such as: "precise balance of protein, fat, carbohydrates, vitamins and minerals", "managing caloric intake", "scientifically formulated for proper bone and joint development" These statements, defined by AAFCO as "unqualified claims", are unregulated as they do not provide a specific health claim (which would put it under the jurisdiction of the FDA). The fact that this potentially meaningless information is presented undifferentiated alongside regulated terminology and information packaging serves to dilute any value for the consumer that official terminology might convey beyond that of the emotional plane.
It is important to note that in the U.S., advertising information, such as websites and brochures, are not generally regulated. In comments to the FDA, the Pet Food Institute points out that extra-label communication from companies is protected free speech under the US Constitution, where "even when advertising communicates only an incomplete version of the relevant facts, the First Amendment presumes that some accurate information is better than no information at all" (32). It continues "Nor may FDA argue that such claims should not be allowed because they may be misleading. As the DC Circuit clearly stated in Pearson v. Shalala, "the States may not place an absolute prohibition on ... potentially misleading information ...if the information also may be presented in a way that is not deceptive." This is not the standard for Industry Canada, which states "An industry member must not, directly or indirectly, by way of endorsement, testimonial, award, advertising, labelling, brand, trade name, or otherwise, make any false or misleading representation" (33). Still, due to provisions requiring "national treatment" in the U.S.-Canada Free Trade Agreement (FTA) and North American Free Trade Agreement, (NAFTA), American companies are exempted from regulations like these that would restrict U.S. access to the Canadian market.
The product name, along with the brand, is the first written part of the label noticed by the consumer. Since many consumers purchase pet food based on the presence of specific ingredients, this is a vital piece of information, and a key way for producers to market their product and sway the buying decision. Many, if not most, product names incorporate the name of an ingredient to highlight its inclusion in the product. AAFCO has defined very specific rules about how product names can be formulated. Despite their specificity, and assuming that they are followed by the industry without exception, they are unlikely to be helpful for consumers who have not brought along a chart. Even a minor difference in the wording of the name has a dramatic impact on the potential amount of the named ingredient in the food. For example, a "Lamb Dog Food" would be required to contain at least 70% (by weight of the finished product) of lamb, but a "Lamb Dog Food Formula" would only need to have 25% lamb, while "Dog Food with Lamb" need only be 3% of the headline ingredient. Least informative is the title "Lamb Flavour Dog Food," which needn't contain lamb at all, but must contain an amount of chemical digest "sufficient to be able to be detected by animals trained to prefer specific flavours" (27). Those who have read on the subject will have seen the "Lamb Dog Food" variant referred to as the "95%" rule. This 95% is only a theoretical value, as it does not include a total product that includes water and "condiments for processing (27). The rules become even more complex for pet foods with more than one ingredient in the title. The fact that the FDA needs over 1,000 words to describe these rules to consumers on this one single labelling issue further highlights the fact that while regulated, the product name is clearly not useful for informing consumers (or veterinarians) what they are buying. In its guide, "Interpreting Pet Food Labels," the FDA recommends checking the ingredient list to prevent making mistakes (27).
Ingredients: List by Weight
As much as the product name, it is difficult to judge the quality of the diet from the ingredient list. All are required to be listed in order of predominance by weight. Crucially, the weights of ingredients are determined as they are added in the formulation, including their inherent water content. This means that meat (which is about 75% water) may appear prominently or even first in the ingredient list, though this highly digestible protein source may only contribute a small percentage to the total protein content of the finished product. In contrast, meat meal, a rendered dry product of widely-varying protein digestibility, with a typical maximum of 10% moisture (34)(35), may contribute significantly more to the diet's total protein, though it appears lower on the ingredient list.
Ingredients: Common Names
Ingredients must be listed by their "common or usual" name, which are recognized by the FDA as those listed in the AAFCO Official Publication (36). Since only the AAFCO definitions are considered the "common or usual name," an ingredient that is not recognized by AAFCO is prohibited from use in pet food. The curious consumer can pay US $50 to order this publication to find out what these "common" and "usual" names mean. The definition of meat meal, an ingredient found in many pet foods, is defined in the AAFCO publication as "the rendered product from mammal tissues, exclusive of any added blood, hair, horn, hide trimmings, manure, stomach and rumen contents except in such amounts as may occur unavoidably in good processing practices" (27)(29). Being strictly industry terms, it is doubtful that consumers or veterinarians will understand these "common" names and what constitute "good processing practices."
This situation is partly a result of the fact that the pet food industry (including what it considers a "common name" or "good processing"), from its inception, has been an outlet for the animal rendering industry. This industry provides an invaluable service in re-purposing uncountable tons of "waste" towards an audience that is not as picky as the western-culture human consumer. Today, this argument has been weakened, as meat and bone meal are being increasingly used as a fossil-fuel replacements for renewable energy generation, containing about two-thirds the energy value of coal (37)(38).
Instead of working to clarify these issues for increasingly concerned customers, the feed industry has consistently resisted specifically naming what goes into rendered products (chicken meal, bone meal, etc.). Both the National Grain and Feed Association (NGFA) and Pet Food Institute (PFI) have opposed regulation that would require producers to clarify AAFCO-approved (but vague) terms like "animal protein products" with an actual breakdown of which animals are involved and in what proportions (When asked about the presence of dogs and cats ending up in rendered food products, the then AAFCO president, Hersch Pendell, said: "If the ingredient says meat or bone meal, you don't know if it is cattle, or sheep, or horse...or fluffy" (39)) The arguments against such clarification include increased cost and inefficiency of pet food production. Perhaps most telling, the NGFA and PFI (both "strategic" partners of AAFCO) claim in response to this subject that "AAFCO's model regulations, which are adopted by most states, are designed to enhance uniformity in state feed regulation (40). Although "animal protein products" are not an AAFCO-approved ingredient for pet foods (it is for livestock feed), the participation of the PFI makes clear the pet food industry's stake in the issue. Clearly, the emphasis of regulation here is on successful regulation as an end unto itself, not in providing meaningful information for the consumer or veterinarian. Reducing the current regulatory scheme to simply requiring the term "feed" on the label would also greatly enhance uniformity in state feed regulation. The fact that the current regulation is being defended by the direct voices of the regulated industry in question makes clear whom the rules serve. The U.S. state that proposed the changes claimed that the proposal would facilitate enforcement of FDA regulations and provide more information to consumers (40). It is clear that one must look beyond the ingredient list for clear information on the nutritive value of a pet food.
The Guaranteed Analysis
This element is another piece of regulated information required according to FDA and AAFCO standards, listing the minimal amounts of crude protein and crude fat and the maximal amounts of water and crude fibre on an as-fed (not dry-matter) basis. Instead of specifying the actual amount of protein, fat, water, and fibre in the product, it only indicates the legal minimums and maximums in the product. If these seem a bit superficial for dog and cat foods made of complex ingredients, keep in mind that this same analysis is applied to all animal foods, including livestock feed grains, where it is more useful. The greatest advantage of these standards is that they are very easy to measure, reducing the resources needed to keep the industry tightly regulated. A pet food producer may also choose to include a laboratory proximate analysis, which lists the actual nutrient concentrations in the food. This is much more useful, since two foods with the same guaranteed analyses may differ considerably in actual nutrient content.
Nutritional Adequacy Statement
While much of the current regulation may seem to be the result of historical or political forces, and lacking in helpful information, veterinarians should take a closer look when the industry comes to the issue of proof. Today most small animal veterinarians will recommend diets that meet or exceed AAFCO standards. The standards for the claim 'formulated to meet ---"are the 1991 nutrient profiles for growth/gestation and lactation or maintenance. Nutritional adequacy statements based on feeding trials means that the product, or "lead" member of a "family" of products, has been fed to dogs or cats under AAFCO guidelines and found to provide proper nutrition. These products should bear the nutritional adequacy statement "Animal feeding tests using AAFCO procedures substantiate that (name of product) provides complete and balanced nutrition" (29). These two claims represent only the minimum standards for maintenance, gestation/lactation and growth stages, yet they are the justification made on packaging for the "complete and balanced" claim.
The nutritional adequacy statement will also state for which life stage(s) the product is suitable, such as "for maintenance," or "for growth." A product intended "for all life stages" meets the more stringent nutritional needs for growth and reproduction. On the other hand, an "all life stages" ration can be fed for maintenance. Although the higher levels of nutrients would not be harmful to the healthy adult animal, they are not really necessary. A maintenance ration will meet the needs of an adult, non-reproducing dog or cat of normal activity, but may not be sufficient for a growing, reproducing, or hard-working animal.
A product may be labelled for a more specific use or life stage, such as "senior" or for a specific size or breed. However, little information is available as to the true dietary needs of these more specific claims, and no rules governing these types of statements have been established. Thus, a "senior" diet must meet the requirements for adult maintenance, but no more. A product that does not meet either of these methods must state, "This product is intended for intermittent or supplemental feeding," except if it is conspicuously identified as a snack or treat. Neither AAFCO nor the states responsible for regulation conduct the trials. Rather, the trials are either run by the company itself or by a contracted facility, and the company then attests to the results. This makes it harder for the regulator to verify that the trials were run competently and without bias or conflict of interest and that the data are accurate.
Feeding Trial Protocols
The AAFCO protocols for dog food trials require a minimum of eight healthy participants. The breed distribution must be similar for both test and control groups. A maximum of two dogs or 25% can be removed from the trial for non-nutritional reasons or poor food intake. To test an adult maintenance diet, dogs over one year of age and of optimal body weight are fed the test diet for 26 weeks. To test a gestation/lactation diet, eight bitches past their second heat period are used. The trial begins at or before oestrus and ends when the puppies are four weeks of age (about 14 weeks in total). To test a growth diet, eight puppies (four males and four females) from 3 different bitches are required over a 10-week test period following weaning.
At the end of the trial, all data collected is compared to a historical colony average of 30 peer dogs fed a diet that has passed the minimum feeding protocol for adult maintenance or gestation/lactation, or data from a concurrent control group of eight dogs fed an approved diet or to a standard data set established by AAFCO.
This means that the "complete and balanced" nutrition claim can be justified from a single short-term feeding trial. The claim to the pet owner is that by meeting the AAFCO standard for growth, all the nutrient needs of the pet are met, for a long-lasting healthy productive life. The protocol for "growth" does not even cover the full growth stage of puppies - after the ten-week test period, large breed puppies will be just under 50% of adult body weight while a puppy from a breed with an average body weight of five kilograms will be at 64%.
Also, because some aspects of the trial depend on subjective assessments, subtle signs of nutrient inadequacy may be missed. The pre-trial status of the test subjects could also affect the results, especially for maintenance trials. For example, a vitamin A deficiency may not manifest itself over the course of the trial if the animal had large body stores of vitamin A prior to initiation of the test (41). These AAFCO trials for growth also do not evaluate any parameters associated with normal skeletal growth (42).
Feeding Trial Approval Without Trial
Products bearing nutritional adequacy statements using the "Animal feeding tests following AAFCO procedures substantiate that..." verbiage may or may not have been actually tested. An additional statement that the family member is nutritionally "comparable" to a tested product is allowed, but to date has not been used by industry. This is because of a nuance in the regulations that allows family members to bear the exact same statement as the lead members as long as they meet the following criteria:
Be from the same company
Be of the same processing type
Be in the same moisture category determined by the same analytical type
The dry matter Metabolizable energy determined by the same method must be within +/-7.5% of the lead product
Meet the laboratory determined dry matter nutrient levels and ratios of the tested product for crude protein, calcium, phosphorous, zinc, lysine, and thiamine.
All other nutrients in the AAFCO Nutrient Profiles shall be formulated to meet or exceed those of the lead family product or the AAFCO Nutrient profiles whichever is lowest and must not exceed the maximums established by AAFCO (29).
Apparently there was concern as early as 1994 regarding the application of the family concept by manufacturers, and AAFCO was said to be considering new model regulations (43). Twelve years later, both products directly tested and those approved via the "family" method are allowed to bear the same adequacy statements.
Manufacturers disagree as to which method, animal testing or nutrient profiles, is superior. Realistically, both methods have shortcomings. The nutrient profile method does not test nutrient bioavailability in the same way as the "feeding test" method. Nor does it test the palatability of the foods. In contrast, the "feeding test" method doesn't always test the actual product sold. Because of the AAFCO "family member" rule, products that are nutritionally similar to other products tested under the "feeding test" method do not need to be tested themselves. Since these family member products aren't directly tested, they suffer the same problems as those undergoing the nutrient profile method: uncertain nutrient bioavailability and palatability (44).
6. A Conclusion
At present, only 8% of the Veterinary Colleges in North America have nutrition as a prerequisite for admission into the veterinary programme (45). Introductory nutrition courses are taught in 75% of the veterinary colleges in the United States. Applied clinical nutrition in both large and small animals is taught as an elective in 14 to 28% of the colleges. Exit interviews of graduates and surveys of practicing veterinarians indicate that they are not adequately trained in nutrition (46).
Unfortunately, the information that pet food producers are providing the public is not likely to improve in the near future. In this year's annual meeting, AAFCO decided to drop (after seven years of work) proposed regulations on when nutrients should be listed as minimums or maximums. It also dropped consideration for mandatory caloric content statements for dog and cat foods (47), which had been proposed by the American College of Veterinary Nutrition in 2005 to the Pet Food Committee of AAFCO (48).
After reading this review, a veterinarian should ask:
Am I, or my staff, well trained and truly comfortable giving nutritional advice to my clients?
What are the sources for the information on nutrition that I give to my clients?
Why have I selected the pet foods that I recommend and sell?
Have I asked for or critically reviewed the scientific information that pet food manufacturers provide?
Are you satisfied that your answers are ones that are worthy of the trust that your clients have in your opinions? We believe that veterinarians must become more proactive in requesting peer reviewed scientific evidence from the pet food industry that the diets are formulated and manufactured based on sound nutritional principles. When provided, a veterinarian must critically evaluate this information as a true validation of the claims made by the manufacturers.
The pet food industry is rife with misleading and confusing information. Clearly veterinarians need to improve the level of their knowledge in the area of nutrition. Pet food producers should also step up and know that providing better information will improve both the industry and customer loyalty. Some efforts, like Nestlé Purina's "Advancing Life Through Diet Restrictions" (49) study has shown the value of long-term non-invasive research and the considerable information that can be obtained from good research. Still, such efforts remain rare, despite the demand and their value. As Dr. John Bauer, Mark L. Morris professor of clinical nutrition at Texas A&M University pointed out, "Any significant effort to help separate fact from fiction regarding pet animal nutrient for busy veterinarian practitioners, groomers, breeders, and pet owners will have an important multiplier effect on pet health, the human-animal bond, and ultimately, everyone involved in pet ownership" (50).
While the pet food industry has done an admirable job of regulating itself (when compared to other industries allowed similar reign), it has clearly balked at doing more than a minimum that was established quite a while ago. In view of its claims and other activities, its arguments (30) against and inactivity in the face of the well-researched and scientifically sound reports like the NRC 2006 are somewhat specious. To borrow a phrase (51), modern pet nutrition has not been tried and found wanting; it has been found difficult and left untried. The potential for the future is great. As veterinarians, we must work together to realize it.
Share your thoughts with colleagues
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