An Integrated Industry

Integration is defined as the unified control of several successive (vertical) or similar (horizontal) economic, especially industrial, processes formerly carried out independently. When that definition is applied to the various animal industries, it is notable that the poultry industry is vertically integrated with the exception of the primary breeders who produce the parent strains for commercial production. The swine industry is progressing rapidly toward complete vertical integration. The dairy industry, by its very nature, involves some degree of vertical integration, and the beef and sheep industries remain largely unintegrated. Some effort has been made, starting with the processors, to integrate beef cattle production, but in general the various segments of these industries continue to operate independently.

In vertical integration, the integrator (the poultry company) buys the breeder's eggs that become the parent stock of the broilers and delivers the hatched broiler chicks to others who are under contract to grow the birds, usually in floor pens with 10,000 to 20,000 birds per pen (Lasley 1983). Turkeys are bred and managed similarly to broilers, except that pens of 5,000 to 10,000 birds are more common (Lasley et al. 1983). The integrator maintains ownership of the birds, and supplies the feed and medication to the grower. Integrators also own their feed mills (to control costs and customize feed) where the grain can be purchased in bulk at cost savings to the grower–producer. In addition, integrators own the slaughter and processing facilities, and they generally market the finished product.

Poultry diets, which constitute 68 percent of total production costs, consist of corn and soybean-meal mixtures with vitamins and minerals, and typically include two or three medications (North 1984). Starter, grower, finisher, and layer diets are designed to meet the needs of the birds in each phase of development. Medications and vaccinations make up 2.16 percent of the total production costs (Agrimetrics Associates 1994).

History and Trends in Drug Use

The growth-enhancing effect of antibiotics was first demonstrated for poultry. Various nutritional studies in chicks showed that antibiotic-fermentation products influenced the growth of chicks (Moore et al. 1946; Stokstad et al. 1949). By 1951, the addition of growth-promoting antibiotics to feed had become standard practice (CAST 1981). The history of antibiotics, growth-promotion compounds, arsenical compounds, and coccidiostats has been reviewed (NAS 1969; Fagerberg and Quarles 1979; CAST 1981; IOM 1989). An earlier review of poultry experiments showed an important advantage in the use of low concentrations of various antibiotics (NAS 1969) that was evident in the superior growth of birds that received antibiotics. The majority of drug use in poultry management practice today is prophylactic, with the bulk of medications encompassing application of antiprotozoal compounds and antibiotic growth promoters.

The poultry production system serves as an interface between animal and human health and affects the environment, so it is important to describe drug use in the context of the overall system as well as to define what process controls are in place to address the safety and quality of the products. In terms of the overall system, intensive management and confinement operations minimize some kinds of infection and facilitate control of others. For example, Salmonella gallinarum and Salmonella pullorum, which are spread congenitally through the fertilized egg, are controlled by using breeding birds that test negative. Tuberculosis has been virtually eliminated by culling from the flock birds that test positive.

Calnek et al. (1991) assembled a comprehensive treatise on diseases of poultry. Vaccination of day-old chickens controls some viral infections, such as Newcastle and Marek's diseases. Turkeys are routinely vaccinated against Newcastle (5 days of age) and hemorrhagic enteritis (2 to 3 weeks of age), and sometimes against erysipelas, Bordetella avium, cholera, and influenza, depending on local experience. Antibacterials and other chemicals are frequently used for controlling other infections such as coccidia, worms, fungi, ectoparasites, and several bacterial infections.

In practice, broiler producers almost always include a coccidiostat (Table 2–1) in grower rations, as well as an arsenical, and an antibiotic (Table 2–2) for improved feed efficiency and body weight gains and for reduced morbidity and mortality. Control of coccidiosis is imperative with modern management systems for broilers and turkeys. Table 2–1 lists 20 coccidiostats labeled for use in broilers (Shepard et al. 1992), 11 of which also may be used in turkeys; only 2 are approved for layer chickens. The ionophores dominate the coccidiostats, but evolution of resistant coccidia has led many broiler producers to alternate coccidostats in “shuttle” programs. Several turkey farms now use a coccidiosis vaccine with good results.

TABLE 2–1

Coccidiostats Approved for Use in Broilers (B), Turkeys (T), and Layers (L).

TABLE 2–2

Major Claims of Antibiotics Approved for Use in Chickens and Turkeys.

All of the antibiotics listed in Table 2–2 are marketed over the counter. Several of these antibacterials are labeled for use against some other specific infections, but some viral infections still periodically devastate the industry. For example, in extreme cases of avian influenza, houses can be depopulated and sanitized to eradicate the virus. Mycoplasma galisepticum and Mycoplasma synovia were ubiquitous and required prophylaxis in broilers, for example, with tylosin or oxytetracycline. On the other hand, mycoplasmas have been controlled in most turkey flocks by using breeders that test negative. According to Shepard et al. (1992), 16 antibiotics are approved for use in broilers or turkeys (Table 2–2), but only 4 of these may be used in layers. In addition, 2 arsenicals are approved for control of blackhead, 4 compounds are available for worms, and 1 fungicide is approved for broilers.

There are three categories of antiprotozoal drugs: ionophores, sulfonamides, and other chemical compounds. They are routinely administered through feed. Some ionophores are not well absorbed across the intestinal wall or are not sufficiently toxic to dictate a withdrawal period and so they can legally be used until slaughter. (Withdrawal is the period required by law between the final administration of a drug and the time when the animal can be harvested for food. The withdrawal period allows drug residue concentrations to fall in the tissue or milk of treated animals to those considered nonthreatening to human health.) Chemical coccidiostats (e.g., amprolium, roxarsone) are most often used in broiler starter diets and traditionally have been followed by ionophores. Most chemical coccidiostats require withdrawal periods.

Antiprotozoal drugs used to combat Histomonas infections in turkeys and pheasants are similar to the organic arsenical compounds used in broiler chickens. Nitrarsone (4-nitrophenyl arsenic acid) is the only compound approved to prevent histomoniasis and the subsequent sequella produced by the protozoa in combination with some bacteria. Two other compounds previously approved for this purpose, ipronidazole and furazolidone, were recently removed from the market. Furazolidone is a member of the nitrofuran family of compounds, which were removed from the market by the FDA's Center for Veterinary Medicine because of their carcinogenic potential; however, similar compounds are still in use in human medicine today.

The integration of the poultry industry facilitates tracing a potential residue in meat or eggs to its origin. The integrator companies have much to gain by avoiding altogether any hint of problems, such as drug residues in poultry foods. This constitutes a powerful motivation to control drug and chemical use.

Routes of Drug Administration

Water Medication

Sick poultry are generally medicated through drinking-water systems. Systemic or intestinal medication can be given that way, and the industry has learned how to achieve and maintain therapeutic concentrations of drugs by studying the actual water use for each class of poultry, and accounting for the age of the birds and the environmental temperature. Although the actual overall water-soluble systemic use of drugs in poultry is declining, a recently approved therapeutic-concentration fluoroquinolone antibiotic may now be administered to poultry via drinking water. Summaries of drug use in poultry from 1989 to 1994 are presented in Tables 2–3, 2–4, and 2–5. The amount of antibiotics administered to poultry, especially the amount administered in medicated feeds, declined for the following reasons:

TABLE 2–3

Cost of Drug and Vaccine Use in Broilers from 1989 to 1994.

TABLE 2–4

Turkey Medication and Vaccine Cost Analysis.

TABLE 2–5

Cost of Medication and Vaccination Used for Turkeys and Broilers in the United States.

• use of preventive medicine, including implementation of biosecurity procedures, vaccination, genetic selection, and eradication of various pathogens, resulting in specific-pathogen-free stocks;
• reduction in the number of available efficacious compounds for treating respiratory diseases caused by Escherichia coli and Pasteurella multocida, and for treating other infections such as those caused by Staphylococcus aureus;
• efforts to control cost, including improving environmental conditions and culling unhealthy birds;
• concentration and focus on residue avoidance; and
• innovation on the part of manufacturers of vaccines and biological agents to rapidly meet the demands of industry when exotic diseases occur.

These reasons notwithstanding, there is cause for concern in the poultry industry. In recent years only one new systemic antibiotic, a fluoroquinolone, has been approved for treatment of diseases caused in poultry by E. coli. The use of that antibiotic is being criticized because its effectiveness as a last line of defense in human antibiotic therapy might be undermined by further FDA approval and use in animals. The removal of the nitrofurans from the market further complicated the situation. When exotic or variant respiratory viruses emerge in an area, septicemic E. coli infections cause excessive mortality if no treatment is initiated. In the past, vaccine strategies were developed and implemented to prevent the spread of the newly emerged virus and to decrease the stresses on poultry that facilitate opportunistic secondary bacterial infection such as occurs with E. coli.

Growth Promotion

The poultry industry no longer uses low concentrations of tetracyclines, penicillin, or tylosin for growth promotion. Arsenical compounds are still used as partial coccidiostats and growth promoters. The primary reason for the use of nonsystemic growth promoters is for specific activity against clostridial species. The current practices of drug use for growth promotion in poultry are (1) use of low concentrations, 1 to 50 g/t; (2) routine use; (3) use of minimally or nonabsorbed drugs; (4) use of antibiotics having activity against Gram-positive organisms; and (5) use of nontherapeutic drugs. These drugs include bacitracins, bambermycins, lincomycin, and virginiamycin. All four of these drugs are classified by FDA as category I drugs, requiring no withdrawal period (Feed Additive Compendium 1995).

Disease Control

The three most serious bacterial diseases in poultry are caused by Salmonella, E. coli, and Clostridium. All have human health implications and highlight the need for safe and effective drugs to control these pathogens in birds as well as for the development of vaccination strategies to prevent clinical infection by pathogens (Cooper et al. 1994).

Disease Control and Use of Drugs and Chemicals

Pork producers and herd veterinarians view human food safety as an integral part of total herd health programs. Producers pay strict attention to the health of their herds, taking precautions and using a variety of management practices to protect herd health. Individual herd health programs are developed in close consultation with veterinarians.

Antibiotic drugs are used in pork production for disease prevention, treatment of disease, and growth promotion. The management system in place for individual swine production operations will determine the antibiotic used and the quantity.

In the extensive management of hogs until after World War II, common diseases, such as erysipelas and cholera, were controlled by vaccinations, slaughter, or treatment of individual hogs (Fredeen and Harmon 1983). Epidemics of the common infectious diseases were kept in check by stocking with low-density population. However, in the intensive management of common diseases today hogs usually are given subtherapeutic concentrations of antibiotic drugs in feed. Shepard et al. (1992) listed 29 antibiotic drugs approved by FDA (21 antibiotics and 8 chemotherapeutics).

Thus, in addition to antibiotics, antiparasitics are another major category of drugs for hogs. Nine chemical entities are approved in the United States (Shepard et al. 1992), several marketed by more than one company and in forms suitable for use in feed or by injection. They are recommended routinely for breeding animals, when new animals are introduced into a herd, and when weaned animals enter the feedlot. Controlling helminths is the principal objective, but insects also must be controlled. In general, although parasites can severely restrict productivity in hogs, several bacterial and viral infections are more cataclysmic (see Tables 2–6 and 2–7).

TABLE 2–6

Major Claims of Antibiotics Approved for Use in Hogs.

TABLE 2–7

Major Claims of Chemotherapeutics Approved for Use in Hogs.

Growth and Metabolic Performance

Hog performance (growth rate and feed efficiency [pounds of feed consumed for a gain of 1 pound in carcass or body weight]) is improved with the use of subtherapeutic concentrations of any of 12 antibiotic drugs with claims for increased rate of gain or improved feed conversion. An important result of subtherapeutic use is reduced morbidity and mortality in growing pigs (Cromwell 1991). In breeding animals, feed-additive antibiotic drugs improve farrowing rate, litter size, birth weight, and pigs weaned per litter; and they reduce the incidence of mastitis (bacterial infection of the mammary gland), metritis, and agalactia. It is not surprising, therefore, that antibiotic drugs are used in about 90 percent of starter feeds, in 75 percent of grower feeds, in more than 50 percent of finisher feeds, and in at least 20 percent of sow feeds (Cromwell 1991). Although antibiotic resistance emerges in herds medicated continuously (Tribble 1991), the procedure does not seem to diminish the enhanced productivity effects (Cromwell 1991).

In swine production today, producers vaccinate piglets for some or all of the following diseases or microbes: erysipelas (46 percent), atrophic rhinitis (42 percent), Pasteurella pneumonia (28 percent), Haemophilus pleuropneumonia (13 percent), Streptococcus infections (12 percent), E. coli scours, and C. perfringens infections (FSIS 1993a). The piglets are castrated by the age of weaning (90 percent), given iron supplements and have tails docked (80 percent), treated for worms (48 percent), treated for mange and lice (40 percent), and given antibiotic injections (33 percent). Among sows and gilts, 60 to 70 percent are vaccinated for leptospirosis, parvovirus, and erysipelas; 50 percent for E. coli scours; 33 percent for atrophic rhinitis; and more than 20 percent for transmissible gastroenteritis, C. perfringens infections, and pseudorabies (FSIS 1992). Eighty-five percent of sows and gilts are wormed, and 72 percent are treated for mange and lice.

Disease Control and Prophylactic Treatments

Most dairy producers vaccinate heifers for diseases such as leptospirosis (81 percent), infectious bovine rhinotracheitis (IBR, 90 percent), bovine viral diarrhea (BVD, 87 percent), parainfluenza type 3 (PI3, 85 percent), bovine respiratory syncytial virus (BRSV, 66 percent), and brucellosis (65 percent). In addition, 54 percent are given coccidiostats in their feed and 60 percent are wormed. Dairy farmers also vaccinate more than 30 percent of nonlactating cows for leptospirosis, IBR, BVD, and PI3; and 22 percent for BRSV. Parasiticides are used extensively, mostly in heifers for control of coccidia and nematodes.

Therapeutic Treatment of Disease

Although vaccinations are a major means of controlling viral and bacterial infections in dairy herds, diarrhea and respiratory disease are the most common illnesses among calves and heifers. Therapeutic use of drugs is called for in the treatment of such reproductive problems as retained placentas and metritis. Among the diseases afflicting dairy cattle, mastitis is recognized as the most costly. In fact, intramammary infection (Table 2–8) is the most costly disease to U.S. animal agriculture. In Table 2–9, health costs for dairy animals are divided by functional category (Shook 1989). The mammary-gland category is the largest, accounting for approximately half of the total health costs for the dairy cow. More than 80 percent of dairy farmers used veterinarians to treat sick animals and supply drugs relating back to a high level of accountability for drug use in the dairy industry. However, a substantial number of farmers also obtained drugs elsewhere. In most rural agricultural regions of the nation, many FDA-approved drugs are available over the counter at feed supply, milk plant cooperative, or general farm supply stores. In the dairy industry, as well as in all other food-animal industries, the availability and use of antibiotics make it more difficult to produce accurate statistical documentation of drug use and disease incidence.

TABLE 2–8

Intramammary Antibiotics Approved for Dairy Cattle.

TABLE 2–9

Distribution of Health Costs ($) per Cow by Functional Category.

Questions have been raised about the appropriateness of over-the-counter drug availability. However, with the dairy industry as an example, most dairy farmers are very good at recognizing commonly-encountered illnesses in their cows and calves, and they opt for the convenience of treating the animals as the need arises. This is rather successful for the dairy industry because of the active residue surveillance program and the penalties associated with drug use violations (discussed in detail in subsequent chapters). As a result, difficulties in tracking and predicting the emergence of drug resistance are increased.

Mastitis was found to be second only to milk yield in explaining variance in profit (Andrus and McGilliard 1975). Annual losses due to mastitis shown in Table 2–10 average $184 per cow (DeGraves and Fetrow 1993). Thus, with a current cow population of approximately 9.6 million, the annual cost of this disease to the dairy industry approaches $2 billion. This figure is approximately 11 percent of the total value of farm milk sales.

TABLE 2–10

Estimated Annual Losses Caused by Mastitis.

Organisms present in milk from mastitic cows pose little threat to human health. The bacteria that commonly cause bovine mastitis seldom cause disease in humans. Some strains of Staphylococcus aureus, a common cause of mastitis, can produce enterotoxins that cause nausea, vomiting, abdominal cramps, and diarrhea when ingested. However, if milk is cooled properly, pasteurized, and handled correctly thereafter, the danger of toxin formation is remote.

An important public health concern is the potential for antibiotics used in mastitis treatment to remain as residues in milk or meat. Careful use of antibiotics (avoidance of products not approved for use in dairy cattle, use of proper dosages, and compliance with withdrawal times specified on product labels) is intended to minimize the potential for antibiotic residues to carry over into meat and milk. Given the potential for drug residues in dairy products, the industry is seeking alternatives to antibiotic use in herd health programs.

Antibiotic Drug Use

A comprehensive program of mastitis control has been adopted for reducing the incidence of intramammary infections in dairy cows. The key is prevention of the disease, and prevention is best accomplished by improving milking hygiene and decreasing exposure to pathogens between milkings. However, new infections still occur and must be eliminated to reduce the overall incidence of mastitis in the dairy herd.

Established infections caused by major udder pathogens can be eliminated by spontaneous recovery, culling of chronically infected cows, treatment during lactation, and treatment at time of drying off (Philpot and Nickerson 1992). Spontaneous recovery occurs when the infected cow is cured of an intramammary infection without medical intervention; however, that phenomenon takes place at most in 20 percent of established infections. The majority of spontaneous recoveries occur in mammary gland quarters with mild or recent cases of mastitis and only rarely in quarters with well-established or chronic infections. Culling is often used as a last resort to eliminate chronic infections from herds that are unresponsive to therapy. Consideration should be given to culling those cows whose continued presence in the herd constitutes a reservoir of infection that might ultimately spread to uninfected cows.

Obviously, spontaneous recovery and culling have serious limitations in terms of usefulness for eliminating established infections. Drug therapy remains the principal alternative for eliminating existing infections in a herd. During lactation, treatment is efficacious against some mastitis-causing bacteria and poor against others. Most preparations have been designed with little or no attention to the natural defense mechanisms operating within the udder. In addition, several host factors might influence or be influenced by antibiotic therapy. Thus, because of treatment failures, new strategies are needed to improve cure rates for existing mastitis and to reduce the incidence of new infections.

Production Enhancers

The potential to exploit hormone-dependent mechanisms to increase the production of milk has been understood for several decades. Some 50 years ago, research showed increased growth rates in rats injected with a crude pituitary extract. Later it was discovered that the extract, which contains a protein hormone called somatotropin, also affects lactation, and research with lactating cows ensued. Before the 1980s, progress was slow in bovine somatotropin (bST) research because the availability of bST was restricted to that which could be extracted from pituitary glands of slaughtered animals, limiting studies to a few cows and short time frames (OTA 1991).

In the late 1970s, new research showed that the physiological basis for more efficient milk production in genetically superior cows was the better use of absorbed nutrients. Scientists recognized the need for new concepts regarding nutrient regulation in animals. More recent work demonstrated that somatotropin exerts key control over nutrient use. When administered exogenously, either pituitry-derived or the recombinant DNA-derived analog markedly improves milk production efficiency in lactating cows. In the last decade, the refinement in production technology and development of easily used delivery technologies (i.e., long acting hormone delivery implants) has established an important role for somatotropin in the dairy industry. Today recombinant DNA-derived somatotropin is approved by FDA for use in dairy cattle to boost milk production.

Disease Prevention

To safeguard against disease emergence during periods of stress, calves are given vaccinations against respiratory (for Clostridium and respiratory-disease complex) and gastrointestinal (primarily viral) diseases, and they are treated for worms and ectoparasites. After shipping, on entry into the feedlot, cattle are typically vaccinated again for Clostridium and respiratory-disease complex, further treated for worms and ectoparasites, and given a steroid-type implant for growth promotion. For 28 to 65 days they also are given a prophylactic combination of tetracycline and sulfamethazine to prevent disease during the initial stressful period accompanying feedlot entry. Other antibiotic drugs are fed throughout the finishing period, including ionophores to improve feed efficiency and growth rate and tylosin to prevent liver abscesses (Koch and Algeo 1983).

The following measures can be taken to prevent diseases in beef cattle:

• use of adequate and balanced nutrition, which is essential for optimal immune functioning in animals;
• elimination or reduction of the population of vectors, for example, the face fly, which transfers pinkeye; the mosquito, which transmits anaplasmosis; and the culicoid, which transmits bluetongue;
• good pasture management, such as weed control, rotational grazing, adequate fertilizing, fresh water, and fenced-out muddy areas to help control disease infestations and prevent stress, which might leave animals, especially newborns, weak and more susceptible to disease; and
• keeping the facilities and environment as clean as possible. Any invasive procedure, such as that requiring an esophageal tube or a syringe, should be done with clean hands and clean equipment to avoid human transmission of disease.

Trends in Drug Use

Anabolic compounds are widely used to promote weight gain and feed efficiency in cattle. Most are derivatives of reproductive steroid hormones (estrogen, progesterone, or testosterone) and generally work by interacting with specific steroid hormone receptors (Hancock et al. 1991). Residue data indicate a wide safety margin for human health in the use of those drugs in cattle (Henricks et al. 1983). Some data indicate that increases in estrogen residues from implanting steers are no greater than are those found in heifers at some stages of the natural estrus cycle (Henricks et al. 1983).

Some of the most devastating cattle diseases, such as foot-and-mouth disease, brucellosis, and tuberculosis, have been controlled through national eradication and surveillance programs. Others, such as clostridial infections, are controlled by vaccination. Respiratory diseases are managed by mass vaccinations and treatment of affected individuals. Such diseases as diarrhea are managed by treatment of individual calves.

Because the largest potential for creating drug residues in beef tissues arises from treatment of cattle in feedlots, feedlot operators emphasize control of infectious diseases at the time cattle enter the lot, 2 to 4 months before slaughter (the duration of this period depending mostly on the price of grain and on market prices for finished cattle). Various feed additives (Tables 2–11 and 2–12) and implant treatments are approved for use throughout the feeding period. Eight feed-additive antibiotics are labeled for improved growth or feed efficiency. Shepard et al. (1992) also list 11 antibiotics with no claims for growth or feed efficiency, 18 parasiticides and 6 sulfonamides for cattle, and 3 estrus synchronizers for beef cattle and dairy heifers. The parasiticides include 11 wormers, 2 coccidiostats, 4 ectoparasiticides, and 1 endectocide. Additionally, insecticides and insecticidal ear tags for beef cattle are approved by EPA.

TABLE 2–11

Major Claims for Systemic Antimicrobials Approved for Use in Beef and Dairy Cattle.

TABLE 2–12

Steroid Products Labeled for Improved Growth and/or Feed Efficiency in Cattle.

Therapeutic Drug Use

Therapeutic use of drugs in cattle is often necessary. Most commonly drugs are administered for enteric and respiratory diseases in calves and feeder cattle, and for reproductive infections in breeding herds. Although therapy is more expensive than preventing disease and injury through the use of healthful conditions and vaccination, it is necessary when these measures fail. The costs incurred are for:

• medication;
• visits by the veterinarian;
• additional time required to move infected animals to and from the treatment area;
• segregation of infected animals, which might involve separate feeding, watering, shelter, and observation;
• weight loss;
• reduced value of chronic cases that never return to their original condition; and
• death.

Feeding low concentrations of antibiotics to cattle with the intention of increasing the dose as signs of disease occur is different from subtherapeutic feeding to increase weight gain. The method of administration is through feed rather than injection, but the intention is therapeutic. Cattle are sometimes fed low concentrations of antibiotics during particularly stressful times when they are most apt to get sick—for example, at weaning or after being shipped a long distance. That regimen might be used for 2 or 3 weeks. Data from the former National Cattleman's Association (1995) suggest that penicillins are not used for growth promotion in cattle and that the use of tetracyclines is in sharp decline as a result of the suggestion to limit the use of these drugs pending results of research on human health.

Vaccinations

Like dairy cattle, beef cattle are vaccinated against brucellosis, leptospirosis, clostridial infections, and a bovine respiratory complex of diseases, which usually include IBR and PI3. Many outbreaks of disease in herds can be prevented on farms with good vaccination programs.

Poultry Quality-Assurance Programs

In the United States, with the help of various public and private institutions and the implementation of the National Poultry Improvement Plan (NPIP) of 1935 and the National Turkey Improvement Plan of 1943, the poultry industry has been able either to eradicate or to minimize disease exposure. That undertaking has improved profitability and expanded the industry.

The eradication of various diseases caused by Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, Salmonella pullorum, and Salmonella gallinarum; velogenic Newcastle disease; and highly pathogenic avian influenza could not have been accomplished without the NPIP system.

The goal of the National Turkey Federation's Chemical Residue Avoidance Program is to ensure that the tissue of turkeys produced and slaughtered in the United States will not contain any chemical residues and will meet or exceed all tolerance and action levels for known harmful residues as established by the federal regulatory agencies (the U.S. Environmental Protection Agency, FDA, and the USDA Food Safety and Inspection Service [FSIS]).

The National Broiler Council's recommended Good Manufacturing Practices address every quality-control point in the production and processing of broiler chickens to enhance product quality and consumer protection. The procedures are drawn from quality-control programs throughout the broiler industry, from the scientific literature, and from existing regulatory documents. In production, recommended practices include:

• maintaining proper facility standards,
• providing growers with pesticide information,
• including pesticide-use statements in grower contracts, and
• enforcing biosecurity programs.

Regarding animal health care, the following practices are recommended:

• ensuring that pharmaceutical laws and regulations are followed (only FDA-approved pharmaceuticals and regimens are to be used), and
• enforcing company standards for pharmaceutical use.

In breeder operations, standards are to be maintained for feeds and animal health. In addition, procedures to control poultry-borne and egg-borne pathogens and diseases should be a routine part of breeder-monitoring programs. Hatchery recommendations address sanitation and microbiological controls, which continue through the growing period, transport, slaughter, and processing. Testing for microbiological quality, pesticide and chemical residues in feed ingredients is recommended for feed preparation during the growing period. Maintaining records of feed distribution and pharmaceutical inventories, and ensuring that FDA regulations are adhered to, are important aspects of good poultry management practice.

Pork Quality-Assurance Programs

In June 1989, NPPC introduced a management education program called the Pork Quality Assurance (PQA) program. It was designed to help producers avoid violative drug residues, improve management practices, reduce production costs, and increase awareness of food safety concerns. The PQA program emphasizes good management practices in the handling and use of animal health products and encourages producers to review their herds' health programs annually.

The program provides information covering the following topics:

• food safety and the pork industry,
• products used today,
• routes of administration,
• on-farm feed preparation,
• minimum withdrawal times,
• current regulatory system, and
• on-farm testing.

The PQA program (NPPC 1997) was developed by NPPC to institute safety, uniformity, and consistency in the production of pork. The program refers to three achievement levels in the quality-assurance certification process. Levels I and II are self-instructional and self-paced reading from a booklet obtainable from NPPC. All producers are encouraged to learn and implement the 10 “good production practices” defined in the booklet. Producers can achieve Level III through a professional consultation, which takes them step-by-step through the design of a herd health program. For producers this 10-step program is developed around the appropriate uses of medications and the need for accountability. The plan results in an understanding of the need for the oversight of the veterinarian and in written accounts of animal-by-animal drug use. Level III of the PQA program applies principles from the Hazard Analysis and Critical Control Points (HACCP) to the production of pork. The HACCP involves determining where problems could develop and establishing procedures to monitor those problems. To complete Level III, a producer must annually perform the following 10 critical control points:

1)

Establish an efficient and effective herd health-management plan.

2)

Establish a valid veterinarian, client, and patient relationship.

3)

Store all drugs correctly.

4)

Use only FDA-approved over-the-counter or prescription drugs with professional assistance.

5)

Administer all injectable drugs and oral medications properly.

6)

Follow label instructions for use of feed additives.

7)

Maintain proper treatment records and adequate identification of all treated animals.

8)

Use drug-residue tests when appropriate.

9)

Implement employee and family awareness of proper drug use.

10)

Complete quality-assurance checklist annually.

In the implementation of the PQA program, extensive cooperation has been received from veterinarians, packers, media, agriculture teachers, FDA, FSIS, extension personnel, feed manufacturers, and pharmaceutical companies.

Producer response to the PQA program has been favorable. As of July 1, 1995, approximately 32,000 pork producers who provide 63 percent of the market hogs in the United States were enrolled in the program. Thirty percent of U.S. pork is from producers who have completed the program and an even larger percentage comes from producers who have implemented some aspects of the program.

According to the 1993 nationwide monitoring program administered by FSIS, violative residues for sulfamethazine and antibiotics in market hogs have decreased (FSIS 1993c). The violation rate for sulfamethazine has continued to remain low in recent years. FSIS has congratulated NPPC for its work in reducing the violation rate and has encouraged the NPPC membership to continue to follow the recommendations in the PQA program to avoid illegal residues. To continue reducing violative drug residue rates and reach the industry goal of no violative residues, NPPC urges all producers to enroll in and complete the PQA program.

In addition to its Compliance Policy Guides directed toward use of animal health products by veterinarians, FDA has issued a Compliance Policy Guide on Proper Drug Use and Residue Avoidance by NonVeterinarians. The objective of this guide is to ensure proper use of animal health products in food-producing animals when administered by producers. The guide describes the records FDA inspectors would ask to see when doing on-farm investigations after a violative drug residue has been discovered. The guide addresses identification of treated animals; maintenance of treatment records; storage, labeling, and accounting of medications; use of prescription products only through a valid VCPR; and education of employees and family members. The PQA program provides a means for producers to comply with the FDA guide.

Dairy Quality-Assurance Programs

To ensure that only the highest quality dairy foods and residue-free products reach the consumer, two important documents have been developed. The first was the Grade A Pasteurized Milk Ordinance, also known as the FDA PMO (FDA 1995b). The premise of the original PMO, developed in 1924, was that effective public-health control of milk-borne diseases required the application of sanitation measures through the production, handling, pasteurization, and distribution of milk and milk products.

The second document was the Milk and Dairy Beef Residue Prevention Protocol (Boeckman and Carlson 1995), which addresses the need to market residue-free milk and dairy beef. That 10-point plan for the Milk and Dairy Beef Quality Assurance Program was developed by the National Milk Producers Federation and the American Veterinary Medical Association (AVMA). Both organizations emphasized that the plan would require cooperation and communication between dairy farmers and veterinarians, so that the industry could remain active in preventing drug residues in milk and beef. In the plan's guidelines, the producer is viewed as providing a safe product, and the consumer as benefiting by drinking uncontaminated milk. The 10-point plan has been adopted as part of the PMO by individual states, and it is mandatory for all producers after one contaminated load of milk is detected.

An extremely important aspect of quality-assurance programs is the establishment of a valid VCPR. This relationship ensures that farm animals receiving antibiotics will be withheld from the food chain until drug concentrations are below those permitted by FDA. Both the producer and the veterinarian must work closely with quality-assurance program coordinators and extension personnel to ensure that the drug-avoidance programs are followed.

The 10-point quality assurance plan deals specifically with the drug-residue issue and for milk and dairy beef production includes:

1) Practicing healthy-herd management. Investments in disease prevention are more cost-effective than is disease treatment. Some examples include proper milking management versus treatment of clinical mastitis, good hoof care and trimming versus treatment of foot infections, calving cows in a sanitary location versus treatment of uterine infection, and proper vaccination versus treatment. Producers are encouraged to practice herd health management by consulting with licensed veterinarians and other related professionals.

2) Establishing a valid VCPR. AVMA (1998) defines a VCPR as follows:

An appropriate veterinarian/client/patient relationship is characterized by these attributes: (1) [t]he veterinarian has assumed the responsibility for making medical judgments regarding the health of the animal(s) and the need for medical treatment, and the client (owner or other caretaker) has agreed to follow the instructions of the veterinarian; and when (2) [t]here is sufficient knowledge of the animal(s) by the veterinarian to initiate at least a general or preliminary diagnosis of the medical condition of the animal(s). This means that the veterinarian has recently seen and is personally acquainted with the keeping and care of the animal(s) by virtue of an examination of the animal(s) and/or by medically appropriate and timely visits to the premises where the animal(s) are kept; and when (3) [t]he veterinarian is readily available, or has arranged for emergency coverage, for follow-up in the event of adverse reactions or failure of the treatment regimen. (Pp. 49–50)

A valid VCPR is mandatory if drugs are to be used for reasons different from those stated on the label; this is called an extra-label use. Dairy farmers need the benefit of a valid VCPR to make sure they are following the veterinarian's instructions properly.

3) Using only FDA-approved over-the-counter or prescription drugs with a veterinarian's guidance.

FDA-approved drugs have been tested extensively to show that they perform consistently according to the manufacturer's claims and that they cause no harm to the animal when administered according to the label. As a result, dairy farmers will reduce the risk of violative drug residues in the milk and meat of animals receiving drugs and protect their market by supplying safe and wholesome milk and meat.

FDA-approved over-the-counter drugs are those that can be purchased anywhere without a veterinarian's prescription or supervision. Drugs are labeled for over-the-counter sale when instructions that are adequate for a layperson can be printed on the label, including the package insert.

4) Ensuring that all drugs have labels that comply with state or federal labeling requirements. Because dairy farmers are ultimately responsible for any drug residues, they should be careful to follow drug label instructions. They should not be concerned about the accuracy of a label, because the manufacturer must meet all the requirements to get the drug approved, and veterinarians are responsible for all labels of drugs they prescribe for their clients' animals.

5) Storing all drugs correctly. All medications for cattle must be properly stored, so that they will not come into contact with milk or the milking equipment. Topical antiseptics, wound dressings, vaccines, and other biological products and vitamins or mineral products are generally exempt from labeling and storage requirements. However, some states might have specific storage regulations.

6) Administering all drugs properly and identifying all treated animals. The best way for dairy farmers to avoid problems associated with this critical control point is simply to follow the drug's label and package insert, and to identify each animal that receives the drug at the time it is administered. Immediate identification of the animal will greatly reduce the risk of putting adulterated or contaminated milk into a tank or sending an animal with tissue residues to slaughter.

7) Maintaining and using proper treatment records on all treated animals. Dairy farmers must identify treated animals with a paint stick, leg bands, hock markers, neck strap, numbered ear tags, or other marking devices. Proper identification is crucial for keeping violative drug residues out of milk and meat. Equally important is maintaining a record of all treated animals. The records should be accessible to everyone who works with the animals. The records need to be used to ensure that cull cows, dairy beef, steers, or calves whose markings have worn off are not sold before the withholding time has expired. The records also should be permanent, so the veterinarian can refer to them to prescribe effective therapy and to serve as protection in case of a regulatory follow-up.

8) Using drug-residue screening tests. New technology has made it possible to conduct milk, urine, and blood tests that are easy to use on the farm. Many of these tests are as sensitive as those done at milk or slaughter plants. On-farm testing gives dairy farmers an additional way to avoid violative drug residues in meat and milk. The key is to match the drug administered with the correct drug test at the desired level of sensitivity.

9) Implementing employee and family awareness of proper drug use to avoid marketing adulterated products. Many cases of adulterated meat or milk occur because one person treats the animals and someone else takes care of the milking or decides to sell the animals. If different individuals are carrying out those tasks, it is important that the critical control points of the quality-assurance program be explained to everyone involved with the animals.

10) Performing the 10-point Milk and Dairy Beef Residue Prevention Protocol annually. Producers need to go through these 10 points with their veterinarians at least once a year. Conditions on the farm change; new employees are hired and different drugs are used because of a change in herd health. In addition, new drugs or screening tests come onto the market. These factors make it worthwhile for producers to review the plan with their veterinarians and farm staff a minimum of once each year.

Voluntary implementation of the 10-point plan has met with varied success. Even highlighting the incentive of reduced costs associated with a herd health program and the reduced need for drugs has not been completely effective. The Implementation and Communication Subcommittee of the Drug Residue Committee (Buntain et al. 1993) reviewed the quality-assurance initiatives and suggested that insurance companies sponsor premium reductions or price breaks on liability insurance for voluntary participants. Another suggestion was for milk processors and cooperatives to include plan participation in their requirements for quality bonuses. The cooperatives and processors could then use the information as a marketing advantage and advertise that a high percentage of their producers participated in the residue-prevention program. Another possible incentive mentioned was to have voluntary implementation of the 10-point plan defer the penalty of a first violation under the PMO. Suggestion was also made for veterinarians to go through the 10-point plan at no charge to producers who implement the plan voluntarily.

Although the incentive of reduced costs associated with a sound herd health program has not enticed a majority of producers to adopt the 10-point plan voluntarily, it still should be a major focus of preventive herd health management. The resulting decrease in disease and increase in production also would lead to a decrease in finding violative drug residues. Residue avoidance would be best served by encouraging and emphasizing the need for on-farm treatment records. The use of treatment records as a source of residue information for withholding milk and meat from the market is obvious. Establishing drug use patterns from treatment records on each farm also would provide a basis for discussing changes in or alternatives to current drug use. This information could provide opportunities for educating producers about better management alternatives in certain stages of the production cycle.

Continuing-education programs on current and changing regulations are necessary for inspector, veterinarian, and producer groups. A centralized task force, perhaps encompassing extension personnel, would be helpful in gathering and reviewing the educational, labeling, and form material available, and distributing the most up-to-date information to producers. Along with details on changing regulations, information needs to be made available on sources such as Food Animal Residual Avoidance Databank (FARAD) project for determining withholding times of extra-label drugs, on drugs prohibited from use in food animals, on the liability associated with drug labeling and signing the 10-point plan, and on the definition of a valid VCPR. The relationship and importance of FARAD to drug use policy in the United States is further detailed in Chapter 3.

Beef Quality-Assurance Program

In 1996, the beef industry initiated the Beef Quality Assurance (BQA) program, a voluntary initiative designed by producers for producers (NCBA 1997). Because of the tremendous diversity across the United States in the beef cattle industry, the BQA program is implemented state by state. Although the National Cattlemen's Beef Association provides technical support and national leadership to beef cattle producers, the administration and implementation of the BQA program are carried out by state cattle affiliates and state beef councils, with the assistance of practicing veterinarians.

The BQA program is designed to educate and train beef cattle owners, their employees, and their veterinarians on the day-to-day management practices that influence the safety, wholesomeness, and quality of beef. Subjects emphasized through producer and veterinarian seminars, workshops, and chute-side demonstrations are (1) the importance of proper and safe animal drug use; (2) adherence to product label withdrawal periods; and (3) record-keeping relative to animal product use, drug inventories, and animal treatment regimens. The program teaches testing procedures for sampling and analyzing feed and feed ingredients for potential chemical and pesticide residues at the farm or feedlot. Through the BQA program, residue drug violations for feedlot cattle essentially have been reduced to zero, as reported by the USDA Residue Monitoring Program (FSIS 1994b).

In the past few years, the BQA program has launched an aggressive effort designed to eliminate injection site tissue damage resulting from intramuscular administration of animal health products. Educational efforts regarding injection site awareness have resulted in a significant reduction in tissue quality defects. The success of these efforts demonstrates the ability of the BQA program to create an effective and responsive network of cattlemen and veterinarians.

The BQA initiative is structured to reach all segments of beef cattle production, including cow and calf, stocker, backgrounding, and feedlot operations. To date, 42 states sponsor aggressive BQA programs. These states produce more than 98 percent of the feedlot cattle and account for more than 95 percent of the cow and calf producers in the United States.

More recently, the state BQA programs have implemented producer BQA certification programs. The certification procedure requires a specified amount of structured quality-assurance training and the verification of quality-assurance practices implemented in the actual operation. It is expected that the momentum for quality-assurance certification will increase throughout the industry.

Finally, the BQA program is prepared to launch a major quality-assurance initiative for cull dairy and beef cows. Violative drug residues in cull dairy and beef cows remain a major concern for the industry.

The industry's BQA program is an effective producer network for addressing product safety concerns now and in the future. However, on-farm food safety interventions must develop around sound science if these efforts are to be effective and further enhance the safety of beef and beef products.