T. F. SHARBY. Can. J. Anim. Sci. Downloaded from by on 04/10/19

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1 SOME OBSERVATIONS ON THE USE OF FEED ADDITIVES IN CANADIAN ANIMAL PRODUCTION T. F. SHARBY Dawe's Laboratories of Canada Ltd., 110 Ormont Drive, Weston' Ontario MgL ll7. Receivedl Jan. 1979, accepted I Mar SHnnev, T. F. 19'79. Some observations on the use of feed additives in Canadian animal production. Can. J. Anim. Sci. 59: Antibiotics have been used in animal feeds for almost 30 yr to improve growth, enhance feed efficiency, and control disease in birds and animals. In 1974 antibiotics used in animal feeds in Canada totalled million dollars while those used in veterinary medicine totalled 28.8 million dollars. Antibiotics, sulfonamides and antibacterials used in human application that same year equalled 77.4 million dollars. Concerns regarding potential health hazards to humans with continued low-level antibiotic supplementation of animal feeds have resulted in a number of countries implementing or proposing more rigid legislation covering antibiotic use in animal agricultuie. Possible consequences of such legislation being introduced in Canada are discussed. Les antibiotiques s'emploient dans I'alimentation des animaux depuis prds de 30 ans pour am6liorer la croissance et f indice de consommation et pour combattre les maladies de la volaille et des mammifdres d'6levage. En 1974,leur emploi dans les aliments du b6tai1, au Canada, s'est chiffr6 par I millions de dollars, alors que les usages v6t6rinaires se montaient ir 28.8 millions. Cette mome ann6e, la m6decine humaine a consomm6 pour 77.4 millions de dollars d'antibiotiques, de sulfamid6s et de substances antibact6riennes. Les riques 6ventuels que pourrait comporter pour I'homme la compl6mentation continue des aliments par des doses sub-th6rapeutiques d'antibiotiques ont incit6 plusieurs pays it mettre en place ou i proposer une r6glementation plus stricte de I'emploi des antibiotiques en zootechnie. L'auteur passe en revue les 16percussions possibles de I'introduction d'une telle 169lementation au Canada. The use of antibiotics in animal feeds to improve growth and feed efficiency originated with Jukes and Stokstad in Commercialization began in 1950 and their use has increased steadily. In 1914 antibiotics used in animal feeds in Canada totalled million dollars while those used in veterinary medicine totalled 28.8 million dollars. For comparative purposes, antibiotics, sulfonamides and antibacterials used in human application that same year equalled 11.4 million dollars (Statistics Canada 191 4). By 1955 the question of benefits vs. risks regarding low level antibiotic supplementation of animal feeds was already being Can. J. Anim. Sci. 59: (June 1979) debated. Concerns of those opposing such use of antibiotics in animal feed centered around three major areas: (l) Possible contamination of animal products with drug residues which may pose health problems in humans upon consumption of these products. (2) Possible allergy responses in humans consuming products from animals fed antibiotics. (3) The use of antibiotics in animal feed may add to a pool of organisms that are resistant and either directly or indirectly make it difficult to treat disease in humans. An example of direct effects on treatment in man would be a salmonella infection picked up from animals where J-t-t

2 334 canadtan JoURNAL OF ANIMAL SCIENCE the salmonella organism had become resistant because of antibiotic use in animals. A possibility of indirect influence on resistance in human infections from the use of antibiotics in animal feeds is based on the theory that a resistant bacterium is capable of transferring this resistance to other bacteria that have never been exposed to antibiotics. Because of these concerns, legislation severely restricting the use of antibiotics in animal feeds has already been implemented in the United Kingdon. The Food and Drug Administration in the United States is proposing rigid restrictions on the use of tetracyclines and penicillins in animal feeds. Health and Welfare Canada has stated that the Health Protection Branch is committed to a policy of reducing the unnecessary use of antibiotics in animal feeds. How this commitment will be put into practice is. as yet, unknown. CURRENT USE OF FEED ADDITIVES IN CANADA Feed additives (drugs and growth promotants) are currently being employed in three ways: (l) At low levels for growth promotion and enhancement of feed efficiency. (2) At intermediate levels for disease prevention. (3) At higher levels for treatment of specific or non-specific diseases. Inclusion of drugs and growth promotants in Canadian animal feeds is controlled by the Feeds Act and Regulations. All animal feeds, with the exception of pet foods, feed for export, feeds to be administered via injection or drench, and raw mink feed are subject to these regulations. The Compendium of Medicating Ingredients contains detailed drug clearances and includes approved levels, drug compatabilities, length of treatment and withdrawal times for all medicating ingredients approved for use in Canadian animal feeds. Within certain limits, medication levels and drug combina- tions, other than those shown in the Compendium, may be allowed provided that they are supported by a veterinarian's prescription. Canadian regulations require that each drug or feed additive must be cleared for use before it is permitted to be included in animal feeds. It normally takes approximately 5 yr from the filing of Investigation of New Drug Application with Ottawato when theproduct can be marketed. During this period an average of five feeding trials would be conducted at producer farms, commercial feedlots, and universities. The cost incurred in having a new feed additive cleared may approach the one million dollar mark. Each brand is regarded as a separate drug under present Canadian regulations and thus only those brands listed in the Compendium may be included in animal feeds. All feeds manufactured for resale in Canada must be registered with Plant Products Division, Ottawa. If the feed is medicated, registration documents and feed tags must list all medicating additives, their levels, cautions, warnings, claims, and withdrawal times and all of these must conform with the Compendium. Any deviation from the Compendium will result in registration refusal. Plant Products Division inspectors may visit a feed mill at any time and take samples of any feed manufactured at the mill. Should a discregancy exist between the tag guarantees and the assayed results obtained on the samples, the suspect lot of feed may be red-tagged, thus preventing sale of that lot. A good system of checks and balances exists to insure that the feed manufacturer is conforming with the regulations and is capable of correctly mixing feed additives throughout the feed. The Compendium lists a total of 1l (including tetracycline and penicillin) growth promoting medicating ingredients approved for use in poultry and swine rations and two (Monensin Sodium and Melengestrol Acetate) for use in beef cattle rations. An excellent condensation of the Compendium

3 SHARBY * FEED ADDITIVES IN CANADA 335 has recently been presented by Blair (1978). Published data on the actual use of drugs and additives in animal feeds are scarce. Due to the competitive nature of the marketplace most commercial firms involved in the marketing of such products are reluctant to release these figures. The most recent data found are those reported by Statistics Canada for the year In that year Canadian feed manufacturers used approximately 2.5 million dollars worth of antibiotics; 1.6 million dollars worth of coccidiostats; 1.9 million dollars worth of growth promotants; and 3.5 million dollars worth of other veterinary preparations and medicaments in the manufacture of 9.8 million tonnes of complete livestock and poultry feeds (Table l). Thus an average of one dollar's worth of feed additives was included in every tonne of complete feed manufactured in The majority of these feed additives would have been used in the manufacture of beef, swine and broiler rations which for 1975 amounted to approximately 2,3 and I million tonnes, respectively. Accepting that Table 1. Feed additives and drugs used in manufacturins feeds in the vears 19'74 and 19'75 Antibiotics Coccidiostats Blackhead control Worm control Growth promotants Tonics & conditioners Other veterinary prep. and medicaments Thousands of dollars t9' JJJ t t3 l 895 8l 3523 Total equivalent complete livestock and poultry feed manufactured in Canada in 1975 : 9.8 million tonnes. Statistics Canada. (1975). Species Beef Swine Broiler the efficiency of feed utilization is improved by 77a for beef cattle, 47o for swine and 37o for broilers when the feed contains feed additives, the resulting dollar value of the feed saved would be 19.4 million dollars, 21.3 million dollars, and6.4 million dollars for beef cattle, swine and broiler production, respectively (Table 2). Using the liberal estimate of $4 per tonne of complete feed as the cost of including a growth promotant, the total dollar value, after taking into account the cost of the additive, of the feed saved would have been approximately 24.4 million dollars had all beef, swine and broiler rations contained growth promotants in This dollar saving is realized just by the effect of feed additives on feed efficiency. Additional saving would be realized via their effects on production costs due to their speeding up the growth process and reducing death losses. It would thus appear that the use of antibiotics and feed additives in animal agriculture does lead to economic benefits. POSSIBLE CONSEQUENCES OF STRICTER REGULATIONS Canadians in 1976 spent o of their disposable income on food expenditures whereas in 1941 they spent o (Hussand and Karamchandani 1977). This reduction is to a large extent due to the ability of our livestock and poultry producers to convert less input into more output in the form of meat, milk and eggs. Improved knowledge of nutrition, improved genetic material, improved and intensified management practices and the discovery and use of feed additives have all contributed to this improved productive efficiency. Today it is commonplace for our producers to achieve I kg of broiler with 2 kg of feed; I kg of eggs Table 2. Effect of removal of growth promotants on feed costs (1975) 7o improve G/G) ' Total feed (1000 kg) s Feed saved (1000 kg) t I t Ration cost ($/1000 ke) g value saved l

4 336 CANADIAN JOURNAL OF ANIMAL SCIENCE with 4 kg of feed; and I kg of pork with 3.8 kg of feed. Just 20 yr ago this amount of broiler, eggs and pork would have required 3, 6 and 6 kg respectively. Rising land, labor and energy costs have resulted in intensified and automated management practices where greater and greater numbers of animals and birds are reared in less and less space. Such conditions are conducive to health problems, and disease prevention via the use of prophylactic levels ofantibiotics and antibacterials has allowed the producer to remain economically viable while rearing animals under these intensive conditions. Under current animal management practices, feed additives are a tool that animal producers must rely on if they wish to maintain their current level of production. It appears quite clear that any legislation restricting rhe present use of feed additives in animal production would have adverse effects on the cost of animal production. The extent of this effect would be determined by the extent and type of restrictive legislation introduced and followed. This increased cost of animal production will eventually be reflected in increased costs for animal products at the food counter. Stricter clearance procedures for feed additives may result in a reduction in the development of new products as manufacturers of such products may be reluctant to invest the time and money required when the risk of product refusal is greater. It would also follow that those that are cleared will be more costly to the animal producer. The withdrawal from animal production of those antibiotics used also in human application may, however, stimulate drug manufacturers to develop new feed additives so that they could continue to enjoy their place in the animal production market. There has been some discussion that certain antibiotics will only be allowed for disease treatment purposes and only with a veterinarian's prescription. The objective here is to reduce the amount of those antibiotics used in animal aericulture which are also used in human medicine, thereby minimizing potential risk of antibioticresistant bacteria infecting humans. Under current production practices, the incidence of disease among birds and animals would conceivably increase if the preventative use of antibiotics was removed. This situation could result in even greater use of antibiotics in animal production since treatment levels are considerably higher than those employed for growth promotion or disease resistance. Any change in legislation regarding feed additive use in animal agriculture would have to be such that it could be effectively and fairly regulated. The present system, where the approximately 700 feed mills across the country are monitored by Plant Products Division, would appear to be more manageable than a system requiring each and every animal producer to be monitored. A real concern of many producers regarding any suggestion of revised regulations for the use of feed additives is that once one product is removed from use, it will only be a question of time before all such products are withdrawn from use leaving the producer vulnerable. The question of actual threat to humans from antibiotic-resistant bacteria resulting from antibiotic use in feeds is yet to be adequantely answered. After nearly 30 yr of use, there have not been any identified instances where the treatment of disease in humans had been hampered by the fact that antibiotics were used in animal feeds. Until this association is clearly demonsffated, we should not react prematurely by removing a valuable tool from the hands of our food producers. The use of antibiotics in animal feeds was based upon scientific fact and it is hoped that should it be necessary to now remove them from this application, the removal is also based upon scientific fact. BLAIR, R Canadian regulations governing drugs and growth promoters in animal feeds. Feed stuffs 5O(25) : COMPENDIUM OF MEDICATING INGRE- DIENT BROCHURES. Publication Pub-

5 SHARBY - FEED ADDITIVES IN CANADA 33'7 lishing Center, Department of Supply and Services. Ottawa. Ontario. HUSSAN, Z. A. and, KARAMCHANDANI, D. I 977. Handbook of food expenditures, prices and consumption. Agriculture Canada. Publ. 7'7 I 13. STATISTICS CANADA Shipments of prepared stock and poultry feeds. Catalogue 32-OO4 (monthly). STATISTICS CANADA Feed industry. Catalogue (annual). STATISTICS CANADA Manfuacturers of pharmaceuticals and medicines. Catalogue (annual). STOKSTAD, E. L. R., JUKES, T. H., PIERCE, J., PAGE, A. C. Jr. and FRANKLIN, A. L The multiple nature of the animal protein factor. J. Biol. Chem '7-654.