We believe this group was not infected with B.ovis for a number of reasons. E.ovis localises in the genital tract within 3 to 4 weeks of the development of a serological response (Biberstein ef al 1964; Cameron and Lauerman 1976; Webb ef a1 1980), and all of these rams had been positive serologically for at least that period of time. There were no gross or microscopic inflammatory changes in the genitalia and al- though localisation elsewhere in the body, for example, the urinary tract or abortive infection is possible, it is unlikely.

The bacteria isolated from the rams with “other lesions” are representative of the numerous species that had been isolated from ovine epididymides (Watt 1972; Jansen 1980). The 7 rams that yielded A.serninis-like organisms had path- ological changes indistinguishable from those described by Biberstein ef al (1964) for infection with B. ovis, indicating that routine histological examination alone will not allow accurate diagnosis of ovine brucellosis. The 9 spermatic gran- ulomas which failed to yield significant bacteria may have been chronic lesions from which the infectious agents had been eliminated. Alternatively, they may have been the result of spermiostasis due to congenital blind ducts which have been reported, particularly in the head of the epididymis (Galloway 1 984).

Palpation which is a compulsory part of the accreditation scheme was shown to be of no benefit in the detection of ovine brucellosis in serologically negative rams. These findings confirm the superiority of serological procedures relative to manual methods previously described by Hughes and Claxton (1968). In the context of the accreditation scheme however, palpation may be of benefit in detecting infection in young rams below the minimum age for serological testings or where sample testing is employed.

The identification of isolated low titre (usually 8 or 16) reactors, in the CF test for B.ovis, during accreditation testing of ram flocks with no evidence or history of disease presents a diagnostic problem for field veterinarians. Based on the findings in our investigations, we recommend such rams be isolated and a second CF test performed after approximately

4 weeks. If the second test is negative, the rams should be regarded as uninfected and accreditation should proceed. Rams with persistent titres should be subjected to the examinations outlined in this paper. If still no evidence of disease is found, the serological reactions should be classed as “false positive” and accreditation proceed. If the results are inconclusive or indicate infection, further flock testing is required.

Our system of examination has contributed greatly to the administration of the accreditation scheme. An accurate as- sessment of the status of the flock with regard to infection with B.ovis was possible in 89% of cases. A negative finding has been particularly useful, as it has facilitated prompt ac- creditation and made further testing unnecessary with consid- erable economic benefit. The flocks from which the inconclu- sive group originated could not be assessed and together with positive flocks, required further testing.

References Biberstein, E I , McGowan, B, Olander, H and Kennedy, P C (1964) -

Cameron, R D A and Lauerman, L H (1976) - Vet Rec 99: 231 Corner, L A, Alton, G C and Iyer, H (1985) - Aust Vet J 62: 187 Galloway, D B (1984) - In Proc. Workshop on Ovine Contagious

Epididymitis, Standing Committee on Agriculture, Hamilton, Vic- toria, April 1984, p 31

Hughes, K L and Claxton, P D (1%8) - Aust Vet J 44: 41 Jansen, B C (1980 - Onderstepoort J Vet Res 41: 101 Ludford, C and Claxton, P D revised by Searson, J E (1981) -

Ovine Brucellosis, Standard Diagnostic Techniques Published by Aust Bur Anim Hlth, Canberra, p 5

Rahaley. R J (1978) - Aust Vet J 54: 423 Searson, J E (1981) - Studies on the Pathogenesis of Brucella ovis

Infection MVSc Thesis, University of Sydney Searson, J E (1982) - Aust Vet J 58: 5 Thompson, D R (1984) - In Proc. Workshop on Contagious Epi-

didymitis, Standing Committee on Agriculture. Hamilton, Victoria, April, 1984, p 5

Watt, D A (1972) - Vet Bull (Weybridge). 42: 181 Webb, R F, Quinn, C A Cockram, F A and Husband, A J (1980) -

Aust Vet J 56: 172

Cornell Vet 54: 27

(Accepted for publication 6 January 1986)

Ante-modem and post-mortem meat inspection: an Australian Inspection Service perspective* G MURRAY

Inspection Service, Department of Primary Industry, Canberra, Australian Capital Territory 2600

SUMMARY: Australia, a major exporter of meat, has met and continues to meet the import requirements of various countries. It is free of many epizootic and zoonotic diseases and is eradicating bovine brucellosis and tuberculosis. Frequently, individual country requirements have not been relevant to the animal and public health status in Australia. Such a situation is unscientific, wasteful and unnecessary, and may divert priorities away from areas of major public and animal health significance which should be the main concern of consumers both in Australia and overseas.

In recent years the Inspection Service of the Department of Primary Industry has reviewed meat inspection procedures necessary to protect public and animal health in Australia and in countries importing Australian meat. Prioritles include attention to national or regional occurrence of disease in Australia and to the use of scientific principles in inspection, including disease identification, concepts of pathogenesis and effectiveness in removal of diseased tissue from meat. Revised post-mortem procedures for cattle, pigs, sheep and goats more relevant to disease occurrence and consideration of public health are described. In particular, this involves a reduction in the number of lymph node incisions.

Future directions for meat inspection in Australia are postulated. Concern is expressed that the requirements of some Importing countries are fixed in their legislation and consequently might inhibit desirable developments. In this context it is important that scientifically sound national codes for meat inspection of the exporting country be accepted by importing countries as providing public and animal health safeguards. Aust Vet J 63: 211-215

Introduction In recent years, considerable attention has been given in

Various countries to the relevance of traditional meat inspec- tion practices to modern systems of livestock and meat pro-

211

A summary of a more detailed paper presented to the Inter- national Symposium on Meat and Poultry Inspection in a Dynamic World, Ernst Sillem Conference Centre, Den Dolder, Netherlands, May 1985

Australian Veterinary Journal, Vol. 63, No. 7. July, 1986

duction (Skovgaard 1981; Blackmore 1983; Goodhan 1983; Blamire 1984; Dubbert 1984). Such considerations have arisen largely from acknowledging that diseases for which gross inspection techniques are appropriate, such as tuberculosis, are generally less prevalent, while the relative importance of unseen conditions, such as salmonellosis, has increased (Wat- son 1981). Similarly, greater recognition is now given to the integration of the slaughtering process into the overall system of animal production, particularly in terms of determining or monitoring health status of livestock (Christiansen and Hells- tron 1980).

Australia is a major producer of livestock for slaughter, derived from a wide range of climatic and geographic regions. Although pigs and poultry are increasingly produced under controlled intensive conditions, grazing livestock are derived mainly from extensive (range) systems of agriculture, which nevertheless ultimately depend upon health and productivity of the flock or herd, not of the single animal.

Animal Disease Status in Australia Inspection procedures should be consistent with the occur-

rence of disease in Australian livestock. However, specific requirements of some importing countries impose additional procedures reflecting priorities of those countries (Table 1).

It is now intended to review such procedures. Australia is free of many of the major pestilences of livestock (including all of the International Office of Epizootics list A diseases and many list B diseases) and of major zoonoses, including trichinellosis; thus its meat is acceptable to many markets (French and Geering 1978; Kouba 1984). It has been widely recognised, and specifically by the European Community, that “the animal health situation in Australia is excellent, stable and completely controlled by well structured and organised veterinary services particularly as regards diseases transmissible through meat” (Anon 1980). Further, programs for the erad- ication of bovine brucellosis and tuberculosis are well ad- vanced, and Australia successfully eradicated contagious bo- vine pleuropneumonia by 1973.

While some common diseases of livestock such as ovine caseous lymphadenitis (CLA) are widely distributed in Aus- tralia, others have a peculiar local or regional distribution. Such occurrences are related variously to climatic and geo- graphic factors (for example, onchocercosis or the absence of fascioliasis in Western Australia); to quarantine restrictions or to regional progress with the eradication program (for example, tuberculosis) or simply the opportunity for infection, as might occur for Cysticercus bovis.

TABLE 1 Post-mortem procedures required by importing countries in

addition to those relevant to Australian ilvestock diseases

Country Species Additional procedure

U S A bovine longitudinal bile duct incisions

EEC bovine tongue incision

porcine mesenteric lymph node palpation

lung incision blood visual examination additional heart incision additional liver incision spleen palpation mesenteric lymph node incision hepatic lymph node incision diaphragm examination spinal column examination renal lymph node incision supramammary lymph node incision superficial inguinal lymph node incision (in bulls)

porcine blood visual examination gastric lymph node visual examination renal lymph node visual examination spinal column visual examination (in pigs over 4 weeks of age) tonsil visual examination

212

In developing minimum requirements for inspection pro- cedures, such factors have been considered. Specific tasks of recognising and removing lesions of a particular disease should be undertaken only in regions where its occurrence is likely. However, the monitoring role cannot be ignored. Minimum procedures are considered adequate to detect a disease should it occur unexpectedly in a region. Examples of such priorities are the continued examination of lymph nodes of the head and thorax for tuberculosis in cattle or pigs, and the transverse incision of the bile duct of the liver of cattle and sheep even though fascioliasis is known to be restricted to south eastern Australia and other major trematodes, such as Dicrocoelium dendriticum. d o not occur (Seddon 1967).

Ante-modem Inspection Australia does not use the sanitary-abattoir concept, which

includes heavy dependence on bacteriological examination of meat, but rather relies on clinical and historical assessment of suitability for slaughter as a primary safeguard of the final product. In particular, salvage slaughter is not practised apart from those animals having a recent uncomplicated injury that are slaughtered on humane grounds. Public and animal health safety rather than the relative economic worth of the individual animal is considered to be the primary basis for decision in accepting animals for entry into the food chain.

The manner of rearing, sale and transport of animals for slaughter is usually determined by the farmer. The interaction of such processes is also relevant to ante-mortem inspection, *

because each can affect the suitability of animals for slaughter on account of disease, injury or stress, and determine the ultimate quality of meat produced. It is the Australian view that ante-mortem inspection should consist of a balanced veterinary professional judgment involving animal welfare, handling practices, public health and animal health in relation to regions and individual animals. However, there appears to be a need to constantly re-evaluate the veterinary role and the relevant contribution of lay inspectors or stockmen to maintain maximum efficiency of veterinary manpower.

Post-mortem Inspection In Australia, initial efforts to revise current procedures have

been directed towards disease status of 4 species - cattle, pigs, sheep and goats - with emphasis on increasing the efficiency of post-mortem inspection.

In general, procedures used to detect specific diseases such as bovine cysticercosis, tuberculosis or ovine CLA take account of the sites of predilection for lesions. Final disposition of affected carcases is frequently determined by the number of such lesions and their location, incorporating concepts of whether a disease has become “systemic”. However, such a system fails to take account of current knowledge of infectious disease. It is now appreciated that bacteraemia or viraemia may be part of the pathogenesis of many diseases. By the time an animal is presented for slaughter the disease is fre- quently in a chronic phase or is in some way resolving and the systemic distribution is no more than a historical event that should not determine suitability of meat for human con- sumption. This is often the case in porcine arthritis caused by E. rhusioparhiae infection (Cross and Edwards 1981).

Such considerations are also relevant to disease in which distinct localisation is known to occur, with organisms being contained by the host response. An excellent example of such a disease is ovine CLA. This disease commences with primary wound infection, followed by systemic distribution and sec- ondary localisation in lymph nodes, lungs and other viscera (Batey 1974; Nairn and Robertson 1974). Once localisation has occurred, rapid resolution of infection takes place. His- tological studies of experimental ovine lesions have shown that some sites develop caseous lesions, generally in lymph nodes, where effective containment of the organism results (Burrell 1978).

Thus it is proposed that disposition of CLA-affected car- cases be entirely based upon evidence of acute or chronic

Australian Veterinary Journal, Vol. 6 3 , No. 7 . July, 1986

systemic effect, rather than distribution of organisms. Such distribution becomes macroscopically evident with caseous lesions in lymph nodes once the infection is resolving. This is

'now known to be a characteristic of the disease. The above example of inspection requirements for CLA may also provide a model for other diseases involving systemic distribution, particularly those due to facultative intracellular bacteria. Fur- ther work may be necessary to ensure direct relevance.

Of considerable importance is the finding of Salmonella spp localised within lymph nodes receiving afferent lymph from the gastrointestinal tract. This has been determined in several animal species and appears to be a world wide phe- nomenon (Moo et a1 1980; Samuel et ul 1980 a, b; Keteran et a1 1982; Nabbut and Al-Nakhli 1982). This must call into question the incision of mesenteric and hepatic lymph nodes as routine procedures, because of risk of cross-contamination from carrier animals which has been shown to occur with traditional inspection systems (Samuel et ul 1980). The revised procedures for meat inspection in Australia require only those compulsory lymph node incisions deemed necessary to ade- quately detect likely pathology in animals from any region of the country. Such procedures are directly relevant to minim- ising cross-contamination by food-borne pathogens or by or- ganisms with possible implications for meat workers and in- spection personnel handling the meat or lesions. Further, attention has for some years been given to adopting hygienic dressing procedures, particularly those that minimise direct or indirect contact between hide and carcase.

Revised Post-mortem Procedures for Beef Revised post-mortem procedures were developed in part

after consideration of results of an earlier bovine lymph node survey that detailed likely occurrence of disease (Archer 1981). The results indicated that disease in lymph nodes is generally not common in Australia and that apart from tuberculin- reactor cattle, incision of mesenteric and hepatic lymph nodes is not warranted. Similar conclusions have been recorded for tuberculosis cattle in the United Kingdom, where since 1977 no case of bovine tuberculosis detected at slaughter would have been missed by the omission of incision of mesenteric lymph nodes, although tuberculin reactors would still have required such incisions to be made to ensure detection of all cases (Goodhand 1983).

At the commencement of the Australian national eradication program, lesions of tuberculosis in cattle were reported as comprising mainly lesions of the head or thorax, with lesions of abdominal lymph nodes or viscera relatively uncommon (Tammemagi el a/ 1973). This was further examined during a four-week period in October-November 1983 by the De- partment's Inspection Service for the 356,000 cattle slaugh- tered during that period (D Moo, J McMahon: unpublished data). The results were derived from returns from 69 abattoirs representing all states and the Northern Territory, with 273 (0.076%) positive for the disease by culture or histopathology and macroscopic appearance. Again, the majority of lesions occurred in head or thorax - 28.3% and 64.7% respectively - with 98.2% of single-site involvements in these locations. Mesenteric lesions occurred in 4.0% of cattle, comprising 1.9% of total lesions. There was only one occurrence of single-site involvement (0.4% of infected carcases), representing only 0.0003% of the cattle slaughtered (approximately 1 in 350,000), and it appears difficult in public health terms to justify in- spection effort to detect such low frequencies. Thus. incision of mesenteric lymph nodes has been deleted as a general procedure for cattle, except for tuberculin-reactor cattle, where incision of such lymph nodes is still required. During the same survey, the sites of lesions in 3150 water buffalo slaughtered at 2 abattoirs in the Northern Territory were examined. 127 (4%) of buffalo inspected were positive for the disease with 19% of lesions occurring in the head and 62.2% in the thorax. 10.8% of lesions occurred in the mesentery and/or mesenteric lymph nodes with 2 lesions in mesenteric lymph nodes being the sole detectable site of infection. In this species, mesenteric involvement appears to be more common, and so at this stage

Australian Veterinary Journal, Vol. 63, No. 7 , July, 1986

it is considered necessary to include incision of such nodes to ensure detection.

Current and revised inspection procedures for cattle are shown in Table 2. Their relative effectiveness of inspection at the head, viscera and carcase inspection stations has been evaluated by studies undertaken in 4 abattoirs, involving more than 4000 cattle. Statistical analysis by chi-square test revealed no significant difference between procedures (D MOO et 41, unpublished data). However, it should be appreciated that these represent minimum requirements, and further detailed incision or palpation might be required where identified risks are present. For example, in areas of Australia where Cysti- c e r m bovis occurs, identified at-risk cattle may require ad- ditional inspection effort to ensure detection, but the revised procedures would suffice elsewhere to achieve the monitoring function.

Revised Post-mortem Procedures for Pigs The occurrence of lesions in porcine lymph nodes in Aus-

tralia has been previously reported, with abscesses comprising 97% of lesions detected (Arthur 1981). The commonly in- volved nodes were mandibular (submaxillary), superficial in- guinal and cervical. Mesenteric and iliac lymph nodes were uncommon sites of disease. Tuberculosis due to Mycobucte- rium avium which is not transmissable to humans is known to occur in certain regions, particularly in southern and central districts of eastern Australia. with occasional lesions due to saprophytic (atypical) mycobacteria elsewhere (Seddon 1967).

TABLE 2 Mlnlmum procedures for post-mortem Inspection of cattle

Current Revised

Head Head Observe all exposed surfaces Observe all exposed surfaces Incise parotid, submaxillary Incise parotid, submaxillary and retropharyngeal lymph and retropharyngeal lymph nodes nodes Incise internal (once) and ex- Incise internal (once) and ex- ternal (twice) masticatory ternal (once) masticatory muscles muscles Observe and palpate tongue Observe and palpate tongue Viscera Viscera Observe and palpate s u r - Observe and palpate s u r - faces of lungs faces of lungs Incise bronchial and medias- Incise bronchial and medias- tinal lymph nodes tinal lymph nodes Observe and palpate external Observe and palpate external surface of heart surface of heart Incise and observe muscu- Incise and observe muscu- lature of heart lature of heart Observe and palpate spleen Observe spleen Observe and palpate liver Observe and palpate liver Incise portal lymph nodes Observe and palpate portal

lymph nodes Incise large bile ducts Ion- Incise large bile ducts trans- gitudinally versely Observe oesophagus Observe oesophagus Palpate ruminoreticular Observe rumen and reticu-

Observe intestines and mes- Observe intestines and mes- enteric lymph nodes Incise reasonable number of mes- enteric lymph nodes Observe enucleated kidney Observe and palpate enu-

cleated kidney Carcase Carcase Observe external and internal Observe external and internal surfaces surfaces Incise superficial inguinal, in- Observe and palpate super- ternal iliac and prepectoral ficial inguinal and internal il- lymph nodes iac lymph nodes Palpate precrural and super- No longer required ficial cervical lymph nodes Observe exposed neck mus- Observe cut muscle surfaces cles, incise if necessary exposed during dressing o p

eratians

lum

enteric lymph nodes

Denotes change

213

It is now considered that lesions due to M. bovis or M. tuberculoses are unlikely to occur, because of the success of eradication of the bovine disease and of public health programs directed at human tuberculosis. Thus, porcine tuberculosis might now be considered to be of extremely low public health significance and specific detailed examination for detection is no longer necessary.

Current and revised inspection procedures for pigs are shown in Table 3. Their relative effectiveness of inspection at the head, viscera and carcase inspection stations has been evalu- ated by studies undertaken at 3 abattoirs, involving more than 3000 pigs. The original proposal was to omit incision of cervical lymph nodes, but evaluation suggested that significant lesions occurred at that site. However, following adjustment of data to exclude that difference, there was no further sig- nificant difference between the revised and current procedures by the chi-square test (D Moo et 01, unpublished data). Again, the procedures represent minimum requirements appropriate to all Australian abattoirs but further inspection effort might be required for particular animal populations.

Proposed Post-mortem Procedures for Sheep and Goats Proposed new procedures for sheep and goats relate only

to CLA. A major change involves judgment being based on actual systemic effect of the disease rather than on the current complicated system based on number, size and sites of lesions. In addition, the disease is perceived as not being of significant importance to human health and thus much of the removal of lesions could be by meat workers under inspection super- vision.

C. pseudotuberculosk is a cause of CLA but has also been involved in non-specific wound infection in various mammals, including humans (Benham el al 1962; Lopez et a1 1966). Infection of a butcher has been reported in Australia (Battey et a1 1968) suggesting that some safeguards are desirable for those who are occupationally exposed. Thus it is considered that all inspection systems requiring incision of ovine lymph nodes be abandoned to reduce contamination by the organism. As has been correctly pointed out by Blackmore (1983), an inspection service does have responsibility to minimise risks to inspectors and meatworkers.

Removal of the main sites of predilection, including super- ficial cervical (prescapular), subiliac (precrural) and superficial

TABLE 3 Minimum procedures for post-mortem inspectlon of plgs

Current Revised

Head Observe head surfaces Incise cervical and mandi- bular lymph nodes

Viscera Observe and palpate lungs Incise bronchial and medias- tinal lymph nodes

Observe and palpate heart Palpate liver Observe portal lymph nodes, palpate and incise if neces- sary Observe spleen, stomach and intestines Incise gastric and mesen- teric lymph nodes Observe kidneys

Carcase Observe external and internal surfaces Incise superficial inguinal i l - iac and lumbar lymph nodes

Head Observe head surfaces Incise cervical and mandi- bular lymph nodes

Viscera Observe and palpate lungs Observe and palpate bron- chial and mediastinal lymph nodes Observe and palpate heart Palpate liver Observe portal lymph nodes, palpate and inclse if neces- sary Observe spleen, stomach, and intestines Observe mesenteric lymph nodes Observe and palpate kidneys

Carcase Observe external and internal surfaces including joints Incise superficial Inguinal lymph nodes and palpate i l - iac and lumbar lymph nodes

Denotes change

inguinal lymph nodes, from affected animals or from all sheep in high prevalence groups is proposed as the most appropriate method. When summarised, survey reports between 1929 and 1980 on the occurrence of CLA in Australia’s sheep indicate that 85 to 99% of lesions occur in these predilection sites. Survey data suggest that under such a system, residual lesions would occur at a very low frequency, consistent with a highly acceptable level of detection and removal.

Nevertheless, this could be further reduced by such a system enabling inspection staff to concentrate on the examination of ischiatic, iliac and popliteal lymph nodes - sites of lesser occurrence. This proposal challenges a tradition of not re- moving lymph nodes from carcases, but nevertheless, consid- ering the disease status of Australian sheep with the absence of other specific causes of lymphadenitis, it is regarded as the most appropriate method, particularly considering its in- creased effectiveness and the absence of significance for human health.

Efficiency of Inspection Procedures If, as suggested by Blackmore (1983), individual carcase

inspection may indicate a fundamental error in emphasis, it should become increasingly possible to have meat workers remove defects under veterinary supervision. Inspection staff could consequently be better occupied dealing with areas of high public health priority. The recognition and/or removal of lesions or blemishes of limited or no health significance could be regarded as a commercial concern for processing companies.

To achieve this, it becomes necessary to identify lesions or blemishes to which such processes might apply, the likely effectiveness, and the level of supervision by an inspection service of processing company efficiency at removal of such lesions or blemishes, necessary to ensure compliance with acceptable standards.

When it is considered that traditional meat inspection ex- pends substantial effort in detecting, recognising and removing lesions of disease that has little or no significance to public health, there must be scope for savings in terms of both economics and the redirection of inspection effort to areas of greater priority.

Indeed, Blackmore (1983) has questioned the emphasis on individual wcase inspection, and has proposed that alter- native priorities be developed, including on-farm assessment of health status to control zoonoses, minimising occupational risk to meat workers, and controlling factors that determine meat quality. While such new emphases are highly desirable and may be attainable as the major objectives for intensively husbanded species, and even for grazing livestock from certain districts, they must be considered in parallel with post-mortem inspection under Australian conditions. In this context the system of categorisation of livestock presented for slaughter to determine relative disease status as proposed by Minderhoud (cited by Jagger 1984) and modified to take account of regional differences in livestock processed through individual abattoirs, may be more appropriate.

In the future, the meat inspection practices must be con- stantly reassessed on a scientific basis to ensure implementation of changes occurring in detection of disease, animal health status and the introduction of new technologies. In this regard, enshrining inspection procedures in legislation is likely to inhibit the achievement of desirable and appropriate codes or standards.

Nevertheless, in the short term, greater efficiencies are pos- sible by the definition of priorities in post-mortem inspection, introducing revised procedures to take account of current disease status, the removal of incidental pathology by meat- workers under appropriate supervision and the devolvement of responsibility for quality control to industry under inspec- tion control. This is achievable without compromising human health and, indeed, as illustrated by the proposed changes to sheep inspection, may achieve better removal of lesions of specific diseases.

Australian Veterinary Journal, Vol. 6 3 , No. 7 , July, 1986 214

However, to attain these efficiencies and redirection of inspection effort to areas of public health concern, it is im- portant that scientifically sound national codes be accepted as providing the public and animal health safety which is espoused in an importing country’s food law. Indeed for a major meat exporter such as Australia, such an accepted code allows the proper direction of meat inspection effort, provides greater safeguards for consumers overseas and reduces waste and expense in meeting individual importing country require- ments which in any case may not be relevant to the production and health situations in the exporting country.

Acknowledgments Thanks are given to M r R Batey for his assistance in preparing a

preliminary draft, and to Mr Moo, Mr J McMahon and Ms S Kahn for their involvement in field testing of revised inspection procedures. Particularly appreciation is given to field inspection staff who assisted in compiling data and trialling the new inspection procedures.

References Anonymous (1980) - Commission Decision Concerning Animal Health

Conditions and Veterinary Certification for the Importation of Fresh Meat from Australia. 80/801 /EEC. Official J European Com- munities No. L234: 41

Archer, J F (1981) - In Advances in veterinary Public Health Vol I , ed Hein, W Aust College of Veterinary Scientists, Indooropilly,

Arthur, R (1981) - In Advances in Veterinary Public Health Vol I , ed Hein, W, Aust College of Veterinary Scientists, Indooroopilly,

Batey, R G (1974) - An Investigation of the Mechanism of Immunity to Corynebacteruim pseudotuberculosis M Sc Thesis, University of Western Australia

Battey, Y M, Tonge, J I , Horsfall, W R and McDonald, I R (1968) - Med J Aust 2: 540

P 38

P 36

Benham, C L, Seaman, A and Woodbine, M (1962) - Vet Bull 32:

Blackmore, D K (1983) - Nord Vet-Med 35: 184 Blamire, R V (1984) - J Royal Soc HIth 104: 180 Burrell, D H (1978) - Res Vet Sci 24: 269 Christiansen, K H and Hellstrom, J S (1980) - In Proc 2nd Inter-

national Symposium on Veterinary Epidemiology and Economics, Canberra, May 7-11, 1979: 168 Cross

Dubbert, W H (1984) - J A m Vet Med Ass 184: 266 French, E L and Geering, W A (1978) - Exotic Diseases of Animals.

A Manual for Diagnosis, 2nd edn, Aust Govt Publishing Service, Canberra

Goodhand, R (1983) - J Royal Soc Hlth 103: 11 Keteran, K, Brown, J and Shotts, E B (1982) - A m J Vet Res 43:

706 Kouba, V. ed (1984) - Animal Health Yearbook 1983. FA0 Rome Lopez, J F, Wong, F M and Quasada, J (1966) - Am J CIin Path

McCool, C J (1979) - Aust Vet J 55: 214 Minderhoud, J, cited by Jagger, F (1984) - Vet Rec 114: 441-442 Moo, D, O’Boyle, D, Mathers, Wand Frost, A J (1980) - Aust Vet

Nabbut, N H and Al-Nakhli, H M (1982) - J Food Protection 45:

Nairn, M E and Robertson, J P (1974) - Aust Vet J 50: 537 Samual, J L, O’Boyle, D A, Mathers, W J and Frost, A J (1980) -

Res Vet Sci 28: 238 Samual, J L, O’Boyle, D A, Mathers, W J and Frost, A J (1980) -

Aust Vet J 5 6 : 526 Seddon, H R revised Albiston, H E (1967) - Diseases of Domestic

Animals in Australia Part I , Helminth Infatations, 2nd edn, Com- monwealth Aust, Canberra, p 7

Seddon, H R revised Albiston, H E (1967) - Diseases of Domestic Animals in Australia. Bacterial Diseases, Vol I , 2nd edn, Com- monwealth Aust, Canberra, p 182

Skovgaard, N (1981) - In Proc 8th Int Symp World Ass Vet Food Hygienists, p 3

Tammemagi, L, Simmons, G C, Kelman, R and Hall, W T K (1973) - Aust Vet J49: 507

Watson, W A (1981) - J Royal Soc HIth 101: 163

645

46: 562

J 5 6 : 181

1314

(Accepted for publication 12 February 1986)

CORRECTION

Influence of frequency of anthelmintic treatment on the growth rate of Australian

Friesian Sahiwal heifers

On page 190 of the Australian Veterinary Journal Volume 62, 1985, Figure 1 is incorrect. Some of the detail in the graphs and caption is wrong or missing. The correct Figure 1 and caption are reprinted below.

2 5W

SAMPLE DATE 1981

Figure 1. Mean faecal helminth egg counts (epg) at each sampling date. 0-4 Untreated Friesian heifers U Untreated Australian Friesian Sahiwal heifers 0 - 4 Australian Friesian Sahiwal heifers treated with levamisole oncelmonth c--l Australian Friesian Sahiwal heifers treated with levamisole oncelthree months. Arrows (t) indicate anthelmintic usage.

Australian Veterinary Journal, Vol. 63, No. 7, July, 1986 215