M01013: Farm management practices to improve the visible and microbiological cleanliness of cattle hides at slaughter

Study Duration: January 2000 to September 2003

Contractor: ADAS Consulting Ltd

The point of entry of livestock to the abattoir has been identified as a critical control point in slaughterhouses. The objective of this research is to examine the principal processes that may be used by farmers in order to achieve visibly clean slaughter cattle and to assess their effect on faecal and the hide-borne microbiological load. The results will allow the Agency to formulate precise, science-based advice to the livestock industry on the optimal methods for reducing the visible dirtiness and pathogenic microbiological contamination of finishing cattle, thus reducing the risks of contamination of their carcasses. The information from this and previous projects will be used to develop an on-farm technology transfer event.

Contamination of meat by faecal material or intestinal contents coming into contact with carcasses at the abattoir is an important risk factor contributing to the outbreak of foodborne illness. The management of cattle from farm to lairage may provide a means for ensuring that cleaner animals are presented for slaughter. The overall objective of this project was to investigate the interacting effects of dietary and transport factors, and of straw bedding, clipping and time in lairage on the visible and microbiological cleanliness of cattle found at the abattoir.

• Finishing ration was found to be the most significant factor affecting faecal shedding of potentially zoonotic bacteria. Feeding cattle on cereal-based rations for a two-month finishing period was associated with significantly higher levels of bacteria compared with cattle finished on a silage-based ration. Increased levels of bacterial contamination were also found on the hides of animals fed cereal-based diets, particularly at the brisket site.
• The effect of restricted feed intake before slaughter was investigated, by switching cattle to straw-only diets for zero, one, two or three days. Significant reductions in Total Viable Counts (TVC), E. coli and total enterobacteria were found on the hides of animals with increasing time on straw-only feeding.
• The effect of journey time to the abattoir was also investigated in cattle used in the feeding experiments. Unexpectedly, no major differences in visible or microbiological hide cleanliness were found between journey times of two and a half and six hours. A well-designed and maintained lorry along with an approved and experienced haulier may have masked some of the problems that could arise during cattle transportation.
• In another experiment, clipping and the provision of additional straw bedding was found to improve the visible cleanliness of cattle hides, although the effects on the microbiological cleanliness were again more variable and dependant upon the class of bacteria studied. Clipping was associated with a reduction in the TVC at the flank and shoulder sites, but not at the brisket site. This is thought to reflect the difficulty in clipping the brisket of live cattle. Improvements in microbiological cleanliness at flank and shoulder sites were relatively short-lived, indicating that clipping would need to be carried out almost immediately before slaughter to have any significant beneficial effects on meat hygiene. Providing additional straw represents a much safer but costly approach to cleaning dirty cattle.
• Providing additional straw bedding in the abattoir during overnight lairage reduced TVCs at the brisket site, compared with counts from animals receiving normal bedding levels. However, effects at other sites and with other classes of bacteria were less perceptible.
• The effect of clipping and visible cleanliness of cattle on the leather quality produced from their hides was investigated. The incidence of dung damage was relatively low at less than 5%, although all downgraded hides were derived from cattle that had been visibly dirty at the start of the experiment. No clipper damage was observed on any of the hides, and was thought to reflect the fact that animals were clipped in accordance with best practice guidelines.
• The findings of this and an earlier project (M01009) were disseminated to the wider industry, through a technology transfer programme, which were focused on disseminating ten key messages:
  1. Livestock may carry harmful bacteria
  2. The 'Clean Livestock Policy' has improved cattle cleanliness
  3. Dirty cattle cost money
  4. Pre-slaughter diet needs consideration
  5. Providing adequate bedding improves cattle cleanliness
  6. Clipping can remove visible dirt
  7. Wet cattle are a significant hazard
  8. Transport factors can affect cattle cleanliness
  9. Mixing unfamiliar animals increases cross-contamination
  10. Bacteria survive well in livestock environments

The results generated by this project have been used to produce a booklet and poster series, aimed at cattle producers, which contain guidance on 'best practice' for the production of clean cattle for slaughter. Technology transfer in the form of information days, open days and press launches were also organised to disseminate information to the farming community.

Publications

Heasman, L. (2000) The effect of dietary management on the excretion by cattle of potentially zoonotic bacteria. Cattle Practice 8: 345-349.

Heasman, L., Hutchison, M. L. and Davies, M. H. (2002) The effect of level of bedding provision and time in lairage on the contamination of hides of finished cattle with potential zoonotic bacteria. Proceedings of the British Society of Animal Science.p188.

Heasman, L., Davies, M. H. and Hutchison, M. L. (2001) The effects of finishing ration and straw-only feeding prior to transport on faecal pathogen excretion and hide contamination of finished cattle. Society of Chemical Industry Conference - Pathogens in Agriculture and the Environment

Heasman, L., Webster, S. D., Hutchison, M. and Davies, M. H. (2001) The effects of straw only feeding prior to transport and journey time on faecal pathogen excretion and hide contamination. British Society of Animal Science.p84.

Final Report

The final report is available from the FSA Library and Information centre.

To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency (tel: 020 7276 8181/8182 or email: infocentre@foodstandards.gsi.gov.uk)

Contact: For any enquiries concerning this research project, please contact the relevant programme contact or email science@foodstandards.gsi.gov.uk