Reducing Dark Cutting Beef

Identifying practical ways to reduce the prevalence of Dark Cutting Beef by better animal handling ante-mortem

Project number:                    72502

Lead contractor:                   University of Bristol

Start & end date:                   01 January 2008 – 01 March 2009

Actual end date:                    October 2008

 

The Problem:

Dark Cutting Beef (DCB) is economically of concern to the UK Industry because consumers discriminate against its abnormal colour, the eating quality is poor, and shelf life may be reduced by its high spoilage potential.  Additionally, DCB is often associated with high levels of bruising which can lead to carcass downgrading.  Mixing unfamiliar animals before slaughter is considered to be the main factor that leads to DCB, possibly exacerbated by food deprivation and fatigue caused by transport.  However, despite our understanding of the principal cause of the problem the commercial levels of DCB are still significant, indicating that cattle are not all being handled optimally ante-mortem.  This may reflect gaps in our detailed knowledge of the deleterious effects of specific handling procedures associated with sending animals to slaughter, for example the exact time and duration for which individuals are mixed, or an increased predisposition of some individuals to produce DCB caused by their husbandry during rearing.  It might also to some extent reflect poor technology transfer or uptake of knowledge by farmers and processors.

 

Project Aims:

  1. To identify specific husbandry and ante-mortem handling practices used in the UK that pre-dispose cattle to produce dark cutting meat.
  2. To define a protocol for the optimal handling of cattle ante-mortem that could form the basis of an Industry “blueprint to reduce overall levels of DCB.

 

Approach:

This project will collect data on live animals and incidence of dark cutting form animals going through a commercial slaughter plant.

 

Results:

Information was collected from 717 bulls which were delivered in 47 consignments from 16 producers to one plant between March and June 2008.

The prevalence of DCB assessed in the sirloin was 12.3% based on objective measurements of pH and 8.8% based on subjective assessments.  Five per cent of carcasses showed serious dark cutting with a pH greater or equal to 6.0.

There was good agreement between objective and subjective assessment methods.  Subjective assessment would be an effective way of monitoring DCB on the boning line.

The main identified cause of DCB was mixing unfamiliar animals in the pre-slaughter period.  As the number of rearing pens from which animals were drafted to make up a consignment increased, so did the amount of fighting and mounting behaviour shown in the lairage, the average pH of the meat, and the %DCB based on both objective and subjective assessments.  Producers whose animals exhibited more DCB on average selected the animals in their consignments from a larger number of rearing pens.

The overall level of DCB varied slightly, but not significantly, in bulls from different breeds.  Dark cutting animals tended to have a slightly lower carcass weight, probably because they grew more slowly.  There were no discernible differences in feeding system, transport time, lairage time, or the total time spent from drafting on the farm to slaughter, between animals that produced normal or dark cutting beef.  Feed and water provision immediately pre-slaughter was similar for all animals, and variation in ambient temperature was small, and there was no evidence that either of these factors affected the %DCB.

 

Planned activity:

A briefing note on dark cutting beef has been prepared and used as the basis of practical guidance in a number of BRP and other farmer- and abattoir-facing communications.