The problem of dark-cutting in beef : a seminar in the EEC programme of coordination of research on animal welfare, organised by D.E. Hood and P.V. Tarrant, and held in Brussels, October 7-8, 1980

484 Pages·1996·35.35 MB·English

by  D E Hood, P V Tarrant, Commission of the European Communities. Coordination of Agricultural Research., Commission of the European Communities

THE OCCURRENCE, CAUSES AND ECONOMIC CONSEQUENCES OF DARK-
CUTTING IN BEEF - A SURVEY OF CURRENT INFORMATION.
P.V. Tarrant
Meat Research Department, Agricultural Institute,
Dunsinea, Castleknock, Co. Dublin, Ireland.
ABSTRACT
In the ppepa:t'ation of this semin= on stpess in cattle and dapk-eutting
in beef, infoPmation vas eo Hected from a wide baekgpound by means of a
survey to detemine the ppesent position and pecent deveLopments in this
aPea. Questionnaires (see Appendix 1) were sent to senior scientists in
meat peseapch LabomtoPies. Twenty-seven compLeted questionnaipes Wepe
returned from nineteen aount'Pies 1. Respondents were asked to present the
situation as it exists in their own countries.
The results represent informed scientific opinion based on research
findings and practicaL expePience of the ppobLem in the meat industry. They
ppovide a peasonabLe estimate of the extent of the pmHem, in tems of
incidence and type of cattle affected, the ppincipLe chapactePistics of
the condition and its impact on the meat industpy.
In ppesenting the pesuUs, pesponses ape frequently identified on a
nationaL basis. This was found to add considembLy to the usefuLness of the
data. Howevep, it is necessary to emphasise that the infol'm'J.tion ppese-nted
in any particuZ-ar case does not necessarily represent the national position,
but pathep a ppevaiUng situation within each eountPy. In assessing the
resuLts, aU pepUes were given an equaL weighting.
Australia, Belgium (2), Britain, Bulgaria, Canada, Czechoslovakia, Denmark,
France, Finland, West Germany, Ireland, The Netherlands, New Zealand, Norway,
Poland (2) r South Africa, Sweden, The United States (Maryland, Illinois,
Missouri, Wyoming, Texas (2), Oregan) and Yugoslavia.
D. E. Hood et al. (eds.), The Problem of Dark-Cutting in Beef
© ECSC, EEC, EAEC, Brussels-Luxembourg 1981
The principal results of the survey follow and the detailed
results are presented in Appendix 2.
Question: What sectors of the beef trade have problems associated
with dark-cutting?
The sectors of the beef trade most widely considered to
have p~oblems associated with dark-cutting are the Cdrcass
sector, vacuum-packed primal sector and retail fresh beef
sector. All the other sectors of the trade which were listed
in the questionnaire, (see Appendix 1) were occasionally consid-
ered to have problems with dark-cutting beef.
Question: What category of animal is affected?
Young bulls are universally. considered to be affected by
dark-cutting, whereas opinions regarding the other sex cate-
gories were divided. In steer-producing countries, in general,
all categories of cattle were considered to be affected. In
countries with substantial bull beef production, dark-cutting
is predominantly associated with young bulls and other cate-
gories were not frequently thought to be affected.
Question: Is there a breed effect?
There is a lack of information concerning the effect of
breed on the incidence of dark-cutting in beef.
Question: Can you estimate the incidence of dark-cutting?
Estimates of incidence varied. The incidence was most
frequently estimated at 1 - 5 per cent for steers and heifers,
6 - 10 per cent for cows and 11 - 15 per cent for young bulls.
Question: What muscles are most liable to be affected?
M. Longissinm.s dorsi was universally considered to be one of
tne muscles most liable to be affected. Other muscles were much
less frequently cited. These tended to be the major hindquarter
muscles more often than forequarter muscles.
Question: What ultimate pH values (measured in M. 1. dorsi) would
indicate dark-cutting to you?
Beef quality deteriorates when the ultimate pH value is
equal to, or above, 5.8. The precise value at which a carcass
is deemed 'dark-cutting' depends largely on processing and
marketing factors and is in the range pH 5.8 - 6.3. Values
above this range are always associated with an unacceptable
degree of dark, firm, dry (DFD) beef.
Question: Is there a seasonaZ effect? If your answer is ryes I,
please indicate in which months dark-cutting is most likely.
A majority of respondents reported a seasonal effect.
These respondents were mainly from the traditional steer-prod-
ucing regions. There was considerable agreement concerning
which months are most frequently associated with incidence or
intensity of DFD. In the northern hemisphere, these are Sept-
ember to January, inclusive, and the month of April.
PZease suggest three causes of dark-cutting in your' country in
order of importance.
Mismanagement of cattle before slaughter, resulting in
physiological stress and exhaustion, was the most frequently
suggested cause of dark-cutting in beef. In particular, the
practice of penning cattle together in mixed lots at the abbatoir,
and unsuitable transport conditions, were often cited. The other
causes suggested concerned climatic conditions, nutrition, path-
ological conditions, genetic factors and stress in general.
Question: What do you think are the main objections to dark-cutting
beef?
There was general agreement that abnormal colour and
spoilage characteristics are the main reasons for objecting
to DFD beef. The appearance, consistency and organoleptic
characteristics of the meat are also considered to be object-
ionable.
Question: Is theY'e an economic penaUy foY' daY'k-cutting beef at any
stage in the m=keting chain? If so, what is the economic
Zoss relative to a normaZ carcass or meat out?
A majority of replies indicated that there is an economic
penalty. The economic loss relative to normal meat was most
frequently put at 10 per cent. ~ch higher losses were
occasionally reported.
Question: Is theY'e down-gY'ading of caY'Casses on a national, Y'egional
or local classification or grading scheme?
Down-grading of dark-cutting carcasses at beef classific-
ation or grading is fairly common and was reported by 44 per
cent of respondents.
Question: Are there other economic consequences?
Rejection of DFD beef at various stages of the marketing
cnain was the principle area of concern. Cost of -disposal of
DFD beef and substituting normal meat, loss of reputation for
quality and down-grading of non-affected cuts were also cited
as additional economic consequences.
CONCLUSIONS
The survey confirms that dark-cutting is a persistent
condition in cattle, occurring in all categories of cattle and
in all countries surveyed. Conclusions relevant to the subjects
of meat quality and animal welfare can be drawn and these will
be considered separately.
Meat quality
The results of the survey show that dark-cutting beef is
rejected by the meat industry and by the consumer on the basis
of a number of serious quality faults. These are such as to
exclude its use in normal fresh meat products. The frozen beef
trade is a possible outlet. However, the reduced organoleptic
characteristics of the product raise the question whether such
meat can be diverted into frozen beef outlets, particularly the
home freezer market, without long-term repercussions.
The estimated incidences (Table 4, Appendix 2) show that
the condition is of considerable proportions in many of the
countries surveyed. The reported high variability in the daily
incidence makes detection and control by industry more difficult.
For example, the seasonal effect in Ireland is estimated to
cause a four-fold increase in the average incidence and this is
made up of a highly variable daily incidence.
Young bulls were, predictably, reported to have the
highest incidence. The meat industry itself has control over
the major causes of dark-cutting in these animals, which concern
pre-slaughter management procedures. Proper control of penning
and handling procedures at abattoirs would greatly reduce the
incidence in young bulls and other cattle from intensive product-
ion systems. As it is often economically more favourable to
produce beef from bulls rather than steers, it is clearly impor-
tant for the industry to minimise meat quality defects in bull
beef.
The acceptability of beef of abnormal ultimate pH is
greatly influenced by production and trading circumstances.
There is scope for the preparation of a comprehensive pH stand-
ard for use in quality control and quality assessment. Measure-
ment of ultimate pH is widely practised and pH standards vary
considerably, to meet particular production and marketing
circumstances. A suitable pH standard for use within" the
European Community would take into account the type of carcass
under examination and the process and market for which it is
intended. In this context it is important to emphasise the
wholesomeness of dark~cutting beef, despite its technological
and organoleptic disadvantages.
Substantial economic penalties were widely reported.
These may serve as an impetus towards developing practical
procedures aimed at reducing the incidence and improving the
methods of detection. Suitable procedures should be developed
for utilising DFD beef. Any attempt to market DFD as normal
beef should be discouraged in the long-term interests of the
industry.
Animal Welfare
The dark-cutting condition is relevant to animal welfare
because it results from exposure to stress and is indicative
of physical exhaust10n before slaughter. The condition is
unknown in well-fed and rested animals. Some categories of
cattle are more likely to be affected than others. This may
be due to inherent sex characteristics as in the case of young
bulls. Alternatively, in the case of cows, it may be due to
lower standards of care before slaughter.
The difficulty of inducing dark-cutting experimentally,
e.g. by fasting, exercise or similar stressors, has been
reported in the literature. It follows that the observed
incidence of dark-cutting underestimates the number of cattle
exposed to stress before slaughter. The observed incidence of
dark-cutting represents only the most severely stressed animals.
From the point of view of animal welfare, young bulls
should be considered apart from the other categories of cattle.
The high incidence of dark-cutting in these animals is assoc-
iated with the sex characteristics of an excitable temperament
and aggressive or sexual activity. These activities are more
pronounced in a novel environment and, although stressful,
represent normal animal behaviour. Dark-cutting in these animals
does not necessarily indicate ill treatment before slaughter.
Dark-cutting was attributed to severe environmental
stress factors, sometimes potentiated by genetic factors. The
causes reported in the survey are obviously the most common ones.
In practice, any situation which results in substantial depletion
of muscle glycogen reserves will cause dark-cutting if the animal
is slaughtered before recovery takes place. The mechanisms of
muscle glycogen depletion are (a) the performance of heavy
muscular work resulting in an increased intra-cellular energy
demand, (b) adrenergic activation of glycogenolysis by increased
adrenaline concentration in the circulation, and (c) long-term
depletion of glycogen reserves as a consequence of inanition.
Because of the frequency with which mismanagement of
cattle before slaughter was cited as a cause of dark-cutting,
the results suggest that there is a need for further information
concerning procedures for handling and transport of cattle.
Standards must be agreed upon and made available to cover the
various situations which exist in the industry. The construction
of pens and their method of use would appear to require partic-
ular attention. The recommended holding time for the different
categories must be clarified, together with procedures for
allowing exhausted cattle to recover before slaughter.
The results suggest that the climate and other seasonal
factors are important in the aetiology of the dark-cutting
condition. Exposure to the elements and inadequate nutrition
obviously occur, particularly in extensive beef production
systems, and the consequences are apparent in the carcass.
Alleviation of animal suffering due to seasonal factors is a
more difficult proposition than is the case with pre-slaughter
factors.
ACKNOWLEDGEMENTS
Information was kindly provided by the following persons:
Dr. A.J. Bailey, United Kingdom; Dr. H.F. Bernholdt, USA;
Ir. H. de Boer, the Netherlands; O.S. Braathen, Norway;
Mrs. L. Buchter, Denmark; Canada Packers Ltd., Canada;
10
Ir. M. Casteels, Belgium; Dr. B. Chrystall, New Zealand;
Dr. E. Cosentino, Italy; Dr. C.L. Davey, New Zealand;
Dr. T.R. Dutson, USA; Dr. R.A. Field, USA; Eng. Geraldo Cia,
Brazil; Dr. Maria Gorna, Poland; Dr. H.B. Hedrick, USA;
Ing. J. Jedli~ka, Czechoslavakia; Dr. D.E. Hood, Ireland;
Prof. Dr. E. Kallweit, Federal Republic of Germany;
Dr. W.H. Kennick, USA; Dr. A.W. Kotula, USA; Dr. K. Krzywicki,
Poland; Dr. G. Monin, France; Dr. R. Naude, South Africa;
Prof. Dr. N. Nestorov, Bulgaria; Prof. F.P. Niinivaara, Finland;
Prof. Dr. H. Pfeiffer, German Democratic Republic; E. Puolanne,
Finland; Dr. S. Rahelic, Yugoslavia; H. Ruderus, Sweden;
Prof. Dr. L. Sch8n, Federal Republic of Germany; Dr. G.C. Smith,
USA; Prof. N.M. Tulloh, Australia; Prof. Dr. J. van Hoof,
Belgium; Dr. D.J. Walker, Australia; Dr. Maria Vada, Hungary.
II
APPENDIX 1
QUESTIONNAIRE DARK-CUTTING IN BEEF
Please tick (thus I) the box on the questionnaire that best
expresses your opinion of the situation in your country or
region. Where appropriate more than one box may be ticked.
Please give additional information which you consider to be
relevant to this subject.
Please give the country or general region to which your answers
apply:
1. What sector(s) of the beef trade in your country or region
has (have) problems associated with dark-cutting:
D D D D 0 0 D
Carcass Vac-pack Retail Ground Cured/ Fermented Other
trade fresh beef fresh beef salted products (please
primals beef products specify
COMMENT:
2. What category of animal is affected:
D D 0 0 0 0
Steer Heifer Cow Young bull Other All
(castrate) (virgin) (lactating) (entire) (specify) categories
if
+0 ~ if
COMMENT:
3. Is there a breed effect?
o D o
Yes No Don't know
If 'yes', what breeds'are most susceptible:
12
4. Can you estimate the incidence of dark-cutting:
Don't
o 1-5% 6-10% 11-15% 16-20% 20%+ know
Steer
Heifer
Cow
Young bull i
i
All
categories
~ i
ADDITIONAL COMMENTS:
5. What muscles are most liable to be affected:
1~. biceps femoris M. sem~memb.~anosus M. trapezius
M. psoas major M. 8em1.- terU1:z.nosus M. infraspinat"
8M. gLuteus medius BM. longissimus dorsi § M. supraspinat"
,~. adductor - M. triceps brachii
Other muscles or meat cuts, please specify:
6. What ultimate pH values (measured in M. L. dorsi) would
indicate dark-cutting to you:
U 0 i_I D U 0 0 0
pH 5.7 5.8 5.9 6.0 6.1 6.2 6.3 6.4
COMMENT: