Canadian Centre for Swine Improvement Inc.
The Ontario Carcass Appraisal Project has produced a wealth of
information, on growth performance carcass and meat quality, and
relationships between live, grading and carcass measurements.
This information has already been used to complete a number of
It is important to understand the relationships between these
various projects or programs. Some activities are undertaken primarily
for research, while others aim to monitor meat and carcass quality,
and others to provide data for selection. The purpose of this
paper is to review the strengths and weaknesses of the tools available
for research, selection or monitoring of meat and carcass quality
and examine how they can be used together to advance the industry.
Why is carcass and meat quality important?
The industry produces only one product and pork meat. Making sure this product is of good quality is essential to preserve or extend markets for Canadian pork. In addition, the development of value-added products is key to the future of the industry. In order to produce specialized, ready to market products that seek premium prices in Canada or abroad, we must be able to control product quality.
Meat and carcass quality can be controlled or improved in several
ways: they are affected by genetics, management and feeding, health,
transportation and handling, packing and processing. In this paper,
we will focus primarily on genetic improvement and the monitoring
of its impact in breeding herds, commercial herds, and slaughtering
plants. There is a good reason for paying special attention to
the genetic improvement of meat and carcass quality: it responds
well to selection. Table 1 shows that the heritabilities of most
carcass traits are in the 30% to 50% range, i.e. between one-third
and one-half of the total variation in these traits is of genetic
origin. For meat quality (Table 2), the heritabilities are generally
in the 30% range, with some in the 60% range (e.g. marbling).
Swine test stations
One of the tools that has been used very early in the genetic
improvement of meat and carcass quality is the test station. It
consists of bringing together, in one location, animals from several
sources evaluating their growth performance and collecting slaughter
data. Recent examples are OPCAP, the Commercial Product Test in
Quebec, the NPPC terminal lines trial or the Shur-Gain study in
Ontario. The main advantage of the test station is that it offers
a controlled environment, where many traits can be measured, including
traits that would be difficult to measure elsewhere. Its main
drawback is its cost. Consequently, it generally applies to relatively
small numbers of animals.
For the above reasons, test stations are a very good tool for
research. They can also be used to monitor the meat and carcass
quality of a population, or to compare genetic sources (e.g. comparison
of breed crosses in Quebec commercial product test, or comparison
of terminal lines in the NPPC trial). These comparisons, however,
are generally done on an occasional basis because of the cost.
Test stations can also be used to test the siblings of boars that
have been preselected based on the genetic values of their parents.
Some genetic progress for meat and carcass quality can then be
achieved if the best boars are widely used through AI (Kennedy,
1992). However, the use of test stations for this type of selection
is declining, because other options are available to genetically
improve meat and carcass quality traits at a lower cost.
Selecting breeding animals on the basis of live measurements at
the farm is an effective way to improve carcass quality. Current
measurements include backfat thickness, loin depth and loin eye
area. Biopsies could provide a way to obtain meat quality data
on the live animal, if the process can be carried out without
creating controversy. The cost of on-farm testing is relatively
small, and its accuracy can be fairly high (lean yield predictions
are more accurate from live than from grading measurements). In
addition, testing can be carried out directly on the candidates
for selection. For these reasons, on-farm testing programs are
a key selection tool for meat and carcass quality in breeding
herds. When applied systematically, they can generate relatively
rapid genetic gain. Examples in Canada include the backfat thickness,
halothane gene probe and loin-depth programs.
On-farm testing programs can also be used for monitoring of breeding
herd performance or for comparing genetic lines for traits that
can be measured in the field. The main limitation of on-farm testing
is that it applies to only a relatively small number of traits.
Selection or monitoring for the other traits therefore require
Slaughter plant data
Collecting data in the slaughter plant and returning it to the
producer is the simplest way to provide data for selection and
monitoring of meat and carcass quality traits. Two types of programs
can be developed to carry this out:
These are programs whereby special arrangements are made at the
plant to collect meat and carcass quality information on samples
of animals. Examples include the OSI Home Test Carcass Appraisal
Program, private sampling by plants and/or breeding companies
and the national carcass cut-out.
The approach can apply to a large number of traits; the data can
often be related to specific parents or lines; and the information
can be associated to growth performance if the animals were tested
on the farm. However, cost can be high (special carcass cut-outs,
need to slow down the kill line).
Directed programs are used primarily to monitor the performance
of a population or to compare genetic sources, lines or management
approaches for meat and carcass quality on a periodic basis. The
information can also be used for "within herd" research.
Because of the cost involved, relatively small numbers of animals
are involved, which limits the use of these programs for continuous
Another approach is to develop programs whereby slaughter plant
data is systematically collected and reported back to producers,
and possibly to selection herds. Some information (carcass grading
index, backfat and loin depth, health monitoring information)
is already available through programs such as APHIN (PEI, Ontario).
There is a potential to expand these programs to include additional
meat and carcass quality traits. Swine quality assurance programs
(Alberta) could also evolve to include this type of information.
The systematic collection of meat and carcass quality data in
the plant requires a sizable investment, particularly for the
development of systems to identify carcasses from groups of animals
or from individual animals. However, once this is done, the cost
is moderate. Only traits that are relatively easy to measure in
the plant are ususally considered. However, the number of such
traits is continually increasing with the development of new technologies.
Systematic data collection at the slaughter plant has the potential
to provide considerable amounts of meat and carcass quality information
on a routine basis. This information would be ideal for monitoring
commercial herds. If links can be established between the producer
information and that of the breeder (for example through the identification
of animals or of groups of animals), systematic collection of
meat and carcass quality data at the plant could also form the
basis for the continuous selection of these traits in breeding
herds, and for the comparison of different genetic sources or
lines at all levels of the pork chain.
Strategies for improvement of meat and carcass quality
Each of the genetic improvement and/or monitoring programs described
above has its place and can be used to complement the others.
Test stations, for example, are particularly useful for research.
On-farm testing is an effective means of selection for the traits
that can be measured in the field. However, selection for meat
and carcass quality would be greatly enhanced by the implementation
of systematic data collection at the plant level, and the linking
of this data back to breeding herds.
Evaluating different lines or different genetic sources can be
achieved in different ways, depending on the objectives of the
evaluation: the directed collection of slaughter data will generally
produce information on more traits than on-farm testing or the
systematic collection of slaughter data, but for smaller numbers
of animals because of the inherent cost.
The choice of selection and/or monitoring programs that can be developed to improve meat and carcass quality therefore depends on several factors. Selection goals and a selection strategy must be developed first. Then the objectives of the program must be clarified:
Genetic improvement and monitoring activities can be carried out
through concerted action or as a result of private initiatives.
Both are needed. Privates initiative, involving packers, producers,
breeders or breeding companies can be aimed, for example, at the
evaluation of different genetic sources based on the market needs
of a particular packing plant, or at the monitoring of contract
specifications between a producer and a packer. Concerted action
generally involves national, provincial or state organizations.
Its goal is often research or the development of standards or
information systems that benefit the industry as a whole (e.g.
OPCAP, PEPC in Quebec, National Carcass Cut-out, APHIN).
The collection of meat and carcass quality data is only one step
among the many that are required to have an effective selection
program. Other steps include the development of genetic evaluation
systems that use all available data (station, farm, plant). Separate
economic indices may have to be developed for different markets
objectives, each giving meat and carcass quality an appropriate
weight in relations to other traits. Economic incentives for meat
and carcass quality must also be part of the system so as to provide
a stimulus for the selection effort.
OPCAP, as well as other projects in Canada, have provided a considerable amount of research data on which to build the foundation of a genetic improvement program for meat and carcass quality. What is required next is the development of tools for continuous monitoring and selection of swine for product quality. A key aspect of that development will be building information links across the various industry segments. Although these links are generally easier to establish within integrated enterprises, it would be beneficial for the Canadian swine industry to develop them at a level where they are available to most stakeholders.