Several tools have been developed in order
to accurately select seedstock and evaluate the impact of this
selection on the commercial swine population. Station test programs
for either purebred or commercial swine are one of these tools.
Since the seventies, the use of test stations
has grown in the national swine improvement programs of the main
pork producing countries. In Europe and in Canada, station testing
of purebred animals has made it possible to establish genetic
links among selection herds and to identify top boars. Using these
top boars in selection herds, either as herd sires or through
AI Centres, has increased the rate of genetic improvement in those
herds. The commercial product test program, on the other hand,
has allowed the comparison of various crossbreeding schemes and
the determination of how rapidly genetic change is flowing to
commercial herds.
Genetics
During the last ten years, in Québec as in the rest of Canada and Europe, several factors have changed the purpose and use of swine test stations. Among these was the development of genetic evaluation systems based on BLUP and the animal model, which made it possible to compare the genetic value of animals from different herds, taking in account their different management levels. The efficiency of these genetic evaluation systems was improved by the use of test stations, by the use of AI and by the development of better computer technology. Before BLUP, test stations were the main tool allowing genetic comparisons across herds, but this is no longer the case. Genetic links across herds are now due to AI for the most part.
Health
During the last few years, the fear of disease
spreading associated with the exchange of live animals has greatly
increased. In a test station, pigs from herds with a different
health status are mixed together. As a result, the sale of top
boars from the test station to AI Centres and seedstock herds
has decreased considerably, and the number of herds using the
test station has also decreased.
Need for new selection criteria
For the above reasons, the merit of evaluating
purebred boars in test stations, as it was done during the last
few years, has decreased markedly. It may continue for the purpose
of validating the genetic links used in BLUP but at a much reduced
frequency.
On the other hand, it is necessary to introduce
new criteria in the genetic improvement of swine, such as carcass
yield, meat quality and feed efficiency. Most of these criteria
are still difficult to measure at the farm, and their measurement
has to be standardized before they can be used effectively.
Therefore, the primary purpose of swine test
stations has become the evaluation of carcass and meat quality.
A strict health protocol, including the use of segregated early
weaning, is required in the test station to allow the full expression
of the genetic potential of evaluated animals. It is in this context
that the Commercial Product Test Program (CPTP) is used at the
Deschambault test station. It permits the evaluation of various
genetic crosses for growth and for carcass and meat quality. However,
the role and goals of the CPTP must be assessed continually to
ensure they fit the changing conditions of pork production.
The main objectives of this talk are to present
the first results from the CPTP and their impact on pork production
in Québec, and to identify future directions for the program.
2. RESULTS AND IMPACTS OF THE FIRST 17 TESTS
In Québec, the station test program
for purebred animals was established by Agriculture Canada in
1963 and the home test program by MAPAQ in 1969. Since then, there
has been a continuous improvement in average daily gain and backfat
thickness in purebred animals (figures 1 and 2).
The commercial product test program began in Québec in 1983, through the joint effort of various organizations. From 1983 to 1991 17 tests have been completed by MAPAQ. In 1993, the CPTP has been transfered to the Québec Centre for Swine Improvement Inc.
2.1 Objectives
The objectives of the first 17 tests were :
To meet these objectives and give every commercial
producer a chance to participate, participation to the program
was on a "first come, first served" basis.
An evaluation of the health status of the herds
was an additional condition of participation. This approach made
it possible to obtain a relatively representative sample of the
commercial swine population at the time, and therefore to evaluate
the most frequent crosses in use in Québec.
The results for tests #3 to 14 are shown in
Hammell et al (1993). They correspond to 2,888 commercial hogs
which represent 64 different types of crosses. This reflects the
large genetic heterogeneity of the commercial population at the
time. Sixteen genotypes, all from commercial producers, were kept
for the analysis. They are shown on Table 1.
Of all pigs tested, 81 % came from the
sixteen genotypes. The other pigs came from either unknown or
very heterogeneous crosses.
The most frequent crosses were between a Landrace
x Yorkshire sow and a Duroc (16 %), Hampshire-Duroc (12 %),
Yorkshire (8 %), Landrace (8 %) or Hampshire (7 %)
terminal sire. The genetic make-up of the female line was therefore
fairy stable : a hybrid sow, Landrace x Yorkshire 51 %
of the time. On the other hand, the sire line was not well defined
and one of the objectives of the CPTP was to determine the best
male line to cross to this hybrid sow.
2.2 Results
The results of the first tests were published by Rousseau (1992). The main results for growth performance and carcass and meat quality are shown in Table 2.
For all traits, the Duroc by Landrace x Yorkshire
cross was always in the best performing group. From that time
on, this is the cross that became the most popular in Québec
compared to other crosses.
2.3 Selection strategy and genetics
dissemination in Québec
Comparative results for the different crosses helped decide on the choice of a terminal sire in Québec. This trend is confirmed in two ways :
From this data, it can be seen that the increase
in the demand for Duroc sires was accompanied by a decrease in
the demand for Hampshire sires. The white breeds, Yorkshire and
Landrace, remain popular given their use in female lines.
3. FIRST TWO COMMERCIAL PRODUCT TESTS IN THE NEW TEST STATION (DESCHAMBAULT)
At the request of participating organizations,
the first two tests at the new Deschambault test station have
been similar to the 17 tests carried out previously. The objective
was to validate the results of the comparison of different crosses,
resulting mostly from the mating of Landrace by Yorkshire sows
to Landrace, Yorkshire, Duroc and Hampshire boars. Although the
health protocol was different, the methods of sampling and the
analysis were basically the same. In total 713 commercial hogs
from 20 different genotypes were tested. The distribution of genotypes
is show in Table 5.
The frequency of Landrace, Yorkshire, Hampshire
and Duroc crosses with Landrace x Yorkshire sows was 3 %,
2 %, 8 %, 2 % and 34 %, for a total of 49 %.
Keeping in mind that only two tests were involved,
the following trends were involved :
The first two tests at Deschambault did confirm
the ranking of major crosses used in Québec as determined
from the previous 17 tests. Considering the changes in the production
system (the increase in slaughter weight and the new grading system),
this ranking is based on the traits of main economic importance
rather than on each individual trait. The result of the comparison
for these main traits are shown in Tables 6 and 7.
From the first series of tests to the two Deschambault
tests, a substantial increase in growth performance can be observed
which is related not only to genetic improvement but also to the
use of segregated early weaning and the resulting higher health.
In Hammel's report, the age at the average slaughter weight was
175.35 days at 96.39 kg, while for the first two test in
Deschambault it was 156.54 days at 106.08 kg. Age at slaughter
therefore decreased by 20 days despite an increase of 10 kg in
the slaughter weight.
Carcass length has not changed. On the other
hand, ham weight and even more so loin weight have increased.
These changes probably reflect the increase in slaughter weight
as well genetic change and the improvement in health status brought
about by the introduction of SEW.
Genetic types that included the Hampshire breed
had a more acid, lower quality meat than other types. This was
true for the last 2 tests as well as for the first series of 17.
These commercial product testing results prove
that substantial gains can be achieved through judicious crossbreeding
schemes and through better health. Thanks to the increase in health
status, SEW makes it possible to obtain more accurate data.
In conclusion, the Deschambault results confirmed
earlier fundings from the program. It is necessary, however, to
review the objectives of the program to give it a direction that
will satisfy the future needs of the industry.
4. NEW DIRECTIONS FOR THE CPTP
4.1 Current challenges in the pork
industry
International competition requires the Canadian
pork industry to be vigilant and efficient. As for any other business,
knowing the strengths and weaknesses of the industry is essential
for developing the products that will meet market needs in a relatively
short time.
Cooperation between the different segments of the industry, including selection, commercial production and packing and processing, is a key for future competitiveness. Production without regard for the other segments of the industry is not a viable solution.
This need is reflected by the development of
networks whereby the coordination between the different segments
of the pork chain, from selection to processing, allow rapid dissemination
of the genetic progress. Several pork producing countries have
in fact developed such networks that fit their socio-economic
context. The development of the CPTP will be more successful if
it can take these networks into account.
Whether it is a "selection scheme",
a "pyramidal production structure", vertical coordination",
"integration", "producer groups", etc., the
objective is to ensure that all segments of the pork chain are
aware of each other's needs and constraints, and work together
to develop a high quality, uniform product, which can be, why
not, specific to our context. We must prepare for competition.
4.2 New objective for CPTP
Based on previous results and future challenges,
we must evaluate, and if necessary redirect, our selection objectives
and how we use our selection tools. Considering that there is
a delay of at least five years between the creation of genetic
change in seedstock herds and its diffusion to commercial production,
our tools must be capable of evaluating what will be required
in five years from now. We must be able to forecast demand.
New test station objectives
Tools
4.3 New station tests
Given the CPTP's new objectives, the CPTP's
Committee members will plan for specific tests every two years.
This will make the program flexible enough to meet changing industry
needs and will ensure the scientific value of the tests.
Two projects were developed in 1995 using this
approach.
4.3.1 Comparison between the performance of commercial pigs from Duroc sires of varying genetic merit
This project was financially supported by the
Canadian Centre for Swine Improvement Inc., the Québec
Pork Producers Council, the two main Québec IA Centres
(CIPQ and CAGP), and the Québec Section of the Canada Meat
Council. Its objectives are to validate the genetic and economic
gains resulting from the increased growth rate and decreased backfat
thickness of commercial pigs sired by Duroc sires of different
genetic value.
Six groups of AI boars were formed according
to their EBV; a high and a low group for age EBV; a high and a
low group for backfat EBV; and a high and low group for the sire
line index. Each high group contained the AI boars with the highest
EBV or index for that trait. Each low group contained the AI boars
with the lowest EBV or index for that trait.
Participating producers had to meet the following conditions :
The objective will be to produce 32 litters for each group of Duroc sires. These litters must come from as large a number of herds as possible in order to minimize herd and dam effects. Two piglets per litter, a gilt and a barrow chosen at random, will be transferred to the Deschambault station at between 10 to 14 days of age. The test will proceed in the same conditions as the last two in Deschambault. The next two tests (October 1996 and April 1997) will be used exclusively for this project. Results on the performance of the different groups of commercial pigs should be available at the beginning of 1998.
4.3.2 Development of methods to assess ham quality
This project is funded by the Canadian Centre
for Swine Improvement, the Food Research and Development Centre,
the Canadian Meat Council and the Québec Centre for Swine
Improvement. Its objectives are :
Results from the project will be available in the summer of 1997. The quality assessment methods will be implemented in the CPTP and in slaughterhouses. The objective is to be able to evaluate fresh hams for various market needs, and to foster selection and production of hogs with sufficient ham quality.
4.4 An on-farm Commercial Product
Test Program
Since its inception, the CPTP has been confined
to the test station. As indicated earlier, the evaluation of market
hogs in the test station is a useful tool for evaluating the final
product and various crossbreeding schemes.
However, the test station is not the only evaluation
tool available. It cannot address all production systems and it
cannot be used by all producers. It is therefore desirable to
develop a commercial product test program outside of the test
station, whereby breeders and pork producers will be able to send
samples of their commercial pigs to the slaughterhouse and obtain
meat and carcass quality information on the products of different
breeds, lines or sires.
5. CONCLUSION
The Commercial Product Test Program is key
to the success of the Québec pork industry as a whole.
To get the maximum benefits out of the program, it will be necessary
to ensure that it meets the following conditions :
BIBLIOGRAPHY
Drapeau R., Savoie Y. (1984). Swine A.I. :
genetic, health and economic benefits. Symposium on Pork Production.
CPAQ pp 73-76.
Godbout D., Minvielle F. (1990). Comparison
between Duroc and Hampshire-Duroc sires for the production of
market hogs. Symposium on Pork Production. CPAQ pp 129-138.
Hammell K.L. et al. (1993). Commercial product
test : analysis and synthesis of 1987-1990 results. MAPAQ
Animal Production Services, and Department of Animal Science,
Laval University.
Minvielle F., Langlois A. (1984). Choosing
a crossbreeding scheme : backcross or three-way cross.
Pork Seminar 1984 pp 65-72.
Minvielle F., Savoie Y. (1986). Commercial
product test : what genetic type is recommended? Pork
Seminar 1986 pp 19-27.
Pettigrew D. (1994). Test stations, a tool
for genetic evaluation available to all. Québec Pork,
September 1994 pp 48-51.
Pettigrew D. (1995). Commercial Product
Test Program (CPTP). Test no. 941127. November 1994 to May
1995.
Pettigrew D., Dumas G. (1996). Commercial
Product Test program (CPTP). Test 2 no. 950927. September
1995 to May 1996.
Poudrier M., Pettigrew D., Gosselin D. (1992).
Market hogs and market needs. Symposium on Pork Production.
CPAQ pp 123-129.
Rousseau F., Fillion R., Richard Y., Hammell K.L. (1992). The CPTP : an essential tool for genetic improvement. Symposium on Pork Production CPAQ pp 93-112.
| Purebred | Landrace Duroc | |
| Single Cross | Yorkshire x Landrace Landrace x Yorkshire Duroc x Landrace Landrace x Large White Large White x Landrace | |
| Back Cross | Landrace x Landrace-Yorkshire Landrace x Hampshire-Landrace Hampshire x Hampshire-Landrace Yorkshire x Landrace-Yorkshire | |
| Three-breed Cross | Hampshire x Landrace-Yorkshire Duroc x Landrace-Yorkshire Berkshire x Landrace-Yorkshire | |
| Four-breed Cross | Hampshire-Duroc x Landrace-Yorkshire | |
| Synthetic Lines | S9S9 | |
| Others | ||
| Total |
| Growth Performance
Weight at end of test (kg) Age at slaughter (days) Daily gain on test (g/day) Feed conversion |
|
|
|
|
|
| Carcass yield
Carcass warm weight (kg) Grading index Ham weight (kg) Loin weight (kg) Carcass length (cm) |
|
|
|
|
|
| Meat quality
Loin pH (24h) Ham pH (24h) Color ** |
|
|
|
|
|
Table 3 - Number of Home Tested Boars in Québec from 1980 to 1995
| 1984* | ||||||
| 1990** | ||||||
| 1991** | ||||||
| 1992** | ||||||
| 1993*** | ||||||
| 1994*** | ||||||
| 1995*** | ||||||
| 1995/1984 |
Table
5 - Genotypes included in the
analysis of the first two CPTP tests in the Deschambault Station
| Single Cross | Yorkshire x Landrace *
Duroc x Yorkshire Duroc x Landrace | |
| Back Cross | Landrace x Landrace-Yorkshire
Yorkshire x Landrace-Yorkshire | |
| Three-breed Cross | Hampshire x Landrace-Yorkshire
Duroc x Landrace-Yorkshire | |
| Four-breed Cross | Hampshire-Duroc x Landrace-Yorkshire | |
| Half Synthetic - Half Pure | S9 x Landrace-Yorkshire
Duroc x S9 Yorkshire x S9 | |
| Synthetic Lines | S9S9 | |
| Others | ||
| Total |
| Growth Performance
Number Weight at end of test (kg) Age at slaughter (days) Daily gain on test (kg/day) Feed conversion |
|
|
|
|
|
| Carcass yield
Number Warm carcass weight (kg) Grading index Index at 80-90 kg Ham weight (kg) Loin weight (kg) Carcass length (cm) |
|
|
|
|
|
| Meat quality
Number Loin pH (24h) Ham pH Loin PSE score Ham PSE score Ham colour reflectance |
|
|
|
|
|
Table
7 - Comparison between results
from the first series of commercial product test (1987 to 1990)
and the second (Deschambault 1994 and 1995)
| Feed conversion | ||||||||||
| Average daily gain | ||||||||||
| Age at slaughter | ||||||||||
| Carcass yield | ||||||||||
| Grading index* | ||||||||||
| Fat (mm) | ||||||||||
| Lean (mm) | ||||||||||
| Carcass length | ||||||||||
| Loin colour | ||||||||||
| Number of (+) | ||||||||||
| Number of (=) | ||||||||||
| Number of (-) | ||||||||||