Role and impact of the commercial product test program (CPTP) in swine selection and genetics dissemination in Québec


D. Pettigrew
Québec Swine Improvement Centre Inc.

Collaborators :
Nicole Dion, Québec Swine Improvement Centre Inc.
Claude Gariépy, Food Research and Development Centre
Marc Genest, F. Menard Inc.
Daniel Godbout, Génétiporc Inc.
Guy Gosselin, Coopérative Fédérée du Québec
Candido Pomar, Dairy Cattle and Swine Research and Development Centre


1. INTRODUCTION

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 :

a) to identify the main quality criteria for ham processing based on the needs of domestic and international markets;
b) to develop methods to assess the quality criteria for both unprocessed and processed hams;
c) to develop minimum quality standards corresponding to various ham processing methods;
d) to evaluate these methods and select the most effective ones.

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.

Figure 1 - Phenotypic change for backfat thickness (mm) adjusted to 100 kg for purebred pigs tested in Québec farms (males and females)

Figure 2 - Phenotypic change for age (days) adjusted to 100 kg for purebred pigs tested in Québec farms (males and females)

Source : Québec home test program (1996) QSIC.

Table 1 - Genotypes included in the analysis of the first 17 CPTP test

Genotypes
Breed/Cross
% of total analyzed
Purebred Landrace Duroc
2
Single Cross Yorkshire x Landrace Landrace x Yorkshire Duroc x Landrace Landrace x Large White Large White x Landrace
13
Back Cross Landrace x Landrace-Yorkshire Landrace x Hampshire-Landrace Hampshire x Hampshire-Landrace Yorkshire x Landrace-Yorkshire
17
Three-breed Cross Hampshire x Landrace-Yorkshire Duroc x Landrace-Yorkshire Berkshire x Landrace-Yorkshire
24
Four-breed Cross Hampshire-Duroc x Landrace-Yorkshire
12
Synthetic Lines S9S9
13
Others
19
Total
100
For all crosses, the genotype of the sire is shown before the genotype of the dam.

Table 2 - Synthesis of Results from the first 17 Commercial Product Tests

Genotypes
Traits
LL x LY
YY x LY
HD x LY
HH x LY
DD x LY
Growth Performance

Weight at end of test (kg)

Age at slaughter (days)

Daily gain on test (g/day)

Feed conversion



96.61a

178.02c

688.20cd

3.17b


94.78b

177.04c

680.62d

3.08ab


97.02a

171.95ab

728.14ab

3.04a


96.38a

174.76bc

706.53

3.02a


96.49a

169.91a

740.14a

3.02a
Carcass yield

Carcass warm weight (kg)

Grading index

Ham weight (kg)

Loin weight (kg)

Carcass length (cm)



75.54

104.54b

8.76

8.90

79.83g


75.70

104.78b

8.77

9.00

79.44fg


75.50

105.97a

8.80

8.90

78.97fg


75.59

106.45a

8.83

8.85

79.18fg


75.96

105.95a

8.84

8.91

79.22f
Meat quality

Loin pH (24h)

Ham pH (24h)

Color **



5.67a

5.82a

3.03a


5.66a

5.84a

3.05a


5.60bc

5.67b

2.75b


5.58c

5.68b

2.58b


5.70a

5.81a

2.92a
Source : Rousseau et al (1992)
a, b, c, d : means with different letters in the same row are significantly different (P < 0.05).
f, g, : means with different letters in the same row are significantly different (P < 0.10).
** : Carcass grading indices in this table are for the old grid (10 weight classes, 17 yield classes).
** : Subjective evaluation of primal cuts, ham and loin, recorded according to Agriculture Canada's color scale - publication 5180/B.

Table 3 - Number of Home Tested Boars in Québec from 1980 to 1995

Year
Yorkshire
Landrace
Hampshire
Duroc
1980
1487
2606
602
1081
1981
2130
4062
799
1196
1982
2430
4246
768
946
1983
2499
4675
699
752
1984
2579
4281
710
739
1985
3287
4659
750
1162
1986
2785
4119
874
1554
1987
3892
5427
1103
2369
1988
4247
5866
996
3051
1989
4718
6553
1142
4011
1990
4614
7142
1008
4123
1991
4767
6925
839
3686
1992
4030
6201
638
3841
1993
4107
6464
485
4550
1994
4671
7220
409
5398
1995
4942
6803
372
5132
1995/1980
3.32
2.61
- 0.62
4.75
Source : Québec Home Test Program QSIC (1996).

Table 4 - Number of Boars in the 2 Major AI Centres in Québec
from 1984 to 1995

Year
Landrace
Yorkshire
Hampshire
Duroc
Total
% Duroc
1984*
8
15
5
8
36
22
1990**
12
12
4
12
40
30
1991**
17
16
6
34
73
47
1992**
24
28
9
67
128
52
1993***
23
24
8
101
156
65
1994***
21
22
7
159
209
76
1995***
23
31
5
241
300
80
1995/1984
2.88
2.07
0
30.13
8.33
Sources : * Drapeau R., Savoie Y. (1984).
** CIPQ.
*** CIPQ and CAGP.

Table 5 - Genotypes included in the analysis of the first two CPTP tests in the Deschambault Station

Genotypes
Breed/Cross
% of total analyzed
Single Cross Yorkshire x Landrace *
Duroc x Yorkshire
Duroc x Landrace
1
Back Cross Landrace x Landrace-Yorkshire
Yorkshire x Landrace-Yorkshire
5
Three-breed Cross Hampshire x Landrace-Yorkshire
Duroc x Landrace-Yorkshire
36
Four-breed Cross Hampshire-Duroc x Landrace-Yorkshire
8
Half Synthetic - Half Pure S9 x Landrace-Yorkshire
Duroc x S9
Yorkshire x S9
21
Synthetic Lines S9S9
23
Others
6
Total
100

Table 6 - Result from the first two PEPC tests at the Deschambault station

Genotypes
Traits
LL x LY
YY x LY
HD x LY
HH x LY
DDxLY
Growth Performance

Number

Weight at end of test (kg)

Age at slaughter (days)

Daily gain on test (kg/day)

Feed conversion



20

106.29

161.40bc

0.822b

2.72ab


16

105.68

165.09c

0.778c

2.58a


55

106.11

159.91b

0.822b

2.90c


16

105.19

157.46ab

0.837ab

2.83bc


240

106.27

154.50a

0.873a

2.79bc
Carcass yield

Number

Warm carcass weight (kg)

Grading index

Index at 80-90 kg

Ham weight (kg)

Loin weight (kg)

Carcass length (cm)



20

84.22bc

109.21

109.93ab

9.71b

10.20

78.99b


16

83.42c

108.31

109.38ab

9.40c

9.84

80.49a


55

85.04a

108.33

108.85b

9.90ab

10.16

78.65b


16

83.88bc

109.03

109.54ab

9.80ab

10.02

79.03b


240

84.66ab

109.64

110.34a

9.94a

9.90

79.35b
Meat quality

Number

Loin pH (24h)

Ham pH

Loin PSE score

Ham PSE score

Ham colour reflectance



20

5.81a

5.80a

3.68

3.47a

44.03a


16

5.73ab

5.77a

3.38

3.08ab

47.60b


53

5.68b

5.76a

3.39

2.97ab

47.97b


13

5.53c

5.50b

3.50

2.35c

53.82c


223

5.67b

5.76a

3.29

2.91b

49.47b
Source : Pettigrew (1995), Pettigrew and Dumas (1996).
P.S. Means with different letters in the same row are significantly different (P < 0.05).

Table 7 - Comparison between results from the first series of commercial product test (1987 to 1990) and the second (Deschambault 1994 and 1995)

Genotypes
LL x LY
YY x LY
HD x LY
HH x LY
DD x NY
Number of animals
138*
20**
150*
16**
189*
55**
162*
16**
223*
240**
Feed conversion
-
=
=
+
=
-
=
=
=
=
Average daily gain
=
=
-
-
=
=
=
=
+
+
Age at slaughter
-
-
-
-
=
=
=
=
+
+
Carcass yield
=
=
=
=
=
=
=
=
=
=
Grading index*
-
=
-
=
=
=
=
=
=
=
Fat (mm)
-
+
-
=
=
-
=
=
=
=
Lean (mm)
-
-
-
=
=
=
+
=
+
Carcass length
=
=
=
+
=
=
=
=
=
=
Loin colour
=
+
=
=
-
=
-
-
=
=
Number of (+)
0
2
0
2
0
8
0
1
2
3
Number of (=)
4
5
4
4
8
7
8
7
7
6
Number of (-)
5
2
5
3
1
2
1
1
0
0
+ significantly better.
= similar.
- significantly worse.
P.S. : Genotypes from private schemes are not shown.
* 1987 - 1980 tests.
* 1995 - 1996 tests.