|GUIDELINES FOR UNIFORM SWINE IMPROVEMENT PROGRAMS|
Central swine testing stations are locations where animals are
assembled for the purpose of evaluating differences in performance
traits under uniform conditions. Central stations are used to
1) acquaint and educate producers with performance records; 2)
compare individual pigs' performance for traits such as rate of
gain, feed conversion, and backfat; and 3) provide a supply of
performance tested animals for seedstock and commercial producers.
Appropriate use of central test stations will increase the rate
of genetic change because of accurate data collection under uniform
|1.||Individual pigs must weigh at least 40 pounds when delivered
to the station. Pigs should have a weight per day of age between
0.6 and 1.2 pounds when put on test. Entry pig weight and age
should be reported in test station reports.|
|2.||All pigs must have an interstate health paper stating that
pigs are free from designated communicable diseases outlined by
the participating test station. Details for a comprehensive health
program are found in the next section.|
|3.||If the pigs are purebred, they must be eligible for registration
in the appropriate registry, and the pedigrees must be submitted
to the test station manager before the first interim report.|
|4.||Entry data should include the following:|
|A.||Pig identification (ear notch, birth date, breed, registration number)|
|B.||Breeder information (name, address, breeder mark)|
|C.||Sire (name and registration number)|
|D.||Dam (name and registration number)|
All entries to a test station should meet health standards set by the state regulatory agency or test station committee and be from validated brucellosis-free, pseudorabies-negative herds. Breeders and their veterinarians should also certify that the herd has been free of clinical evidence of swine dysentery and tuberculosis during the 6-month period prior to entry of pigs at the test station. In the case of transmissible gastroenteritis (TGE), the period should be at least 60 days. Entries must be accompanied by a certification statement similar to the one in Appendix F, and a current interstate health certificate. Stations may require more stringent health regulations if deemed necessary. If barrows are tested, castration wounds should be well healed before delivery to the station.
Pigs entering test stations should be tested and be serum neutralization
negative for pseudorabies at the following times:
No pigs will be accepted from herds that 1) show clinical signs of pseudorabies, 2) have had positive florescent antibody test to PRV, 3) have had PRV isolation, and/or 4) have had a positive reaction to the pseudorabies serum neutralization test. Pigs will not be accepted from such herds until it is subsequently demonstrated that the herd is free of pseudorabies.
Pigs should be vaccinated against erysipelas and atrophic rhinitis upon entry into the station and again before sale. Breeding animals should also be vaccinated against all strains of Leptospirosis. Test animals should be dewormed with a compound proven effective for control of internal parasites during the adjustment period before starting on test, and should be treated for external parasites with an approved product, such as Ivomec7, upon entry into the station, and as recommended thereafter.
Each station should publish in each sale catalog and also post
on the station premises a description of the health program followed
at the station. The following procedures are suggested for station
|NOTE:||The software provided by the University of Georgia used 80 pounds for the average standard on-test weight. If a station chooses to use a lighter starting weight, the software will have to be reprogrammed. Average starting weights greater than 80 pounds are not appropriate.|
The formula for adjusting days required to reach a constant weight (usually 250 " 15 pounds) is:
where a = 50 for boars and barrows, and a = 40
for gilts. If off-test weights for computing gain and feed efficiency
are not taken at the same time it should be so stated in the sale
where b = -20 for boars, +30 for barrows, and +5 for
|D.||Loin muscle area (optional). If reported, adjust to a constant
weight using the following formula:|
|E.||Weight when backfat and loin muscle area are measured, if different from weight off test|
|F.||Feed efficiency (optional)|
|G.||Soundness score (optional). See Appendix D.|
Environmental influences make comparison of pigs tested at different
locations, at different times, or under different management difficult.
Using selection indexes that are based on deviations from contemporary
group averages will provide valid comparisons of animals within
the same test group. These comparisons provide a basis for assesing
genetic merit. Keep in mind, however, that indexes are not appropriate
for making between group comparisons of animals. Note, also,
that the following indexes are to be used strictly for evaluating
performance and carcass traits and not for ranking animals for
any maternal traits. Data must be adjusted to a constant endpoint
before using in a selection index. Traits included in the indexes
are defined below.
|G =||Average daily gain (ADG) recorded on an individual minus the mean ADG of contemporary group.|
|B =||Backfat depth measured on an animal minus mean backfat depth of contemporary group.|
|F =||Feed to gain ratio calculated for an individual or pen of animals minus mean F/G for all pens or animals (if fed individually) in the contemporary group.|
|M =||Predicted percent lean calculated for an individual minus the mean predicted percent lean for the contemporary group.|
Feed Conversion Measured:
Feed Conversion not Measured:
1 Complete information about the recommended indexes are given in Appendix E.
* Use this index if backfat is measured with a metal probe.
These indexes will average 100 for each test and should have a standard deviation of about 25. The test group should have approximately the following distribution:
|More than 150||
|125 to 150||
|100 to 125||
|75 to 100||
|50 to 75||
|Less than 50||
If EPDs are reported, traits may be evaluated with similar indexes. The simplest index consists of all the EPDs added together. For example, if ADG, backfat and feed conversion are of interest, the index would be
Use of economic values (see Table in Appendix E) will weight the genetic information for the relative importance of each trait. In this example, EPD=s are available on ADG and predicted percent lean:
Only animals with an index of 80 or higher within a contemporary group should be offered for sale. This will result in about 20 percent of all animals being culled. Stations may adopt higher standards. If EPD's are reported, make sure buyers are aware of the basis for comparison. It is quite possible that boars with phenotypic indexes below 80 could still be better than average when all animals in a breed are considered. NSIF recommends the use of EPD's instead of phenotypic selection indexes when possible.
Additional animals may be culled because of soundness problems or other genetic or structural weakness. Caution: These problems should be known to have a genetic basis or be so severe that a boar cannot function. If these additional criteria do not lend themselves to objective measurement, they should be scored. Structural soundness and underline soundness are examples of such traits. In all cases, an explanation of the system(s) used should be included in the reports and sales catalog. See Appendix D for details.