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Site last updated on 06/01/2024

The testing program at Shewmaker Genetics is the cornerstone of our entire breeding program. It is designed around four important concepts:

  1. There are indeed visible traits that are correlated to race performance (physical conformation being one example). We do some selection for these.
  2. However, there are many other non-visual traits that can not be directly observed that are also correlated to race performance (desire and determination being just two examples). We select for these as well.
  3. The best overall evaluator of race performance is the contemporary group test with multiple trials. When this can not be done (such as when you are buying a bird at an auction) grading by visual traits can be very useful. When contemporary group testing is possible, it is the preferred method of evaluation.
  4. For a breeding program, race performance must be evaluated from two perspectives - the individual performance of the bird as well as the performance record of its progeny.

What we are looking for are birds that have all of the tools (both the visual and the non-visual) and who are so homogeneous for these genes that they breed on their winning ways for subsequent generations.

The concept of the contemporary group test with multiple trials is key. The idea is that in order to measure genetic differences between different birds, the birds need to be tested in groups where all of the environmental effects are as consistent and equal for all of the birds in the group as possible. This means that they have been raised in the same weather conditions, with the same disease exposure, fed identically and placed in the flying loft at the same time. Obviously all of the environmental effects can not be perfectly shared, but that is the goal. This then allows for the differences that are observed in racing results to be more likely attributed to genetic differences and not environmental advantages or  disadvantages.

The reason for multiple trials is that the reliability of the results is directly related to the number of data samples (races).

Finally, the inclusion of progeny data in evaluating breeders greatly improves the reliability of this measure since it accounts for the environmental advantages of heterosis.

With this in mind, this is how we conduct our testing program:

Our Testing Methods

  • Birds are weaned at approximately 30 days of age. They are vaccinated at this time for Pox and PMV.
  • They are placed in the test loft and given a week to learn how to move in and out of the aviary using the traps.
  • At 5 weeks of age they are given two days to learn how to use the landing board. This consists of allowing open loft for two consecutive afternoons and moving their feeder to a platform a few feet from the landing board.
  • For the next month they are given daily morning tosses as the weather permits. It usually takes about two weeks to get through all the toss stations. These tosses are in the following order:
    • from the lawn in view of the loft
    • from the front of the house out of view of the loft
    • 1 miles South of the loft
    • 2 miles SouthWest of the loft)
    • 5 miles East of the loft
    • 8 miles West of the loft
    • 15 miles South of the loft
    • 20 miles North of the loft
    • 30 miles South of the loft
    • 40 miles NorthWest of the loft
    • 60 miles South of the loft
  • At this point the birds that are remaining are given electronic bands and weekly races begin. The birds are given at least three 40 mile tosses during the week and more 20 mile tosses if the weather permits. They are never loft flown.
  • The weekly races are at the following distances:
    • 75 miles
    • 100 miles
    • 160 miles
    • 220 miles
    • 300 miles
    • 350 miles

The Extent To Which We Test

  • We perform contemporary group testing on approximately 90% of what we raise.

Our Rating Method

  • Animals are given a percentile score (much like the UPR used by the AU) for each toss where the returns are reasonably well distributed. In other words, if there is a large first drop where the top 20% can not be determined, the results are not used for evaluation purposes.
  • At the end of the test series we look at three numbers for each bird that was entered into the test - the total number of tosses successfully completed, the number of times the bird scored in the top 10% of the toss and overall average UPR. Birds not returning from a toss are given a UPR of 100 for that test).
  • We determine the UPR standard deviation for each bird in the test group and look for birds with a high positive standard deviation. For example 2 or more is very good.
  • We also track the percent lost (by mating and by line) as the contemporary group test progresses.
  • We don’t have a single number we look at, but the patterns are usually pretty easy to evaluate. You can tell a lot about which matings and which breeders produce birds that get the job done.
  • In the near future we are going to implement a BLUP analysis of the test data set. BLUP stands for “Best Linear Unbiased Prediction” and can be used to derive Estimated Breeding Values (in other words an estimated numerical value for a birds breeding ability for race performance).
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