Using EBVs effectively

It is essential to determine which traits to focus on for genetic improvement and use the 3 principles of selection consistently over multiple generations. Typically, 3-4 traits are identified for genetic improvement based on data trends indicating they are a top reason for failure in your program. The more traits simultaneously under selection, the smaller the rate of genetic improvement in each generation.  A selection index facilitates simultaneous selection for multiple traits.

IWDR will be able to provide additional EBVs for traits of interest to working dog programs when sufficient data accumulate.

The most important decision made is which dogs are chosen as replacement breeders. Genetic improvement will not be made unless the replacement breeders are overall better than the prior generation. The group of dogs from which the replacement breeders will eventually chosen must be a genetically diverse group of dogs that have the best EBVs.

If the group of dogs to consider for breeding is based on phenotypes of the individual, it is likely that genetically inferior dogs may be selected as replacement breeders. The first chart below displays only the phenotypes where a higher number is best. Most people looking at the chart select Auburn, Irving, Wave and Yoshi because they have more desirable phenotypes. Most will study all available data to get a feel for which dog under consideration has relatives that also have desirable phenotypes.

The chart below shows how the EBVs provide much more information about which dogs are genetically best. EBVs provide displayed in the lower chart provide a simple and easy to use estimate of genetic merit by providing a number for each on which EBVs are calculated. The EBV numbers can be arranged from best to worst which identifies the dogs with the best estimates of genetic merit. Although the raw EBV number is useful, most people prefer the easier to interpret percentile ranking where 100% is best.

Greater genetic progress is made by selecting Curtis, Auburn and Irving for further screening instead of Wave and Yoshi who are nice dogs phenotypically but have lower genetic merit Curtis, Auburn and Irving have the greatest likelihood of possessing more of the desirable genes and passing those genes on to the next generation. Selecting nice dogs with lower genetic merit is often the reason why some nice dogs do not “breed true”.

Focusing on the priority traits does not mean other traits of importance are ignored. The additional screening of the pool of genetically superior dogs allows the opportunity to choose the overall best dogs.

It is important to emphasize the first principle of genetic selection to keep the number of replacement breeders needed from best dogs from genetically diverse litters and avoid the common mistake of keeping only the “perfect” dog. All traits can not be improved simultaneously but after sufficient genetic improvement is made with a particular trait or set of traits, focus can be shifted to additional traits.