1a.Objectives (from AD-416):
Determine traits that would benefit most from expanded educational efforts. Develop computer programs to illustrate how daughters of superior bulls nationally for the traits of interest deliver an advantage within an individual producer’s own herd. Promote the development of an efficient and healthy national dairy herd through demonstration of genetic selection results. Provide a convenient way of using the software developed for extension type meetings of dairy producers.
1b.Approach (from AD-416):
Records from the national dairy database will be shared with PSU cooperators. Existing AIPL programs will be modified to identify the top and bottom quartile of cows each year based on sire PTA + 1/2 MGS PTA. The performance of the top and bottom quartiles will be compared. The number of observations needed to reliably demonstrate that genetic selection results in superior performance will be determined. Web applications will be developed that will allow users to query the AIPL database for herd specific results, including performance charts for each trait with a link to the cows and sires in each group. Demonstrate the tool to producer groups.
The project is related to in-house objectives 2 (develop a more accurate genomic evaluation system with advanced, efficient methods to combine pedigrees, genotypes, and phenotypes for all animals) and 3 (use economic analysis to maximize genetic progress and financial benefits from collected data focused on herd management practices, optimal systems for genetic improvement, quantification of economic values for potential new traits such as feed efficiency, economic values of individual traits, and methods to select healthy, fertile animals with high lifetime production). Previous work has demonstrated that a strong association between milk, fat, and protein yields as well as somatic cell score (mastitis resistance) and productive life (longevity) and genetic merit can be demonstrated within individual dairy herds. A web space is under development to provide Pennsylvania dairy producers with access to their herd's genetic trend data. That will allow dairy producers to visualize how cow performance in their dairy herds changes in response to genetic selection and to make more economical genetic selection decisions. Genomic predictions of feed utilization efficiency have been estimated and are currently being validated. Cows predicted to be more efficient produced significantly more milk and had lower body weight. A field trial is underway to confirm that such cows consume less feed than inefficient cows. If the field trial validates the accuracy of genomic feed utilization predictions, selection of more feed-efficient dairy cows will be feasible, which is of increasing importance because of rising feed costs. One component of differences in efficiency among cows is the tendency to digest feed more completely, and 690 fecal samples from approximately 175 Holsteins have been collected and evaluated for digestibility. Those digestibility measures will be associated with genomic predictions of feed efficiency to determine if differences in feed digestion can be used as indicators of feed efficiency.