Abstract #M99

# M99
Development and application of the GENEX Jersey Ideal Commercial Cow Index (ICC$).
Heather Adams*1, Gamal Abdel-Azim1, Leah James2, Judd Hanson2, Nick Hemauer2, Scott Carson2, Robert Fourdraine1, 1CRI International Center for Biotechnology, Mount Horeb, WI, 2GENEX Cooperative Inc, Shawano, WI.

Selection indexes are a valuable way for producers to simultaneously select several significant traits in a well-adjusted formula, allowing emphasis in multiple areas such as production, health and fertility. The GENEX (Shawano, WI) Holstein Ideal Commercial Cow Index (ICC$) has already proven itself to be a well-designed and useful economic-based selection index, allowing breeders to make selection decisions based on a single ICC$ value, or focus on a more specific area of improvement using sub-indexes that make up ICC$. As the GENEX ICC$ was originally designed for Holstein dairy producers, surveys were conducted on some of the largest and most progressive US Jersey herds with the aim to understand the projected future direction for the Jersey breed, and identify the traits and selection areas of most importance to Jersey producers. The gathered information was used to formulate an ICC$ specific to the Jersey breed. Data used in the model formulation was pulled from the CRI internal dairy research database (54 million health records on 12 million cows) utilizing 128K lactation records on 60K Jersey cows. Three sub-index categories were established: Cheese Maximizer (ChMAX$; component traits), Sustainability (SUST$; health traits), and Fertility (FERT$; cow and heifer fertility). Based on the producer survey responses, several indexes were tested using various trait combinations and corresponding economic weights that directly tie to on-farm profitability, to identify an ideal model. The final index was broken down into 43% ChMAX$, 35% SUST$ and 23% FERT$. Validation was done using active GENEX Jersey bulls measuring individual trait responses and compared with selection on JPI and NM$ based on the ranking of bulls within each index. The Jersey ICC$ is unique from currently available Jersey indexes in allowing individual producers to focus their selection on an area specific to their own farm’s needs using the available sub-index values. The index also places more weight on fertility and health and emphasizes milk components while staying neutral to milk yield, which sets the index apart from currently available indexes.

Key Words: Jersey, ICC$, selection index