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Association between lifetime selection index predictions and lifetime performance.

F. Di Croce

Events

06-22-2020

Abstract:

118
Association between lifetime selection index predictions and lifetime performance.
B. Fessenden1, D. Weigel2, J. Osterstock1, D. Galligan3, F. Di Croce*1. 1Zoetis Genetics Kalamazoo, MI, 2Zoetis Outcomes Research Kalamazoo, MI, 3University of Pennsylvania School of Veterinary Medicine, New Bolton Center Kennett Square, PA.

Selection indexes are critical to genetic improvement as they combine values for many traits into a single value that can be used to rank animals and inform breeding decisions. In 2016, Zoetis Genetics developed the Dairy Wellness Profit Index (DWP$) to estimate the genetic potential for lifetime profit in US Holsteins. This study's goal was to evaluate if selection index genomically enhanced predicted transmitting abilities had the capability to predict observed lifetime profit in US Holstein animals. Five large herds (n = 2,175 enrolled cows) in the United States were chosen for this study because they had: 1) genomic predictions from females born in 2011, 2) recorded production, reproduction and health events to accurately estimate profit per cow, and 3) at least 200 animals born in 2011. Selection index predictions from 2012 were used to rank the 2,175 animals within herd and assign cows to percentile-based DWP$ groups (genetic groups: Worst 25%, 26—50%, 51—75%, and Best 25%). Herd records were used to calculate lifetime energy-corrected milk, income over feed cost, and lifetime days in milk based on the actual performance from first freshening through when they left the herd; for cows that were still in the herd, current totals were used. Analysis results indicated that DWP$ predictions were associated with differences in phenotypic lifetime energy-corrected milk, income over feed cost, and lifetime days in milk between the worst and best genetic groups. The difference between the worst and best genetic groups was 9004 kg lifetime energy-corrected milk (P < 0.01), $1,607 income over feed cost (P < 0.01), and 202 d in milk (P < 0.01). These results demonstrate that a lifetime selection index can in fact predict differences in actual lifetime profit potential of individuals. These results indicate that DWP$ predictions of young calves and heifers can be used to make informed predictions of future lifetime performance.

Keywords: selection indexes, genomics, lifetime profit.