Breeding and Genetics

摘要

Selection indexes are critical to genetic improvement as they combinevalues for many traits into a single value that can be used to rank animalsand inform breeding decisions. In 2016, Zoetis Genetics developed theDairy Wellness Profit Index (DWP$) to estimate the genetic potential forlifetime profit in US Holsteins. This study’s goal was to evaluate if selectionindex genomically enhanced predicted transmitting abilities hadthe capability to predict observed lifetime profit in US Holstein animals.Five large herds (n = 2,175 enrolled cows) in the United States were chosenfor this study because they had: 1) genomic predictions from femalesborn in 2011, 2) recorded production, reproduction and health events toaccurately estimate profit per cow, and 3) at least 200 animals born in2011. Selection index predictions from 2012 were used to rank the 2,175animals within herd and assign cows to percentile-based DWP$ groups(genetic groups: Worst 25%, 26–50%, 51–75%, and Best 25%). Herdrecords were used to calculate lifetime energy-corrected milk, incomeover feed cost, and lifetime days in milk based on the actual performancefrom first freshening through when they left the herd; for cows that werestill in the herd, current totals were used. Analysis results indicated thatDWP$ predictions were associated with differences in phenotypic lifetimeenergy-corrected milk, income over feed cost, and lifetime days in milkbetween the worst and best genetic groups. The difference between theworst and best genetic groups was 9004 kg lifetime energy-corrected milk(P < 0.01), $1,607 income over feed cost (P < 0.01), and 202 d in milk(P < 0.01). These results demonstrate that a lifetime selection index canin fact predict differences in actual lifetime profit potential of individuals.These results indicate that DWP$ predictions of young calves and heiferscan be used to make informed predictions of future lifetime performance.