Author
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Vanraden, Paul |
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Cole, John |
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Submitted to: Government Publication/Report
Publication Type: Government Publication Publication Acceptance Date: 10/1/2014 Publication Date: 10/1/2014 Citation: Van Raden, P.M., Cole, J.B. 2014. Net merit as a measure of lifetime profit: 2014 revision. AIP Research Report NM$5 (10-14). Interpretive Summary: Economic values in net merit (NM$), a genetic-economic index to predict expected lifetime profitability of dairy cattle, were updated in 2014, and 2 more fertility traits were included. A fourth index called grazing merit (GM$) was introduced to rank animals for grazing herds along with the cheese merit (CM$) and fluid merit (FM$) indexes already calculated for herds in differing milk markets. These indexes previously included daughter pregnancy rate and now also include heifer conception rate and cow conception rate. Benefits of fertility not already included in productive life, a measure of longevity, are earlier age at first calving; decreased units of semen needed per pregnancy; decreased labor and supplies for heat detection, synchronization, inseminations, and pregnancy checks; additional calves produced; and higher yields because more ideal lactation lengths are achieved. Recent decreases in the cost of replacements and increases in the beef price for cull cows have decreased the economic values of both productive life and fertility traits as compared with the 2010 index. An increase in genetic progress worth $8 million/year is expected on a national basis, assuming that all of the changes are improvements and that all breeders select on NM$. Technical Abstract: Economic values in the net merit (NM$) genetic-economic index were updated in 2014, and 2 more fertility traits were included. A fourth index called grazing merit (GM$) was introduced to rank animals for grazing herds along with the cheese merit (CM$) and fluid merit (FM$) indexes already calculated for herds in differing milk markets. These indexes previously included daughter pregnancy rate and now also include heifer conception rate and cow conception rate. Benefits of fertility not already included in productive life are earlier age at first calving; decreased units of semen needed per pregnancy; decreased labor and supplies for heat detection, synchronization, inseminations, and pregnancy checks; additional calves produced; and higher yields because more ideal lactation lengths are achieved. Recent decreases in the cost of replacements and increases in the beef price for cull cows have decreased the economic values of both productive life and fertility traits as compared with the 2010 index. For recent bulls, the 2014 and 2010 NM$ indexes were correlated by 0.965; the GM$ index was correlated by 0.984 with NM$, 0.982 with CM$, and 0.938 with FM$. An increase in genetic progress worth $8 million/year is expected on a national basis, assuming that all of the changes are improvements and that all breeders select on NM$. |
