Genetic evaluation for ketosis in the Netherlands based on FTIR measurements

Abstract

Ketosis is one of the most common disorders in dairy cows during the early stages of lactation. In the first 60 days after calving, dairy cows are often lacking energy, which can cause metabolic diseases such as ketosis. Since 2012, cows are routinely checked for ketosis in the regular milk recording scheme. The indication for ketosis is based on FTIR measurements of milk acetone and milk beta hydroxybutyric acid (mBHBA). The ketosis indicator also includes fat-protein ratio, lactation number and month of milking. The incidence of ketosis in the Netherlands is 12.2 percent. Using 2.5 million ketosis observations of 1.25 million cows, genetic parameters were estimated with a multi-trait sire model.  Heritability for ketosis for lactation 1 was 0.16, for lactation 2 was 0.13, and for lactation 3 was 0.18. Genetic correlation was 0.81 between lactation 1 and 2, 0.58 between  lactation 1 and 3, and 0.74 between lactation 2 and 3. In 2014, a routine genetic evaluation was introduced. Breeding values are published as relative breeding value with average of 100 and standard deviation of 4 points, with a higher value resulting in less ketosis. One genetic standard deviation represents 3% ketosis.  The genetic trend in the population is slightly positive, resulting in less ketosis. Correlation between ketosis and milk production yield traits are slightly negative, with fertility traits slightly positive (less ketosis results in better fertility results).