The journal Icelandic Agricultural Science recently published the article Inheritance coefficients for Icelandic dairy cows with a measurement day model by Jón H. Eiríksson, Ágúst Sigurðsson, Guðmund Jóhannesson and Emma Eyþórsdóttir.
It reports an extensive study in which a total of 480,495 measurements of the daily yield of 33,052 Icelandic cows were used to estimate genetic coefficients for milk content, fat content, protein content and cell count during the first three milking periods with a random regression model. It was found that the heritability of all traits was lowest at the beginning of the milking season but highest around or after my milking season. The heritability of product traits was assessed higher in this study than in previous studies on the strain. An interesting conclusion was also that genetic variation in milk tolerance in the herd makes it possible to change the shape of the milking curve for Icelandic cows with a selection.
The article can be accessed here.