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Data from milking can be used to promote cow health

Technology on the dairy farm can be used to improve the genetic evaluation of dairy cow milking traits and thus improve the animals’ health and welfare.

2018.02.28 | Janne Hansen

Researchers from Aarhus University have identified DNA variants that affect udder health in cows. Photo: Colourbox

A healthy udder is crucial not only for a dairy cow’s milk yield but also for her health and welfare. In dairy cattle mastitis is one of the most common diseases and costs farmers money for medicine and visits from the veterinarian besides having negative effects on the cows. It is therefore of high priority to map the genes that promote resistance to mastitis. 

Until now, it has not been easy to select for udder health, since the heritability for it is low and there has not been sufficient data. Researchers from Aarhus University have now taken a big step closer to a solution with the aid of modern genomic  technology. 

Researchers from the Center for Quantitative Genetics and Genomics in the Department of Molecular Biology and Genetics, Aarhus University, have analysed extensive genetic data from 4921 bulls of the breed Nordic Holstein. Even though bulls cannot deliver milk, they contain genes for traits such as milk yield and udder characteristics. They transmit these genes on to their progeny – and the genes are expressed in the bulls’ daughters. 

Previous studies have indicated that there is a correlation between fast milking and increased somatic cell count. Cell count is an indicator of udder health. In Denmark, Finland and Sweden farmers often use technology that automatically measures milk yield and milking time.   

These data can be used to strengthen the genetic evaluation of milking traits. Milking traits include milking speed, average milk flow rate, maximum milk flow and total milking time. 

In the analyses of the genetic data the researchers looked specifically for DNA markers for udder index (a total expression of various physical udder traits) and milking time. They found the strongest signals for the traits on chromosomes 19 and 20, which is in agreement with previous results. 

Localisation of the DNA variants that affect udder health can be used for more precise predictions in routine genomic selection. This can lead to better udder health and animal welfare and reduce antibiotics consumption and the number of visits from the veterinarian.  ­

For more information please contact

Seniorforsker Goutam Sahana
Center for Quantitative Genetics and Genomics (QGG)
Department of Molecular Biology and Genetics, Aarhus University
goutam.sahana@mbg.au.dk - +45 8715 7501