Breeding for Increased Mastitis Resistance

DENMARK - Scientists are working on finding traits that can be used in breeding to predict if cows are prone to developing mastitis.
calendar icon 22 October 2010
clock icon 3 minute read

By comparing data from automatic milking systems with data regarding the number of times cows are treated for mastitis, scientists hope to find an improved tool for breeding for robust and healthy cows.
Photo: DJF

In a new project at the Faculty of Agricultural Sciences, Aarhus University, the scientists will investigate if traits that can be measured through automatic milking systems can be used in breeding for increased resistance against specific bacteria so that the risk of cows developing mastitis is reduced.

"We need to have cows which can manage being home alone. These are cows that do not to be held by the hand and do not get sick. Healthy, robust cows can manage the challenges of modern farming much better and enjoy greater welfare," said the leader of the project postdoc Lars Peter Sørensen from the Department of Genetics and Biotechnology at the Faculty of Agricultural Sciences, Aarhus University.

One of the aims of cattle breeding is to select animals that do not develop mastitis. As things stand now, the trait ”mastitis treatments” is part of the breeding index for udder health but it does not show the full picture.

"Not all cows are treated for mastitis. This means that not all cows have data. It is also an indirect way of measuring the disease and is dependent on whether the farmer or the veterinarian deems it necessary to treat the animals," said Lars Peter Sørensen.

Scientists are constantly looking for new and more precise methods for pointing at heritable traits that can predict if a cow will develop mastitis. Modern technology in the dairy barn and modern genetic methods can be of great help.

Some automatic milking systems measure somatic cell count in the milk. This is an objective measurement that can be used to improve breeding. A model based on lactation curves, the cow’s prior history and current somatic cell count measurements from the automatic milking system estimates the probability of the cow developing mastitis and can nip sub-clinical cases in the bud.

The scientists will compare the data regarding somatic cell counts with data regarding mastitis treatment.

"If there is a good correlation between the two traits, then maybe it can help raise the figure for heritability for mastitis, which in turn could improve genetic progress," Lars Peter Sørensen added.

Another aim of the project is to investigate if knowledge of the bacteria causing mastitis in dairy cattle can contribute more information to breeding. The scientists will study the DNA of the bacteria in milk samples. This way they will catch not only the bacteria that were alive when the milk sample was taken, but also those that are dead. This can help in the evaluation of how well the cow’s immune system works.

"Normally you culture bacteria to find out what kinds there are. This, however, requires a certain number to be present in the sample and that they are alive. By measuring bacterial DNA we will also be able to include the dead bacteria and get an idea of whether the cow has had an infection and if she has been able to combat it successfully," said Lars Peter Sørensen.

The project is supported by funds from the Danish Council for Independent Research, Technology and Production.

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