It wasn't a study on cows , it was testing a new 5G network back in Jan 2017 .
Officially there are no connections between the behaviour of cows while testing .
Farmers reported strange behaviour to the media , A couple of farms in the same area had there cows go in to a panic state , all of them ,, at exactly the same times . It was scary and a mystery at the same time .
Only when a employer of the test site leaked test times to the farmers connections where made .
There are only some media posts about testing 5G and some local news sites reporting on the cows .
There all in Dutch so i hope you will be able to translate .

https://www.google.nl/search?site=&source=hp&q=g5+netwerk+koeien&oq=g5+&gs_l=psy-ab.1.0.35i39k1j0i131k1j0l2.4216.5921.0.8839.4.3.0.0.0.0.86.215.3.3.0....0...1.1.64.psy-ab..1.3.214.0.JOSKZ_lKmyI

There never where official statements made , media went silent on it very fast .
I do not think the public will ever see or hear about it again .
The area is one of tremors and quakes due to gas drilling , most think the cow problem relates to that .
It is nicely covered and hid away behind that now .