Is this going to result in net less greenhouse gas emissions?

Maybe but probably not zero, from parents article: "The use of such treated fertilizers will be most relevant for reducing the carbon footprint of milk in countries such as the United Kingdom, Ireland, and the Netherlands, where N fertilizer is a major contributor to the footprint."

In case you are unaware much of the nitrogen in plant matter (food for yeast or cows) comes from fertilizer. And that is extracted using the Haber process (see: https://en.wikipedia.org/wiki/Haber_process ). This runs on natural gas, because it's effectively a waste product of other hydrocarbons being extracted.