Well yeah the processing and transportation always complicates things, the net-zero is talking about where the carbon that is released is coming from.

Stuff like feed you can't really analyze in the abstract, since there are many different ways it's done, and AFAIK most cattle farms either grow feed on-site or are grass-fed. Transportation costs are expensive, and better farming techniques have expanded the locations grain can be grown. Of course there definitely exists farms that do transport feed in, but looks like this dairy farm in particular is also a grain farm.

I think when looking at investing in things like this it's more important to look at whether it can be net-zero, and whether it's improvement on the status quo. In this case both are true, it could be net-zero with improvements in other areas and it's definitely an improvement on the status quo.