Unfortunately there are very few recent studies on comparing feeding methods for calves but I did include studies from the late 1990's - early 2000's. I reached out to the University of Guelph to conduct a trial in the future, we will see what happens!

drue j Its not really spit swapping that's the issue. It's when they suck on the tails or navals of other calves and ingest bacteria and feces that may be stuck to their hair.