Jack, there was some discussion of cow-related songs on the Ethnomusicology list some time ago. I mentioned the Welsh oxen songs, and someone else came back with details of boys singing to oxen who turned the water pumps in Egypt. Cross-cultural indeed.

Re: the 'shape' of the tunes, I imagine (and I do mean 'imagine') that the arches accommodate both the needs of the human voice, and the job at hand. The sound for calling to animals across a field (or two, or three) would carry farther in a higher register, and it's easier for the voice to build up to that register in stages. That's the case with some of the Cathreiwyr tunes. Similarly, there's a Welsh milkmaid 'call' that fits that bill.

Another thing that took some explaining to me is that back when ploughing with oxen was the norm, farming was also labour intensive so you could look out across Welsh (British, et al) farms and most fields would have someone doing something in them. Factor in the hilly landscape, and a world with no engine noises. It wasn't unusual for a cathreiwr in one field to start competing with the one on the other slope as to who could sing more verses to a tune.

sian