I wonder if it's as simple as wanting to catch the most sun hence a north south orientation to expose the flanks and the shadows from high voltage towers interfere with this hence the difference under those towers.

This sounds like the likely explanation. Crop rows and greenhouses are generally aligned North-South for the same reason: to maximize direct sun exposure.

I found the relevant research: https://www.pnas.org/doi/pdf/10.1073/pnas.0803650105

> Furthermore, there was no correlation between the position of roe deer and the time of day when the observation took place, meaning that the position of the sun had no influence on deer orientation.

Although I'm not sure how credible this information is given that they studied google images where who knows what time of day they are taking images at. Maybe there was a correlation.

Thank you! My curious but busy/lazy ass wanted to know the answer but wasn't gonna do the legwork.

It should be fairly possible to determine the time an aerial photograph was taken by studying the angle cast by shadows in the photograph.

My first though would be a wind, which you can't measure with photos.

I admit that I've never noticed that. They seem to lay whatever direction seems comfortable. In winter time the will lay east-west to catch the most warmth and will often roll on their side to really catch some rays.

Why would a cow magnet settle in the rumen any particular cow related orientation?

I've not read up any studies or papers on this matter. I've lived around farm animals for a large part of my life so I have some anecdotal observations.

From what I've seen, they tend to align themselves into the most pleasant direction depending on the weather conditions of the moment.

- Cold but sunny: Broadside towards the sun

- Wind or rain: back-side towards the direction of origin, heads hung low. So they stand with their butts in the wind to shield their heads against the worst of it.

- Very hot: Butts toward the sun, heads hung low. Often they'll arrange themselves in lines in order to hide in one another's shade.

I've never witnessed them being aligned north-south in a way that can't be explained by the immediate weather conditions.

This was in the southern hemisphere.

This reminds me of the study that concludes dogs shit on north-south orientation (that's why they circle)

Apparently the Corgi on this place didn't get the memo! Generally he just stops and does his thing whatever direction he's going and wherever he happens to be. No, he's not obedience trained or any such thing.