It's been many years, but I always milked from the cow's right side. Just how I was taught. I doubt a cow knows if it is right or left handed, however, and I see calves approach from all the angles to nurse. I suppose it is what they get used to when they are brought in and headgated.

I am just lol, however, I doubt the film makers had any technical advisors for the milking scene. I love to pick out discrepancies as well.

WE milked from the right side, maybe it was just a custom? Why mount a horse from the left side ? probably because thats the way it's trained? Saw a movie the new "farm hand" was shown how to sit on a one leg stool to milk, now that's a real trick:)

We milked from either side, on different properties, depending on the physical arrangement of the bail. But mountng a horse from the left favours the right handers. Some horse trainers mount the young horse from both sides for a while; getting on from the right I find difficult and it sure doesn't look pretty :)

We didn't milk by hand, used a parlor milking setup. Cows came in on both sides of a lower center aisle. We would milk cows from both sides with the milking machines. They didn't seem to mind which side they were done on.
The stanchion barns I saw as a child, had the cows being milked from the left side.
The cows I have seen being hand milked, maybe being stripped out, were done from the cow's left side. I always thought it was because it was easier to reach under cow with right hand, usually the more skilled, preferred hand anyway.
I know that I have seen TV shows with the cows being milked from the left. Seems like they were very old movies or maybe Little House on the Prairie?

With the mention of horses above, I wonder if farmers did left side milking because of horse usage.
We handle, harness and mount horse, most commonly from the left side to keep from tripping over our swords! Riding was first a source of military might. People learned to do things from a military angle. Most people are right handed with swords hung on the left for drawing out across the body. Mounting from the right would get your legs tangled, have to adjust equipment while swinging onto animal. Not good if horse moves during mount!! So even though the right hand/arm, leg, are stronger in right handed people, we mount from the left side to keep the sword out of our way.

All the cultures in Europe or Asia have a sword fighting history. Even the most primitive folks had access to metal for weapons. They all mount from the left side of horses.

American Indians are the ONLY horse culture not able to access metal for weapons during horse development. They used bows, stone knives, wooden lances as horse carried weapons. Never had a sword weapon, military culture. The American Indians used their stronger side, the right, arms and legs to aid mounting. Carried weapons in the left hand. They had no swords to trip them up. Indians really had no metal for weapons until trading with the whites who came along in the mid-1800's and later. Silver, copper were usually used for ornaments, jewelry.

Their horses were trained to mount from the right. Indian pulled themselves up with right arm, swung up or leaped on with stronger right leg to kick off. You could tell a horse was "Indian broke" by being able to easily get on from the "wrong side".

Amazing what things come forward, continue in use, from the ancient past. I practice mounting from both sides for the horse to learn. I do prefer the left after all these years of using my left leg. I also use a mounting block to make things easier on me and my tall horses. Less pull on his shoulder, shorter time in stirrup, while I get up that high!

We're all the creatures of habit - even the milk cows. Like goodhors, we milked for many years the same way. Our cows came in the barn each and every time in the same order and on their particular side of the barn. These girls made no exceptions.

Only milked by hand when there was a power outage. Why weren't backup generators affordable back then? That's when the neighbors would be there to help and you'd help them when needed. Not many of us these days have neighbors we can count on, most neighbors now are gentleman farmers and we don't know their names or they wouldn't be of much help in a pinch. Good people, just don't know what to do or don't like to get dirty.

Gosh, I haven't given a thought in a very long time to how much I hated the dairy years of my life. We had a very large cow/calf operation (beef cattle) and during the very lean years that milk check was what kept our family from going under.

I visited a corporate dairy farm a couple of years ago in western Kansas. They milk hundreds of cows 23/7 in several different barns with semi-tankers pulling out with a load of milk every few hours - the entire operation was high tech and just amazing. Definately not the way I grew up with the milk truck coming every other day to empty our tank. From what I understand a lot of these operations are leaving the California area because of EPA guidelines and relocating to remote rural areas. This is the same area where a huge number of corporate hog operations (SeaBoard)have opened up shop.

Sorry, this got a long way from which side of the milk cow!

as a creature without much habits, I tend to milk my goat on which ever side she prefers, what ever works for her works for me,
When I was a kid, I used to stay at a dairy alot, and they would milk by hand on a first timer, and then hook up the machines on an experienced cow. they always alternated sides, don't remember why. I used to sit on the back of the cow while they milked and rubbed the sides of the cow.
As far as the horse mounting thing, I was always told that if you mount a horse one the right side it would spook them, but being left handed it was easier so I mounted a horse that way and the horse didn't seem to mind too badly.
Like someone else said, we tend to fall to habit. Then it becomes a "I wonder why" topic.