With some exceptions, most dairy farming is done across the northern parts of the US. I’ve worked on farms as a young pup in Vermont, and talked to many dairy farmers from other states, but until now never wondered why this was.
It’s a hard enough job without being subjected to the frigid climate. How come?
Is it because if the cows are not in cold weather, the milk will turn sour? 
Facility and Climate Effects on Dry Matter Intake of Dairy Cattle, by MICHAEL J. BROUK, JOHN F. SMITH, and JOSEPH P. HARNER, III (A .pdf file.)
This doesn’t mean that dairy cattle can’t be used in warmer climates. They are, both in the American south and around the world. More dairy cattle live in South Vietnam than North Vietnam, assuming that means anything. But our modern cattle are descendants of breeds developed in northern Europe so they have been breed for temperate climates for thousands of years. And their feedstock is also mainly temperate, which reinforces the cycle.
In addition to Exapno Mapcase’s research, some other points might be made:
The North grew urban much faster than the South in the U.S. Hence an export market for perishable dairy products was more accessible in the North, at a period when ship-to-market times were critical.
Hysteresis. People often continue to do what they or their predecessors did, because it’s something they know how to do, and because the infrastructure is present to process the results of their work. Raising dairy cattle with the object of producing cheese is far more profitable in Wisconsin or Upstate New York than in, say, Nevada – not only is the climate better for the cattle, but also there are cheese factories within a reasonable shipping distance. While one could ship milk cross-country in refrigerated tankers, it would be competing with the milk produced locally.
The South has a longer growing season, a larger area of richer soils, etc., leading to the ability to grow different crops. Dairy will therefore be a proportionately larger sector of the agribusiness industry in the North than in the South, simply by the principle of there being fewer crop choices.
The South, California, etc., do have dairy farms and a dairy products industry. It’s just more concentrated in the Northeast and Upper Midwest, for reasons given above.
I was raised on a dairy farm in Texas. I had LOTS of neighbors who were also in the dairy business. I understand it is more prevalent in Wisconsin, Iowa, Minnesota and other Northern states, but it is definitely not limited to those areas of the country.
Dairy’s also fairly big in New Mexico, especially in the eastern and southeastern counties. There’s one right next to I-25 somewhere in Valencia County which you can smell driving by if the wind is right and a whole lot in Chavez County (around Roswell.)
California, which is the #1 milk producing state, is a big exception. Other states like Texas are also exceptions.
I believe that some of the reason that you see big dairy farming in California and Texas was due to the Eau Claire Rule, which gave milk producers price support based on their distance from Eau Claire, Wisconsin. This legislation came from the 1960’s. I know this rule was contested in the late 90’s, but my search-fu is failing me, so I don’t know it is still in force. At the risk of a slight hijack, I would certainly be interesting if anyone has more current information on this and other milk price support.
Another interesting cow fact is the difference between Italian Leather and American Leather. Reason Italian leather is so much more expensive is because Italians don’t use barbed wire for their cows, which means the cows don’t scrape up against the barb wire and cause scars.
One further point worth mentioning is that many areas in the North (Vermont, I’m thinking of you) are rocky and hilly – miserable for farming, but fine for grazing cattle.
Here in Panama, almost all of the dairy farms are in the cooler western highlands. There are some dairy cattle in the lowlands, but not many. There are lots of beef cattle in the lowlands - mostly tropical humped breeds, though.
Aay-yup! Each year we raised a new crop of rocks. The fields were so rocky, had to plant corn with a shotgun.
The pastures are so steep the legs on one side of each cow are shorter than the other. Until after I left, the state was famous for having more cows than people. When Vermonter Calvin Cooledge was asked why, he said, “We prefer 'em.” Ad naseum.
Thanks to everybody for every interesting and enlightening posts.
This is a whoosh, right? Italian leather is produced at Italian tanneries, but the hides are almost all imported.
Bull!
First, cows don’t ‘scrape’ against the barb wire. They might lean against it (to reach over the fence and graze on the other side), but that only leaves small pinpricks from the barbs, and usually doesn’t even penetrate the skin. Their skin is pretty tough, after all.
Secondly, any small cuts from barbed wire fences are unlikely to leave a scar. Especially on a modern dairy farm, where the injury would be seen when the cow is milked that night, and promptly treated with wound ointment and antibiotics. Dairy cows are valuable animals, and very well taken care of by their owners. A painful cut like that would reduce the cows milk production if left untreated. And farmers who allow that to happen to their dairy cows don’t stay in business long!
Third, barbed wire isn’t even used that much on dairy farms. Dairy cows are not turned out into big pastures, only smaller ones, since they have to come in for milking twice a day. Barbed wire has an economic advantage only on vast tracts of land, such as the huge ranches used out west for beef cattle.
Perhaps it’s beef cattle you’re think of. They do run in large ranges with barbed wire fences, are left out for weeks at a time without being seen individually by the rancher, and could have untreated wounds that produce scars. And most leather does come from beef cattle, not dairy cows. Dairy cows are kept and milked for many years; beef cattle go to the slaughter house comparitively young.
I think the two biggest reasons italian leather is more expensive is that:
Well, we used barbed wire on our dairy (coincidentally near Bonham, Texas), though we also raised beef cattle. And our dairy herd grazed on a pretty large pasture (200+ acres), but getting them in for milking was usually just a matter of bringing in a few stragglers. Most of the cows would be in the lot waiting at milking time.
I’m not sure how to break this to you, asterion, but the ones around Roswell…
…they’re not really cows! :eek:
Yes, it was cattle, not dairy cows I was speaking of. And yes, I’ve read on a few different occasions that Italian cattle are free range cattle on large acres of land and there is no barbed wire as opposed to a few ranged in the US that do use cattle. I’m only going by what I’ve read. Google it, I’m sure you can find something on it as well. I read it on one of those “Useless Facts” websites. 
I meant to say “as opposed to a few ranged in the US that do use Barbed Wire”, not cattle. DOH ! lol
Well, I tend to use the word a touch metaphorically, to mean “our natural tendency to remain creatures of habit and to do things the way we and our ancestors always have done them.” (Cf. Tevye on “Tradition”)
Tennessee still has quite a few dairy farms. I live within sound of one of them (it would be “within sight” but for the lovely trees in the way.) There are several others in the area, plus a processing plant less than 20 miles away.