I understand that keeping cattle through the winter in temperate climates generally involves feeding them hay. Indeed this is the whole point of hay; it's why hay technology was developed.
So how did early Texas cattle ranches, with their enormous herds, get all that hay?
Before the railroad came through, I imagine it would have been impractical to ship the hay in. That means they had to grow it themselves. But huge hay-growing operations are conspicuously absent from accounts of Texas history.
And then there is the issue of keeping the cattle from eating all their winter feed in the summer. That would have required fencing off the hay fields. But ranchers fought hard to keep the area from being partitioned with barbed-wire fences; this fight doesn't make sense if they were already fencing off their own hay fields in this manner.
Something doesn't add up here. What am I missing?
Really interesting question here, and it made me want to learn more. In 1850, the U.S. Commissioner of Patents (the Department of Agriculture was not created until 1862) posted a fascinating report from a rancher in northeast Texas, who reported, "Cattle require no feeding. In spring and summer, the grass upon the prairies furnishes excellent grazing, and the wild rye, cane, and winter-grass in the bottoms, furnish food during winter."
In his 1977 report, "Early Northeast Texas and the Evolution of Western Ranching," (published in Annals of the Association of American Geographers) Terry Jordan suggests that some ranchers in northeast Texas without easy access to bottomland turned their surplus grain/corn over to their livestock because there was no easy way to transport that surplus out of the territory.
David Surdam, in a 1997 Southwestern Historical Quarterly article entitled "The Antebellum Texas Cattle Trade across the Gulf of Mexico" furthermore suggests that the same problems existed for cattle. While there were drives to the coast and to Louisiana, he suggests that cattle in the pre-Civil War era were valued more for their tallow and hides than they were for their beef. Tallow and hides could be harvested and processed in the winter, relieving some of the population stress on the environment.
C. Allan Jones' Texas Roots: Agriculture and Rural Life Before the Civil War on Page 178 offers this anecdote from a herder named Kuykendall from the 1830s: "The prairie, both winter and summer, furnishes the most abundant and nutritious pasture, and even salt is not necessary for the stock, as the dew is highly impregnated with the saline properties of the sea."
Kuykendall had a league of land near Austin, by the way, and although he seems to offer a pretty optimistic picture, things weren't quite so rosy on the land. Grass, as you know, is subject to the vagaries of weather, and freezing rain or a winter storm could cost ranchers thousands of head. Jones offers other accounts illustrating this.
Ernest Staples Osgood's The Day of the Cattleman offers some more anecdotes of early (pre-Civil War) herds digging grass from beneath four feet of snow and surviving on that forage without great difficulty. While I wouldn't rely on Osgood for serious work, those anecdotes ring true if crossed with other information.