The new iron-shod moldboard plow could open up fields on land that had looked off limits, and it doubled grain yield per acre. Every 50 years, some higher altitude lands were a few degrees warmer, so farming spread upward, away from the coastal plains. Soon after the new plow, someone invented the harrow, a wide rake with iron teeth that leveled the furrows and buried the seeds. Grain farming became more profitable; around this time, the medieval farmer could expect to get back four times as much grain as he planted, which allowed for feeding his family, paying tithe and rent, and saving seed for the next planting.
The year 800 is the time of Charlemagne; we’ll talk more about his influence on European diet, but in this context he was also the most enthusiastic promoter of horse breeding. Charlemagne’s warriors rode horses, and the church had just declared horses unfit to eat, since they were noble like knights. Only the wealthy could ride horses or use them to pull wagons; most people walked on their own feet and used cattle to pull carts. So horses had no place on the farm, at first.
Horses had three specific drawbacks, to their one advantage of speed. Their hoofs, adapted to grasslands, swelled and split in wet farm work. This problem was solved fairly early in the Dark Ages by using early iron smelting to make horseshoes. Cattle had bony shoulders that fitted into wooden yokes, but horses did not; so they were generally harnessed with a strap directly around their chests. As soon as they tried to pull a heavy load (like a plow), the strap cut off their ability to breathe. The padded horse collar (made of leather, stuffed with horsehair) made its way from China to Europe during Charlemagne’s time. It fitted a horse’s shoulders, leaving the chest free to breathe. But there was one more drawback: the horse consumed more protein than cud-chewing cattle and sheep. Grass wasn’t enough for keeping horses; farmer had to grow food not only for human use, but to feed the horses.
When the last farming innovation of the time fell into place, the use of horses expanded rapidly. This last innovation was creating an extra farm season by using a fall-planted crop of oats for the horses, ready to harvest about the time that wheat for humans needed to be sown. And instead of leaving the field fallow (unplanted) for a whole year, planting legumes to restore nitrogen allowed the fallow season to be relatively short. The fields were growing something productive more of the time than before; they could grow just as much human food and still fit in a horse-food crop.
Horses first pulled the relatively light harrows, while oxen still sweated the plows. But a team of horses, once fitted to plow work with shoes and collars, could pull the plow much faster than the oxen. On days when they weren’t plowing or resting, they could pull two-wheeled carts several miles to a town, fast enough to get back before dark.
The more work horses could do, the less the cattle had to do. Horses weren’t being eaten (at least nobody would admit to it if they did), but when cattle could fatten up, cows’ milk and beef both became food options. Before this, most cheese was made from sheep or goat milk. Who could afford to keep a dairy cow in milk when its greatest value was as ox #5 in the 8-ox plow team?
Horses sped up the farm work, allowing for yet more acres in wheat, rye and barley. They sped up transportation; it now made sense to plant a nice strip of wheat just for sale in town. Peasants still had to pay in-kind rent to the landowner, in either/both grain and work days, but if they could get ahead, the landowner didn’t care if they took extra grain for sale in town.
And so horses on the farm pushed the economy one more step toward cash and markets, while allowing hungry farmers to start eyeing their “oxen” in a new way. It took years for beef to catch on as a popular table meat, but cow’s milk for cheese and butter improved country life quickly.