The following observations on this subject are from an excellent work, entitled _The Book of the Farm_, published in 1844:--"This mode of allowing them to lie out always in a sheltered field, no doubt, imposes a good deal of labour on the dairy-maid and her assistant, in carrying the milk to the dairy after the calves have been weaned, but I am persuaded it is an excellent system for the health of the cows. Under it, cows rise from their lair at daybreak, and feed while the dew is on the grass; and by the time when the hour of milking arrives, say six o'clock, they are already partially filled with food, and stand contented, chewing the cud, while the milking proceeds. They then rove about, and fill themselves, and by nine o'clock they lie down in a shady part of the field, and chew their cud until milking-time arrives at mid-day; after which they again roam about for food, and, when the afternoon is hot, will stand in the coolest part of the field, whisking away the flies with their tails and ears. The evening milking takes place about seven, after which they feed industriously, and take up their lair about sunset, from which they rouse themselves in the morning before being milked. Some people are apprehensive that cows must injure themselves by eating grass which is wet with dew in the morning; but it is a fact, which I believe is not so sufficiently known as it should be, that bedewed grass before sunrise, and grass after it is dried by the sun, are alike wholesome for animals; and it is only when the dew is in the act of being evaporated, immediately after sunrise, that grass proves injurious to them. Why it should be injurious at that particular state I do not precisely know, but I imagine it to be so, because the grass then becomes suddenly cold by the evaporation of the dew. When cows lie out, they have nearly filled themselves by the time the dew is evaporated, and therefore feel less inclined to eat the grass while in the dangerous state; whereas cows that are housed all night are usually milked about sunrise, and put out to grass just at the very time the dew on it is being evaporated, and is, of course, in the most dangerous state, just when the cows feel the greatest hunger, and eat most grass."