The principal vitamins, nevertheless — fats, sugar, and proteins — are assembled by the gland’s secretory cells, after which launched into the udder. Milk is food for the newborn, and so dairy animals must give start earlier than they will produce vital quantities of milk. The mammary glands are activated by changes within the balance of hormones toward the tip of being pregnant, and are stimulated to continue secreting milk by regular removal of milk from the gland. The optimum sequence for milk manufacturing is to breed the cow again ninety days after it calves, milk it for 10 months, and let it go dry for the two months before the next calving. In intensive operations, cows aren’t allowed to waste vitality on grazing in variable pastures; they’re given hay or silage in confined heaps, and are milked solely throughout their two or three best years.
The yellow balls and …