Given my own experience with dairy goats, I find it hard to believe that they would agreeably give suck to anything. (Or, for that matter, that any responsible nurse would leave an infant face-up under one.) But Valenze includes a 19th-century illustration of bonnet-wearing nurses gently holding infants beneath what appear to be donkeys. Almost stranger is the fact that, given the sanitation and infectious disease concerns of the time, this wasn't necessarily crazy: In 16th-century France, for example, a widespread outbreak of syphilis made non-nursing mothers apprehensive about handing their babies off to wet nurses, who could pass the disease through their milk. Since fresh animal milk spoiled quickly, some mothers decided to avoid both risks by taking the baby straight to an animal instead. (The distinctions between different animals' milk proteins weren't discovered until 1875; till then, all milk was considered basically interchangeable.)
In general, human wet nurses were more common than hooved ones, partially because using them didn't require such an explicit blurring of the line between animals and humans, which Valenze claims Europeans found "profoundly upsetting." (By connecting humans to their animal natures, breast milk "tied them to a realm opposing civilization.") That's not to say that wet nurses were lavished with respect, though. Up until at least the 1860s, many Europeans and Americans believed that unwanted personal characteristics and social status could be transmitted through bodily fluids such as breast milk, which itself was thought to be a form of blood. As a result, many upper-class families skipped the goat teats and the risk of having a wet nurse corrupt their child by feeding their babies cow and goat milk with a pan and spoon instead.
In the days before modern baby bottles, some advocated even more creative ways of separating milk from its source: Pierre Brouzet, the physician to France's Louis XV, reported admiringly in the mid-1700s that in places like Muscovy and Iceland, wet nursing, breast-feeding and, for that matter, animal suckling, weren't used at all. "Soon after they are born," he wrote, "[infants] are left all day, by their mothers, lying on the ground, near a vessel filled with milk or whey, in which is placed a tube, the upper extremity of which the infant knows how to find, and putting his mouth to it, sucks whenever he is oppressed with hunger or thirst."
That particular method may not have caught on, but neither has one form of feeding definitively trumped all others. Instead, the pendulum of taste has continued to swing back and forth between breast milk and animal milk—or, more recently, formula, which has come a hell of a long way since the days when even seemingly sophisticated formulations were so nutritionally deficient that babies sometimes died. The irony today is that even though formula has never been better, women are subjected to more pressure than ever to nurse: Nature knows better than the food industry, we are told again and again, and "Breast is best."
Through it all, our ambivalence toward our own mammalian nature hasn't abated. A British ice cream parlor prompted near-universal revulsion earlier this year by launching "Baby Gaga," a vanilla-and-lemon-infused flavor made from human breast milk. And our discomfort with public breast-feeding has led to products whose names call attention to the very connection they're designed to hide—consider the Udder Cover nursing cover-up, or the Peek-a-Moo nursing tee (which can be gift-wrapped in a milk carton). At least Bag Balm, a salve for cows' udders invented in 1899 and more recently adopted by nursing mothers, doesn't try to be cute.
But no matter how much—how shall we say—cheesiness is employed, there's a limit to what a Moo Moo Mama nursing blanket can really hide. Women, even those of us who don't have kids, face a reminder that we're animals every time we look down—and this connection has arguably played a bigger role than sex in making breast-feeding so persistently contentious. Or at least that's what I found myself thinking in the goat pen, as I contemplated the row of udders in front of me—all hairier than the ones on my chest, I'm relieved to say, but still fundamentally the same.