On Food and Cooking

from the gland. The optimum sequence for
milk production is to breed the cow again 90
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 energy on grazing in
variable pastures; they’re given hay or silage
(whole corn or other plants, partly dried and
then preserved by fermentation in airtight
silos) in confined lots, and are milked only
during their two or three most productive
years. The combination of breeding and
optimal feed formulation has led to per-
animal yields of a hundred pounds or 15
gallons/58 liters per day, though the American
average is about half that. Dairy breeds of
sheep and goats give about one gallon per day.
The first fluid secreted by the mammary
gland is colostrum, a creamy, yellow solution
of concentrated fat, vitamins, and proteins,
especially immunoglobulins and antibodies.
After a few days, when the colostrum flow has