Cow ate green grasses so, why milk is white ?
Answers
Answer:
Milk will be white regardless what the colour of a cow is—black, brown, red, white, blonde, orange (or “red factor”), grey, brindle, spotted, etc.—thus the fact that chocolate milk comes from a brown cow, or strawberry milk comes from a red cow is pure, yet amusing nonetheless, urban myth.
But just how is milk white when any coloured lactating cow eats green grass? Well, hate to break it to you but the process of milk production in a cow is not directly linked to the cow’s digestive system. There’s a lot of other steps that need to be gone through in order for milk to come about.
Milk is produced from blood, to be extremely basic; Some will also be privy to tell you that milk comes from modified sweat glands, which is also kinda true. The thing is, though, if you’ve seen a cross-section of a cow’s udder (as shown below), it’s not a big hollow bag where milk is somehow *magically* (still chuckling at Ed Elford’s answer below as I write this) made and accumulated, rather there’s many components to it that is actually remarkably similar to that found in the lungs. Except with the udder of a cow, it fills with liquid where lungs are filled with air.
The cells that make up thousands of tiny alveoli in the udder are supplied by capillaries—tiniest of all blood vessels, of course! Milk has similar components to that of blood, except for the hemoglobins and red blood cells that gives blood its red colour. All of these components—lipids, amino acids, proteins, vitamins, minerals, water, and other things available to the milk cells—are secreted into the alveoli in the form they came in, or as a modified component to add to what would now be called “milk.” Casein is also a major contributor that makes milk white.
Milk goes from the alveoli into ducts, which lead to larger ducts and so on and so forth, until it ends up in the gland cistern of that quarter (since a cow’s udder is divided into four quarters). The milk in the gland cistern goes on into the teat cistern or sinus, where it sits until the suction from a calf’s mouth, the hands of a human (who knows how to properly hand-milk a cow), or the gentle vacuum suction of the milking suction cups stimulate the sphincter muscles at the base of the teat to relax and release the milk.
And there you have it. Not only do you now know how milk gets its white colour, but also how it’s made!
ANSWER:
Milk contains no chlorophyll (so no green color) but is an emulsion and a solution of fats, protein, and minerals in water, giving a white appearance, although during certain seasons, if the animal is feeding on fresh lush grass, the cream and especially the butter can take on a slightly more golden hue.