For the Juniors: Why do cows make milk?

CAT:

(Purrs) Wonder what sort of milk this is? (Purrs)

NARRATOR:

That milk came from cows.

CAT:

Goodie. I love cows' milk. I wonder why cows make milk?

NARRATOR:

These calves are the reason. They're about a day old. And their mothers make milk for them to drink. This is because cows, like all mammals, feed their babies on milk. These calves are drinking from their mother's udders. Their udders are full of milk. An udder is like a big sponge full of water. It has to be squeezed to get the liquid out. Cows use the muscles around their udders to squeeze their milk out.

CAT:

(Purrs) How do they know when to squeeze? When a cow feels her calf sucking. That's when she starts to squeeze the milk out. While she has her udder emptied regularly, she keeps producing milk for her calf. A cow usually produces a lot of milk - more than her calf needs - so a dairy farmer milks the cow and takes the extra milk for people to drink. This is Bill's dairy farm. His cows spend the day eating grass and drinking water. As the day progresses, the cow's udders fill up with milk. They're making milk for their calves.

CAT:YYY(Purrs) But where are the calves to drink the milk?

YYYNARRATOR:

Here they are. They have their own paddock. Bill's dad Tom is in charge of feeding them.

TOM:

Put them down. There they are. Alright.

NARRATOR:

Today, he has lots of help.

TOM:

Lift it around here.

GIRL:

Here comes my little calf. Here comes...

TOM:

Sic, sic, sic, sic, sic, hut. Sic, sic.

NARRATOR:

When the calves were a few days old, they were put together in a nursery section. Keeping all the calves together and handfeeding them means their mums can go on making lots of milk without having to feed their calves.

CAT:

Hang on, it doesn't make sense to me. If these cows aren't feeding their calves, then why are they still making milk?

NARRATOR:

We'll soon see. When their udders are full and heavy, the cows start wandering towards the milking shed. They wait patiently in the yard. Cows are clever. When Bill's mum Dorothy opens the gate, they go into a milking bay. Bill gives each cow some special feed. This keeps them healthy and helps them produce more milk. He wipes the cow's teats to make sure they're clean and dry. Teats are the cow's nipples. Hmm, I wonder if that tickles? On go these special pipes. A machine slowly and gently sucks the milk from the cow. To the cow, it feels like her calf is sucking the milk.

CAT:

Ah, so that's why cows keep making milk. They think they're making milk for their calves.

NARRATOR:

That's right. And the more often the cows are milked, the more milk they will try to make. Bill milks his cows twice a day - in the morning and in the afternoon. He can milk around 100 cows in an hour. This cow's udder is empty. Cody sprays the teats with a special antiseptic. This helps to keep the cow healthy. As each row of cows is milked, it calmly leaves and slowly wanders back to the paddock.