Summer in Wisconsin can be an even warmer experience for cows than many other animals. Cows are ruminants...like deer and sheep and goats, cows have a rumen, which is a relatively large organ at the lower end of the esophagus, ahead of their actual "stomach" (abomasum). The rumen, and it's two mates, the reticulum and the omasum, are what qualify an animal as a ruminant. Those three organs are actually outpockets of the esophagus, and in the rumen in particular, there is alot of food the animal has eaten, alot of water she had drunk, and ALOT of bacteria and protozoa. In the rumen, there is very important fermentation going on, allowing the ruminant to digest and make microbial protein and break down fiber, to send down the line through the abomasum and on to the intestines for absorption.
In the photo below, you can see the cows' backs, sides, and faces are wet from the water sprinkling on them.
What's that, you say, "ruminating"? Well, the rumen has a few large bands of smooth muscle around it, and it's on the move all day, contracting and mixing the contents within. (When we examine a cow with a stethoscope, we actually listen to the strength, frequency, and completeness of the cow's rumen contractions...tells us something about what might be bothering her if she is not feeling well.)
During the process of rumination (rumen movement and fermentation), the cow helps the process out by actually regurgitating a wad of hay/silage/liquid (that's called a "cud"), and she chews on it for a minute, swallows it, and regurgitates another cud for chewing. You can imagine the repeat grinding of the plant stems between her molar teeth, exposes more surface area on those stems to the bacteria and protozoa in the rumen.
Cows chew with their mouths open, and chew their cuds...and that's a good thing...tells us the cows are content and healthy, and in the summer, that they're comfortable. (They don't chew their cuds if they feel hot.)
Well, stay cool, and stay safe when you go swimming to cool off. Stop by the farm, and we'll check out the cows together. Sallie