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by Baxter Black, DVM

When the Rumen 
Goes Awry

I am a student of the cow. I have come to conclude that cows lead a fairly boring life. When I am giving cows their sporadic weekly check, I think it’s probably the high point of their day.

They graze their life away and if they are not grazing, they are chewing their cud. This cud is part of a magnificent ruminant digestive process that allows them to digest foodstuffs that are virtually inedible to simple stomached animals like people.

For instance, cows derive nutritional benefit from lettuce! Who’d’a thunk it? Now, I’ll grant you that people eat lettuce, but they eat lettuce because it is the next best thing to eating nothing. If you’re on a diet, we all know that the best way to lose weight is to eat ___?___. No, not lettuce. Nothing! But nobody wants to eat nothing, so they eat the next best thing, which is lettuce.

The cud is chewed, then swallowed into a vast fermentation vat called the rumen. It can hold 300-400 pounds of water and feed. It is nasty, green, and when you get rumen contents on your hand you have to sleep with your arm hanging off the bed for at least a week. The cud takes a soak in the vat and is regurgitated, swallowed, then regurgitated, and remember, it’s not always the same cud!

One of the by-products of the digestive process is that cows give off enormous quantities of carbon dioxide and methane. Horse people are aware that the horse’s exhaust is in the rear. But cattle don’t do that! They belch off the gas. But on occasion a wrench is thrown into the works that prevents the gas from escaping; i.e., an occlusion of the esophagus or a diminution in rumen motility. This gas then collects and distends the rumen, creating a condition we call bloat.

You may be driving by a field of cows and notice one is football shaped. On closer examination, her feet may actually be levitating slightly above the ground. As confirmation of this phenomenon, recall those times you’ve been checking cows, following their tracks, then suddenly…the tracks disappear.

Since bloat is a life-threatening condition, good cattlemen and vets often carry a delicate veterinary instrument called a ‘bloat hose’ (imagine the stack on a Kenworth), which is passed down the throat to relieve pressure. Or, if you’re on your way to church and don’t have your bloat hose in your purse, you might whip out your trocar (a sharpened screwdriver with a sleeve) and puncture the rumen through the left flank.

Finally, when treating a cow for bloat, there are some precautions:
1. Regarding the bloat hose…blow, don’t suck.
2. Don’t attempt to peer into the inserted sleeve after removing the trocar.
3. Wear a protective moustache cover when smoking around bloats, as methane will burn.
4. If you are tracking a suspected bloat and suddenly the tracks stop, don’t forget to look up.

Baxter Black is a former large animal veterinarian who can be followed nationwide through this column, National Public Radio, public appearances, television and also through his books, cd’s, videos and website, www.baxterblack.com.



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Date Last Updated January, 2006