new minds with no programs: February 2010

So for my last class we were learning about ruminant nutrition. In an effort to show us how cattle select forage, our professor set up an exercise with some rumen-fistulated steers.

Ok, so here is how this works. The rumen is the large fermenting section of a cow's 4 chamber stomach. When the steer is fully grown, a veterinarian performs a surgery in which the rumen wall is stitched to the skin and left to heal. This leaves a 4 inch diameter hole directly into the animal's stomach. This is sealed with a plastic cap and the animal can go about their lives with no side effects.

We took 3 fistulated steers up to the Maxwell Research Ranch and let them acclimate for a few days before the study. The morning of the study, we rounded up the steers and got them locked into the chute so that we could handle them. We popped open the plastic caps on their stomachs and got scooping. We had to remove all of the solid matter by hand.
Here I am arm deep in the first steer.

There is a massive volume of material in the rumen. Each animal hadn't eaten since the night before and still had about 30 gallons of material in their rumens. Our professor considers cleaning out rumens to be a right of passage due to the paticular smell of partially fermented cow food. Its not like methane or cow shit as it hasn't been digested that far, but the microbes in the rumen are producing volatile fatty acids that do smell. This is the amount of material taken from one steer. The bubbles are the fermentation byproducts

After scooping out by hand as much as we could we had to use a shop vac to clean out their stomachs. That's right, we used a shop vac inside a live animal. Blew my mind.
Once the steer were empty, we let them back out to graze as they were suddenly very hungry. We had some students trying to clip forage samples similar to what the animals were consuming. After we let them graze for almost an hour we rounded them back up, put them in the shoot and opened their rumens again. We took samples of the recently consumed material, the partially digested material, and the rumen fluid and then put the entire trashcan of goop back in the animal.
The point of this whole exercise was to see what the animals were actually eating. While a .25 square meter plot of forage may have only 3-5% crude protein content, the cattle were able to pick the best parts and ended up with a dietary crude protein content as high as 8%. That pretty impressive considering they look like living lawnmowers.

Here are some of the better pictures from the day.

This guy was a kicker