While it is possible to allow the cows to roam free, you would have to drive a tractor around to scoop up the thousands of tons of manure each week (per farm), which might be viable if you powered the tractors off of the methane from the manure itself.

There is a lot of cow manure that is generated in the US, and it has a severe impact on global warming: dairy farms in California produce more greenhouse gas emissions than every car in the LA metropolitan area. This is largely because molecule per molecule, Methane is 21 TIMES more potent a greenhouse gas than CO2. Thus, eliminating 1 pound of methane gas from the atmosphere eliminates the equivalent of 21 pounds of CO2. If all you do is burn that Methane and release the CO2 into the atmosphere, it will eliminated 95% of the greenhouse gas effect!

Additionally, all this Methane is generated from food and grass, which grabbed its carbon from the atmosphere anyway. So it is carbon neutral – except for the small amount of oil that is used as pesticides/herbicides/fertilizer in growing the corn. However, that is already a sunk cost, as Americans consume a lot of milk.

\”Livestock are responsible for 18% of greenhouse-gas emissions worldwide, according to the U.N. — more than all the planes, trains and automobiles on the planet.\”

See source:
http://www.fao.org/ag/magazine/0612sp1.htm
http://en.wikipedia.org/wiki/Livestock\’s_Long_Shadow
http://www.csmonitor.com/2007/0220/p03s01-ussc.html
http://www.independent.co.uk/environment/climate-change/cow-emissions-more-damaging-to-planet-than-cosub2sub-from-cars-427843.html

\”Methane traps over 21 times more heat per molecule than carbon dioxide\”
http://yosemite.epa.gov/oar/globalwarming.nsf/content/Emissions.html

5 cows wouldn’t produce enough waste to cause the smells you speak of if you were keeping the digestor fed.
There is smell involved with any animal waste product. The reason it gest so bad is most of these operations either pile up the waste for drying or composting. That is a LOT of waste to offgas. Placed in a digestor you solve a lot of the problem.

For those who are concerned, the animals are allowed to move freely in the fields.

Since then, we have designed/patented an inexpensive method to generate multi-times the energy per pound of poop, including human, than the out-of-date method described above and little, if any of the gases are released into the atmosphere. Once we receive R&D funding, we will proceed to bring it to market.

Anyway, global warming or not, I’m all for more efficient use of our resources and anything with a cleaner process. Personally I think it’s all cyclical but, as I said, we’re always better off cleaning up our crap and not wasting mother nature.

Toilet paper is a great example. Did you know there was a cotton based on on the market? PurelyCotton.com – there’s an ecom site listed in this article. It’s made from cotton linters – which is a by-product from the harvest.

Top 10 Awesome Websites That Sell Cool Products You Probably Have Never Visited But Need To.

http://www.comember.net/blogs/firepixel/

Check it out.

Somebody wasn’t impressed with the project due to the bad proctices of the cattle industry. True, the cattle industry does need to change in a lot of ways. The way I’m looking at is, the manure is there whether it’s used for this purpose or not. At least it can help to offset the use of coal and other fossil fuels a bit. Cattle are best raised on grasses and hay. Feeding cattle grain actually has a very negative effect on their health and happiness. Sure it packs the weight on quickly as well as increasing the marbling of the meat. It’s just not a good way to raise cattle.

Methane digestors can run with just about any material that biodegrades. They can use, wood chips, grass clippings, leaves, any sort of animal and human waste.

Methane digestors are actually simple to build and there is much info available on the net to do so.
The resulting gas can be used to generate electricity, heat water or homes, cooking, run vehicles, etc. Natual Gas is mostly methane.

The leftover material that comes out the other end of a digestor is a 99.99% clean and natural fertilizer.
The nitrogen content is higher than if straight manure were used. And you don’t have the potential for spreading bacteria to your gardens that you would with using manure for fertilizer.

As long as the digestor is designed so that manure is held within the device for 90 days or longer, human waste comes out safe as well. If you are still concerned about that, you could compost the material just to be sure.

To a lot of people, the fertilizer coming from a digestor is more valuable than the methane produced.

I’m happy with any attempts I see to take what was once a waste product and make it useful.
Many small steps like these will be required to make ourselves more self sufficient.