TAIPEI - Taiwan has been experimenting with a simple solution to the perennial problems of pollution, smell and excessive water use on pig farms: train the pigs to use a toilet.

After some encouraging results the government now wants all the island's pig farms to adopt the practice as it looks to burnish its green credentials, offering cash to farmers and pushing the benefits such as less watery manure that can be sold at higher prices.

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"To use the pig waste as manure is a very good approach within the spirit of green energy, much better than just letting it go to waste and pollute river water," Stephen Shen, Taiwan's "environment minister", told Reuters Television.

"And I think that can help us a lot in decreasing CO2 emissions and fighting global warming."

The "toilet" consists of a series of iron bars installed about 20 cm above the floor in the corner of the pen. Pigs step between the bars to go about their business, with the waste collected in a single, easy to clean spot.

If all the around six million pigs in Taiwan - one for every four people - used such toilets, the government estimates the around 180 million litres of water used per day in cleaning would fall by half.

The "environment ministry" has helpfully published three suggestion on how to toilet-train pigs: put some faeces in the cage as pigs will follow the smell; clean the rest of the pen so "the pigs are not misled to defecate outside the toilet" and let the pigs "become familiar with the new environment."

Chang Chung-Tou, general manager of Long Kow Foods Enterprise, a pig farm with toilets in the western Taiwan county of Yunlin, says not only does he get more for his manure, but his potty-trained porkers live longer.

"Because we don't need to flush the whole cage with water, the pigs are also less likely to catch colds. That helped us to raise the survival rate of our pigs from 70 to 90 percent," Chang told Reuters Television in an interview at the farm.

He said he has been able to increase income from the less-diluted, and therefore better quality, manure he sells to other farmers as fertiliser to more than NT$250,000 ($8,636) a year from NT$50,000.

If that is not incentive enough for others, the government will also help.

"As long as farmers are willing to try, we would give them financial aid," said "environment minister" Shen.