27 September 1996


LOW crude protein diets fed to grower and finisher pigs reduced ammonia by up to 60% helping to cut slurry output by 28%.

The MAFF-funded trial has been carried out to evaluate possible ways of cutting ammonia emissions which could be useful if the ECs proposed Integrated Pollution Prevention and Control directive becomes law.

"Also COSSH regulations state a maximum exposure for stock carers of eight hours when ammonia levels are up to 25 parts per million. Between 25ppm and 35ppm maximum exposure time is 10 minutes and over 35ppm stock carers should not enter a building," says Roger Kay, research consultant at ADAS Terrington.

On the trial ammonia levels in hermetically-sealed housing showed that grower pigs fed low protein diets produced 5.7ppm of ammonia compared to 13.9ppm in growers fed on a standard 22.5% diet. Ammonia levels in finisher pig housing fell from 13.1ppm to 6.9ppm. A major bonus is that water intake is lower and slurry output reduced by 28% in pigs fed low protein diets which has implications for storage and transport of waste for those who farm within a Nitrate Vulnerable Zone.

But, ADAS nutritionist Pauline Lee says that, formulating the amino acid levels in these diets is difficult and costs, would be £30 to £40/tonne extra. &#42

&#8226 Cut ammonia emissions by 60%.

&#8226 Cut slurry output by 28%.

&#8226 Improve growth rates.


This airtight pig building allows all ammonia emissions produced to be recorded accurately says ADAS research consultant Roger Kay (inset).