Dutch dairy farmers will have to reduce the size of their herds in order to meet EU phosphate limits, farm minister Martijn van Dam said in a briefing to MPs.

In total, Dutch farms may have to have up 100,000 fewer cows in order to meet EU targets on phosphate production – a major component of animal manure, news agency ANP reported. The exact figure – a cut of up to 8% – will be agreed next year.

The size of the national herd has grown since EU milk quotas were abolished last year and now totals some 1.6 million animals. These produce 12.5 billion kilos of milk a year.

The Netherlands has some 18,000 dairy farms, most of which are family firms. Of them, 150 farms have more than 300 cows.

The government has agreed that farmers will be issued with phosphate rights, based on the number of cows they had in July 2015.

Farmers will be able to trade those rights, so that farms which manage to cut phosphate production will be able to sell their rights to more polluting farms.