Milk urea as indicator for Low Nitrogen Feed in Dairy husbandry

1. Milk urea as indicator for Low Nitrogen Feedin Dairy husbandry

2. The new focus is on housing

4. Emission factors for Dairy cow housings • Ammonia volatilization • During winter (200 days): 7.1% • During summer (165 days): 17.4% • Effectively: 11.7% • According RAINS • Option SA

5. Low Nitrogen Feeding dairy cattle Relates to • Nitrate Directive • N excretion • Max 170/250 kg N per hectare animal manures • National Emission Ceiling Directive • Ammonia emission • Max 128 kiloton NH3 in the Netherlands

6. Practical policy implication N manure per dairy cow ‘by default’ N = 138.5 + 0,0055 ( MY– 7482 ) + 2,4 ( MU – 26 ) Correction for • milk yield (MY in kg) and • ureum content of milk (MU in mg per 100 g milk)

7. Emission factors LNF Current Milk Ureum average is 26 mg per 100 g milk Milk ureum target is 20 mg per 100 g milk So, 2,4 * (26-20)=14,4 kg N Relatively 14,4/138,5 = ~ 10% EB.AIR/WG.5/1999/8 Rev.1 reads Removal effiency [%]: 15

8. However, farmers find it easier – more economic - to shed their cows ‘year-’round using ‘milk ureum’ to monitor milk quality and environmental pollution ‘year-’round will increase ammonia emissions substantially Removal effiency [%]: -23

9. Low Nitrogen Feeding dairy cattle • Potential reduction: 3,7 kiloton NH3 • In the sandy soil region: • 1,7 kiloton NH3 at € 5 million • Cost effectiveness • LNF ~ € 3 per kg NH3 • housing ~ € 5 per kg NH3 • Alternative: increase grazing • Alternative: decrease use of nitrogen fertlizer • Alternative: improve housing • Alternative: …

10. The proceedings Bron: MCS-Nederland

11. The proceedings Bron: MCS-Nederland

12. Bron: MCS

13. Bron: MCS

17. conclusion • National target for Low Nitrogen Feed seems out of reach • Sandy soil easier than peat/clay region • Low Nitrogen Feed should not lead to ‘year-’round shedding of cows • Ammonia up by 23% in stead of down 15%

19. calculation