Full explanation
The NEL system was developed by NRC (US, 2001) and adopted as the EU standard (INRA France, 2007). Calculation: NEL = ME (metabolizable energy) − heat increment losses (~35% for lactation). Typical feed values: maize silage 1.6 MJ/kg fresh (6.4 MJ/kg DM), alfalfa haylage 1.5 MJ/kg (5.7 MJ/kg DM), maize grain 8.3 MJ/kg DM (densest), soy meal 7.8 MJ/kg DM. For Ukrainian Holstein at peak lactation at 30 kg milk: 30 × 3.1 = 93 MJ NEL for lactation + 45 MJ maintenance + 10 MJ growth = 148 MJ/day. At 24 kg DMI, required = 148/24 = 6.2 MJ/kg DM — the peak minimum. Higher (6.8–7.1) provides energy reserves for maximum productivity. Below 6.2 = weight loss, milk drop, ketosis.