Changes in milk urea after turnout

Friday, 19 March 2021

Don’t worry if milk urea levels increase after turnout: it’s a common finding, due to the high levels of digestible protein in grass. “Milk urea levels are likely to go up – sometimes more than 350 mg/litre – and stay high until grass quality starts to change and crude protein falls to more normal levels, at around 20%,” says AHDB dairy scientist Dr Martina Dorigo.

“How worrying is it? There isn’t much consensus on this, but even if cows are milking well and are healthy, it is worth checking with your vet or nutritionist whether cows need more readily available energy to balance the high degradable protein levels in grass.”

High milk urea levels indicate there is inefficient use of protein in the diet, which can lead to reduced fertility (because it impacts the uterine environment), as well as cause higher ammonia emissions.