Much has been discussed about negative energy balance around calving in dairy cows, but negative protein balance is just as important when it comes to optimising the productive potential of a milking herd.

That’s according to Dr Jim Drackley, Professor of Animal Science at The University of Illinois, who said protein consumption generally falls short of requirements around calving. This means the cow is forced to mobilise body reserves in the first week postpartum which adds to immune suppression at a time when protein and amino acids are essential for immunity.

Speaking at a Mole Valley Farmers Lifetime Dairy Conference in Somerset, he said some of the main issues occur when a cow is forced to mobilise body protein prior to calving, when dietary protein supply is inadequate.

“We don’t want cows to break down muscle protein pre-calving as then there’s less available after calving,” explained Dr Drackley.

He also said that trial work had shown that cows that mobilised more protein pre-calving are more likely to develop ketosis.

To overcome these issues, he said it was vital to provide cows with sufficient metabolisable protein around calving – specifically for the amino acids it provided. Providing methionine and lysine is particularly important as these are likely to be underfed in most diets (see box).

Dr Drackley’s own work has shown that feeding rumen protected methionine in the three weeks before calving and 28 days after calving resulted in improved dry matter intakes post-calving, improved milk yields and better milk proteins (see table). Cows also had better immunity, as shown by better functioning of immune cells.

A Mole Valley Farmers trial with Reading University has also shown similar benefits. The study looked at the effects of feeding very early lactation cows a combination of protected methionine, lysine and histidine. The results showed a benefit of 1.8kg more milk per cow, a 0.16 unit increase in milk protein and a 0.42 unit increase in milk fat.

TABLE: Effects of feeding different forms of protected methionine on performance

Control MetaSmart (protected methionine) Smartamine (protected methionine)

Milk yield (kg/day) 35.7 38.1 40.0

Milk fat (%) 4.27 4.68 4.09

Milk protein (%) 3.04 3.26 3.19

Milk fat yield (kg/day) 1.64 1.84 1.81

Milk protein yield (kg/day) 1.11 1.23 1.24

Energy corrected milk (kg/day) 41.0 44.8 45.0

Table Source: Osorio et al, 2013. Cows were fed a maize silage based diet with alfalfa, straw and concentrates. Methionine was fed at 5g/cow/day pre-calving and 9-10g/day after calving.

BOX: Pre-calving protein recommendations

• >1200g/day of Metabolisable protein (MP)

• Include some high bypass source of MP

• Consider strategic use of amino acids

• 30g/day of metabolisable methionine

• 90g/day of metabolisable lysine