We are now edging closer to St. Patrick's Day, and with a number of cows beginning to reach their peak milk production, milk protein is usually at its lowest at this stage of the lactation.

At this stage of lactation, a huge focus for farmers is to push their milk protein content through the diet of the cow, getting them out grazing when they can.

The weather for the past week has been consistent with dry, sunny spells throughout the country, which is providing ideal conditions for grazing and pushing on milk solids in the herd at a time when they tend to drop.

Focusing on maximising the cow's dry matter intake at this time of the year through grass can be the difference in milk solids sold at the end of the year.

Peak production usually occurs around six to eight weeks after calving and the decline in protein concentration usually occurs from late-February into March on many farms, depending on the calving pattern.

Genetics has a very strong influence on milk protein concentrations with approximately 70% of the variation between individual cows and herds being attributed to genetics or the predicted transmitting ability (PTA) from milk protein percentage.

The other 30% of variability accounts for pasture digestibility with concentrate feeding having a small effect on milk protein content and will struggle to compensate for poor forage quality or low genetic merit for protein content, according to Teagasc.

Teagasc has outlined in a curve chart the typical milk protein concentration for three different annual milk protein concentrations ranging from 3.4% to 3.7%.

Usually, milk protein percentage drops 0.3-0.4% below the annual average at this stage of the lactation.

The expected weekly milk protein profiles for three levels of annual milk protein, ranging from 3.4-3.7% per Teagasc is as follows:

A severe drop in milk protein concentration below 3.2% in herds with high genetic merit for protein percentage can indicate that fermentable energy in the diet is limiting.

This often happens when cows are out grazing and the weather turns causing them to be rehoused and eating poorer quality forage.

The energy density of the diet and the digestibility of the forage is lower than grazed grass as grazed grass at this time of the year has an energy value of 1.0-1.1 UFL/kg of dry matter (DM) whereas 70% DMD silage has a value of 0.8UFL/kg DM.

The dietary drop in production can lead to protein dropping near 3.0% and for low protein genetic merit herds, it can go below this threshold.

In recent years, when February and March have been wet and difficult for grazing, milk protein concentrations struggled to get above 3.2%.

This shows the importance of getting cows out to grass and even when the bad weather comes, within reason, try and get cows out for a few hours, as on/off grazing in tough conditions can maintain milk protein concentrations at decent levels.

If the genetics of the herd are poor in terms of milk solids production, then changing the diet and implementing on/off grazing may be effective in the short-term but in the long run when genetics is the limiting factor, it can be hard to make a real difference in the bulk tank.

If it is the limiting factor, farmers should consider changing their breeding targets and analyse their current PTA for fat and protein percentage.

The base cow with a PTA of 0.0% for milk protein will deliver an annual milk protein percentage of 3.36% and so every 0.05% PTA above this will result in about a 0.2% increase, provided the herd are receiving their required nutrition.