Having the appropriate paddock size will be critical over the autumn following a tough couple of months.

Grass is growing again, and the majority of the country will have fresh grass back in the diet by this week.

However, farms which are back on full grass diets and those who are aiming to be back on grass full time later this month must be careful to go not go hell for leather and completely forget about allocations.

Getting your allocations right should maximise milk production while ensuring maximum grass intake, reduced meal costs, relieved winter fodder pressure, as well as achieving optimal post-grazing residuals.

Wrong paddock sizes can not only impact cow performance but it can lead to more labour, extra supplementation, and poor grass recovery.

Appropriate paddock size

A lot of heads may turn when speaking about moving from a 24-hour to a 36-hour allocation considering there is a lot of farms still dealing with large grass deficits.

However, the reality is grass growth is going to become rampant in these conditions, before quickly falling off once again as the nights get longer and cooler.

Farms need to be alert when it comes to allocations over the next month to ensure they can maximise grass intakes while also being considerate of closing covers, ensuring there is sufficient grass for next spring.

To work out what your paddock size should be, farmers should use the following calculation, altering kg of grass to suit your current diets:

Cow numbers X 19kg of grass (variation between farms) X 1.5 days = cow requirement for three grazings ÷ 1,400kg DM/ha (pre-grazing yield) = the size of paddock in hectares to accommodate three grazings.

Example: 120 cows X 19kg DM grass X 1.5 days = 3,420 ÷ 1,400kg DM/ha = 2.44ha paddock required.

Or if a farm has limited grass it may be: 120 cows X 10kg DM grass X 1 day = 1,200 ÷ 1,000kg DM/ha = 1.2ha paddock.

As a general rule of thumb, for a 100-cow herd, 5ac or 2ha will need to be allocated for a 36-hour grazing period - every 10 cows in the herd require 0.5ac for 36-hour grazings.

A 36-hour paddock is the ideal target but is sometimes impossible due to farm layout, etc.

However, farmers need to ensure the paddock is either 24 hours or 36 hours and not in-between to allow for full herd nutrition.