The welcomed appearance of the warmer weather this month has been reflected in the increase in grass growth. In Grass Check GB’s recent bulletin (May 20), the average growth in Scotland was cited as 79kg DM/ha/day.

Nutrition of suckler cows’ post-calving is as important as pre-calving. To achieve a 365-day calving interval, she has around 80 days to recover from calving to her next conception. Energy is the top priority for breeding as it influences the time she will start cycling and egg quality.

As well as fertility, she is also lactating and therefore, to support milk yield, energy requirements must be met to avoid any sudden change to the cow’s condition. During the breeding period it is important to avoid condition loss to encourage oestrus, and particularly in the six weeks after the bull is removed to prevent early embryonic loss.

Following peak lactation (around 75 days post-calving), cows can gain condition more easily. For a 700kg suckler, her energy requirements for both lactation and gaining condition are around 155MJ of energy. In a well-maintained grass sward the energy content will be around 11-12MJ kg/DM.

In a rotational grazing system, the aim is to maintain good pasture quality at the three-leaf stage, this will ensure high energy grass is available for the cow and this will also benefit the grazing calves alongside their mother. The target grass height entry for spring calving cows and calves is 8cm and the target height at exit is 5cm. On a set-stocking system, the target entry from June onwards is 7-9cm.

Top tips:

  • A 700kg lactating suckler cow needs approximately 155MJ of energy (requirements include gaining condition) which is around 70kg of good quality grass. This is an intake of around 14kg of dry matter.
  • Use a swardstick to measure a representative area across the field. The target entry height for rotationally grazing is 8cm. In a set-stocked system target from June onwards is 7-9cm (around 2500kg DM/ha).
  • Think about how many cattle there are per hectare (daily demand) and what the growth of the grass is likely to be each day (daily supply) to ensure cattle are getting what they need. This is particularly important later in the season as grass growth inevitably declines.
  • At current grass growth levels (79kg DM/ha), 1ha can meet the needs of five cows.
  • Where grass growth exceeds demand (typically in May and June) it is important to adjust the grazing area to prevent a reduction in grass quality.

SAC Consulting’s Forage First Suckler Systems booklet is an excellent source of information on the pros and cons of different summer grazing strategies.

It also includes advice on how best to sustain grazing quality throughout the season and troubleshooting tips on managing grass supply and demand.

This is particularly useful in June, when grass growth will often exceed demand.

Forage First Suckler Systems is available on www.sac.co.uk/livestock, in the technical guides