What grass covers should I be turning my cattle into?

After paddocks are set-up, the next job is to utilise all of the grass available to the animal. By doing so, animals will have improved live weight gain and the quality of the pasture will be increased.

Ground conditions still remain problematic; however, farmers are going to be building up silage supplies after the hard winter. With this in mind, it’s important to maximise the amount of grass on the grazing platform.

Speaking at the recent Irish Grassland Association (IGA) grazing infrastructure event, UCD’s Bridget Lynch highlighted the importance of monitoring grass supply and demand during the peak grass growing season.

She said: “Farmers need to aim for two targets during the summer grazing period – grass utilisation and sward quality.

“There are overall farm approaches to keep on top of grass utilisation, pasture supply and quality. There are also measures that can be put in place on a paddock scale.

“On a farm scale, monitoring grass supply and demand is very important. This can be done by walking every paddock on the farm weekly and assessing how much grass there is on the farm.”

Bridget also outlined the advantages of measuring grass on suckler and beef farms, adding: “If you’re measuring grass every week and you’re working with PastureBase, it will calculate the days ahead for grazing.

“However, farmers can simply walk the farm and count how many days are ahead on the grazing platform. But, there are benefits of measuring grass; it can identify the poorer-performing paddocks that need attention.”

The UCD lecturer also explained that it’s important not to lock out the silage paddocks for long periods of time.

“Taking bales from a paddock after a week or 10 days post-closing will ensure that farmers don’t run into a deficit. Taking it out and getting the paddock back into the rotation is important,” she added.

Pre-grazing yield and residuals

Bridget touched on the required pre-grazing cover that farmers should be turning their cattle out on, adding: “The importance of the pre-grazing yield ahead of the animals is key with regards to grass quality and utilisation.

“If the pre-grazing yield is between 1,300kg/ha and 1,600kg/ha (dry matter), the sward would be approximately 8-10cm in height. The importance of keeping the pre-grazing yield in this range is to maximise sward quality,” she added.

“By keeping the pre-grazing yield to 1,300-1,600kg/ha, the amount of leaf material in the sward is maximised. If we are hitting our target of 8-10cm, we are also minimising the amount of stem that will be present in the paddock.”

It is not only the pre-grazing covers that are important when it comes to grass quality; farmers must also pay close attention to the residual (the amount of grass left after grazing). Farmers should aim to graze out paddocks to 4.0-4.5cm.

Bridget added: “The residuals are equally as important. By not grazing paddocks out fully, the stem material will creep up in the sward. It is easier to utilise that grass if you are going in at the right covers.”

Organic matter digestibility % (OMD):
  • Leaf: 75-80%;
  • Pseudostem (leaf wrapped up in tillers): 65-80%;
  • Mature stem: 50-60%;
  • Dead: 40-50%.

Commenting on the situation that some – if not all – farmers found themselves in this spring, she said: “If farmers have paddocks that were grazed poorly in the first rotation – if these were grazed when it was wet and there’s a higher residual than desired – these paddocks could be earmarked for bales.

“It is important to get it cut early and get the paddocks back in the rotation quickly,” she concluded.