Managing the swing from shortage to excess grass

Date published: 19 April 2018

Ground conditions are improving but remain marginal in many parts of the country. However, grass growth is expected to rapidly accelerate in the very near future and it is important to manage this burst carefully. Once swards get out of control quality can be adversely affected for the rest of the grazing season.

One potential risk is having a ‘flat wedge.’ In this scenario fields have all been tightly grazed and are all at the same low cover. After a period of rapid growth, many of these fields will have the same high cover. It will be important to quickly identify when an excess is developing and take fields out for silage. While it may be tempting to let swards grow on and harvest them along with the main first cut, this simply creates another ‘flat wedge’ later in the summer. Taking some silage as round bales allows a staged approach to be taken, is more flexible if weather conditions deteriorate again and allows fields to be returned to grazing over a period of time.

On the other hand, there may a situation where excess grass is developing already as grass is growing but field conditions have not permitted grazing. It is important to have suitable stock ready to turn out as soon as possible. Lighter youngstock are ideal for this as they are less likely to cause poaching damage. Ideally heavier covers should be block grazed so that smaller areas can be grazed out cleanly and stock moved on before ground is damaged.

Dairy cows are ideal for on-off grazing. Cows can eat almost all of their full day’s allocation of grass in two three-hour blocks per day. This also limits time spent in the field and reduces opportunities for poaching.

It is highly likely that young animals will be exposed to bare soil containing pathogens. It is therefore important that all susceptible animals are fully vaccinated against clostridial diseases. There is some variation between products in the minimum age of first administration. In addition, this may also vary with the vaccination status of the dam so it is important to carefully follow all instructions on the datasheet.

Further veterinary issues that can occur after turnout include grass tetany, cold cow syndrome and delayed white muscle disease following vigorous exercise. Stockmanship at turnout is important to identify any clinical cases early so that veterinary advice or intervention can be sought promptly. Fluke may also be an issue for concern given the prolonged wet weather. Seek veterinary advice on appropriate treatments for the time of year.

Summary

• Budget carefully and walk swards regularly as conditions can and will change rapidly at this time of the year;
• Aim to establish and maintain a grazing wedge;
• Start grazing heavier covers with youngstock as soon as possible;
• Practise on-off grazing if facilities and stock groups permit;
• Ensure all vaccination programmes are up to date;
• Monitor stock closely and seek veterinary advice if necessary.