Autumn Grazing Management
Grass growth in Ireland is highly seasonal with little growth from November to February. Michael Egan and Deirdre Hennessy take us through some of the key points with regard to autumn grazing management.
Irish grassland farmers must make careful decisions on grass allocation in autumn and spring to optimise the quantity of grazed grass in the herd’s diet. Increasing stocking rates together with increasingly calving and lambing has increased spring feed demand on farm. Extra grass must be grown and utilised in this period to avoid unnecessary supplementary feed use. These changes in feed demand necessitate careful planning of autumn and spring grazing management practice to guide farmers in achieving sufficient grass to feed the herd.
Sean Doorley, Teagasc Advisor caught up with Brian McCarthy, Research Officer, Teagasc at #Ploughing2022 to get an insight into extending grazing into the autumn. Farmers need to go out and measure how much grass they have and then come up with a plan in terms of a budget as to how they are going to extend the rotation out towards the start or the middle of November. This might entail putting in a lot of supplement either in the form of concentrate or baled silage to try and extend the rotation. While autumn grass is important spring grass is even more important.
Autumn closing date is one of the most important management factors influencing the supply of grass in early spring. To ensure adequate quantities of grass are available in spring, farmers must ensure that an average farm cover (AFC) of ≤ 700 kg DM/ha is achieved at closing (December 1st). To achieve this target, farmers should use the autumn planner, which allocates an area of ground to be closed from October to November. It is recommended that the first paddocks should be closed between October 5th and 10th, and 60% of the paddocks should be grazed by November 7th, with 100% grazed by mid-November. Heavier farms or ones with low autumn growth rates should close approximately one week earlier.
Farmers need to implement a grazing plan on farm from early August in order to achieve these targets in October and November, rotation length should be increased from 21 days in July to 45 days by early October, by adding 2.5 days per week from the beginning of August. This allows for an increase in grass supply on farm to achieve an extended grazing period into November without compromising average farm cover at closing.
The aim in spring is to gradually increase the proportion of grazed grass in the diet of the grazing animal, while at the same time budgeting so that there is enough grass until the start of the second grazing rotation. A low AFC at turnout in spring will result in increased levels of supplement being fed, increasing costs on farm. Farmers should target an opening AFC of 900 kg DM/ha in early February to ensure that supplementation is kept to a minimum.
The spring rotation planner (SRP) should be used to manage grazing in the first rotation. The first rotation should start in early February and continue until early April. Thirty percent of the farm should be grazed by March 1st and 66% by March 17th. Average farm cover should not be allowed to drop below 550 kg DM/ha in March or early April. It is important to monitor AFC in conjunction with the autumn planner and SRP to ensure that AFC does not drop below target levels.