Young, growing cattle benefit most from an earlier start to the grazing season, according to Pat McCambridge in the latest management notes from the Department of Agriculture in Northern Ireland.
He said young stock can be spread out over larger areas when grass covers are lighter (1,900-2,000kg dry matter per hectare,7 to 8 cm in height) and he advises farmers to start at a low stocking rate of 1,000kg per hectare.
McCambridge commented: “Stock will be turned out to grass over the next few weeks and I am sure farmers are hoping for a decent spell of weather to start the grazing season.”
He said farmers should aim to turn cattle out when grass covers are ‘adequate’. As a guide this is when there is about two weeks supply of grass in front of the stock. Avoid keeping cattle housed until there is an oversupply of grass as this can quickly lead to more difficult grassland management.
McCambridge noted suckler cows and calves should be on grass when ground conditions allow and ideally when average grass covers on the grazing area are at 2200 kg dry matter per hectare (9 cm).
Nitrogen (N)
McCambridge remarked that most farmers will by now have sown N fertiliser on grazing areas and the benefits of slurry applied in mid-March should now be apparent.
He said urea fertiliser is the most cost effective form of N and can still be used where there is some grass cover and suitable moist conditions. If grass cover is low and conditions are drier, it is preferable to use other forms of N fertiliser.
Grass tetany
After turnout a major concern is grass tetany (staggers) which is due to magnesium deficiency. Grass tetany mainly affects cows, suckling calves and lactating ewes. It is often associated with high potash applications from fertiliser and slurry, particularly on soils that are already high in potash. The risk is greatest for animals which are under stress as a result of unpredictable weather and change of diet at this time of year.
Prevention involves ensuring animals have a daily supply of magnesium. This can be provided by:
- Adding magnesium to drinking water while making sure no other sources of water are available.
- Dusting magnesium (calcined magnesite) on the grazing pasture.
- Treating stock with magnesium boluses.
- Offering a 50:50 mix of calcined magnesite and molasses. Approximately 2.5kg of the mix will provide for 20 cows on a daily basis. Keep the mix stirred and topped up regularly.
- Magnesium licks or blocks and/or feeding a high magnesium meal.
