Getting higher yields from silage and matching stocking rate with grass grown are the keys to ensuring a plentiful supply of silage, according to Richard O’Brien.

“Dairy and livestock farmers need to think more like tillage farmers do when it comes to growing silage. If a tillage farmer is growing a crop of barley, they will give it all the nutrients and care it needs for a high yield. If more farmers treated silage like a crop then yields might be higher,” O'Brien said.

Slurry

A high-yielding crop of first cut silage needs three bags/acre of 0:7:30 and 100 units/acre of nitrogen, either in the form of urea or CAN (ideally with sulphur). Second cut silage needs 2.5 bags/acre of 0:7:30 and 80 units/acre of nitrogen. O'Brien added that the value of slurry is often overrated by farmers, particularly when it is coming from lagoons or open yards.

“There’s a big difference in the nutrient value of thick versus very dilute slurry. About 3,500 gallons/acre of thick slurry would want to be spread before first cut to replace the 0:7:30 and 2,500 gallons/acre of slurry should be spread for second cut. In general terms, 1,000 gallons/acre of typical slurry is about equivalent to half a bag/acre of 0:7:30.

“Building up soil fertility should be looked at after the second cut, as too much potash spread before harvesting will end up in the silage and can cause metabolic problems for the cow. The best time to build up soil fertility is the autumn. But on dedicated silage fields, if the focus is on feeding the crop, it doesn’t really matter a whole lot if the field is at index one or two.”

Stocking

O'Brien said feeding the crop will help to manage supply, but that stocking rate determines demand. To make sure you never run out of silage the two need to be in balance.

“Even where 800kg of meal is being fed per cow, the farm needs to be growing 15t/ha if the farm is stocked at 2.7 cows/ha. Even at 2.5 cows/ha the farm needs to be growing 14t/ha," Richie concluded.

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In pictures: Dairy Day 2018