Dairy Management: how much fertiliser to put on silage ground?

Grass: Most farmers are getting worried about grass, but let’s face it, it’s a good problem to have because it means a lot of grass has already been eaten by cows. On average, the situation isn’t too bad.

The PastureBase figures show that average farm cover is 658kg DM/ha and cows are being fed 9.5kg of grass, 5kg of meal and 3.5kg of silage. Of course that’s only among farmers who measure grass, so there is likely big variation between farms. Teagasc are predicting growth rates in the high 20s for this week, which is a bit behind normal.

The forecast is for cooler temperatures next week, which will probably restrict growth rates.

For the next while, it’s all about monitoring the covers on the highest paddocks in the second round, and delaying starting into them until there is enough on them. For most farmers, they would like to see a cover of 1,200kg on those paddocks before going into them. If there is 900kg on them now and if you predict they are going to grow 40kg per day (they will grow higher than the average), then you will need eight days before starting the second rotation. If there is, say, 9ha left in the first round, then you can only graze 1.13ha per day.

How much grass in those paddocks being grazed will determine how much meal and or silage you will need to feed. Monitor the situation every few days and react to changes in the weather.

IP bulls: The four biggest AI companies now have intellectual property (IP) rights assigned to their young bulls. These are the current crop of what they call G1 bulls – so last year’s calves. In order to purchase these young bulls whether as part of the Gene Ireland programme ran by the ICBF, or whether directly through the AI companies themselves, farmers are being made to sign these IP contracts. By doing so, they are committing to not selling any progeny from these bulls and their progeny’s progeny to a competing AI company without their approval. The rules govern both males and females.

Stock bull sales can continue as normal. While it only affects this year’s G1 bulls now, in a few years’ time nearly all of the Irish-bred bulls for sale will be IP protected, presuming each new generation of G1 bulls is IP protected. Most farmers have never sold a bull into AI and never will, but it is a big issue for farmers who have a track record of breeding AI bulls. Of course, it will negatively affect all farmers if the move leads to a slow-down in the rate of genetic gain.

Silage fertiliser: Conditions are close to perfect for spreading fertiliser on silage ground. How much to spread is dependent on a number of factors, including what was spread so far this year.

For fields that have received no fertiliser, the rule of thumb for a decent first cut is 80-90 units/ac of nitrogen (N), 20 units/ac of phosphorus (P) and around 90 units/ac of potash (K). All of the P and K and about 20 units/ac of nitrogen can be supplied in 2,500-3,000 gallons/ac of slurry. If nitrogen was spread earlier in the spring, presume about one third of this is still available now and so can be deducted from the total amount of N required.