Dairylink: getting on top of grass quality in Antrim

There has been a significant improvement in the quality of grass on James King’s farm near Ballymena, Co Antrim, over the past two weeks.

James is a phase two participant in Dairylink Ireland and, like the rest of his phase two counterparts, is relatively new to grass measuring and budgeting.

There have been some teething problems, but initial issues are gradually being addressed.

Programme adviser Aidan Cushnahan walked and measured the grazing block with James two weeks ago and the consensus was that there were too many paddocks with high covers, meaning grass quality was becoming an issue.

This was confirmed when the figures from the walk were keyed into James’s grass management programme AgriNet. The programme produces a grass wedge which compares grass supply to demand for individual paddocks.

The grass wedge showed that there was a surplus of grass on the King farm and five paddocks were subsequently skipped and taken out for baled silage.

However, this shortened the grazing rotation length and left James short of grass for grazing.

He has been buffer-feeding cows with around 2kg DM/cow/day of third-cut bales from last year to bridge the gap.

Too much?

Did James bale too much of his surplus if it ultimately left him with a grass deficit? The short answer is no, because the grass wedge showed that most paddocks were either already too heavy for grazing or were going to be too strong by the time they came around in the grazing rotation.

James and Aidan walked the grazing block on Monday and the improvement in the quality of grass over the past 10 days was plain to see.

This week’s grass walk showed that average farm cover is 900kg DM/ha utilisable cover (ie total cover minus 1,500kg DM/ha) and growth over the past 10 days stood at 55kg DM/ha/day.

At the current stocking rate of 4.23LU/ha, cover per cow is 207kg DM/LU, which is above the mid-season target of 160kg to 180kg DM/LU.

This indicates a grass surplus, but it is important to note that cover per livestock unit is a single figure which represents an average over the whole grazing block.

The grass wedge, which matches supply and demand in individual paddocks, shows that some of the next paddocks in the grazing round are below the target line and overall grass growth is behind current demand of 63kgDM/ha/day.

Plan

The grass budget will change again later this week as James is due to dry off 20 out of 145 cows, which will reduce demand. The plan in the meantime is to gradually phase out buffer feeding and top any high post-grazing covers with the mower.

The grazing block will be walked and measured at the weekend to see if a grass surplus is still projected from the updated grass wedge.

James is also considering bringing in 10 acres of silage ground into the grazing round and holding some of the milking platform for third cut to improve sward quality in a few paddocks ahead of autumn grazing.

He had some issues with his platemeter overestimating grass covers and is considering trying out the cut and weigh method of grass measuring.

This can be a common issue in covers where there is a higher stem content, although it should hopefully be less of an issue now that James has improved sward quality.

James mainly selects cows for drying off based on calving date and an eight-week dry period. All cows get dry cow tubed and teat sealed. A pour-on for roundworms and lungworms, a triclabendazole drench for fluke and a high-iodine mineral bolus is also administered at drying off on the King farm.

Across the milking herd, cows are currently yielding 21 litres/cow/day from 3kg of concentrates on average. Cows that are due to be dried off shortly are receiving no meal, later autumn-calving cows are on 1kg of parlour nuts and a spring-calving group of 54 cows are getting 6kg.

Soil samples were taken from individual paddocks on the grazing block over the winter and the results showed that soil fertility is generally in a good place on the King farm. Overall, only 3% of the grazing block is deficient in phosphorus (P) and no paddocks were low in potassium (K).

With no benefit of applying additional P and K, James has only been using urea, CAN and nitrogen with added sulphur fertiliser products on the grazing block this year. There has been no compound fertiliser spread on the milking platform and all slurry has been targeted to silage ground.

The only soil fertility issue on the King farm is pH, with 59% of the grazing block analysing slightly sub-optimal between pH 5.9 to 6.1 and only 5% below pH 5.8.

James is planning to get lime spread on the lowest pH paddocks in the late summer and early autumn.

Read more

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