Farm Ireland

Thursday 22 February 2018

Strategic cutting required to maintain grass quality

Hopefully the first cut silage is now in
Hopefully the first cut silage is now in

Mary Kinston

It's mid-season in the dairy calendar. Hopefully the first cut silage is now in and the bulls have either gone in with the cows to mop up after the AI period or are about to go in. Grass is trying its best to go to seed which is making grass quality somewhat challenging.

To deal with the later issue, now is a time for strategic cutting. Quality needs addressing by using pre-mowing or topping techniques.

The idea is to take surplus bales where possible to capture the boost in pasture growth that occurs at this time.

These high quality bales can then be strategically used to support the milking cow in spring and autumn when pasture supplies run short.

This practice can increase the utilisation of pasture grown when compared to topping or pre-mowing the whole farm or allowing the grazing residual to rise, where this surplus pasture will ultimately be wasted.

However, where the whole farm seems to be running to seed, baling large areas of milking ground can put the farm into a feed deficit so tactical decisions will be required.

Essentially within the present and next two grazing rotations, decisions need to be made to cut in some form or fashion a third of the farm per rotation to get pasture quality back on track.

Expert opinion is divided on the merits of topping versus pre-mowing.

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While both techniques have shown benefits on pasture quality and provide uniform grazing, the increase in milk solid production has often been small, with no significant differences between the two techniques.

Cutting can complement good grazing management but cannot replace it. Pre-mowing or topping should not be used in a period of grass deficit or during dry weather when pasture is moisture-stressed.

The key management technique in all of this is the regular assessment of the pasture cover to assess whether there is a clear surplus to be managed.

When considering the cows and the introduction of bulls, a few key points come to mind.

Firstly, on many farms there was a noticeable lag during this year's calving between the finishing up of AI and the introduction of natural mating.

It also appears that there was an increase in the use of white head bulls verses dairy breeds.

While the average gestation length of all breeds is 283 days, it's widely accepted that Friesian and Jersey X cows have a gestation length of 279 days.

In comparison, a Hereford mated to a Hereford has a gestation length of 289 days, and a AA to AA 272days.

Crossing the Hereford onto a Friesian cow is therefore likely to add gestation time of around five days where the cross falls somewhere between the two paternal breeds.

However, the gestation length within a breed can vary by two to three weeks before or after due date. My second and most important point is to make sure you have adequate bull power in the paddock.

Not having adequate numbers of bulls in paddock at all times is a simple yet common failure on farm.

Whatever your herd size, try to ensure there are at least two healthy bulls running with the herd at all times.

Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in Co Kerry

Indo Farming