The last of the autumn-calving cows at Johnstown Castle are being dried off this week, giving farm manager Aidan Lawless and the farm staff time to prepare for the winter milk event on 4 September. Aidan says the autumn-calving herd has had one of its best years ever, with production sitting at almost 600kg MS/cow, from 1.5t of meal/cow and 10% not in calf after 12 weeks of breeding.

“Last autumn was very good, with excellent grass growth and grazing conditions. Spring was also good.

"We had cows out on 25 January. We said we’d grab the opportunity, thinking that we might have to house them again later, but we never did.

"We got a bit dry this summer, but still managed to grow our demand,” Aidan says.

When the Irish Farmers Journal visited the farm last week, Aidan had the dry cows grazing in front of the last of the milking cows. The milking cows were still milking 17l/cow and Aidan said he’d prefer to have them down to around 10l/cow before drying them off.

Restricting these cows for the week prior to dry off by grazing the leftover grass tight, while still milking twice/day has been working well as a dry off strategy.

Aidan Lawless.

“The biggest challenge at the moment is managing cover.

"Our demand on the autumn block is very low, so we’re constantly growing surplus grass.

"We effectively take three cuts of silage, the main first and second cuts and then a third cut from surplus bales. I’d say about 75% of the farm will be cut for silage at least once and we try to rotate what we cut,” he says.

The dry cows are currently grazing covers of about 1,500kg/ha. Aidan says a lot of the farm has a cover of about 1,000kg/ha.

He will keep taking out surplus paddocks so that the farm has an average farm cover of about 800kg/ha by the time the cows start calving in late September. He doesn’t want a big cover of grass for freshly calved cows, the most he wants to be grazing is covers of 1,800kg/ha.

“You have to remember that grass in autumn doesn’t have the same value as grass in spring. The energy levels are about 15% to 20% lower compared with grass in spring.”

The due date for calving is 25 September, but he reckons the first of the cows will start calving a week before that. The vast majority of the cows will calve outside in a 4ac field that researcher Joe Patton calls ‘standing hay’.

The plan is to draft cows from the dry mob to this mob twice a week

This field is just a little bit too strong for grazing, so in a month’s time it’ll be ideal for calving cows.

The plan is to draft cows from the dry mob to this mob twice a week. They will get ad-lib access to low-potash hay in a round feeder and get 4kg DM of grazed grass per day.

Aidan will just move the fence about 2m/day, as you would if feeding a fodder crop. Cows will be fed 1kg of meal per day – just to carry the minerals and vitamins. In the main bunch of dry cows they are getting minerals through buckets of mineral lick.

Dry cows at Johnstown Castle with the milking cows in the background.

“The outdoor calving works well. We put up a back fence after a while to keep them from walking back over grazed areas. Calves are taken away morning and evening, and we check them at night if we think something is going to calve,” Aidan says.

After calving the cows will stay on grass full-time until the end of October.

The herd will start off on 2kg of meal and will be built up to 4kg-5kg of meal over time

Depending on average farm cover, growth rate and ground conditions, the herd is usually in by night and out by day for a week or so in November, prior to being housed fully.

Aidan is slow to put in silage during October as he says post-grazing residuals get too high when cows are fed silage while grazing.

The herd will start off on 2kg of meal and will be built up to 4kg-5kg of meal over time.

Cows are fed a flat rate in the parlour and while the facility is there to feed to yield, the research is based on flat-rate feeding.

Aidan has been farm manager at Johnstown Castle for 10 years now, and the biggest change he has seen over that time is to do with fertility.

“Autumn calving means winter breeding, and it can be hard to see cows bulling in a shed.

"Originally, we had an outdoor woodchip loafing area to help identify cows bulling and give them a safe place to mess around.

“Now we don’t do any of that and fertility has never been better.

The field in Johnstown Castle where the cows will calve.

"We’re consistently getting around 10% empty now and the only thing I can put it down to is better genetics in the herd.

“We use the same criteria when picking bulls for the autumn herd as we do for the spring herd, except we try and avoid bulls with a negative PTA for milk volume.

"The EBI of the herd is €153, with €51 for milk and €63 for fertility,” Aidan says.

Cows will be fed a TMR with grass and maize silage, along with 2kg of blend during the housed period, before being turned out to grass in spring.

Results

For the last three years the dairy research team at Teagasc Johnstown Castle has been comparing 100% spring or autumn-calving systems to split calving, where 50% of the cows calve in spring and 50% in autumn.

The stocking rate on all three systems was the same, at 2.9 cows/ha.

Over the three years of the study, the autumn-calving cows averaged 561kg MS/cow, while the spring-calving cows averaged 488kg MS/cow, with 1,380kg of meal fed to the autumn cows and 536kg fed to the spring cows.

The peak period was considered to be the May-June period. During that time, the autumn-calving cows produced 23.1kg/day

The purpose of the study was to identify what effect calving date had on peak milk production.

The peak period was considered to be the May-June period. During that time, the autumn-calving cows produced 23.1kg/day, the spring-calving cows produced 27.1kg/day, while the split group produced 24.6kg/day.

Based on these results, Joe Patton says that the reduction in peak milk with autumn- or split-calving is relatively modest, despite a radical change in calving date.

He says most of the reduction in volume occurred in the autumn period, with that milk shifted to winter.

In terms of system costs and profitability, Joe says that the feed costs were lowest with the spring-calving herd and highest with the autumn-calving herd.

However, on a margin-over-feed basis, before winter premiums, the difference across a number of milk and concentrate feed price scenarios was at most €60/cow.

However, capital and operating costs are higher with the autumn- and split-calving systems.

It’s important to note that the performance of both the autumn and the spring herd at Johnstown Castle has been excellent

At a 7.5c/l winter milk bonus between November and February, the highest premium that could be claimed for an autumn-calving herd would be €234/cow, or €23,400 for a 100-cow herd.

This premium would need to cover the extra costs involved in autumn calving to make it worthwhile.

It’s important to note that the performance of both the autumn and the spring herd at Johnstown Castle has been excellent.

Joe says that when looking at the profit monitor data there is often very little difference in profitability between the top spring- and autumn-calving farms, but that the average autumn- or split-calving farms rarely make the same profit as an average spring-calving farm.

He is alluding to the extra complexity and management capacity required for autumn, but particularly for split-calving farms.

New research

Two new studies are kicking off at Johnstown Castle this autumn. The first is a new autumn-calving project looking at two different stocking rates.

The low stocking rate is at 2.75 cows/ha, with no bought in feed and the cows will be fed as much low-carbon footprint native grains as possible.

The other treatment will be stocked at 4.0 cows/ha, with winter feed purchased in and fed conventional dairy ration.

Multi-species swards at Johnstown Castle.

The second study is with spring-calving cows stocked at 2.6 cows/ha. One treatment will be grazing only multi-species swards, while the other treatment will be grazing perennial ryegrass and white clover swards.

Performance, profitability and environmental footprint will be measured in both studies.

The open day at Johnstown Castle takes place from 11am to 2pm on Wednesday 4 September.

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