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John Barry January/February Update 2023

Improving shed ventilation

Improving shed ventilation

  • A smoke bomb test showed inadequate ventilation in one shed
  • Autumn born calves were getting sick with respiratory disease
  • Slits were cut along the side sheeting to act as an air outlet
Setting the farm up for spring

Setting the farm up for spring

  • Walk farm to assess the grass cover
  • Make a plan for spring grazing – paddocks to go to, when they should be grazed by
  • Target 30% farm grazed by 1st March, 60% by 17th March and 100% by 5th-12th April
Autumn breeding season finished & spring calving starting soon

Autumn breeding season finished & spring calving starting soon

  • Spring herd are due to calve soon
  • Calving pens have been set up & calving camera checked
  • Breeding has finished with the autumn herd and they are due to be scanned in the next month

Animal Health

There was an issue with air flow in the lie back section of John’s slatted shed where the autumn calves are housed. John has had health issues with them there in the past. Good ventilation is required in a shed to help remove gasses, odours, dust and bacteria. It should also remove the moisture and heat generated by the animals. The ‘stack effect’ is driven by the heat produced by the animals and by the roof slope. The animals produce heat and warm the air. The warm air rises following the slope of the roof, escaping through the outlet (highest point of the house) and is replaced by clean fresh air via the inlet.

After doing a smoke bomb test, it was clear that the stale air was struggling to reach the top of the shed to exit and was coming back down to the calves and causing respiratory issues. John cut 20 slits at the top of the vented sheeting along the shed (7cm wide) to act as an air outlet for removing stale air. It is letting more light into the shed and appears to be working well so far.

The other side of the shed needs a greater air inlet and will need 32 slits, at 8cm wide and 1.35m length to allow sufficient air into the shed for the cattle that are housed there.

Slits cut in side sheeting for ventilation


John measured grass on the farm on 15th February. It showed a farm cover of 582 kg DM/ha. John’s priority for the next few weeks is to get all paddocks grazed off before his second rotation starts. The autumn calves have been grazing by day over the winter period, and he had a group of store cattle that were out wintered on forage rape. As ground conditions are very good, John plans to turn out his spring weanlings and is going to move them onto the forage rape, which is near to the yard. The store cattle that are used to being outdoors will go to graze the silage ground up the road.

As the farm is dry, the spring targets are to graze:

  • 30% of the farm by 1st March
  • 60% of the farm by 17th March
  • 100% of the farm by ‘Magic Day’ when grass growth meets demand, i.e. around 5th-12th

John can very easily monitor this through Pasturebase Ireland by entering the start and end grazing dates for the first rotation, and then recording paddocks as they are grazed. This will show if he is ahead, behind or on target. If he is behind target, John can let out more stock or graze lighter covers until they catch up. If he is ahead of target he can graze the heaviest covers, re-house some stock or possibly graze silage ground a second time.

However the most important thing is that there is a ‘wet weather plan’ in place. Weather forecast needs to be monitored and cattle can be housed before any adverse weather if necessary. If there is an opportunity to graze some of the wetter fields now, John will take it. Back fencing can also be used to avoid excessive damage to land.

The benefits of this will be healthier cattle, less labour feeding and bedding, less slurry/dung produced and higher daily live weight gains.

Grass Wedge


The spring herd have not started calving yet but are due to start in the next 7 to 10 days. John has cleaned, disinfected and bedded the calving pens in advance of this. The calving camera was also checked to make sure it is working. He has expected calving dates from ICBF for the cows, but will monitor them closely. His plan is to let them out to a grass paddock beside the yard soon after they calve to help re-build body condition for the breeding season.

35 heifers and cows have been bred in the autumn herd since 1st November and John plans to scan 35 days after the last cow was bred. Any females not in calf will be sold.