To Vent Or Not To Vent...?

BenF

Member
Livestock Farmer
Morning all,

Just wondered if ventilation with fans is something anyone is doing or thinking about at the moment? For those weeks we get above 20ish degrees in the sheds and parlour - reckon it's worth it? Seeing stuff about it on LinkedIn - studies down south about humidity index, country is getting warmer...that type of thing.

Thanks,
Ben
 

Sandpit Farm

Member
Livestock Farmer
Location
Derbyshire
Morning all,

Just wondered if ventilation with fans is something anyone is doing or thinking about at the moment? For those weeks we get above 20ish degrees in the sheds and parlour - reckon it's worth it? Seeing stuff about it on LinkedIn - studies down south about humidity index, country is getting warmer...that type of thing.

Thanks,
Ben

I would consider a few things first before investing in fans. Do you know if your building is adequately vented? If you are considering fans but still have a capped ridge, I'd suggest there are plenty of places to look before adding to costs. See the link below.


If you have done all of this, I would be thinking about fans or similar. Heat stress seems to affect higher yielding herds greater in terms of profit so you need to look at the balance of financial needs of your fixed costs vs cow output. I would suggest that if you aren't heavily borrowed in terms of building infrastructure, it could be worth doing the sums of extra costs of running fans etc with the reduction in costs and problems that would be created by reducing your lactation yields from the cows.

It is a long way to say - careful you don't end up buying more milk to then sell at cost.
 

Rossymons

Member
Location
Cornwall
As you mentioned it directly below is the humidity graph I have in my box of things

230518125454.png


There were 3 of my farms last season that had very sharp drops in fertility when the weather was uncomfortably hot. I'll dig out the dates and temps later and report back.
 

BenF

Member
Livestock Farmer
I would consider a few things first before investing in fans. Do you know if your building is adequately vented? If you are considering fans but still have a capped ridge, I'd suggest there are plenty of places to look before adding to costs. See the link below.


If you have done all of this, I would be thinking about fans or similar. Heat stress seems to affect higher yielding herds greater in terms of profit so you need to look at the balance of financial needs of your fixed costs vs cow output. I would suggest that if you aren't heavily borrowed in terms of building infrastructure, it could be worth doing the sums of extra costs of running fans etc with the reduction in costs and problems that would be created by reducing your lactation yields from the cows.

It is a long way to say - careful you don't end up buying more milk to then sell at cost.
Brilliant thank you!
 

Sandpit Farm

Member
Livestock Farmer
Location
Derbyshire
As you mentioned it directly below is the humidity graph I have in my box of things

View attachment 1022649

There were 3 of my farms last season that had very sharp drops in fertility when the weather was uncomfortably hot. I'll dig out the dates and temps later and report back.
This is great actually. It highlights the main reason to get rid of moisture out of the air (i.e. the need for fresh air). You can quite easily work out how much moisture the cows are putting out into the environment (slurry, urine, breath). Compare that to the amount of moisture coming through an open ridge from your annual rainfall and the surface area that is 'open' and you soon realise that rain is not your issue.

Another useful step is to create more outdoor space. Just some temporary gates or whatever work well. It spreads the slurry and urine out more, gives them more space to socialise and allows them to breathe fresh air.
 

Rossymons

Member
Location
Cornwall
Looking back through the herds mentioned earlier they would all have been bouncing around the levels between mild and severe stress with several consectutive days going above 82. The cows would have been outside grazing at the time and not in a shed.
 

Sandpit Farm

Member
Livestock Farmer
Location
Derbyshire
Looking back through the herds mentioned earlier they would all have been bouncing around the levels between mild and severe stress with several consectutive days going above 82. The cows would have been outside grazing at the time and not in a shed.

I suspect energy balance comes into it from a fertility perspective. i.e. those with poor transition or that are higher yielding in those first 50 days are going to be challenged more.

I guess we are lucky with our climate for grazing cows but it is interesting that cows tend to shelter under trees (if available) on hot days which tells us all we need to know. I suspect grazing cows drop in yield slightly on hot days simply because they need to consume so much water to regulate their body temperature so could that limit intake?? We tend to get that FPD issue every year so I wonder if better shading in paddocks has a role to play
 

BenF

Member
Livestock Farmer
Looking back through the herds mentioned earlier they would all have been bouncing around the levels between mild and severe stress with several consectutive days going above 82. The cows would have been outside grazing at the time and not in a shed.
Do you think outside shade is necessary too? If its 20 odd degrees outside with very little breeze, the heat they'll feel especially with how humid it can be would be right up there on that humidity index. A few days of that would surely have quite a big impact on production, fertility, etc. They do seem to find trees to stand under as @Sandpit Farm said above.
 

BenF

Member
Livestock Farmer
This is great actually. It highlights the main reason to get rid of moisture out of the air (i.e. the need for fresh air). You can quite easily work out how much moisture the cows are putting out into the environment (slurry, urine, breath). Compare that to the amount of moisture coming through an open ridge from your annual rainfall and the surface area that is 'open' and you soon realise that rain is not your issue.

Another useful step is to create more outdoor space. Just some temporary gates or whatever work well. It spreads the slurry and urine out more, gives them more space to socialise and allows them to breathe fresh air.
Yeh that's really useful.
I guess removing the 'bad' moisture out of the air (bit like a chicken shed) would have to be done by fans? Thinking about it moisture comes from everywhere!! Double whammy with fans will be we can cool the cows housed year round while moving good air around.
Seen some fancy barns in Switzerland which can run big fans backwards (upwards) during winter to stir up the air, then run forwards (down) to cool in summer.
All comes down to cost and return though...!
 

Sandpit Farm

Member
Livestock Farmer
Location
Derbyshire
Do you think outside shade is necessary too? If its 20 odd degrees outside with very little breeze, the heat they'll feel especially with how humid it can be would be right up there on that humidity index. A few days of that would surely have quite a big impact on production, fertility, etc. They do seem to find trees to stand under as @Sandpit Farm said above.
You can only control what you can control. Cows tend to seek shade so a cow will try to shade in another cow's shadow and so on. You end up with a big huddle of cows that are heating up while trying to keep cool if that makes sense. I think trees and high hedges have a really useful function in pasture but if you don't have them, what can you do? You can plan them but how practical is that, trying to keep a new tree protected.

The collecting yard is worth thinking about. If it isn't covered, could you cover it? Worth working out the cost benefit on that one. If that isn't feasible, could you bring them into the yard in smaller groups?
 

Sandpit Farm

Member
Livestock Farmer
Location
Derbyshire
Yeh that's really useful.
I guess removing the 'bad' moisture out of the air (bit like a chicken shed) would have to be done by fans? Thinking about it moisture comes from everywhere!! Double whammy with fans will be we can cool the cows housed year round while moving good air around.
Seen some fancy barns in Switzerland which can run big fans backwards (upwards) during winter to stir up the air, then run forwards (down) to cool in summer.
All comes down to cost and return though...!
Ah kind of. My point before was that a good shed can ventilate naturally (without fans). You can create slits in the roof or open the ridge. If you can add upstands to the ridge, it limits the rain that can get in and if the prevailing wind blows at right angles to the ridge, it creates a 'draw' that literally pulls the air out of the shed (it is called the Benoulli Effect and it is the same effect that causes planes to take off or lorries to be drawn towards each other as they pass closely). You need to calculate how much outlet you need for the number of cows housed (see the doc in the link above).

Then think of the walls (inlet). Calculate how much inlet you need. If you are in a pleasant county down south somewhere, you can open the sides up like those Swiss barns you talk about. However, in harsher weather or further north, you are going to get water on the beds and frozen pipes. You can get away with space boarding on the East side but on the West side you need to consider either Yorkshire boarding (the double clad type) or a letter box vent where the upper cladding is anchored to the wall 'stepped out at the bottom' so air can move in (fast) but weather is left behind.

If I had everything nailed and still wasn't getting good enough ventilation - only then would I think about fans.

If you message me your number, we can have a chat if you like.
 

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