Laminitis Risk with Snow on the Grass?

[LuckyRed]

Hi guys

Just thought I'd sound you out about the laminitis risk with horses eating grass under the snow. Our soil and grass isn't frozen despite being covered with 3-4 inches of snow and when I turned my boy out yesterday, he was munching the grass (after snow-ploughing the snow out of the way with his nose).

I have the smartphone app (courtesy of Kelly, who mentioned it on her FB page) which shows the lamintis risk for your location, and was somewhat suprised to see that the risk over the last few days has been low despite the snow all over the ground so I was wondering whether the impact on the sugars in grass is different with frost compared with snow? Or is it based on temperature and as we've only been at about 0'c to -2'c so not that cold and the snow provides a layer of insulation to the grass?

Any thoughts?

[cookie]

Could it be lack of light to the grass?

With a covering of snow perhaps the light not getting in might limit the sugars compared to the same temps on a sunny day?

I don't know but that's what sprung to mind.

Of to find that app

Sent from my GT-I9100 using proboards

[calekio]

Interesting... but i know when i quizzed my vet she said no danger on the eating snow covered grass side of things with laminitis...

[specialized]

If it is anything like ours the grass is totally unfrozen under the snow so it should not be a problem, along with the fact that the amount of grass they are eating when they have to dig for it will be much smaller.
I am not sure about relying on these apps as they only give a general idea of what might be going on, for instance we can be frost-free here and it can be -5 down in the valleys below us. There was one day a couple of weeks ago that was warm and sunny and the horses were gorging themselves but I doubt the app would have signaled that one day could be a lami danger.

[mandal]

Grass can still photosynthesize under snow in sunny conditions. It cannot respire (use the sugars) under 4-5 degrees so a period of snow/cold with sunny days sugars quickly build up and become a risk. When overcast the risk is reduced as photosynthesis is impeded. That's my basic understanding and I may need correcting but as said above the app is a guide and may not be local enough for your local weather. It is a tool among others to use to make judgments about risks.

[cookie]

That makes sense mandal, my o level biology was a long time ago

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[specialized]

Jan 21, 2013 17:49:29 GMT 1 mandal said:

Grass can still photosynthesize under snow in sunny conditions.

Sorry, struggling to understand your terminology - sunny conditions, what are those?? ;D ;D

[mandal]

Jan 21, 2013 18:10:19 GMT 1 specialized said:

Jan 21, 2013 17:49:29 GMT 1 mandal said:

Grass can still photosynthesize under snow in sunny conditions.

Sorry, struggling to understand your terminology - sunny conditions, what are those?? ;D ;D

Lol.

Yes cookie I think it's the low light (for bloomin ages!) that might be keeping the risk down on the app.

[LuckyRed]

Fully on board with the nature of the app, but the question about the grass under snow still applies - and if photosynthesis is the key, is grass under snow at night a low, low risk?

[LuckyRed]

Fully on board with the nature of the app, but the question about the grass under snow still applies - and if photosynthesis is the key, is grass under snow at night a low, low risk?

[mandal]

Jan 22, 2013 0:31:10 GMT 1 LuckyRed said:

Fully on board with the nature of the app, but the question about the grass under snow still applies - and if photosynthesis is the key, is grass under snow at night a low, low risk?

In warmer months when the grass is able to use sugars the levels drop overnight (usually lol) in my understanding, but in cold temperatures grass cannot use sugars so the level doesn't drop at night. So I don't think it applies in cold winters, but that is my understanding. The biggest help keeping levels down a bit atm is the constant cloud cover I think. As cold nights continue the levels will creep up over time even in cloudy weather during the day.

[Deleted]

Yep, in warmer weather when its sunny, the plant produces sugar during the day through photosynthesis. At night photosynthesis stops (due to lack of sunlight) but respiration continues using up the sugars built up during the day. So in warm sunny weather the sugar (in theory) is at its lowest in the early hours of the morning before sunrise.

In the cold, if it's sunny during the day AND that sun can reach the grass photosynthesis still occurs (albeit much slower as any biological process is slowed down in the cold), but resipration is at a much much lower rate day and night, so not so much sugar is used up overnight so there is the potential for the sugar level to gradually build up day on day.

However, as I said all biological processes slow down in very cold conditions, including photosynthesis so its only a rule of thumb. A thick layer of snow will not completely exclude sunlight but will reduce the amount reaching the grass. On very cold overcast days like we've been having I'd imagine photosynthesis to have all but stopped. This will be proven if your snow clears and reveals yellowy brown grass. Photosynthesis maintains the green colour of grass which is lost if photosynthesis is halted for a while (like when you move a tent after 2-3 days camping).

[LuckyRed]

thanks michellep - very interesting! As our snow is clearing, the grass is green (and the mud is brown so making a very depressing sight!) More snow forecast for tonight!