peak sugar in spring grass

[Harley_s_mom]

I know, this has been discussed at length by many… but I can’t be the only one who still finds this confusing. I am transitioning my horses to pasture increasing by 15 minutes/day. We are now at 2.5 hours a day. I know that morning is considered peak time for sugar content in spring grass. But that is affected by cold nights and often based on locations that differ from mine. So, in the following scenarios, when is it safest to let them out? I live in eastern Canada and we have very cold, wet springs. There is good grass growth, but nights are often still cold (near or at freezing - heck, there were snow flurries a couple of nights ago).

1 - sunny day followed by mild night (well above freezing): morning? Since the sugar will have been spent during the night for plant growth?

2 - sunny day followed by cold night (frost or close to it): late afternoon/evening? To give the grass time to use up the sugars that were stored, but not used during the night?

3 - cloudy or rainy weather, no sun, consistently cool temps (around 5°C) so there is some growth, but it is slow: anytime?

And before everyone jumps in with unrelated suggestions, I have 3 easy keepers, none has a history of founder or IR, all at healthy weights (on a very specific nutritional plan) and my pastures are not seeded, but have natural mixed growth though predominantly timothy. They are out 24/7 but when not on grass, they are in a dry lot. I have a gelding who is much better on pasture (history of ulcers) so this lifestyle suits him best. They are all happier and fitter on pasture.

[S1969]

Peak sugar in grass is not in the morning, but after the sun has been on it. Safest time for grazing is morning.

https://thehorse.com/150600/pasture-sugars/

Controlling for sugar in grass is really hard, because it depends on time of year, time of day, temperature, soil conditions, weather conditions, etc.

If you are looking for the safest, short time block to put them on pasture, I would say first thing in the morning. But even that may be too much sugar for many easy keepers.

My pony and mini get zero grass. My two easy keepers have to be limited. My old TB mare could probably be on 24/7 but would eventually get fat.

With a mixed herd (two easy keepers, one TB), I start by putting them out for a short period of time in the morning only. By the time the sun is up (9:30-10:00am) they are hot and will choose to come in anyway.

Once the peak of the season is over (temps are higher, less rain), and I’ve mowed several times, I will switch to overnight turnout.

[JB]

Lowest sugars are from 3-10am, all else equal.

Sun triggers sugar production. Dark triggers sugar usage for growth and health. The warmer the night, the more sugar is used up. This is why Spring and Fall are the worst times for metabolic horses - sugar accumulation during the days, not much gets used at night.

So for your examples:

1 - sunny day followed by mild night (well above freezing): morning? Since the sugar will have been spent during the night for plant growth?

2 - sunny day followed by cold night (frost or close to it): late afternoon/evening? To give the grass time to use up the sugars that were stored, but not used during the night?

3 - cloudy or rainy weather, no sun, consistently cool temps (around 5°C) so there is some growth, but it is slow: anytime?

2 has the most sugar in the morning, but then it still rises again during that sunny day.
1 has the most “normal” cycle - highest at the end of the day, lowest early morning
3 lowest in general - lower if the cloudy cycle came after a warmer night (where sugars were used).

I wouldn’t worry about any of this for horses who are just easy keepers. The issues come in with weight more than anything. Muzzles are your friend. But if you want, they can be dry-lotted from late afternoon until early morning, or just overnight. But if they are happier and fitter on pasture, then use muzzles if weight starts becoming an issue.

www.safergrass.org is an excellent resource for this info.

[Harley_s_mom]

Thanks for the detailed response JB! Yes, my issue is that everyone assumes morning grass is safest, but that is not always the case in my location since scenario 2 is probably most common here this time of year. I had no idea about scenario 3, which has been the weather here for the last few days and appears to be the continuing trend for the next week.

I have a grazing muzzle for my older gelding, but he dropped weight over the winter (dr’s orders) and looked great in the spring, but then we started conditioning him for show season and he looks a little too thin so right now, I’m letting him have grass. If he starts to get chunky, the grazing muzzle will go on, but he’s getting a lot of work right now, so he can use the calories. I prefer a muzzle to dry-lotting because he is getting exercise.

BTW, I did eventually get photos of his hooves which I will get around to posting in a separate thread soon. So far so good though, he is looking great this spring.

[AppaloosaDressage]

I’m in FL and I’m still having trouble navigating this too. Where I am, it’s wet, especially with the morning dew, so I wait to turn out til it dries up around 10 or so to prevent white line. Seems to me the sugar content would be climbing around this time though. They only go out for a few hours in the late morning because it gets pretty warm pretty quickly, so they come in for the hottest part of the day and then it’s back out for a few more hours in the evening, 5-8 or so. Im wondering if the sugars in the evening are safer or more harmful after accumulating all day? Weight is good on all of them except one chub who’s on a more restricted grazing schedule. Sorry, no advice here just more questions!

[Snowdenfarm]

1 and 3, basically yes. 2, as you know, is the most dangerous. Unless the following day is a very dark, cloudy day, any uv rays are going to add more sugar on top of what has accumulated the day before and not used during that night. If it is a very dark, cloudy day I guess the afternoon would be better, but still scary to me with an IR horse.

[JB]

@AppaloosaDressage

I’m in FL and I’m still having trouble navigating this too. Where I am, it’s wet, especially with the morning dew, so I wait to turn out til it dries up around 10 or so to prevent white line. Seems to me the sugar content would be climbing around this time though. They only go out for a few hours in the late morning because it gets pretty warm pretty quickly, so they come in for the hottest part of the day and then it’s back out for a few more hours in the evening, 5-8 or so. Im wondering if the sugars in the evening are safer or more harmful after accumulating all day? Weight is good on all of them except one chub who’s on a more restricted grazing schedule. Sorry, no advice here just more questions!

As per above, sugars are lowest from 3-10am, all else equal. Then they start rising as the sun and daylight hours continue. Cloudy days is just a slower/low sugar accumulation.

By the time sundown arrives, sugars are at their highest - been accumulating all day

If you aren’t dealing with metabolic issues, don’t worry about the timing, only the number of hours and/or muzzles.

[S1969]

@Snowdenfarm

1 and 3, basically yes. 2, as you know, is the most dangerous. Unless the following day is a very dark, cloudy day, any uv rays are going to add more sugar on top of what has accumulated the day before and not used during that night. If it is a very dark, cloudy day I guess the afternoon would be better, but still scary to me with an IR horse.

With an IR horse you are just comparing “a lot of sugar” to “a lot of sugar.” The reality is that the spring grass is probably not good for your horse, period.

I’m not sure how much lower the “off peak” sugar is in the spring grass, but it can’t really be that much lower. It’s still grass, it’s still spring. It’s not like a dark cloudy day makes grass safe. We haven’t seen much of the sun here in New England in 2 months. I guarantee that my grass is too high in sugar for my metabolic horses anyway.

[Palm_Beach]

@AppaloosaDressage

I’m in FL and I’m still having trouble navigating this too. Where I am, it’s wet, especially with the morning dew, so I wait to turn out til it dries up around 10 or so to prevent white line. Seems to me the sugar content would be climbing around this time though. They only go out for a few hours in the late morning because it gets pretty warm pretty quickly, so they come in for the hottest part of the day and then it’s back out for a few more hours in the evening, 5-8 or so. Im wondering if the sugars in the evening are safer or more harmful after accumulating all day? Weight is good on all of them except one chub who’s on a more restricted grazing schedule. Sorry, no advice here just more questions!

Location is also important - you probably have more warm season grasses in your pastures than cool season grasses. The cool season grasses are more dangerous than the warm season grasses. And watch the clover. If in doubt, put a muzzle on the chub!

[LookmaNohands]

I am in the same boat–still just learning about this with my 22 yr-old, thin OTTB who is IR (as of 2 years ago) and Cushionoid as of last August. I have been turning him out at night in a muzzle but now I am worried with all the sun we have had. He is on two of Dr. Joyce Harman’s preparations and seems fine. But I feel like I might be gambling. I took him off of Prescend last fall because he wasn’t eating well on it. I could try him on a 1/4 tab again and see how he does.

Everything else he eats is low sugar and he is thin so Dr. Harman has not been terribly worried as of a few weeks ago. But the grass is growing like crazy so I am back to using the weight tape again. Now the weather is really warming up so that changes things again.

Hard to keep up!

[JB]

@LookmaNohands

I took him off of Prescend last fall because he wasn’t eating well on it. I could try him on a 1/4 tab again and see how he does.

Taking them off the Prascend isn’t supposed to be long-term. It’s unfortunate your vet didn’t discuss this with you It’s fine to stop it until the appetite returns, but then it needs to start up again, at as small a dose as you can do, and slowly work up to whatever the desired dose is. Sometimes it’s easiest to feed the pill entirely separate from meals, so they don’t associate food with meds, but many people don’t have to do that.

It’s definitely a big(er) concern with the metabolic horse, whether that’s IR or PSSM. Obviously the best hours would be those 3-10am hours, but for sure that’s rarely doable. 6/7am, to 10/11am, might be all those horses can handle, maybe a bit more if there’s a stretch of cloudy days with nights well above 45*. Sometimes it’s about which hours. Sometimes it’s only about how many hours.

[candyappy]

@JB

Lowest sugars are from 3-10am, all else equal.

Sun triggers sugar production. Dark triggers sugar usage for growth and health. The warmer the night, the more sugar is used up. This is why Spring and Fall are the worst times for metabolic horses - sugar accumulation during the days, not much gets used at night.

So for your examples:

2 has the most sugar in the morning, but then it still rises again during that sunny day.
1 has the most “normal” cycle - highest at the end of the day, lowest early morning
3 lowest in general - lower if the cloudy cycle came after a warmer night (where sugars were used).

I wouldn’t worry about any of this for horses who are just easy keepers. The issues come in with weight more than anything. Muzzles are your friend. But if you want, they can be dry-lotted from late afternoon until early morning, or just overnight. But if they are happier and fitter on pasture, then use muzzles if weight starts becoming an issue.

www.safergrass.org is an excellent resource for this info.

@Harley’s mom I have an easy keeper who I have been able to manage on pasture without a muzzle until this year. Despite continuing to reduce her grazing ( or mixing up the times) her weight was creeping up alarmingly fast. She now has a GG muzzle and that might be something to think about for the future.

I went with it because I didn’t want her spending 22 hours a day in a dry lot which is where we were obviously headed.

I will say that she hates wearing it, but she spends all day out with her head down, she drinks well and I can still catch her to put it on ( she gives me a dirty look though). When I tried muzzles in the past I could not approach her at any time after 1 day with it on.

She is slowly dropping the excess pounds too.

[JB]

@candyappy

I will say that she hates wearing it, but she spends all day out with her head down, she drinks well and I can still catch her to put it on ( she gives me a dirty look though). When I tried muzzles in the past I could not approach her at any time after 1 day with it on.

Yep, the basket-style muzzles made 1 of my horses impossible to catch if I needed to put them on while they were out. So, if they were able to do 12/12 on and off, I had to put them on in the morning before I let them out after breakfast, and then go out before bed, find them in the pasture, and take them off.

The GG is SO much nicer. Nobody rolls their eyes or tries (halfheartedly) to get away in their stall when I come in with it. So it’s not just me who approves, they are much more forgiving of it.

[LookmaNohands]

@JB

Taking them off the Prascend isn’t supposed to be long-term. It’s unfortunate your vet didn’t discuss this with you It’s fine to stop it until the appetite returns, but then it needs to start up again, at as small a dose as you can do, and slowly work up to whatever the desired dose is. Sometimes it’s easiest to feed the pill entirely separate from meals, so they don’t associate food with meds, but many people don’t have to do that.

It’s definitely a big(er) concern with the metabolic horse, whether that’s IR or PSSM. Obviously the best hours would be those 3-10am hours, but for sure that’s rarely doable. 6/7am, to 10/11am, might be all those horses can handle, maybe a bit more if there’s a stretch of cloudy days with nights well above 45*. Sometimes it’s about which hours. Sometimes it’s only about how many hours.

Thanks JB. My horse has done great without the Prescend, just on Dr. Harman’s stuff. I think I will try a 1/4 again and see if he will keep eating. I do worry about him and am monitoring his weight carefully—he is thin and a little ribby so at least he has that going for him.

Also, how warm is a warm night? We are definitely getting warm and it is supposed to be in the 60s tonight and several nights in the next week. Might be 90 during the day tomorrow.

Green Guard muzzles are great. I have it duct taped to the halter in such a way that it doesn’t touch his nose at all. And I padded the noseband of the halter and wrapped it in duct tape and it is not rubbing his nose. I had an extra wide crown piece made for his halter and he doesn’t mind having the muzzle put on because he gets low sugar cookies before and after. I have to stuff them in the side of his mouth once it is on but he likes that part. I take it off for an hour starting at 6:30 am and he is waiting for me near the gate.

I wish I could ride him but he is not sound. I know that helps with IR too.

[S1969]

@LookmaNohands

Thanks JB. My horse has done great without the Prescend, just on Dr. Harman’s stuff. I think I will try a 1/4 again and see if he will keep eating. I do worry about him and am monitoring his weight carefully—he is thin and a little ribby so at least he has that going for him.

I wish I could ride him but he is not sound. I know that helps with IR too.

“Great without Prascend” - in what way?

Cushings doesn’t go away, and often gets worse. At the very least I would be retesting him at least a couple times a year to make sure you’re not missing it if things are getting worse before he ends up with acute issues.

My Cushings pony is on the thin side and Prascend makes him picky with grain but he eats hay very well. His feet are a disaster, though, from a lifetime of metabolic issues. At this point, keeping him from being heavy is better for his feet. But without the Prascend he’d be dead. So, it’s definitely a careful balancing act. I’d like more weight on him but he needs the meds more.

[LookmaNohands]

He is being treated for Cushings with Rehmannia 11 and for IR with Joyce Harman’s OB formula. I know these things don’t go away. He is tested when the vet says he should be tested. I have another older horse who will be tested in June as this is when the vet says is the best time to test. I am working with both Joyce Harman and a traditional vet too for this treatment.

[Texarkana]

What’s really telling about the comfort of the GG muzzle is that I can walk up to my horses in the field and put it on.

With traditional style muzzles, as soon as they saw it, they would be GONE! In the stalls at feeding time was the only way I could get it on them.

They do seem to get quite a bit of grass with the GG muzzle. I can “hear” them grazing with it on when I stand next to them. But it seems to reduce their intake enough that they stop gaining weight, sometimes even lose a little weight. And there are a lot less muzzle rubs to deal with.

But it doesn’t even sound like the OP is at this point yet.

For your herd, OP, I don’t think you need to worry all that much. I wouldn’t worry about the sugar all that much, either. Just keep increasing the pasture time like you’re doing and if weight starts to balloon on any of them, then start worrying about sugar reduction strategies and/or muzzles.

[JB]

@LookmaNohands

Thanks JB. My horse has done great without the Prescend, just on Dr. Harman’s stuff. I think I will try a 1/4 again and see if he will keep eating. I do worry about him and am monitoring his weight carefully—he is thin and a little ribby so at least he has that going for him.

Please be careful using herbs for Cushing’s. They are not addressing the tumor, only the symptoms. Pergolide (made into Prascend) is the only thing known currently to help keep that tumor, and therefore the symptoms, slowed down. I can’t find any studies on using Rehmannia 11 for Cushingoid horses. Or even animals outside of mice (though I didn’t look very long). It is likely no better/worse than Chasteberry Tree leaves- helping manage symptoms, but not at all helping the root problem.

June is not the best time to test. June is peak sunlight hours which is when Cushing’s horses tend to be at their best. Late Summer to early Fall is best, as they are more likely to have higher seasonal rise than the normal horse.
https://thehorse.com/113764/testing-for-equine-cushings-disease/

Also, how warm is a warm night? We are definitely getting warm and it is supposed to be in the 60s tonight and several nights in the next week. Might be 90 during the day tomorrow.

At least 40, maybe 45, I don’t remember offhand. But 60s is great. It sounds like you’re getting the heat wave we are, upper 80s/low 90s for the next 10 days or so

I wish I could ride him but he is not sound. I know that helps with IR too.

It’s definitely hard managing the unsound metabolic horse

@Texarkana

They do seem to get quite a bit of grass with the GG muzzle. I can “hear” them grazing with it on when I stand next to them. But it seems to reduce their intake enough that they stop gaining weight, sometimes even lose a little weight. And there are a lot less muzzle rubs to deal with.

I was skeptical when I saw how much space there was for grass to come through with those slots. But between reading their explanation about why it’s designed this way, and seeing for myself, it really does work. They have to work harder to get the grass from all around the muzzle, moving their lips a lot, and that somehow slows them down, despite what seems like an awful lot of grass real estate.

[LookmaNohands]

@JB

Please be careful using herbs for Cushing’s. They are not addressing the tumor, only the symptoms. Pergolide (made into Prascend) is the only thing known currently to help keep that tumor, and therefore the symptoms, slowed down. I can’t find any studies on using Rehmannia 11 for Cushingoid horses. Or even animals outside of mice (though I didn’t look very long). It is likely no better/worse than Chasteberry Tree leaves- helping manage symptoms, but not at all helping the root problem.

June is not the best time to test. June is peak sunlight hours which is when Cushing’s horses tend to be at their best. Late Summer to early Fall is best, as they are more likely to have higher seasonal rise than the normal horse.
https://thehorse.com/113764/testing-for-equine-cushings-disease/

At least 40, maybe 45, I don’t remember offhand. But 60s is great. It sounds like you’re getting the heat wave we are, upper 80s/low 90s for the next 10 days or so

It’s definitely hard managing the unsound metabolic horse

I was skeptical when I saw how much space there was for grass to come through with those slots. But between reading their explanation about why it’s designed this way, and seeing for myself, it really does work. They have to work harder to get the grass from all around the muzzle, moving their lips a lot, and that somehow slows them down, despite what seems like an awful lot of grass real estate.

The Rehmannia 11 is Chinese herbs and doesn’t have Chasteberry leaves in it. Read more about Joyce Harman here: https://harmanyequine.com.

I trust her and her formulas. When I first put his horse on the OB formula he finally shed his winter coat in June. That was two years ago. I pretty much have to trust this. I could put him back on Prescend but if he stops eating he will get thinner than he already is. I don’t mind trying just a 1/4 or one, but still.

A balancing act to be sure. On top of a weird personality too!

[JB]

@LookmaNohands

The Rehmannia 11 is Chinese herbs and doesn’t have Chasteberry leaves in it. Read more about Joyce Harman here: https://harmanyequine.com.

Yes, I know what it is My point was that there are no studies (that I can find) showing its value for horses, and is likely no different/better than CTB - symptoms may be managed short-term, but without slowing the progression of the root cause: the tumor

I trust her and her formulas. When I first put his horse on the OB formula he finally shed his winter coat in June. That was two years ago. I pretty much have to trust this. I could put him back on Prescend but if he stops eating he will get thinner than he already is. I don’t mind trying just a 1/4 or one, but still.

A balancing act to be sure. On top of a weird personality too!

Many Cushing’s horses shed in June in the early stages. You need to put him back on the Prascend, starting with as low a dose as possible, even every other day, and very slowly ramp back up. That is the only thing we know of that will help slow the progression of the tumor, not just help symptoms

Has your vet really not talked about this issue with Prascend? if you want, do a search here for “pergolide veil”, as it’s often called. Lots and lots of discussions on how people have managed it