Grass Founder
May 21, 2009
Lush spring pastures can be dangerous temptations for horses.
To protect your horse's health, you may need to limit his access to sugar-rich spring grass.
By Dr. Tom Lenz of AQHA Corporate Partner Fort Dodge Animal Health
Spring is upon us. As lush, green grass begins to grow, it could be the beginning of serious founder problems – laminitis.
Laminitis is inflammation of the laminae of the horse’s foot. Laminae make up the delicate, accordion-like tissue that attaches the inner surface of the hoof wall to the coffin bone (the bone in the foot.) The sensitive laminae cover the bone and interlock with the insensitive laminae lining the inside of the hoof wall to keep the coffin bone in place within the hoof.
A horse suffering from laminitis experiences a decrease in blood flow to the laminae, which in turn begin to die and separate. The final result is hoof wall separation, rotation of the coffin bone and extreme pain. In severe cases, the coffin bone can actually rotate through the sole of the horse’s hoof where it becomes infected and usually results in the death of the horse.
Laminitis is triggered by a variety of causes, including repeated concussion on hard ground (road founder); grain overload; retained placenta; hormonal imbalance (Cushing’s disease or metabolic syndrome); certain drugs (corticosteroids); obesity; and lush grass.
Laminitis is not the only potential health complication that your horse faces. Let Dr. Lenz teach you more about other common threats to your horse’s health. In the three-disc “Your Horse’s Health” DVD set, you’ll learn how to prevent, spot and treat diseases.
Grass Founder
Veterinarians and nutritionists have known for some time that plants store energy in their seeds in the form of starch that can cause laminitis if the horse is introduced to grain too quickly or eats too much grain. Only recently have researchers discovered that grasses not only store energy in their seed heads as starch, they also store energy as sugar.
In the spring, as grass is growing rapidly, it stores more sugar than it needs for growth, and horses consume the sugar as they graze. Later in the year, when the daylight and nighttime temperatures are more consistent and grass growth rates decrease, the plant uses up most of the sugar produced during the day each night.
Here are some tips for avoiding grass founder:
- Keep horses off lush, fast-growing pastures until the grass has slowed in growth and produces seed heads.
- Graze horses on pastures containing a high percentage of legumes. Legumes, such as alfalfa or clover, store energy as starch, not sugar.
- Avoid grazing horses on pastures that have been exposed to bright sunny days followed by low temperatures, such as a few days of warm sunny weather followed by a late spring frost.
- Avoid grazing horses on pastures that have been grazed very short during the winter and are growing rapidly.
- Keep overweight horses in stalls or paddocks until the pasture’s rate of growth has slowed, then introduce them to pasture slowly.
- Turn horses out on pasture for a few hours in the early morning when sugar levels are low, not at night when levels are at their highest.
- Allow horses to fill up on hay before turning them out on grass for a few hours.
Dr. Tom Lenz, along with Dr. Kenton Morgan, offers expert advice on a wide range of horse health topics in AQHA’s “Your Horse’s Health” DVD set. Any responsible horse owner would do well to have these informative DVDs in their library. Don’t get caught unprepared – learn how to keep your horse healthy before problems arise.
At Risk
Horses that are over the age of 10, “easy keepers,” overweight or those with crested necks seem especially vulnerable to grass founder and should be the focus of your preventive program.
After the horses are turned out on pasture, check them often for early signs of laminitis such as heat in the feet and a pounding pulse at the back of the pastern. Foundered horses also assume a characteristic “sawhorse” stance with their hind feet up under their body and their front feet placed farther forward than normal. This is because the horse is trying to shift its weight off its painful front feet to its hind legs.
Grass-foundered horses also move gingerly, as if walking on eggshells, and are often unwilling to turn or move at all. In severe cases, the horse may refuse to stand. If your horse demonstrates these signs after being turned out on grass, immediately pull him off the pasture and call a veterinarian.
If you have horses that are prone to grass founder, visit with your veterinarian or equine nutritionist to develop a strategy for introducing them to spring grass. This is truly a situation where an ounce of prevention is worth a pound of cure.
Comments
23 Comments on “Grass Founder”
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June 15th, 2009 at 10:10 am
How long before founder shows up. hours or days?
July 3rd, 2009 at 9:01 pm
Great question, that is the answer I’m looking for as well~
How long before founder shows up –hours or days?
August 22nd, 2009 at 3:23 am
I have a horse that has founders on grass, it actually for him took about a month before we noticed him gipping on the front end.
September 1st, 2009 at 3:25 pm
I had a horse that developed equine laminitis, we got it to go away for the time being, hopefully it doesn’t come back in the future. I would recommend watching the diet of your horse if you suspect laminitis.
April 16th, 2010 at 10:16 am
Im trying to put a thin 7 year old mustang walker out on grass full time what would be the rate that I increase the time that he spends out on the grass. right now he is out for 3- 3 1/2 hours a day and this has been for a week if anyone has an idea please fill me in thanks
June 11th, 2010 at 5:25 am
Cricket…err on the side of caution…increase time up for an hour 2x a day for 2 or 3 days…repeat this pattern until the horse is up to 12 hours a day then you should be able to go 24/7…make sure you feed the horse hay BEFORE you put the horse out…that way he is not going out hungry and be less likely to consume too much…
If your doing three hours a day now…try 2 hours in the morning…then 2 hours in the evening…for 2 days…then go to 3 hours in the morning and 3 hours in the evening for 3 days…then 4 hours in the morning and 4 hours in the evening for 4 days…see the pattern? Again, give him hay each and every time prior to turning him out.
It is the sugars in the grass that create the founder issue so you may want to cut back on his grain if you feed a sweet feed (replacing the loss of sweet feed with oats or beet pulp).
August 15th, 2010 at 1:14 pm
I have a horse that foundered 3 yrs.ago was treated and is fine now. Im wondering if there would be a problem letting the horse grazing the pasture in June – August when the grass is slow and not much surgar etc . in it. Thanks
August 30th, 2010 at 1:46 pm
I also am wondering about dell’s question
September 9th, 2010 at 4:02 am
[...] far as I know, there is no place in the United States where you can grow alfalfa and be guaranteed blister beetle-free,” says David Buntin, a professor of entomology at the [...]
October 16th, 2010 at 8:32 pm
what about the fall and winter time of the year is it ok to let our horse stay out all night to he has founder on us twice this year but is doing fine now just wondering if we need to keep putting him up at night.
December 4th, 2010 at 8:02 am
I have a 15 year on pony I bought for my grandson. I am pretty sure that she has been foundered before. Is it ok to leave her out this fall and winter? The lot is about 1/4 – 1/2 an acre. She has free access to hay. I give her very little gain.
March 22nd, 2011 at 2:03 pm
i was wondering how long can you put a horse on grass when they are on a dry lot with hay 24/7 and gets triple crown senior feed and beef pulp. how long can i put her on grass? she is 16 year old arabian
March 24th, 2011 at 7:46 am
[...] plush grass is every horse owner’s dream for a pasture. Unfortunately, it is not always a [...]
September 28th, 2011 at 3:56 pm
I am buying a horse in 2 weeks. She is used to a run all day and night, but the grass she has been eating is short and worn down. The place she is coming to is full, green and a horses dream. Should I let her stay out all day and eats as she pleases?
September 28th, 2011 at 3:57 pm
I am buying a horse in 2 weeks. She is used to a run in all day and night, but the grass she has been eating is short and worn down. The place she is coming to is full, green and a horses dream. Should I let her stay out all day and eats as she pleases?
April 13th, 2012 at 12:51 am
Is it better to let your horse graze in the day time or night time?
I have a 15 year old quarter horse and she founders every year. I am trying my best to prevent it this year.
April 22nd, 2012 at 8:49 pm
I have several hunky horses. I’ve been reading alot on when and when not to let horses out on green pastures. So far, it seems, that late afternoon and early evening on sunny days has high sugar content. But, I’ve been putting my horses up from about 2-3 pm until early am (5-6). Our grass is growing like crazy so I’ve been giving plenty of hay to fill up on. They only get about 1 cup of grain now.
April 25th, 2012 at 6:11 am
I have 5 horses. We have a 1/4 mile fenced in lane with wide strips of grass on each side. I let my horses out gradually for grazing and everything seemed fine. We opened up a new pasture for them with lots of thick long grass. I’ve always been really careful but since I already had them grazing on grass I thought it would be okay to go 24/7. Well, yesterday, I let them out in it and they would eat for awhile, come back to the barn, then go out and eat some more. I started worrying last night because they were out there still eating. I went out and checked them, a couple were laying down and then got up and went back out to eat. I read about founder again as a refresher, got really worried and chased and locked them out of that pasture for now. I’m going to keep an eye on them but was wondering what other people’s thoughts were on how careful I need to be with reintroducing them to the pasture if they don’t show any signs of founder. I have one that I’m most worried about because he is slightly overweight.
May 4th, 2012 at 5:24 pm
Once they have foundered, always suseptible. Grass is over rated and is the humans dream for their horse. Lush green, which we think is great is like a buffet, whereas graving truly means to walk and search for food similar to in the wild. Refer to the writings of Jamie Jackson or Pete Ramey,
My youngest boy has foundered twice on me…first from haylage and a grass founder which he would have been exposed to in early spring…showed up in January…hope this helps…ps my boy gets zero grain, sweet feed, just 1/2 c equalizer for vitamins in winter and a good probiotic…starts with the pancreas and gut…shows up in the feet,
Hope this helps
May 6th, 2012 at 7:27 am
I have a 3 years old gelding. I own a 30 acre ranch, and he has full access to 20 acres 24/7. The only other food I give him is about a cups worth of oats mixed with a little tiny bit of horse pellets one cup in the morning…and one in the supper time to keep him used to coming when I call him in. I noticed today he is walking very slowly and I just feel like he is not himself. Have not changed his diet or access to pasture. This is the same routine he has had for 2 years. I’m perplexed. Is it just cause its summer and its been hot a couple of days…or…is he starting to founder?
May 12th, 2012 at 10:28 am
I have a horse that got grass founder around a month ago and has somewhat gotten better, but in the last week she’s gotten worse and we might have to put her down if she doesn’t get better. What can I do to help her recover?
May 14th, 2012 at 7:15 am
I have two quarter horses that wear grazing muzzles 24/7 (it’s taken off for 20 min. while they get their hand full of grain w/ supplements), the TB’s don;t have to wear them. Even if you take the muzzle off for 1/2 the day, studies have shown they make up for it. If you train your horse by putting a treat in the grazing muzzle, they automatically put there head down to let you put it on.I will always feel bad making them wear it, but it’s better than laminitis.
May 17th, 2012 at 6:01 am
I am moving my horse from florida to rich georgia grass. What schedule do I need to put her on? She is not used to the grass in Georgia.