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  Discussion on Grapes
Author Message
Member:
Dres

Posted on Saturday, Oct 22, 2005 - 6:30 pm:

Ok stupid question.. I called UCD they are closed, and I can't believe it but my local vet clinic could not answer my question.. are grapes on the vine harmful to horses..? yup, my mare wondered into the grapes and found out that she LOVES the raisin like grapes left hanging on the vines... I put her back in her paddock and am keeping an eye on her... I am figuring they are like other fruit only maybe more sugar ...

thanks in advance...
On the first day God created horses, on the second day he painted them with SPOTS..
Member:
Vickiann

Posted on Sunday, Oct 23, 2005 - 4:39 pm:

Some horse owners say their horses eat grapes in season without problems. AKC says not to feed grapes or (even worse) raisins to dogs because even a small amount can, in some instances, cause enough kidney damage to result in death. I have fed horses a few grapes (handful) off the vines without ill effect when out riding (before knowing what they can do to dogs), but would probably avoid giving them in the future just in case. Whenever my horses have gotten into anything toxic (acorns, mistletoe, toxic weeds) that seemed to be causing any problem, the Veterinarian always said to give Banamine due to its endotoxin properties. Good luck -- hope your mare will not suffer any ill effects!
Member:
Dres

Posted on Sunday, Oct 23, 2005 - 5:47 pm:

Vicki, thanks for the heads up... I watched her last night and this AM.. she is fine.. phewwww!! today I have cut down what is left of the grape vines... so she won't be getting into them again...
dang horses anyway....
On the first day God created horses, on the second day he painted them with SPOTS..
Member:
Vickiann

Posted on Sunday, Oct 23, 2005 - 8:08 pm:

Many folks believe horses will not eat anything that will harm them, but with my crew (though they have all the grass or hay they could desire),I am constantly amazed by what they will ingest that could and has made them ill. So glad your mare is fine.
Moderator:
DrO

Posted on Monday, Oct 24, 2005 - 7:22 am:

There are no reports of grapes or raisins being toxic to horses and we have a report of one farm feeding the left overs of grape pressings to horses for a forage. However there continues to be mounting evidence that grapes are poisonous to dogs, or at least some dogs:

J Vet Diagn Invest. 2005 May;17(3):223-31.
Canine renal pathology associated with grape or raisin ingestion: 10 cases.

Morrow CM, Valli VE, Volmer PA, Eubig PA.
Veterinary Diagnostic Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA.

Ten dogs suffered acute renal failure after ingesting > or = 3 g/kg (dry matter) of grapes or raisins. All dogs had degeneration or necrosis (or both) of proximal renal tubules with basement membranes remaining intact, and epithelial regeneration was observed in 5 out of 10 cases. Mineralized tubular debris or granular to proteinaceous casts (or both) were present in all cases. A golden-brown, globular, intracellular pigment of varying amounts and sizes was observed in 6 out of 10 cases with variable reaction with Prussian blue. Multifocal fibrinous arteritis of the large colon was seen in 2 out of 5 cases with globulin insudation of vessel wall demonstrated by immunohistochemical staining for immunoglobulin (Ig)G and IgM. Mineral analysis on frozen renal tissue from 2 out of 2 cases revealed mildly elevated Ca:P ratio in both. Clinically significant observations were preservation of the integrity of basement membranes after grape-induced tubular injury and presence of early epithelial regeneration. Thus, recovery may be possible if anuria is aggressively managed. With respect to potential pathophysiologic mechanisms, further research into the roles of calcium homeostasis, vascular reactivity, and the significance of the golden-brown pigment is indicated.
DrO
Member:
Dres

Posted on Monday, Oct 24, 2005 - 10:00 am:

Thanks Dr. O... like I said I watched her pretty closely for 24 hours and she was fine.. :-) ok now the dogs... THEY LOVE THE GRAPES... I have found them, all three, eating them off the vine when ripe.. ALWAYS SOMETHING TO WORRY ABOUT....
On the first day God created horses, on the second day he painted them with SPOTS..
Member:
Sully

Posted on Tuesday, Oct 25, 2005 - 12:12 am:

Could it be the seeded grapes that cause problems? My dog eats the seedless. Just wondering.

Thanks,

Nancy
Moderator:
DrO

Posted on Tuesday, Oct 25, 2005 - 6:50 am:

I have to admit when I first read about this, from some of you my dear members, I "hurumphed" but this is just one of several very recent reports that strongly supports this idea. The thing I cannot figure is why we don't hear more about this, or at least have more unexplained acute liver failures in dogs. There is still something here that we are not seeing...

Nancy there is a suggestion that it may have to do with the pigment in the grape, it may only be red or deep purple grapes. But until understood I think I would switch to some other treat.
DrO
Member:
Dres

Posted on Tuesday, Oct 25, 2005 - 9:44 am:

My grapes are the deep purple variety, don't know the name.. seedless as well... Next year I will make sure they are cut/ trimmed so that the dogs and horses can't get to them... **** UCD called back, said they could not find anything about grapes being toxic but to watch for possible colic signs...
On the first day God created horses, on the second day he painted them with SPOTS
Member:
Vickiann

Posted on Tuesday, Oct 25, 2005 - 12:24 pm:

Very interesting! One must wonder whether there could be an additional link between the dogs who have been lost. For instance, isn't Heart Guard an Ivermectin product? We know (or it is believed) that ivermectin use in horses greatly intensifies the toxicity of nightshade if both are ingested during the same time frame. Maybe there is some factor present that when combined with the grapes or raisins, sets the kidney destruction into motion. One would think, however, that would have been examined in the studies.
Member:
Shanson

Posted on Tuesday, Oct 25, 2005 - 12:54 pm:

I have no experience with horses and grapes, but last year, one of my dogs fell in love with the mustang grapes that grow wild at my country place. I didn't realize it at the time and don't know how many he ate, but I suspect it was quite a few. Within a day, he fell violently ill with diarrhea that was full of these undigested grapes. He didn't eat for several days and was seriously dehydrated. I was worried enough about him to have some tests run, but there was no permanent damage. A couple of days later, he was back to normal. I'm hoping he learned his lesson because there's no way to keep him out of those wild grapes when they're in season. Mustang grapes are deep purple and very sour/tart, so they're probably pretty hard on a dog's digestive tract.
Member:
Sully

Posted on Wednesday, Oct 26, 2005 - 12:58 am:

Thank You Dr. O. I have only feed her the light green seedless, but will refrain until I hear one way or the other.
Moderator:
DrO

Posted on Wednesday, Oct 26, 2005 - 8:03 am:

Ann, you should call UCD and give them the reference above, someone did not do a very good job of research. Or if they need more information this is an interesting recent study:
J Vet Intern Med. 2005 Sep-Oct;19(5):663-74.
Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992-2002).

Eubig PA, Brady MS, Gwaltney-Brant SM, Khan SA, Mazzaferro EM, Morrow CM.
American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center, Urbana, IL, USA. peubig@apcc.aspca.org

A review of records from the AnTox database of the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center identified 43 dogs that developed increased blood urea nitrogen concentration, serum creatinine concentration, or both as well as clinical signs after ingesting grapes, raisins, or both. Clinical findings, laboratory findings, histopathological findings, treatments performed, and outcome were evaluated. All dogs vomited, and lethargy, anorexia, and diarrhea were other common clinical signs. Decreased urine output, ataxia, or weakness were associated with a negative outcome. High calcium x phosphorus product (Ca x P), hyperphosphatemia, and hypercalcemia were present in 95%, 90%, and 62% of the dogs in which these variables were evaluated. Extremely high initial total calcium concentration, peak total calcium concentration, initial Ca x P, and peak Ca x P were negative prognostic indicators. Proximal renal tubular necrosis was the most consistent finding in dogs for which histopathology was evaluated. Fifty-three percent of the 43 dogs survived, with 15 of these 23 having a complete resolution of clinical signs and azotemia. Although the mechanism of renal injury from grapes and raisins remains unclear, the findings of this study contribute to an understanding of the clinical course of acute renal failure that can occur after ingestion of grapes or raisins in dogs.
DrO
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