Aspirin for cattle

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Jan 7, 2016
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Hey folks this is a 2 part question. So got a 8 month old calf that's become lame. So I have been told I can use Aspirin for pain relief. From what I have read there's no withdrawal time on it, is it true?? Secondly what is the dosage of normal household Aspirin? Before anyone asks yes I've checked his hoof and leg it all appears fine. I fear it's a shoulder sprain or something like that. And if he can't come out of it in a week or 2 I want the option of sending him off to butcher.
yeah that's an option but I don't want too be waiting on withdrawal times. And if Aspirin has no withdrawal time then thats a better fit for my situation.
At the last seminar I attended on pain relief in cattle (within the last 5 years)... the presenter mentioned aspirin... but said it was so close to ineffective that they no longer recommend it.

Pulled this from the abstract of a published paper on administration of aspirin to cattle (ca. 1975... almost 50 years ago, now... so consider accordingly):
"Despite slow absorption (half-time of absorption, 2.91 hours) of orally administered aspirin and rapid elimination (biologic half-life, 32 minutes) of salicylates, oral dosage of 100 mg/kg every 12 hours maintained serum salicylate concentration greater than 30 mug/ml, which was considered to be therapeutically effective."

Based on typical adult human aspirin tablet containing 325 mg, you would need to give 1 tablet per 7.15 pounds of body weight, twice daily, to achieve that target 30 mug/ml serum level. There are 240 grain and 480 grain aspirin boluses made for administration to cattle... but I've never used them... I never used aspirin while in practice. Perhaps Ken or Buck can weigh in, as I'm blathering strictly as an academic on this point.

An appropriate dose of Banamine(flunixin meglumine) - given INTRAVENOUSLY - has a minimum slaughter withdrawal of 4 days (7 days is better to ensure no residue above accepted limit). Intramuscular or subcutaneous administration is not an approved route for Banamine; therefore, there is no established slaugher withdrawal, if flunixin is given by those routes. FARAD (Food Animal Residue Avoidance Databank) indicates that a single IM dose of banamine has minimum 10-day recommended slaughter withdrawal (if given at 1.1-2.2 mg/kg in volumes of not more than 10 ml per injection site) - last time I looked before today, the recommended withdrawal time for one IM injection was 30 days. If you give more than one dose IM... it could take 60 days or longer for residues to clear.
Flunixin use is one of, if not THE, leading causes of condemnation of cull cattle carcasses due to violative tissue residues... because folks give it IM and then ship that lame cow for slaughter the next week, because she's not better. (Effective half-life of Banamine in the cow is about 9 hours)

I've used meloxicam in calves for post-procedure analgesia following dehorning, and some folks give it when castrating. But those calves are months away from going to slaughter, so withdrawal is not an issue.
Based on typical adult human aspirin tablet containing 325 mg, you would need to give 1 tablet per 7.15 pounds of body weight, twice daily, to achieve that target 30 mug/ml serum level.
Reminds me of few years ago when my vet was out of Meloxicam for my bull with a giant hematoma on his head but called it in to a local pharmacy. Imagine my surprise when I realized I had to give him 63 pills a day for 3 days, then 63 pills every other day. Lucky for me, I just dumped them in a bowl with cubes and the ones he couldn't get with his giant mouth, I just scopped 'em up and shoved them in his mouth (he was a total hand-feeder). Oh, and the bulls name was Johnson. I'm assuming Bo meant Bovine?😂
I can't say I've used it, might have suggested it occaisionally to people who wanted to do something at minimal expense to make themselves feel good about it.
LuckyP, do you know if the antipyretic effect of it requires the same levels?
To the OP if you do a search on here I am sure aspirin will come up, I think it was Dun that used to recommend it a fair bit. I don't know much about clearance times for it but a google search should show something up. I think 144hrs in race horses was needed to ensure a clear swab and if you take it before surgery there is a lasting effect on your clotting time of over a week I think.


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