I learned about these accidentally last year and thought they were hilarious, so I bought some here: https://www.magnetsource.com/collections/cow-magnets-ru-ma

I learned about these accidentally last year and thought they were hilarious, so I bought some here: https://www.magnetsource.com/collections/cow-magnets-ru-master-5 https://www.magnetsource.com/collections/cow-magnets-ru-mast... I'm neither a veterinarian nor a cow, so I don't know how fit for purpose they are, but to me they seem well made.