That’s weird. Maybe the code is placed in the file of your theme or plugins. Could you please try to reproduce the issue on one of the WordPress’ stock themes (like Twenty Sixteen) with other plugins deactivated? If it disappears, then you can activate the theme and plugins one by one to see which one causes the issue.
If the issue disappeared when you changed the theme, then it means that the code is registered in your theme. I suggest you run a text search (field_breed) by using a search tool. There are several tools that can do it: http://stackoverflow.com/questions/317944/tools-to-search-for-strings-inside-files-without-indexing.
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