Fil Tell Tail Spray On Tail Paint is an oil based fluorescent paint used for heat detection in cattle. The paint is easy to apply and the vivid colours makes it easy to see your markings. When applied properly the markings can last up to 28 days. Tell Tail Spray On Tail Paint is weather resistant and does not irritate the skin of cattle. Before using Tell Tail Spray on paint, you should ensure your animals are clean and dry and remove any loose hair. Apply the paint in a stripe along the spine (around 15cm long), starting at the head of the tail.