i don't know if this will help or not! i have been a meat cutter for 10 years, done kill floor all the way to the grocery shelf. During the time on the kill floor i noticed that a beef would have good flow to the neck when i stuck it right after the shot. If i did wait for more than 3 to 5 min. (usaully because it was still kicking) it would slow the flow and start to clot. Not sure but my thoughts are that as soon as the blood cools under normal body temp. it will clot. I hope this help!