Yes, oxytocin works best the first 24 hrs. Delilah got her shot wenesday night, after Owen got home, the uterus contracts and closes after 24 hrs. so for the oxytocin to help with any debris or residue in the uterus it needs to be administer during the 24 hr period after whelping. at least that is how i understand it. My Owen is not available on saturday nights unless is an Emergency ...LOL is College football night..
this is an excerpt from one of his books..
by Dr. Terry E. Reed
If the animals are injected within the first 24 hours after kindling, one usually utilizes Oxytocin U.S.P. for the evacuation effect it has upon the uterus to constrict very rapidly. When the uterus constricts, this forces all the foreign materials that may be contained in the uterus, as a result of kindling, out of the uterus so it does not allow infection to take place.
If the animal is injected after 24 hours of kindling, it is then recommended that one use some type of estrogen product in order to enhance the blood supply to the uterus. By the utilization of estrogen with the antibiotic, this allows the antibiotic to be much more effective.