New intriguing implications of epidural prostaglandin F 2 alpha (PgF 2α) administration in the dairy cow: a case report.

Introduction - Prostaglandin F 2 alpha (PgF 2 alpha) are widely used in bovine reproduction for induction of parturition, oestrus induction, luteolysis, whereas, in mice models, they have been supposed to modulate cervical ripening and uterine remodeling. Recent in vitro studies have shown that the I and II dorsal laminae of the rat spinal cord are endowed with prostaglandin F receptors which are mainly involved in the modulation of pain. The epidural route of administration of many substances has been successfully tested, in vivo, for the resolution of reproductive diseases in the dairy cow. Aim - To describe the effects of the epidural PgF 2 alpha administration in a dairy cow undergone caesarean section. Materials and Methods: A pluriparous Brown-Swiss dairy cow underwent caesarean section on the 312th day after A.I., since, upon clinical examination, a vital calf in longitudinal anterior presentation was perceived, in absence of myometrial contraction and cervical opening. A female macrosomic calf, weighing 72 kgs was extracted; the calf died within half an hour after surgery, despite resuscitation procedures. At necropsy, teratologic traits were noted such as ram-like profile, lack of fusion of the frontal and parietal bones, microcephaly and pituitary agenesia, accounting for the inability of the alive foetus to perceive and transduce foetal stress to the mother and provoke calving. Oxytocin (10 I.U./100 kg B.W.) was administered intramuscular via to the mother, to stimulate cervical opening, lochia expulsion and milk ejection. Given the absence of oxytocin effect, 24 hour later dinoprost (25 mg) was given to the cow, with the same purposes and no results, therefore dinoprost (12.5 mg) was administered again, epidural via, 24 and 48 hrs later, in the sacro-coccygeal space. Results - The epidural PgF 2 alpha administration resulted in cervical dilatation, udder development and colostrum/milk production. Discussion - The results obtained through the unusual epidural administration suggest the hypothesis that dinoprost may have travelled along the nervous fibers (neurocrine process), reaching the cervix and the udder provoking ripening and local prolactin synthesis, respectively. Another interpretation relies on possibility that the bovine spinal cord might bear prostaglandin F receptors such as it has been found in the rat and that, upon activation, dinoprost may have depolarized the fibers innervating the udder and cervix, triggering cervical dilation and lactogenesis. Conclusions - These preliminary and interesting results need testing on a wider number of cows and deepening with histological researches. In this way, the mechanism of action of epidural PgF 2 alpha administration could be inferred. Anyway, this case report, in the present form, could widen the current knowledge about the therapeutic effects of prostaglandins, related to the unusual epidural route of administration.