Fetotomy technique in the mare

Malposture of the long fetal extremities is the major cause of dystocia in the mare (Vandeplassche 1987; Frazer et al. 1997a). Many of these cases can be resolved safely and rapidly by fetotomy if the fetus is determined to be dead. One or 2 well-placed fetotomy cuts can dramatically shorten the intervention time and permit atraumatic delivery of a nonviable fetus. However, if the obstetrician is not familiar with correct fetotomy technique then the best option for the mare’s reproductive future may well be a caesarean section (Frazer 1997). The economic value of the mare, expertise, equipment and facilities available to the veterinarian, and owner’s preference determine which method is ultimately chosen as the method of resolution for those cases where attempts at manual correction of malpositions and malpostures have failed. Economic considerations include the future use of the mare (breeding vs. performance value), veterinary fees (anaesthesia and surgery vs. fetotomy) and the extended hospitalisation required for postsurgical management (Vandeplassche 1988; Youngquist 1988). Prominent veterinary obstetricians have made an important point in stating that, although some dystocias may be best resolved by surgical intervention, the expense of the procedure and aftercare exceed that of fetotomy (Vandeplassche et al. 1972; Vandeplassche 1980; Bierschwal and de Bois 1972). Therefore, the value of the mare is a significant factor to be considered prior to resorting to surgery. To be proficient with a fetotome the veterinarian must be able to recognise when the procedure is indicated, and have the technical knowledge to know where the cut or cuts should be made. However, the technical expertise necessary to manipulate the equipment and to perform the cut(s) required without traumatising the mare’s reproductive tract is achieved only with practice. Experience with bovine obstetrics provides a distinct advantage when it comes to performing a fetotomy in the mare. The procedure is not as easy as in the cow due to the longer equine birth canal and the impediment posed by the rapidly detaching fetal membranes (Frazer 1997). Therefore, this procedure should not be performed on a broodmare until the veterinarian has become proficient at bovine fetotomies and/or has worked under the supervision of an equine obstetrician who is experienced in the technique. For those who work exclusively on horses, the cases which provide an ideal learning opportunity are those where caesarean section is not an option, and the alternative to an attempted fetotomy would be euthanasia. It is the author’s opinion that, once perfected, this technique definitely has its place as a viable alternative to surgery in the management of certain equine dystocia cases, irrespective of the value of the mare. This article discusses the recommended approach to fetotomy in the mare. The reader is referred to previous volumes of this journal for articles on the correction of dystocia by vaginal (Frazer et al. 1999a,b) and caesarean section (Embertson 1992) delivery. Only the most commonly utilised fetotomy cuts will be described. Although more experienced clinicians may be able to perform the necessary cuts for correction of transverse presentations, ‘dog-sitting’ posture and ‘breech’ presentations, these complicated cuts are beyond the scope of this article (Bierschwal and de Bois 1972; Frazer 1997).