Prevention of fetal suffering during ovariohysterectomy of pregnant animals

Abstract

JAVMA, Vol 240, No. 10, May 15, 2012 V who neuter cats and dogs sometimes find, for a variety of reasons, that they are required to spay pregnant animals. Ovariohysterectomy of pregnant animals in animal shelters and humane societies, for example, is commonly recommended to help reduce the overpopulation of unwanted dogs and cats and because shelters have a limited capacity to care for neonatal animals and neonatal animals often fare poorly in shelter environments. For feral cat control programs, ovariohysterectomy of pregnant females furthers the mission of population control and allows all animals brought to the clinic to be spayed the same day, eliminating the need for retrapping or extensive foster care. In the case of owned animals, owners may request pregnancy termination, and ovariohysterectomy is considered the best alternative for termination of unwanted pregnancies in cats and dogs not intended for breeding. Many veterinarians performing ovariohysterectomy in dogs and cats in the middle to later stages of pregnancy question the most appropriate way to ensure a humane death for in utero fetuses removed from the dam. Unfortunately, little guidance is available from published veterinary sources. For example, the 2007 AVMA guidelines on euthanasia, in the section on prenatal and neonatal euthanasia, simply state that “When ovarian hysterectomies are performed, euthanasia of feti should be accomplished as soon as possible after removal from the dam. Neonatal animals are relatively resistant to hypoxia.” However, the guidelines do not cite any research on whether chemical or physical means of euthanasia are recommended for in utero fetuses. In addition, the guidelines do not state the developmental stage at which fetuses might require euthanasia, nor do they recommend effective methods for euthanasia of fetuses or methods for determination of successful euthanasia. Similarly, no mention of fetal disposition is made in the Association of Shelter Veterinarians veterinary medical care guidelines for spay-neuter programs, nor is the topic discussed in other veterinary publications aimed at practitioners in the United States, including journals, textbooks, published guidelines, and trade magazines. The 2011 revision to the AVMA guidelines on euthanasia cites recent reviews indicating that euthanasia of fetuses is unnecessary, but this section is brief and may not provide sufficient information to assuage veterinarians’ concerns about fetal sensory awareness and suffering or provide veterinarians with an understanding of the various factors that influence fetal consciousness. Prevention of fetal suffering during ovariohysterectomy of pregnant animals