Feline reproduction FAQs (Proceedings)
Excerpted with permission from Root Kustritz MV. Feline reproduction FAQs. Clinical Theriogenology 2010;2:230-232.
Many veterinarians graduate with no formal education in feline reproduction; cats were not identified as one of the "major" species in which theriogenology training was required at most schools surveyed. In a study in which practitioners across the United States were asked to rank which procedures in theriogenology they performed most commonly by species, dystocia management and treatment of reproductive tract disease were those listed most commonly for the cat. This mirrors a survey of veterinarians on the Society for Theriogenology small animal list-serve, who rated dystocia management, diagnosis and treatment of pyometra, broad management of infertility, and ovarian remnant syndrome as the most common disorders presented in feline reproduction in their practices. This is a review of three common disorders seen in feline reproductive practice.
DystociaDystocia, abnormal queening, is reported to occur in 3 to 6% of cat parturitions. Veterinary students report great fear around dystocia and practitioners mimic this concern, perhaps because of the possibility of impacting several lives.
Dystocia can be maternal or fetal in origin. The most common reported maternal cause is uterine inertia, lack of synchronous uterine contractions. The most common reported fetal cause is malpresentation, due to oversize or abnormal orientation of the limbs or head relative to the spine. Brachycephalic and dolicocephalic breeds are at increased risk. Dystocia is present if gestation is prolonged, labor is not progressing, the queen appears systemically ill, or the fetuses are in distress.
Normal gestation length is queens averages 66.9 days and varies from 62 to 71 days. Despite induction of ovulation and a commonly restricted number of days of breeding, gestation length is truly this variable and cannot be estimated based on other factors such as litter size. Therefore, gestation is not automatically considered prolonged unless the queen is at least 71 days past the last known breeding.
Normal parturition length in cats is prolonged compared to dogs. Mean parturition length is 16.1 hours with a range of 4 to 42. In the author's colony, one cat queened 4 kittens over 3 calendar days; one of them was stillborn but it was the 3rd one born, not the final one. In general, the first kitten should be passed within 4 hours of onset of active labor and subsequent kittens passed at least every 2 hours. Because queens apparently may inhibit labor voluntarily due to stress, the queen should undergo a complete physical examination and the kittens should be assessed for viability by verification of heart rate greater than 170 to 200 bpm as part of any decision whether to intervene.
Medical therapy is reported to be effective in cats only 29.9% of the time that it is attempted. Whether this is due to medical treatment being used when surgical treatment is called for or to variable responses of queens to medical therapy with oxytocin compared to other species is not clear. Radiography is recommended to best predict whether fetuses are of a size suitable for vaginal delivery.
Medical therapy includes administration of oxytocin (0.1 to 0.25 IU SQ or IM) and calcium gluconate (10% solution, 0.5 to 1.0 ml SQ or IM).5 If the cat does not respond after 1 or 2 injections at 20 to 30 minute intervals, surgical treatment by Cesarean section is recommended. In one survey of 1056 births, 8% were resolved by C-section.