The degree of cleft palate ranges from tiny holes to a large central fissure running from front to back of the roof of the mouth and affecting the upper jaw line (hare-lip). Sometimes both palates may be completely absent. There is a possibility that heredity is involved (e.g. due to short or broad facial shape in Persians and Exotics). Generally cases are random and due to abnormal fetal development in the womb, possibly due to metabolic disturbances, drugs given to a pregnant cat, to chemicals or radiation.
Effects depend on the severity of the deformity. Milk is forced through the holes and into the nasal passages. It trickles or bubbles out of the nostrils during and after feeding. Kittens may sneeze when suckling. The amount of milk exiting from the nostrils affects growth (less milk reaches the stomach). Milk may enter the lungs causing respiratory infections such as aspiration pneumonia or even drowning. The reduced amount reaching the stomach may lead to starvation.
Small holes may cause lesser problems, but the holes cannot heal if the kitten is allowed to suckle. These kittens should be tube-fed to allow the holes to seal shut. Fine holes may close over in approximately one week. Larger holes or fissures will not heal unaided. The kittens must be tube-fed until it is robust enough for surgery at 6 – 8 weeks old (soft palate) with repair of the hard palate at approximately 6 months old. After surgical repair the cat can lead normal lives. The problems involved in rearing affected kittens means that euthanasia is usually advised. If a hereditary cause is suspected, do not breed from affected animals.