Kitten losses will vary from 7% to over 30% depending on the breeds involved and the type of cattery. Research facilities that specialize in disease-free cats will have at least 4% kitten loss. That said, if a cattery is experiencing kitten deaths before weaning in excess of 20%, there is a serious problem and in order for those losses to reduce, the breeder is going to have to find out what is going on.
The most common times for kitten losses are during pregnancy (through resorptions or abortions), at birth (dystocia, stillbirths and weak kittens), within the first 2 weeks, and immediately following weaning.
Finding reasons for higher losses than normal will require veterinary diagnostics and persistence. It is important to keep an open mind to potential causes, in order to more quickly identify and reverse the causes. Usually this process will require several steps of tests, re-evaluation, and re-direction. Normal test results or negative test results are not a waste of money. Knowing what is not the problem can be as valuable as finding what is. It’s like building a pyramid. Your base will be broad, with every successive step becoming more focused until you get to the pinnacle.
What are considered more normal reasons for kitten losses? There are many factors that can impact these very fragile little lives. The very first indication of potential problem is the birthweight. Normally, a kitten will weigh between 90 and 110 grams. In terms of ounces, this is approximately 3 to 4 ounces. If you are using an ounce scale to weigh newborns, you are already at a disadvantage because you don’t have specific enough information to fully appreciate their birth weight. There are just over 28 grams per ounce. It is hard to evaluate weight gain, or lack of weight gain, from day to day with that much play room between ounces. Kittens smaller than 90 grams are at greater risk of dying.
Birth weight can be influenced by breed as well as the number of kittens in the litter. Understandably, large litters will likely have smaller kittens, while a singleton or small litter kittens are quite likely to be larger. Larger is not always better if the size is such to cause dystocia.
By weighing the kittens as soon after birth as possible, you establish a baseline from which to determine the health status of each kitten. This is tremendously valuable data since the first signs of a problem can usually be found in lack of weight gain from day to day. Picking up on this anomaly, even before other symptoms are evident, can mean the difference between life and death.
Healthy kittens will gain between 10 and 15 grams per day. By the time they are 2 weeks old, the kittens should have at least doubled their birth weight. Observation of these kittens will show content, well-fed babies with plump abdomens. When kittens are not getting enough to eat, they cry, restlessly seek out nourishment, and their abdomens are more flat.
By recording the birth weights and daily weight, you establish a definite pattern, not only for that kitten or litter, but over several litters, you also establish a norm for your cattery.
If you do have kittens with low birth weight (under 90 grams) there are several possible reasons. Obviously, premature kittens are usually going to be smaller. Some metabolic diseases (inherited), birth defects, and uterine infections will also cause small kittens. If a kitten weighs as little as 75 grams, it has significantly lower potential for survival. Those kittens born within the normal weight range, but who lose more than 10% after birth also have a greater risk of dying.
Kittens born with congenital defects are more likely to die. These birth defects can occur from a range of causes including drugs given to the mother during pregnancy, infections, and the kitten’s own genetic make-up among others. Of those kittens that are born dead, or die shortly after birth, approximately 20% will have an anatomical abnormality such as cleft palate, facial and or skull defects, heart defects, an abdomen that did not join sides at the midline, and incomplete twinning.
The act of being birthed can traumatize the newborn and cause insufficient oxygen. If the momma is over aggressive or cannibalistic, she may inflict trauma even if she doesn’t kill the kitten. A queen that is negligent may also cause problems. It is estimated that up to 10% of kitten losses can be attributed to birth or post-partum trauma.
When kittens are born, they are incapable of maintaining their body temperature. This makes them very vulnerable to hypothermia. The normal temperature of a newborn is 95° to 97° F. It isn’t until week 4 that they will reach 100° F. So the environmental temperature is critical for the survival of the young kittens. Room temperature should be between 85° and 95°F, with about 60% humidity.
If a kitten’s body temperature drops below 95° F, it is hypothermic. The lower the temperature, the more serious the condition. Other symptoms that may be seen include, slow heart rate (normal is 220 – 260 beats per minute), poor breathing, and coma. The cold kitten will not have a functioning intestinal tract, but that can be difficult to evaluate from outward signs.
A cold kitten needs to be re-warmed slowly using an incubator, a heat lamp, and a hot water bottle (be careful not to burn the kitten). It must be monitored closed and turned often. The body temperature should be taken frequently by rectum to make sure it doesn’t get over-warmed.
One of the biggest risks to a hypothermic kitten is when the owner attempts to feed it due to the risk of aspiration pneumonia or even drowning. The kitten must return to normal temperature range before it is fed. If it will nurse, that is best.
Along with the risk of hypothermia, hypoglycemia and dehydration are common causes of kitten death. The kitten does not have full function of its liver for a few weeks after birth. This means it does not have the resources an older animal does to access energy stores within the liver. It must get frequent feedings to maintain the necessary blood glucose levels. If it doesn’t take in the milk or food it needs as frequently as needed, it becomes hypoglycemic.
Dehydration is the other domino that commonly falls when a kitten is weakened by hypothermia or hypoglycemia, just as it can be the trigger to affect the other two conditions. All three interact closely. The kidneys in the newborn kitten cannot concentrate urine. The kitten looses water consistently, so if it is not nursing, it is quickly at risk of dehydration. Normally, a kitten’s gums should be moist, and have a dark red or pink color. If the gums have a pale color, and feel dry, the kitten may be 10% (or more) dehydrated. Since the kidneys can’t concentrate urine, normal urine is clear and colorless. If you are seeing dark urine, your kitten is dehydrated at the very least. If the kitten is only moderately dehydrated, not hypothermic or hypoglycemic yet, warmed electrolyte solutions such as Pedialyte can be used. If the kitten is also hypothermic and showing slow heart rate or other signs of illness, it needs to be treated by a veterinarian with IV fluids immediately; it is an emergency.
A difficult birth may well result in kittens that are too exhausted or traumatized to be able to nurse. Not only do they need the energy from nursing, but they need the maternal antibodies in the colostrum. They only have 16 to 20 hours to absorb those antibodies intact, before the cells of the intestines stop transporting those large proteins into the blood stream.
A queen that can’t produce the amount of milk needed to support her kittens will have crying, small weak kittens. First time queens can be slow coming into milk. Older queens may have trouble keeping milk production up because their body stores are not adequate to meet the demand of nutrients. If they have any dental disease, they may not be able to eat efficiently enough to take in the calories and nutrients needed as well. Understandably, sick or malnourished queens can have production problems. A difficult labor can exhaust the queen and she won’t eat when she needs to replenish her energy or drink enough to re-hydrate. Some family lines in breeds just are not strong lactation queens. Uterine infections and mammary inflammation or infection can decrease milk production. This is one of the situations that can be quickly identified if the kittens are getting weighed frequently. The sooner a queen with low milk production can be treated by a veterinarian, the more likely it will be to reverse it.
Cats are unique in terms of the queen’s colostrum and blood type incompatibility with the kittens. Most commonly, the queen will be a type-B, and the kittens type-A when this situation occurs. The queen’s antibodies attack the red blood cells in the kitten. Depending on the degree of polarity between the blood types, the kittens can die within 3 days, have severe anemia and illness that takes longer to kill them, or come out relatively unscathed with little more than the tips of their tails dying. This condition, called neonatal isoerythrolysis, is very preventable by simply blood typing queens and toms prior to breeding, and breeding only compatible animals.
Infectious causes of kitten loss can hit during pregnancy, during birth (exposure), the first two weeks after birth and at weaning. Those losses that occur during pregnancy may go undetected if the fetus is resorbed rather than aborted. Feline calicivirus, feline leukemia virus, feline herpesvirus type 1 and feline panleukopenia (parvo) virus are all capable of aborting pregnancies, causing stillbirths and weak kittens, and some of them can cause birth defects that will cause the death of kittens. Bacteria such as E.coli, ?-hemolytic strep, and specific types of staph can infect kittens through the placenta, during birth, by way of the umbilicus, through ingestion with nursing, respiratory exposure and skin wounds. While not primary causes of kitten deaths usually, intestinal parasites such as roundworms and hookworms, coccida, toxoplasmosis, and Giardia can weaken kittens to the point of vulnerability to secondary invaders.
If excessive kitten losses occur, it may well be a combination of several causes. To unravel the tangle, the breeder must be prepared to respond quickly when losses occur, in getting the appropriate samples to the veterinarian as soon as possible. Freezing tissue samples, dead kittens, afterbirth, etc, may damage the cells and microorganisms to the point where it is impossible to detect the original damage and source. Talk to your veterinarian and prepare ahead of time to know how to handle abortions, stillbirths, premature delivery and neonatal deaths. It takes persistence, but the effort will pay off in future saved lives.