In this article Dr.Andrea Münnich explains how to recognise and treat specific diseases that may affect neonates during the first weeks of life. The physiological parameters of neonatal kittens are different from adult cats and this makes neonates more susceptible to particular disease conditions. This article will outline how to identify abnormalities (including hypothermia and bacterial infections).
Neonatal Development of a Kitten
Neonates present some physiological differences when compared to adult cats including:
- Hypothermia (low body temperature)
- Reflex urination and defecation (usually taken care of my the mother)
- Glucosuria (glucose in the urine)
- Leucocytosis (increased presence of white blood cells in the bloodstream)
- Reduced drug metabolism (more susceptible to drug overdoses and toxicity).
Normal Development of a Kitten:
- Newborn body weight is often breed specific and dependant upon the parents
- Respiratory rate: 15-35 breaths / min
- Heart rate: 180-220 beats / min
- Body temperature: from 34.4 to 37.2 °C (depending on age of kitten in weeks).
||> 4 weeks
|34.4 - 37.2 °C
||35.0 - 37.8 °C
||36.1 - 37.8 °C
||38.3 - 38.8 °C
Table 1: Body temperature depending on age of kitten in weeks
||Umbilical cord drops off
||Flexor to extensor tendon dominance (tone in legs)
|From day 6-8
||Shivering during sleep, crawling starts
|From day 8
||Birth weight has doubled, opening of eyelids
|From day 13
|From day 18
||Walking begins, own defecation possible
|From day 28
Table 2: Kitten development timeline - first four weeks
Neonatal mortality is common and often unavoidable. Mortality rate is highly variable, ranging between 5-35% and is of highest risk during parturition, immediately after birth and in the first days of life.
Mortality depends on different factors including:
- Difficulties encountered during birth (dystocia)
- Low birth weight, and/or immaturity
- Genetic and/or teratogenic defects
- Maternal issues (e.g. uterine infection and/or mastitis)
- Environmental conditions (e.g. hygiene)
It is important to note that many non-infectious causes of disease can predispose kittens to more serious infections (as shown in the table below).
Pathologic hypothermia is defined as a body temperature less than 34°C.
This hypothermia could be the result of:
- Insufficient care of the mother and a cold environment
- Underlying disease and loss of body temperature if close to death.
Pathologic hypothermia predisposes the kitten to reduced intestinal motility (often referred to as ileus) and generalised bacterial infection. It is important to keep the kitten warm, and in the case of hypothermia to warm slowly.
Ill neonates frequently present with non-specific clinical signs that rarely hint at the underlying problem.
The following signs are abnormal in kittens and indicate a potential problem:
- Crying for longer than 20 minutes, restlessness
- No sucking and/or swallowing reflex
- Irregular breathing
- Weight stagnation
- Congenital abnormalities (visible or masked)
- No muscle tone (limp body).
Infectious diseases are the second most common cause for kitten losses (after perinatal losses during parturition or after a dystocia). These infections happen most frequently within the first weeks after birth with a second peak observed around weaning.
These infections can occur while the kitten is still in utero, during birth, , after birth, and within the first weeks of life. The first occurrence of clinical signs depends on the causative agent and time of infection.
There are many different bacterial species that can cause an infection in kittens (including: E.coli, S. intermedius, S. aureus, S. canis, Klebsiella sp., Pseudomonas sp., C. perfringens, and Enterococcus sp.). The queen and cattery itself can be the source of the infection. The Queen can infect kittens in utero or from vaginal secretion during birth, in the milk, oropharynx, skin, and faeces. Kittens can be infected orally, through the umbilicus, by breathing in infectious agents, skin contact and bacterial translocation (generally through the gut).
Normally, newborns are colonised during the first days by bacteria. Under non-stressful conditions, bacteria are commensal or will only induce mild symptoms, self-limiting disease or subclinical infection.
However some factors can predispose to infections including:
- Premature birth, difficult birth, and hypoxia during birth
- Factors affecting immunoglobulin absorption (i.e. maternal antibodies not absorbed by the neonate through the umbilicus)
- Hypothermia (reduced intestinal motility)
- Low birth weight
- Congenital abnormalities
- Poor hygiene in the cattery or birthing area.