Reproductive performance in a cat colony over a 10-year period

Abstract

Various aspects of reproductive performance in a cat colony are analysed in order to provide a basis for future studies. The aspects considered are: effect of mortality on litter size at different stages, and differential effect of losses on sex ratio of kittens reared; trend in litter size for successive parities; monthly variation in frequency of litters and litter size; output of kittens per queen per year. The sex ratio for live kittens was found to be 99.3 males per 100 females. Significant lower sex ratios of 65.6 and 79.7 were found in stillborn and in kittens which died between birth and weaning respectively. The mean litter size was 4.20 born (4.07 after deducting stillbirths), 3.65 at weaning. An inverse relation was found between incidence of stillbirths and subsequent loss before weaning. The mortality rate in each case was 1.5 kittens per affected litter. The mean litter size was smaller for the first litter but then increased to a constant 'plateau' until almost the end of the queen's reproductive life. Litters were produced throughout the year, but with greater frequency in the early spring months and again in the late summer. Litter size was greater in the summer months. Kitten mortality was lower in the summer than in the winter. A mean of 10.8 kittens were born per queen per year, and the mean number weaned was 9.4, representing a survival rate of 87 per cent.