The birth sex ratio of domestic cats is close to 50/50 with slight male prevalence
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Studies examining the reproductive patterns and litters of domestic cat breeds find that the birth sex ratio is close to even while demonstrating a slight, statistically significant predominance of male kittens.
Some aspects of maternal behaviour and their effect on kittens’ performance were investigated, analyzed, and compared among three breeds of domestic cats. Twenty-six pregnant queens (18 Persian, 6 Baladi, and 2 Siamese) and their kittens (88 kittens) were studied. Recorded parameters included dam’s age/year, body weight (kg), number of parities, Gestation Length (GL), Litter size (LS), Stages of parturition (3 stages), Circadian Rhythm of parturition, and Total Kittening Time (TKT). Hormones controlling pregnancy, parturition, and maternity (Progesterone [P4], Estradiol [E2], and Prolactin [PRL]) were analyzed 10 to 2 days before kittening. Five maternal behaviour traits were evaluated: Licking, Suckling, Defense, Retrieving, and Placentophagia. Kittens’ performance was assessed through birth weight, body weight over four weeks, Sex ratio, Kittens’ loss, and Single Kitten Syndrome (SKS).GL ranged from 56 to 58 days, and parity ranged from 1 to 5. LS. varied between individuals and breeds: Persian recorded (1–7), Baladi and Siamese recorded (2–4). TKT was affected by LS, maternal behaviour, and parity. Most parturitions (73.1%) occurred between 18:00 to 06:00hrs, versus 26.9% between 06:00 to18:00hrs. Higher hormone levels were recorded in Persian queens (especially Progesterone and Estradiol) (Progesterone: 14.86 ± 11.77 ng/ml; Estradiol: 20.52 ± 12.07 pg/ml); while Prolactin recorded 11.80 ± 6.75 ng/ml compared to Baladi queens (P4: 9.62 ± 8.89; E2: 8.55 ± 10.87; and higher
A survey of Brisbane catteries was carried out to investigate reproductive patterns of pedigree cats. Eighteen breeders supplied data on 751 litters with a total of 3171 kittens covering the Persian, Chinchilla, Siamese, Burmese and Abyssinian breeds. The overall sex ratio at birth was 100 males to 92 females. There was a significant seasonal effect on sex ratio with litters conceived during the wet season (September to February) producing more males than expected and litters conceived during the dry season producing more females than expected. Litter size and breed had no significant effect on the sex ratio. The average litter size varied with the breed with the most prolific being the Burmese (5.0) then the Siamese (4.5), Persian (3.9), Abyssinian (3.5) and Chinchilla (2.8). The average litter size was smaller for the first litter than for the subsequent 3 litters. The maximum average litter size was reached at 6 years with only a moderate decline thereafter. There was a seasonal fluctuation in births with the greatest numbers being born in spring and the least in late autumn. Longhair cats showed a more marked seasonal distribution of births than the shorthairs which reproduced for most of the year, particularly the Burmese breed.
The main goal of purebred cat breeding is to produce healthy offspring while maintaining breed purity. Pedigree cat breeders are affiliated with international federations that enforce similar breeding regulations, which helps prevent the overexploitation of cats in breeding. The minimum age for allowing a cat to breed is at least 10 months. This study aimed to analyze the breeding performance of three cat breeds: Maine Coon (MCO), British Shorthair (BSH), and Devon Rex (DRX). These breeds are classified as late-maturing (MCO), medium-late maturing (BSH), and early-maturing (DRX). The analysis was based on pedigree data obtained from the Polish Felinological Association, which operates under the auspices of the World Cat Federation. In total, data from 1016 litters (453 MCO, 453 BSH, and 110 DRX) were analyzed. Breeds differed significantly in age at first birth (p = 0.041), mean interval between litters (p < 0.01), and mean number of kittens per litter (p < 0.01). Breed effects were also noted for the mean interval between births (p < 0.01), mean number of kittens per litter (p < 0.01), and the total number of kittens sired by the mother (p = 0.007). Within each breed, differences were found in the sex ratio of litters, with a predominance of males in DRX (p = 0.049), MCO (p = 0.003), and overall breeds (p = 0.036). In contrast, the BSH breed showed no significant difference in the sex ratio of litters (p = 0.455). In both the MCO and DRX breeds, the lowest average interval between litters was observed in females that gave birth to their first litter early compared to those that gave birth later. The total number of kittens raised by the mother was highest in the MCO breed (p ≤ 0.05), while the shortest litter spacing was found in the DRX breed (p ≤ 0.05).
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