Relationships between fetal biometry, maternal factors and birth weight of purebred domestic cat kittens

The goal of this study was to evaluate the relation between kittens' birth weights and biometrical factors from the kittens and the mother during pregnancy. Knowing fetal birth weight could help in detecting abnormalities before parturition. A Caesarean-section or a postnatal management plan could be scheduled. Consequently, the neonatal mortality rate should be decreased. We used ultrasonographic measurements of femur length (FL) or fetal biparietal diameter (BPD), pregnancies, and maternal factors to obtain a model of prediction. For this purpose, linear mixed-effects models were used because of random effects (several fetuses for one queen and a few paired measurements) and fixed effects (litter size, pregnancy rank, weight, wither height, and age of the queen). This study was performed in 24 purebred queens with normal pregnancies and normal body conditions. Queens were scanned in the second half of pregnancy, using a micro-convex probe. They gave birth to 140 healthy kittens whose mean birth weight was 104 g (ranged 65 to 165 g). No correlation between the birth weight and the age of the queen, as a maternal factor alone, was observed. But the birth weight was found to be inversely proportional to the pregnancy rank and the litter size. Moreover, birth weight increased when the weight and wither height of queen increased. BPD and FL increased linearly during pregnancy so a model was used to estimate mean birth weight. Using this model, we found a correlation between mean birth weights and an association of parameters: maternal factors (wither height and age), and litter size.