Effect of does parity order on litter homogeneity parameters

In rabbits’ reproductive performance, litter size, birth weight, growth, and mortality rate are among the most important indicators to define the productive potential and they are associated to parity order. Birth weight and little size are valuable parameters as related to mortality and weaning weight. Thus, it is important to study individual newborn and intra-litter homogeneity parameters. This trial aimed to consider the litter homogeneity weight at birth, both within each litter and in the whole population, in order to suggest new proper within-litter homogenization parameters. In this study, the 1st and 6th parity order had, respectively, the lowest and highest values in litter size (8.96 vs 12.39, n), born-alive (8.36 vs 12.22, n), litter weight (456.4 g vs 719.8, g), born-alive weight, and quartiles’ homogeneity. These parameters decreased in greater parity orders. No significant effects on still-born numbers and mortality rates were evidenced. All these litter homogeneity evaluation parameters appeared interesting in describing differences between parity orders. The results confirmed that does parity order influences litter size and born-alive weight, but also the intra- and inter-litter homogenization. Litter homogenization is crucial to ensure a proportionate share of milk, more equal growth, and better productive performances. Based on these results, we suggest for the commercial genetic centers to equalize the litters according to the birth weight, by dividing the population into quartiles and rearing kits with light birth weight in smaller litters and those with heavier birth weight in larger litters.