Records of 840 litters of Bauscat (B) and Giza White (G) rabbits were analyzed to quantify sire of doe, doe within sire, parity, month of kindling, birth litter size and birth litter weight effects for litter traits at weaning. No definite trends for parity effects on weaning litter size and preweaning litter mortality were detected. Preweaning litter gain and mean kit weight at weaning (except mean kit weight in B rabbits) increased linearly (P < 0.001) as parity advanced. There was a general tendency for litter size, litter gain and mean kit weight to be low when kindling took place in the early months of the year of production (October and November) and to increase significantly in a curvilinear manner as month of kindling advanced. Prewean-ing litter mortality decreased in quadratic pattern (P < 0.001) as month of kindling advanced until March and increased thereafter during April and May.
Litter size at weaning and preweaning litter gain increased linearly (P < 0.01 or P < 0.001) with increase of litter size at birth while mean kit weight decreased linearly (P < 0.001) hut at a decreasing rate. Birth-litter-size effects on preweaning mortality were very limited.
Litter size, litter gain and mean kit weight increased by the improvement of weight of litter at birth. Preweaning mortality decreased as birth litter weight increased, but the differences were of little magnitude and can be ignored.
The sire of doe significantly affected all litter traits studied with the exception of litter size in G breed and preweaning mortality in B while the doe had a non-significant effect on traits of both breeds, with the exception of litter gain (P < 0.05 or P < 0.01). |
