Impact of Crossing Baladi-Red and Acclimatized Bauscat Rabbits (Oryctolagus Cuniculus) on Post-Weaning Weights of Offspring in A Semi-Arid Egyptian Environment

Abstract

The study aimed to determine the effects of reciprocal-crossing rabbits on post weaning growth traits. The breeding plan included Bauscat and Baladi-Red rabbit breeds and their F1 reciprocal crosses. The studied effects, focused in particular on the significance of the direction of the cross and the direct and maternal additive effects. Results revealed that Crossbreeding Bau and BR rabbits consistently resulted in positive heterosis, meaning that offspring outperformed the average of their purebred parents. This translated to a 3.09% to 19.07% increase in post-weaning weight for crossbreds, representing a gain of 61.54 g to 114.32 g. The direction of the cross had a major impact on the magnitude of heterosis. The crossbreeding direction BR(♂)xBau(♀): showed the most significant positive heterosis, meaning the offspring were substantially heavier and grew faster. However, the cross (Bau,♂xBR,♀) though still showing some heterosis, it was less pronounced than the BR,♂ x Bau,♀ direction, highlighting how crucial sire and dam selection is. Bau sires consistently passed on favourable genes for growth, resulting in positive direct additive effects. Their offspring showed a consistent growth advantage, particularly between weeks 5 to 9. This finding suggests that prioritizing Bau rabbits as sires, in crossbreeding programs can significantly enhance growth traits in offspring. Maternal Additive effects, were generally less significant than direct additive and heterotic effects, suggesting the sire's genetic contribution plays a more prominent role in this cross. However, BR dams showed a slight advantage in some growth traits, indicating a possible, but less impactful, (non-significant), maternal influence.