Characterizat Ion of Straightbred and Crossbred Rabbits for Milk Production and Associative Traits I

Two hundred twenty-five lactation and litter performance records from 82 does representing four genetic groups and two diets were analyzed to quantify breed, heterosis, reciprocal F1 cross and diet effects for milk production and associative traits. Doe genetic groups were New Zealand White (NN) and Californian (CC) straightbred and Californian x New Zealand White (CN) and New Zealand White x Californian (NC) reciprocal crossbreds. Pelleted diets fed to does and litters were either a commercial control or a 74% alfalfa diet. Three sire breeds of litters included NN, CC and Flemish Giant (FG) straightbreds. Doe genetic group and diet were important sources of variation (P<.05) for all traits examined except for lit ter milk efficiency (litter gain/milk intake) and doe feed efficiency (milk yield/feed intake). The sire breed of l i t ter effect did not influence (P>.05) lactational performance of does nor associative preweaning traits. Straightbred NN does were heavier at kindling, yielded more milk, reared a heavier litter by 21 d and were more efficient in converting feed into milk than were straightbred CC does (P<.01). Significant heterosis was detected for milk production and for litter size and weight at 21 d. Reciprocal differences between crossbred doe groups were observed (P<.05) for lit ter mitk efficiency and doe feed intake. The 74% alfalfa diet was superior to the commercial