Preweaning variables' influence on market traits in rabbits

Abstract

Influence of several preweaning variables on market trait determination was investigated using 338 fryer rabbits from 52 litters. Variables measured at 1, 8, and 15 d included litter size, individual kit body weight (BW), within-litter rank score for BW, and litter uniformity (coefficient of variation for BW among littermates; CV). Daily milk consumption in wk 1, 2, and 3 was used to determine average weekly dominance rank score and total weekly milk consumption. Market traits were individual average daily gain (ADG) and litter feed intake (FI) from 28 to 70 d, and 70-d BW (BW70), litter uniformity (CV70), litter size (LS70), and within-litter rank score for BW (RANK70). Market traits were analyzed separately by week involving preweaning variables and season of weaning as covariates. The week models provided the most accurate predictions of ADG, BW70, FI, and LS70 (R2 = .542, .712, .906, and .970, respectively). Prediction of CV70 and RANK70 was poor (R2 = .202 to .369). Season influenced ADG, BW70, and FI (partial R2 values of .285 to .435). Path analysis indicated that milk consumption and BW were more important in BW70 determination (28.4, 26.4, and 36.9% of total variation in wk 1, 2, and 3, respectively) than litter size (partial R2 < or = 2.0%). In wk 1, litter size plus dominance rank score primarily determined LS70 (direct and indirect contributions of 62.3 and 21.5%). Because of major seasonal influences, management should take measures to optimize feed intake and to improve doe milk yield and fryer gain performance.