Effect of level of fibre and type of grinding on the performance of rabbit does and their litters during the first three lactations

Abstract

To study the effects of fibre level and particle size on rabbit performance, four diets in a 2 × 2 factorial arrangement were used with high (HF) and low (LF) fibre level (34 vs. 27% NDF, % DM) and coarse (CG) and normal (NG) type of grinding of the main sources of fibre (alfalfa hay and wheat straw). This resulted in a proportion of particles > 0.3 mm of 35, 24, 24 and 20% (on DM basis) for HF-CG, HF-NG, LF-CG and LF-NG diets, respectively. HF diets contained 4.2% pork lard to balance the digestible energy/protein ratios. Seventy two nulliparous rabbit does were randomly assigned to the diets (18 per diet) and controlled up to their fourth parturition. Remating interval was fixed at four days after parturition and weaning age at 25 days. Twenty does died or were culled during the experiment because of low prolificacy and infertility. CG diets reduced culling level from 22 to 2.8% ( P = 0.008) compared to NG diets. Digestible energy (DE) intake was not affected by treatments during lactation or among parturitions. However, an interaction NDF level × type of grinding was observed for feed and DE intake from weaning to parturition, as rabbit does fed HF-NG and LF-CG diets ate 10% more feed ( P = 0.040) and DE ( P = 0.053), and showed a shorter parturition-effective mating interval (− 5.3 days, P = 0.028) than those fed HF-CG and LF-NG. Animals fed LF-NG tended to have the lowest feed efficiency among parturitions ( P = 0.079). In rabbits fed LF, total milk production and litter growth rate from birth to 21 days decreased by 9% compared to those fed HF diets that included added fat ( P ≤ 0.013). Litters from rabbit does fed LF or NG diets increased ( P ≤ 0.040) their feed intake from 21 to 25 days, avoiding differences among treatments in litter weight gain during lactation. Post-weaning feed efficiency was less with LF diets ( P = 0.045). Thus, fineness of grinding of fibre sources should therefore be taken into account, especially in low fibre diets to optimize rabbit doe performance.