Effect of Weight at First Mating on the Performance of New Zealand White Rabbit Population in the Rainforest Zone of Nigeria

It has been generally accepted that for breeders to embark on intensive production of rabbits there is a need to use appropriate body weight rabbit that has better performance. To provide such information, this study was therefore carried out to determine the effect of weight at first mating on the performance of the New Zealand White rabbit population at the University of Benin Teaching and Research Farm. The rabbits were grouped into four based on their weight before the first service (1.00 to 1.49kg, 1.50 to 1.99kg, 2.00 to 2.49kg, and 2.5kg and above) as weight groups 1, 2, 3, and 4 respectively. The rabbits were raised under acceptable management. The experimental animals were fed a commercial diet of 18% CP and 2700kcal/kg ME. Data collected were weight of doe before service (WBS), number of time served (NTS), litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB), litter weight at weaning (LWW), pre-weaning mortality percentage (PWM), gestation length (GLT), and stillbirth (SBT). The data were subjected to statistical analysis using the R statistical package version 3.3.3 (2017). Significant means were separated using the Duncan Multiple Range Test. The results obtained showed an increasing trend with body weight at first service. The mean values for LWB were 40.08±1.04, 43.83±2.16, 49.26±2.93 and 45.57±3.74 g for weight groups 1, 2, 3, and 4, respectively. Rabbits in weight 2 and 3 had a higher CV of 30%. Mean LWW ranged from 366.20±26.92 in group 1 to 442.90±29.74 in weight group 4. The average LSB was 4 kits. Litter sizes at weaning (LSW) were 3 kits except for group 4 with 4 kits. The body weight at first mating had no significant effect (P>0.05) on the performance traits. Gestation length (GLT) and pre-weaning mortality (PWM) showed significance (P<0.05). Gestation length (GLT) was highest in weight group 4 with mean days of 32.14±0.40 and the least in group 3 (30.53±0.09). Percentage SBT was highest in group 3 (10.48%) and none was recorded in group 4, 0.00±0.00. Percentage PWM was highest in groups 1 and 2 with 23.25% and 1.50%, respectively, while there was no PWM recorded in groups 3 and 4. The results of the efficiency of gain of offspring from the weight group were not significantly different (P>0.05) except for mortality which showed a significant difference (P<0.05). Rabbits from weight groups 1 and 3 showed better performance but for the high mortality in group 1, it will be better to mate rabbits for the first time at weight group 3.