Genetic analysis of growth traits in the progeny of rabbit does from a diallel cross

Abstract

An experiment was carried out to estimate the genetic group effects and the crossbreeding genetic parameters of growth traits [body weight (BW), average daily gain (ADG), feed intake (FI) and feed conversion ratio (FCR)] in rabbits during fattening between 28 and 63 d. The rabbits were the progeny of does coming from a full diallel cross between 4 maternal lines (A, V, H and LP) mated to bucks of the paternal line R. On thousand fifty five rabbits were controlled and the traits were recorded weekly, with the cage as the experimental unit for FI and FCR (283 cages). The genetic group (V line) was present in all farms in order to connect records among them and to be used as reference group. Crossbreeding parameters were estimated according to the Dickerson model. Regarding dam effects between pure lines for BW at weaning, A line was the heaviest and showed significant differences with LP and V lines (61 and 30 g, respectively). Upon completion of the fattening period, the differences in favour of A line for BW at weaning were compensated. Throughout the fattening period, no significant differences were observed between the lines as dam lines. At the end of the fattening period, no significant differences were observed between the crossbred groups. Regarding the reciprocal effects, the most relevant results were the significances for FCR in favour of H as sire line. For all traits, the confidence intervals at 95% of all contrast and effects were large. The estimates of maternal heterosis were, in general, negative, which could be a consequence of the positive heterosis for litter size. The AH cross showed significant maternal heterosis for BW at 43 d (-53 g), ADG between 28 and 42 d (-3.5 g/d), FI between 28 and 63 d (-7 g/d) and FCR between 42 and 63 d (-0.15). The combination of direct and maternal effects of the V line was the worst for all growth traits, showing significant differences with the LP line for most of them, for instance 0.13 worse FCR between 28 and 63 d. Grand-maternal effects were less important than direct-maternal.

Genetic analysis of slaughter and carcass quality traits in crossbred rabbits coming from a diallel cross of four maternal lines

“…For LW63 no significant differences were observed. Mínguez et al (2015) studied the same animals for body weight at 63 d and, also, they did not observe significant differences. The small differences observed between Mínguez et al (2015) and our study are probably due to the fact that LW63 was measured after a day of fasting.…”

“…L is used to identify the LP line as sire or dam of a genetic group. The animals used for this study were a sample of the animals used by Mínguez et al (2015).…”

“…In each farm, the same experimental design was performed. The distribution of the does in the farms was described by Mínguez et al (2015). The genetic group VV was present in all farms, allowing data connection across farms, but as this was the only genetic type in all the farms, no interaction between farm and genetic type could be considered.…”

“…Estimable functions of the crossbreeding parameters were obtained by adjusting by generalised least squares the estimates of the genetic group effects (as contrasts to the V line) to the coefficients described in Mínguez et al (2015). In this generalised least squares procedure the error (co)variance matrix between the estimates of the genetic group effects was used as weighting matrix (Baselga et al, 2003).…”

“…As Mínguez et al (2015) made for growth traits; we consider the different crossbred groups (the average of a cross and its reciprocal) compared to the V line (Table 3). In a global comparison of Tables 2 and 3, we observed that the contrasts between crossbreds and line V were smaller than between pure lines, i.e.…”