Partial diallel cross for assessing genetic merit of local rabbit breed

This study was carried out to estimate general combining ability (GCA) and specific combining ability (SCA) of pre-and post-weaning traits from a partial diallel cross in three rabbit breeds: Local rabbit (L), Flemish Giant (F), and Rex (R). Body weight at 0 (BW0), 30 (BW30), 42 (BW42), and 63 (BW63) days of age, average daily gains from 0 to 30 d of age (ADG0-30), from 30 to 42 d of age (ADG30-42), from 42 to 63 d of age (ADG42-63), and from 30 to 63 d of age (ADG30-63), litter size at birth (LS0) and at weaning (LS42), and mortality at weaning (MR42) were studied in crossing LL, FF, RR, LF, LR, and FR. Local breed had the highest GCA for BW0, BW30, BW42, and average daily gain before weaning (ADG0-30, and ADG30-42) compared to Flemish Giant and Rex, while GCA of Local breed for average daily gain after weaning (ADG42-63), litter size (LS0, and LS42), and mortality (MR42) was higher than for Rex and similar to that of Flemish Giant. Crossing LF and LR showed higher SCA for BW30, BW42, BW63, ADG0-30, ADG42-63 and ADG30-63 than FR. In conclusion, based on GCA and SCA, the Indonesian Local breed has a high genetic potential in the crossing with Flemish Giant and Rex breeds.

Genetic analysis of functional longevity in a complete diallel crossing experiment involving four maternal rabbit lines

In a diallel cross between four maternal lines of rabbits, the four maternal lines and the corresponding crossbred females (does) were evaluated concerning functional longevity, estimating their crossbreeding components. Sixteen genetic groups were produced by using four maternal lines of rabbit (A, V, H and LP (L)). The groups were distributed over 4 Spanish farms. In all farms, the V line was present as the reference group. A total of 7,211 does' longevity records were recorded. Using a Cox proportional hazard model of fixed effects, survival analysis was performed to study longevity analysing the hazard of death or culling. Does from lines A, H and V had similar risks of death or of being culled, and they were more susceptible compared with those from line L. The lowest hazard was associated with L line does. No significant differences were found between the average of all crosses and the V line except when comparing the V line to the cross between A and H lines, favouring the former (1.30 higher risk of replacement for AH animals). Significant differences between reciprocal crosses were observed between VH and HV, in favour of HV (0.72 of relative risk of replacement) and between LH and HL, in favour of HL (0.76 of relative risk). Line V had the highest risk due to the direct genetic effects, and these differences were significant with the lines H (1.40 of relative risk) and L (1.43 of relative risk). The differences in maternal genetic effects were small and not significant except between lines H and V in favour of V line (0.75 of relative risk). The estimated direct heterosis effects do not always follow the same trend but they showed the importance of the crossing between specialized lines to produce crossbred does for intensive meat rabbit production.

A comparison of the growth performance, carcass traits, and behavior of guinea pigs reared in wire cages and floor pens for meat production

To achieve efficient production of guinea pigs for meat, it is essential to determine the most suitable housing system. A total of 220 guinea pigs were maintained in either wire cages (n = 11, 10 animals per cage) or floor pens (n = 11, 10 animals per pen) containing a deep litter of woodchips, both housing systems having the same dimensions (2 × 1 × 0.4 m). Growth traits, food intake and feed conversion ratio were recorded weekly and expressed as the difference between the two groups. After 77 days, the animals were slaughtered, and carcass traits were evaluated. Growth performance and carcass trait parameters, as well as mortality and behavior trends, were not affected by the housing system type. Nonetheless, the use of wire cages is recommended for raising guinea pigs since water, urine and feces pass through the wire floor, resulting in cleaner animals.

Genetic analysis of meat quality traits in maternal lines of rabbit and their diallel cross

Young rabbits, the dams of which came from a full diallel cross among four maternal lines (A, V, H and LP) and the sires from a single paternal line (R), that produce sixteen genetic groups, was carried out to evaluate the genetic groups and to estimate the crossbreeding genetic parameters of meat quality. The meat quality traits were recorded by NIRS from a sample of 285 longissimus lumborum muscles. Crossbreeding parameters were estimated according to Dickerson model. No differences in protein were found. The line A had significant differences with V line for intramuscular fat, and fatty acids groups. Significant differences for these traits appeared between the crossbred AH and VV (in favor of AH). As conclusion, the significant contrasts between genetic types for chemical composition of the meat are mainly consequence of direct-maternal genetic effects, having grandmaternal and maternal heterosis effects a less relevant role.