Effects of animal type (wild vs. domestic) and diet alfalfa level on intake and digestibility of European adult rabbits (Oryctolagus cuniculus)

The aim of this study was to evaluate the effect of the level of alfalfa in the diet on feed intake and digestibility of two types of rabbits, wild (Oryctolagus cuniculus algirus) vs. domestic (O. cuniculus cuniculus). Ten wild (W; mean LW = 927 g) and 10 domestic (D; mean LW = 4,645 g) adult rabbit does were fed ad libitum two pelleted diets: a control diet (C) with 15% of dehydrated alfalfa hay (as feed basis) and a test diet (A) with 36% of dehydrated alfalfa hay (as feed basis), according to a change-over design. Wild does dry matter (DM) intake per kg live weight (BW) was 55% higher (p < .001) than the intake of the D ones (58 g vs. 37 g DM per kg BW respectively). However, no difference (p > .05) was found when intake was expressed per kg^0.75 BW (ca. 56 g DM) and tended to be higher (p = .07) in D does when expressed per kg^0.67 BW (62 g vs. 55 g DM). Domestic does showed a higher (p < .05) DM, organic matter, crude energy and neutral detergent fibre digestibility (3; 2; 3; 3 percentage points respectively) than W does. The amount of nutrients and energy digested by D does was lower per kg BW (p < .001), similar per kg^0.75 BW (p > .05) and tended to be higher per kg^0.67 BW (p < .1) than in W does. The diet content of alfalfa did not affect (p > .05) the feed intake nor the diet digestibility. This study suggests that W rabbits exhibit a higher intake per kg BW and a lower digestibility than their D counterparts, which results in similar digestible nutrient and energy intake per kg BW powered to 0.75. The nutritive value of dehydrated alfalfa for rabbits, evaluated through intake and digestibility, seems to be equivalent to their base diets (forage plus concentrate).

Growth performance, carcass characteristics and meat quality of growing rabbits housed in cages or open-air park

Abstract. The study was carried out to investigate the effects of two housing systems on the growth performance, carcass traits, and meat quality of growing rabbits during the terminal fattening period. The rabbits were lodged in conventional cages between 35 and 59 days of age (growing period). At this age, they were moved into two different housing systems until they were 87 days of age (fattening period). During the fattening period, 48 rabbits were housed in 12 wire cages (0.5×0.6×0.35 m) and 48 rabbits were housed in one open-air pasture pen (20×9 m). At 87 days, 12 rabbits per treatment were slaughtered and the carcass characteristics and meat quality were evaluated. During the fattening period, the rabbits reared in cages had significantly higher live weights (3 062 vs. 2 705 g), weight gains (45.9 vs. 34.2 g·d−1) and feed intakes (163.4 vs. 110.2 g·d−1) than those reared in pens. The rabbits in the open-air group had a lower percentage of dissectible fat (1.35 vs. 4.19 %), a higher proportion of hind part (34.9 vs. 33.1 %), and less hind leg muscle (79.3 vs. 81.9 %) than caged rabbits. The m. biceps femoris of the rabbits in the open-air group had a higher cooking loss (3.64 vs. 3.02 %), Warner-Bratzler Shear Force (4.26 vs. 3.29 kg·cm−2), and myoglobin concentration (0.41 vs. 0.32 mg·g−1) than caged rabbits. The housing system had no effect on the dressing out percentage, viscera proportion, and ultimate pH. Open-air housing system reduces the growth of rabbits and the fat content of carcasses and increases the redness colour of meat.

Age affects the laying performance and egg hatchability of red-legged partridges (Alectoris rufa) in captivity

Red-legged partridge breeders are frequently reared in captivity with the aim of producing fertile eggs and chicks. However, little is known regarding the role of breeder age on fertility and egg production performance. Therefore, we investigated the effects of breeder age on egg size and shape, flock reproductive performance, fertility, hatchability, and embryonic mortality. In experiment 1, the effects of breeders' age on fertility, hatchability of eggs, and embryo mortality were evaluated. We found that partridge breeder age significantly affected the onset of egg laying, egg production, number and proportion of settable eggs, hatchability, and fertility. Specifically, 1-yr-old females laid their first egg 1 wk later than 2, 3, or 4-yr-old birds. Furthermore, 2-yr-old females produced a significantly higher number of settable and fertile eggs than other females (53.0 vs. 46.4 to 48.5) and had a lower incidence of embryo mortality. In experiment 2, we examined the effects of breeder age, egg size, and egg shape on egg hatchability. We found that small eggs (<17.6 g) had a significantly lower hatchability than medium (17.6 to 18.9 g) or large eggs (>18.9 g). However, we did not observe any significant correlation between egg shape and hatchability. These results suggest that red-legged partridge breeders attain maximum reproductive capacity at 2 yr of age and produce fewer eggs with lower weight and hatchability thereafter.