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[EN] The objective of this study was to estimate the response to selection for total body fat content of rabbits measured by computer tomography (CT). A divergent selection experiment was performed using Pannon Ka rabbits, which were previously selected for number of kits born alive. The so-called zero generation consisted of 351 Pannon Ka rabbits, from which the index, total body fat volume (cm3) divided by the body weight (kg), was measured. Rabbits with low and high fat index values were selected to form the parent groups of the lean and fat lines, respectively. The lines consisted of 55-72 females and 35-47 males, depending on the line and generation. After three generations, the rabbits were evaluated by means of a single trait animal model. The fat index showed a moderate heritability estimate (0.28±0.03). The magnitude of the common litter effect was small (0.10±0.02). The breeding values averaged per generation provided slightly asymmetrical responses. Based on the results, the divergent selection was successful in confirming that CT is a very suitable method for performing selection for body composition traits.

[EN] The aim of the study was to examine the effect of hair shearing in growing rabbits reared at high ambient temperature. The live performance and carcass traits of growing rabbits reared at 20°C (not sheared, C, n=50) or at 28°C (not sheared, H, n=50, or sheared at 5, 7 and 9 wk, HS, n=50) were compared. The ambient temperature and relative humidity were 20.5±1.1°C and 54±11% in the 20°C room and 28.8±0.2°C and 35±8% in 28°C room, respectively. Feed intake of H and HS groups decreased by 29.0 and 20.4%, respectively, compared to C rabbits (P<0.001). The same data for weight gain were 24.6 and 16.9% (P<0.001), and for body weight at 12 wk were 16.8 and 11.5% (P<0.001). At the same time, the feed conversion ratio improved (C: 3.53, HS: 3.34, H: 3.31; P<0.001). Nevertheless, the mortality rate of rabbits was not affected by the studied treatment and was overall low (0-4%). No differences were observed in dressing out percentages either (ratio of chilled carcass (CC) to the slaughter weight: 61.6-61.9%). The ratio of liver to CC differed among the experimental groups, with the highest value recorded in C group and the lowest in H group; HS rabbits showed intermediate results (C: 4.86%, HS: 4.27%, H: 3.91%; P<0.001). Lower ratios of fat deposits to reference carcass were also observed in rabbits kept at high ambient temperature (perirenal fat: C: 2.59%, HS: 1.82%, H: 1.60%; P<0.001; scapular fat: C: 0.89%, HS: 0.66%, H: 0.51%; P<0.001). It can be concluded that the negative effect of higher ambient temperature (28 vs. 20°C) on production in growing rabbits can be reduced significantly by hair shearing.

[EN] Nest quality is important for the survival of new-born rabbits. Nesting material in rabbit farms generally consists of wood shavings, which is completely different from the dry grass used by the European wild rabbit (Oryctolagus cuniculus). The aim of the experiments was to examine which nest materials are preferred by rabbit does when building their nest. In experiment 1, the choice of multiparous rabbit does (n=37) among nest boxes bedded with different nesting materials was monitored. In each pen (1.0×1.83 m) 1 doe and 4 nest boxes (0.37×0.23×0.31 m) with different nest materials (meadow hay [H], wheat straw [S], fine fibre material [Lignocel®, L] or wood shavings [W]) were placed 3 days before the expected parturition (gestation length is about 31 d in the Pannon White breed). Some 48.6% of the does kindled in nest boxes that contained pure materials (L: 40.5%, S: 5.4%, H: 2.7%), and 51.3% of the does kindled in nest boxes where the nest materials of different nest boxes were mixed by the does (S with L: 21.5%, S with L and H: 5.4%, W with L: 8.1%, L with H and S: 5.4%). Does preferred kindling in the nest box bedded with L, and most of them refused the nest box with W. In experiment 2/a (n=32 does) and 2/b (n=25 does), each pen (1×0.91 m) was equipped with 3 and 2 hay racks and filled with H, S or L, and H or S, respectively. The experiments lasted from the 27th day of pregnancy until the day of parturition and 24-h video recordings (10 does/experiment) were evaluated throughout the experiment. The events of carrying the nest materials from the hay racks were registered. In experiment 2/a, the frequency of nest material carrying was highest on the day of parturition. The preferred nest material was L (compared to H and S) on each experimental day except day 30 of pregnancy. At the day of kindling, 87.5, 6.3 and 6.3% of the nests contained pure L, mixed L-H and L-S, respectively. In experiment 2/b, the frequency of nest material carrying (mostly S) was high

[EN] The aim of the experiment was to compare the reproductive performance and nursing behaviour of rabbit does reared under 2 different light intensities and observe the preference of does among cages with different light intensities. Female rabbits were randomly housed in 2 identical rooms, under the same housing conditions in wire-net cages. The 2 rooms only differed in the light intensity; group L: 150-200 lux (n=54 does, 230 inseminations), group D: 10-20 lux (n=54 does, 232 inseminations). Reproduction data from the first 5 consecutive reproductive cycles were evaluated. Nursing behaviour of the does (n = 24) was observed at the 2nd or 4th lactation. The preference of does (n=8) among 4 cages with different light intensities (10, 35, 75 or 155 lux) as examined. There were 6-7% difference between the 2 groups in the number of kits born in total and those born alive (born total: 11.25 vs. 10.59 kits, P<0.1; liveborn: 10.75 vs. 10.00 kits, P<0.05; in groups L and D, respectively). Suckling mortality was nearly 2% higher in group D (L: 8.1, D: 10.0%; P<0.1), and in consequence the litter size of this group at 35 d of age was lower than that of the L rabbits (L: 8.75, D: 8.45 kits; P<0.05). The light intensity did not affect litter and individual weights at 35 d of age. The average numbers of daily nursing events (L: 1.23/d, D: 1.32/d), the length (L: 208±49, D: 213±43 s) and the daily distribution of nursing events were not affected by high light intensity. During the light period of the day, the darkest cage (10 lux) was the most preferred by the does (44.0, 18.6, 17.9 and 19.5% in 10, 35, 75 and 155 lux cages, respectively; P<0.001). The lower light intensity had no unambiguously unfavourable effect on the reproductive performance and nursing behaviour of the does. Based on the preference test, a lower light intensity may be advantageous from the point of view of animal welfare.

[EN] The aim of the experiment was to compare 3 genetic groups, slaughtered at similar weights, to examine their productive and carcass traits and economic value. Three lines of the Pannon Breeding Programme, selected for different criteria, were examined in the experiment. Pannon Ka (PKa, maternal line) does were inseminated with semen of PKa, Pannon White (PWhite) or Pannon Large (PLarge, terminal line) bucks. The kits (PKa×PKa, PWhite×PKa, PLarge×PKa; n=60 in each genetic group) were weaned at 35 d of age and reared until 88, 83 and 79, respectively, when they reached similar body weights for slaughtering (2.8 kg). The weight gain of PLarge×PKa was the largest (51.0 g/d) and that of PKa×PKa was the smallest (47.2 g/d), while PWhite×PKa (41.8 g/d) was intermediate (P<0.001). Difference was found in feed conversion ratio between weaning and the age of slaughter PKa×PKa: 3.03 respect to PWhite×PKa: 2.75 and PLarge×PKa: 2.66; , P<0.05). Dressing out percentage and ratio of hind part to reference carcass of PWhite×PKa, PLarge×PKa and PKa×PKa were 62.4 and 37.7, 61.8 and 37.5, 61.3 and 36.8%, respectively (P<0.01). Results show that PLarge×PKa rabbits were able to exceed the average economic indicators compared to other groups. It may be concluded that the production performance of growing rabbits was affected by the adult weight, but the carcass traits were influenced by the computer tomography (CT)-based selection.

[EN] The aim of the experiment was to compare the reproductive performance and nursing behaviour of rabbit does reared under 2 different light intensities and observe the preference of does among cages with different light intensities. Female rabbits were randomly housed in 2 identical rooms, under the same housing conditions in wire-net cages. The 2 rooms only differed in the light intensity; group L: 150-200 lux (n=54 does, 230 inseminations), group D: 10-20 lux (n=54 does, 232 inseminations). Reproduction data from the first 5 consecutive reproductive cycles were evaluated. Nursing behaviour of the does (n = 24) was observed at the 2nd or 4th lactation. The preference of does (n=8) among 4 cages with different light intensities (10, 35, 75 or 155 lux) as examined. There were 6-7% difference between the 2 groups in the number of kits born in total and those born alive (born total: 11.25 vs. 10.59 kits, P<0.1; liveborn: 10.75 vs. 10.00 kits, P<0.05; in groups L and D, respectively). Suckling mortality was nearly 2% higher in group D (L: 8.1, D: 10.0%; P<0.1), and in consequence the litter size of this group at 35 d of age was lower than that of the L rabbits (L: 8.75, D: 8.45 kits; P<0.05). The light intensity did not affect litter and individual weights at 35 d of age. The average numbers of daily nursing events (L: 1.23/d, D: 1.32/d), the length (L: 208±49, D: 213±43 s) and the daily distribution of nursing events were not affected by high light intensity. During the light period of the day, the darkest cage (10 lux) was the most preferred by the does (44.0, 18.6, 17.9 and 19.5% in 10, 35, 75 and 155 lux cages, respectively; P<0.001). The lower light intensity had no unambiguously unfavourable effect on the reproductive performance and nursing behaviour of the does. Based on the preference test, a lower light intensity may be advantageous from the point of view of animal welfare.