Zsolt Szendro

Genetic parameters, genetic trends and inbreeding depression of growth and carcass traits in Pannon terminal line rabbits

Abstract. Genetic parameters, inbreeding depression and genetic trends were estimated for average daily gain between the ages of 5-10 weeks and thigh muscle volume (measured in vivo with computerized tomography) in a group of 22 098 Pannon terminal line rabbits born between 2006 and 2011 and reared in 3 396 litters. The data sets were analysed with bi-variate animal models taking pedigree completeness (complete generation equivalent) into account. By 2011, all rabbits were inbred and the average inbreeding coefficient and complete generation equivalent of the population were 7.69 % and 11.89 %, respectively. Estimated heritability was moderate both for average daily gain (0.23±0.02) and thigh muscle volume (0.25±0.03). Litter effects were low for both traits (0.16±0.00 and 0.09±0.01 respectively). The genetic correlation coefficient estimate between average daily gain and thigh muscle volume was also low (0.02±0.08). Significant inbreeding depression (per 10 % inbreeding) was only detected for average daily gain (0.57 g/d). The estimated annual selection response was substantial both for average daily gain and thigh muscle volume (1.49 g/d and 5.84 cm3, respectively), proving the efficiency of the breeding programme.

Effect of Digestarom® Dietary Supplementation on the Reproductive Performances of Rabbit Does: Preliminary Results

The study investigated the effect of Digestarom® dietary supplementation on the reproductive performances of rabbit does. Pannon Ka (maternal line) multiparous does were randomly divided into two dietary groups since insemination and fed ad libitum. In the first group (n=51), rabbit does were fed with a commercial diet (C), whereas in the other group (n=52) they received the same diet supplemented with 300 mg/kg of Digestarom® (D). The experiment lasted for two reproductive cycles (kindling 1=K1; kindling 2=K2). Body weight of does and litter size (kits born total, alive, stillborn) were recorded at kindling. Litter size and litter weight were registered at 7, 14, 21 days of age after nursing, and the average individual weight of kits was calculated. Kits’ mortality was recorded daily. At K1, rabbit does performances were unaffected by dietary treatments. During K2, D does were significantly lighter than C ones (P<0.05) and displayed a lower kindling rate (P<0.05). Digestarom® did not improve the reproductive performance of rabbit does. They seemed to dislike the D diet in K1 and such behavior could have led to the negative results in K2. Further studies should focus on feed acceptance, dose-dependent effect, physiological adaptation and in vivo oxidative status of does. Finally, several consecutive reproductive cycles are recommended to test the efficacy of new feed supplements.

Heritability and genetic trends of number of kits born alive in a synthetic maternal rabbit line

Abstract Heritability and genetic trends for number of kits born alive in a synthetic maternal rabbit line were estimated in this study. The data were collected from 1999 to 2007 on 5640 kindlings of 1425 does. The total number of animals in the pedigree was 2576. The mean number of kits born alive was 8.42 with a standard deviation of 2.87. Genetic parameters and breeding values were estimated using the VCE-5 and PEST software based on the REML and BLUP methods using a repeatability animal model. For litter size, the first, second and third parities were treated as repeated trait, while the fourth and further parities were pooled and considered as same repetition. The estimated heritability and the repeatability for number of kits born alive were low (0.05 and 0.14). The observed selection response was about 0.04 rabbits/year.

Effect of maternal lysine supplementation on the performance of growing rabbits. Preliminary results

Abstract The experiment studied the effect of dietary lysine supplementation to rabbit does on the performance and on meat’s protein and lysine content of their offspring. Half of the does (n=43) fed control diet (C; Lys: 0.68%), while the other half a lysine supplemented diet (L; Lys: 0.80%) from 3 days before AI until weaning. After kindling, half of the litters of C does were put under C does, while the other half under L does. The same procedure was followed for offspring of L does. After weaning, rabbits fed the same diet (0.68% Lys). Does’ dietary treatment significantly affected the weaning weight, however, only lysine supplementation during suckling age had negative effect (340 vs 315g for C and L does, respectively; P<0.01). The kit’s milk intake, measured at 3rd and 7th day of age, nursed by L does was significantly lower. Other productive and carcass traits did not differ significantly.