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    ABSTRACT: The aim of this paper was to study the effect of the intensive breeding system (IBS: insemination 4 d postpartum and weaning age at 25 d) vs. the semi-intensive breeding system (SIBS: insemination 11 d post-partum and weaning age at 35 d) on lactating does' performance and the combined effect of the type of farm hygiene (cleaned and disinfected or not) on the performance of growing rabbits from weaning until 56 d of age. A total of 58 New Zealand x Californian rabbit does (29/reproductive rhythm) and 168 young rabbits per combination weaning age x type of farm were selected at random over two consecutive reproductive cycles. Mortality during lactation presented higher values (P=0.067) in young rabbits weaned at 35 d than in those weaned at 25 (19.1 vs. 9.60%). In the first cycle, the number of kits weaned per litter was similar for both reproductive rhythms (7.89 and 8.01 for IBS and SIBS, respectively), whereas in the second cycle, the number of rabbits weaned was lower in rabbit does that weaned their litters later (6.90 vs. 9.06; P=0.049). Weight at parturition and at weaning, fertility, parturition interval, numerical productivity and the number of young rabbits born dead and weaned were not affected by treatments. The fattening mortality was higher in the second cycle than in the first (20.2 vs. 14.5 %, P=0.051), in the farm without cleaning and disinfection between cycles (20.0 vs. 14.2%, P=0.032) and in the animals weaned at 35 d than at 25 d (20.0 vs. 14.7 %, P=0.063). Animals weaned at 25 and 35 d of age both had a peak of mortality around two weeks after weaning. The average weight of rabbits at 56 d was not significantly different between the animals weaned at 25 or 35 d (1805 vs. 1787 g, respectively; P=0.64). However, the feed efficiency in the whole fattening period was higher in young rabbits weaned at 25 d than in those weaned at 35 d (0.392 vs. 0.298 g/g; P<0.001).
    07/2010; 17(2). DOI:10.4995/wrs.2009.660
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    ABSTRACT: This article reviews how frequent feeding and selection programmes can affect resource allocation in rabbit does during reproduction. The consequences of these programmes and the central role of body condition for suitable female performance are analysed considering genetic level, health and welfare. Future reproductive potential of reproductive rabbit females is decided before first partum. There is enough evidence of a possible threshold for the rabbit female birth weight to reach the beginning of reproductive life in a suitable body condition to maximise their future reproductive potential. The moment of first mating could be identified as the last of the 'pure' data on the animal, a sign of the animal soma that is probably related to its productive potential. An adequate feeding system during rearing and first pregnancy is relevant for the reproductive performance of rabbit females in the short and long term. The body condition of females changes during the reproductive cycle and throughout their reproductive life according to their genetically determined level. The problems arise when the animals are forced to diverge from this appropriate level, increasing susceptibility to disease, other stress factors and eventual failure. Negative energy balances detected during lactation do not seem to have the strength of those observed in late pregnancy. Genetic selection for litter size at weaning has increased prolificacy, but also the ability to obtain resources without compromising the survival of rabbit females. However, it could also have increased the susceptibility of animals to the environment, focusing more on the maternal investment in the future litter rather than on the current one under restricted conditions to maximise their fitness. Rabbit does selected for reproductive longevity have a greater soma, which enables them to better cope with the possible productive challenges. There is also evidence that they have greater plasticity in using their soma, making them more robust to overcome demanding situations. In addition, there is evidence of a possible improvement of immune system modulation in such robust animals.
    09/2013; 21(3). DOI:10.4995/wrs.2013.1236