Letter from editor: World Rabbit Science website. Setting new standards in rabbit science

Pascual Amorós, JJ. (2008). Letter from editor: World Rabbit Science website. Setting new standards in rabbit science. World Rabbit Science. 16(4). doi:10.4995/wrs.2008.613SWORD16

Letter from the editor. World Rabbit Science at the 9th World Rabbit Congress and the Journal citation report

Pascual Amorós, JJ. (2010). Letter from the editor. World Rabbit Science at the 9th World Rabbit Congress and the Journal citation report. World Rabbit Science. 16(3). https://doi.org/10.4995/wrs.2008.910216

Letter from editor: Editorial Board changes and Journal Citation Report

Pascual Amorós, JJ. (2009). Letter from editor: Editorial Board changes and Journal Citation Report. World Rabbit Science. 17(3). doi:10.4995/wrs.2009.65011317

Long-term implications of feed energy source in different genetic types of reproductive rabbit females: III. Fitness and productivity

[EN] The specialization process associated with genetic selection could be associated with functional disorders, affecting the reproductive success of females (fitness). We hypothesized that by modulating energy acquisition and allocation of females we could balance productivity and reproductive success. To test this hypothesis, we used 203 rabbit females belonging to three genetic types: H (n=66) maternal line specialized in prolificacy, LP (n=67) generalist maternal line, R (n=70) paternal line specialized in growth rate. We fed each genetic type with two diets specifically designed to promote milk yield (AF) or body reserves recovery (CS). We controlled females between their first and fifth reproductive cycles, recording traits related with productivity and fitness of females. H females fed CS had on average 11.2 +/- 0.43 kits with an individual weight of 54 +/- 1.2 g at birth and 525 +/- 11 g at weaning. Their conception rate when multiparous was 44% and their survival rate at the end of the experiment 30%. When they were fed AF, the individual weight of kits was 3.8 g heavier (P<0.05) at birth and 38 g heavier at weaning (P<0.05), the conception rate when multiparous increased 23 percentage points (P<0.05) and the survival rate at the end of the experiment 25 percentage points (P<0.05). LP females fed CS had on average 10.8 +/- 0.43 kits with an individual weight of 52 +/- 1.2 g at birth and 578 +/- 11 g at weaning. Their conception rate when multiparous was 79% and their survival rate at the end of the experiment 75%. When they were fed AF, it only increased individual weight of kits at weaning (+39 g; P<0.05). R females fed CS had on average 8.4 +/- 0.43 kits with an individual weight of 60 +/- 1.2 g at birth and 568 +/- 11 g at weaning. Their conception rate when multiparous was 60% and their survival rate at the end of the experiment 37%. When they were fed AF, they presented 1.4 kits less at birth (P<0.05) but heavier at birth (+4.9 g; P<0.05) and at weaning (+37 g; P<0.05). Therefore, we observed that genetic types prioritized different fitness components and that diets could affected them. In this sense, seems that more specialized genetic types, were more sensitive to diets than the more generalist type.This study was supported by the Interministerial Commission for Science and Technology (CICYT) of the Spanish Government (AGL2014-53405-C2-1-P). The authors thank Juan Carlos Moreno for his technical support. Grants for Alberto Arnau from the Ministry of Economy and Finance (BES-2012-052345) are also gratefully acknowledged.Arnau-Bonachera, A.; Savietto, D.; Pascual Amorós, JJ. (2018). Long-term implications of feed energy source in different genetic types of reproductive rabbit females: III. Fitness and productivity. animal. 12(9):1886-1894. https://doi.org/10.1017/S1751731117003305S1886189412

Recommendations and guidelines for applied nutrition experiments in rabbits

[EN] The aim of this paper was to draw up a set of recommendations for applied nutrition and feeding trials with rabbits, in relation to certain aspects such as determining the nutritive value of raw materials or diets in growing or reproducing animals, studying digestive physiology and obtaining growth and reproduction parameters. We deal first with animals, size of the sample, housing conditions, diets, handling, measurements, and the data analyses relevant to the design of the experiment are described. Secondly, we give a list of recommended items and include some comments.This study was partly supported by the EUROPEAN COMMISSION (ERAFE program and the COST 848 Action).Fernández-Carmona, J.; Blas, E.; Pascual Amorós, JJ.; Maertens, L.; Gidenne, T.; Xiccato, G.; García, J. (2005). Recommendations and guidelines for applied nutrition experiments in rabbits. World Rabbit Science. 13. doi:10.4995/wrs.2005.516SWORD1

Early development and reproductive lifespan of rabbit females: implications of growth rate, rearing diet and body condition at first mating

[EN] Factors influencing early development such as birth weight, nest competition, and the diet received during rearing have been proposed as elements conditioning the future reproductive performance of European rabbit (Oryctolagus cuniculus) females. To evaluate their effects, we followed the life of 1513 females from birth to time of death, culling or censoring (animals alive at a fixed date). Between 0 and 63 days of age 353 females died. From the remaining 1160 females, 864 were chosen based on their birth weight to be transferred from the selection to the production farm. At this farm, 431 females received the control diet (184g of CP, 381 g of NDF and 11.8 MJ of DE per kg DM), while the other 433 received the fibrous diet (134 g of CP, 436g of NDF and 10.0 MJ of DE per kg DM). Throughout the rearing period, we checked for the individual live weight and body condition (perirenal fat thickness) at first artificial insemination. Reproductive lifespan was defined as the number of days between the first parturition and the time of death, culling or censoring. Birth weight affected the survival of newborn females during lactation and the presence of a milk spot at birth (related to nest competition) increased the survivability of newborns weighing <45g (P <0.001). Rearing diet altered the growth curve of females and their body condition at first insemination. The diet also altered the relative risk of death during the rearing period, which was lower among females fed on the fibrous diet (-12.5%; P < 0.001). Therefore, a higher number of females fed with this diet reached their reproductive life, directly affecting the productivity measured per housed female. Fatter females at first insemination had smaller litter sizes and a higher risk of being culled than lean ones (P < 0.05). In general, the fibrous diet reduced the risk of leaving the herd at early rearing, and both birth weight and perirenal fat thickness affected female's reproductive lifespan. An excess of fat (positive change in one unit of perirenal fat) at their first insemination represented an increased the risk of death or elimination of 13%.The authors acknowledge Cesar Villalba (Fabara, Spain), Luis Eroles (Valderrobres, Spain) for the technical support in managing the animals and for kindly providing a space to conduct our study. They also thank the Commission for Science and Technology (CICYT) of the Spanish Government (AGL2014-53405-C2-1-P) for the economic support to carry out this study.Martinez-Paredes, E.; Ródenas Martínez, L.; Pascual Amorós, JJ.; Savietto, D. (2018). Early development and reproductive lifespan of rabbit females: implications of growth rate, rearing diet and body condition at first mating. animal. 12(11):2347-2355. https://doi.org/10.1017/S1751731118000162S23472355121

Welfare and performance results in meat rabbits during their lactation and fattening. A review

[EN] This review summarizes the main scientific works focused on the welfare of rabbits in lactation and growing periods. A suitable material for building the nest has a positive impact, improving kits' welfare by reducing their mortality. A careful and regular daily handling of newborns during lactation, such as habituation to the farmer, can provide less fearful and stressed rabbits even in adulthood, showing lower mortality in the group period and higher fertility later. At a similar density, fattening in conventional cages (6-9 rabbits) enriches specific behaviours (locomotor, social, exploratory) and provides bolder rabbits, reducing their daily growth and consumption, the slaughter weight and the muscle:bone ratio compared to individual cages. If locomotion is promoted by specific stimuli or with a larger area and group size, it increases the resistance and weight of the leg bones and can increase the hind part percentage. Physical activity and bone resistance are also increased in rabbits from large groups fattened in pens, but growth performance deteriorates and it is not sure that welfare is improved because rabbits show more injuries, higher glucocorticoids level and worse hygienic-sanitary conditions. Adding wooden objects (sticks or blocks) for gnawing in fattening cages does not have negative effect on growth performance traits, and could even improve them with blocks with trace elements, besides reducing the aggressiveness in larger fattening groups. Inclusion of a platform can enrich behaviours even though deteriorates several growth traits and the hygiene of these enclosures will be worsened.[ES] En esta revisión se estudian los principales resultados científicos orientados a mejorar el bienestar de los gazapos en el nido y en el periodo de cebo. Un material apropiado para que la coneja construya el nido reduce la mortalidad mejorando así las condiciones de bienestar en el nidal. La manipulación metódica de los gazapos durante la lactación les habitúa al cuidador, haciéndoles menos asustadizos y estresados, mostrando inferior mortalidad mientras crecen y mayor fertilidad posteriormente. Con similar densidad, el cebo en jaulas convencionales (6¿9 gazapos) enriquece comportamientos específicos (locomotor, social, exploratorio) y proporciona conejos más audaces, reduciendo su crecimiento y consumo diarios, el peso de sacrificio y la relación músculo:hueso respecto a las jaulas individuales. Si además se promueve la locomoción mediante estímulos o ampliando el espacio y tamaño del grupo, aumenta la resistencia y peso de los huesos de la pierna y puede incrementar la proporción de tercio posterior. La actividad física y el desarrollo óseo también son mayores en parques grandes con elevado número de gazapos, pero sus resultados zootécnicos empeoran y no parecen alcanzar mayor bienestar, porque muestran más lesiones, elevado nivel de glucocorticoides y peores condiciones higiénico¿sanitarias. Aportar elementos de madera (varilla, bloque) en la jaula de cebo no deteriora los parámetros de crecimiento y puede mejorarlos si se incluyen elementos traza, reduciendo las lesiones en grupos más grandes de engorde en parque. El enriquecimiento mediante plataforma puede ampliar el repertorio de comportamientos pero perjudica algunos resultados de crecimiento y empeora la higiene de los recintos.López, M.; Cervera, C.; Pascual Amorós, JJ. (2021). Bienestar y resultados zootécnicos en conejos de carne durante su lactancia y engorde. Revisión bibliográfica. ITEA-Informacion Tecnica Economica Agraria. 117(2):108-129. https://doi.org/10.12706/itea.2020.014108129117

Reproductive robustness differs between generalist and specialist maternal rabbit lines: the role of acquisition and allocation of resources

[EN] Background: Farm animals are normally selected under highly controlled, non-limiting conditions to favour the expression of their genetic potential. Selection strategies can also focus on a single trait to favour the most specialized animals. Theoretically, if the environment provides enough resources, the selection strategy should not lead to changes in the interactions between life functions such as reproduction and survival. However, highly specialized farm animals can be required for breeding under conditions that differ largely from selection conditions. The consequence is a degraded ability of specialized animals to sustain reproduction, production and health, which leads to a reduced lifespan. This study was designed to address this issue using maternal rabbit lines. A highly specialized line with respect to numerical productivity at weaning (called V) and a generalist line that originated from females with a long reproductive life (called LP) were used to study the strategies that these lines develop to acquire and use the available resources when housed in different environments. In addition, two generations of line V, generations 16 and 36, were available simultaneously, which contributed to better understand how selection criteria applied in a specific environment changed the interplay between functions related to reproduction and survival. Results: We show that, under constrained conditions, line LP has a greater capacity for resource acquisition than line V, which prevents excessive mobilization of body reserves. However, 20 generations of selection for litter size at weaning did not lead to an increased capacity of nutrient (or resource) acquisition. For the two generations of line V, the partitioning of resources between milk production, body reserves preservation or repletion or foetal growth differed. Conclusions: Combining foundational and selection criteria with a specific selection environment resulted in female rabbits that had a different capacity to deal with environmental constraints. An increased robustness was considered as an emergent property of combining a multiple trait foundational criterion with a wide range of environmental conditions. Since such a strategy was successful to increase the robustness of female rabbits without impairing their productivity, there is no reason that it should not be applied in other livestock species.The authors thank Juan Carlos Moreno Pardo, Luis Rodenas Martinez and Eugenio Martinez Paredes for their technical support, and Doctors Manuel Baselga Izquierdo, Enrique Blas Ferrer and Concha Cervera Fras for their valuable comments in the first version of this work. We also thank the Spanish Ministry of Education and Science (Project AGL2011-30170-C02-01) for the economic support.Savietto, D.; Friggens, NC.; Pascual Amorós, JJ. (2015). Reproductive robustness differs between generalist and specialist maternal rabbit lines: the role of acquisition and allocation of resources. Genetics Selection Evolution. 47(2):1-11. https://doi.org/10.1186/s12711-014-0073-5S111472Knap, P. W. (2005). Breeding robust pigs. Australian Journal of Experimental Agriculture, 45(8), 763. doi:10.1071/ea05041Havenstein, G., Ferket, P., & Qureshi, M. (2003). Growth, livability, and feed conversion of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets. Poultry Science, 82(10), 1500-1508. doi:10.1093/ps/82.10.1500Havenstein, G., Ferket, P., & Qureshi, M. (2003). Carcass composition and yield of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets. Poultry Science, 82(10), 1509-1518. doi:10.1093/ps/82.10.1509Hansen, L. B. (2000). Consequences of Selection for Milk Yield from a Geneticist’s Viewpoint. Journal of Dairy Science, 83(5), 1145-1150. doi:10.3168/jds.s0022-0302(00)74980-0Poggenpoel, D. G., Ferreira, G. F., Hayes, J. P., & du Preez, J. J. (1996). Response to long‐term selection for egg production in laying hens. British Poultry Science, 37(4), 743-756. doi:10.1080/00071669608417904Estany, J., Camacho, J., Baselga, M., & Blasco, A. (1992). Selection response of growth rate in rabbits for meat production. Genetics Selection Evolution, 24(6), 527. doi:10.1186/1297-9686-24-6-527Garcı́a, M. L., & Baselga, M. (2002). Estimation of genetic response to selection in litter size of rabbits using a cryopreserved control population. Livestock Production Science, 74(1), 45-53. doi:10.1016/s0301-6226(01)00280-9Horan, B., Dillon, P., Faverdin, P., Delaby, L., Buckley, F., & Rath, M. (2005). The Interaction of Strain of Holstein-Friesian Cows and Pasture-Based Feed Systems on Milk Yield, Body Weight, and Body Condition Score. Journal of Dairy Science, 88(3), 1231-1243. doi:10.3168/jds.s0022-0302(05)72790-9Lucy, M. C. (2001). Reproductive Loss in High-Producing Dairy Cattle: Where Will It End? Journal of Dairy Science, 84(6), 1277-1293. doi:10.3168/jds.s0022-0302(01)70158-0Felver-Gant, J. N., Mack, L. A., Dennis, R. L., Eicher, S. D., & Cheng, H. W. (2012). Genetic variations alter physiological responses following heat stress in 2 strains of laying hens. Poultry Science, 91(7), 1542-1551. doi:10.3382/ps.2011-01988Vicente, J. S., Llobat, L., Viudes-de-Castro, M. P., Lavara, R., Baselga, M., & Marco-Jiménez, F. (2012). Gestational losses in a rabbit line selected for growth rate. Theriogenology, 77(1), 81-88. doi:10.1016/j.theriogenology.2011.07.019Lavara, R., Vicente, J. S., & Baselga, M. (2012). Estimation of genetic parameters for semen quality traits and growth rate in a paternal rabbit line. Theriogenology, 78(3), 567-575. doi:10.1016/j.theriogenology.2012.03.002Rauw, W. ., Kanis, E., Noordhuizen-Stassen, E. ., & Grommers, F. . (1998). Undesirable side effects of selection for high production efficiency in farm animals: a review. Livestock Production Science, 56(1), 15-33. doi:10.1016/s0301-6226(98)00147-xTheilgaard, P., Sánchez, J., Pascual, J., Berg, P., Friggens, N. C., & Baselga, M. (2007). Late reproductive senescence in a rabbit line hyper selected for reproductive longevity, and its association with body reserves. Genetics Selection Evolution, 39(2), 207. doi:10.1186/1297-9686-39-2-207Sánchez, J. P., Theilgaard, P., Mínguez, C., & Baselga, M. (2008). Constitution and evaluation of a long-lived productive rabbit line1. Journal of Animal Science, 86(3), 515-525. doi:10.2527/jas.2007-0217Van Noordwijk, A. J., & de Jong, G. (1986). 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Mixed model methodology for the estimation of genetic response to selection in litter size of rabbits. Livestock Production Science, 21(1), 67-75. doi:10.1016/0301-6226(89)90021-3Vicente, J.-S., Viudes-de-Castro, M.-P., & García, M.-L. (1999). In vivo survival rate of rabbit morulae after vitrification in a medium without serum protein. Reproduction Nutrition Development, 39(5-6), 657-662. doi:10.1051/rnd:19990511Besenfelder, U., & Brem, G. (1993). Laparoscopic embryo transfer in rabbits. Reproduction, 99(1), 53-56. doi:10.1530/jrf.0.0990053Ferrian, S., Guerrero, I., Blas, E., García-Diego, F. J., Viana, D., Pascual, J. J., & Corpa, J. M. (2012). How selection for reproduction or foundation for longevity could have affected blood lymphocyte populations of rabbit does under conventional and heat stress conditions. Veterinary Immunology and Immunopathology, 150(1-2), 53-60. doi:10.1016/j.vetimm.2012.08.007Ferrian, S., Blas, E., Larsen, T., Sánchez, J. P., Friggens, N. C., Corpa, J. M., … Pascual, J. J. (2013). Comparison of immune response to lipopolysaccharide of rabbit does selected for litter size at weaning or founded for reproductive longevity. Research in Veterinary Science, 94(3), 518-525. doi:10.1016/j.rvsc.2013.01.008García-Diego, F.-J., Pascual, J. J., & Marco, F. (2011). Technical Note: Design of a large variable temperature chamber for heat stress studies in rabbits. World Rabbit Science, 19(4). doi:10.4995/wrs.2011.938Savietto, D., Blas, E., Cervera, C., Baselga, M., Friggens, N. C., Larsen, T., & Pascual, J. J. (2012). Digestive efficiency in rabbit does according to environment and genetic type. World Rabbit Science, 20(3). doi:10.4995/wrs.2012.1152Xiccato, G., & Trocino, A. (s. f.). Energy and protein metabolism and requirements. Nutrition of the rabbit, 83-118. doi:10.1079/9781845936693.0083Fortun-Lamothe, L., & Lebas, F. (1996). 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Diet digestibility in growing rabbits: effect of origin and oxidation level of dietary fat and vitamin e supplementation

[EN] The effects of the dietary inclusion of fats with different origin (lard or vegetal oil), fatty acid profile (linseed or sunflower), oxidation level (fresh, peroxidised: 11 d at 55ºC or oxidised: 31 h at 140ºC) and vitamin E supplementation (0 or 100 ppm) on the rabbit diet apparent digestibility were studied. Digestibility coefficients of dry matter, organic matter, crude protein, ether extract and gross energy were determined in eight diets using 58 rabbits aged 49 d. Contrast analysis between groups of diets showed that lard, characterised by a greater saturated fatty acid content, compared with vegetal oils, rich in unsaturated fatty acid, reduced the apparent digestibility of ether extract (62.3 vs. 68.4%; P=0.0329). However, there were no significant differences in the nutrient digestibility when linseed or sunflower oils (rich in [omega]-3 or in [omega]-6 polyunsaturated fatty acids, respectively) were compared. The oxidation degree of the sunflower oil and the supplementation with 100 ppm of vitamin E to the diets did not modify the apparent digestibility values of any dietary fraction.This work was financed by the Ministry of Science and Technology (AGL2003-06559-C02-02)Casado, C.; Moya, V.; Fernández, C.; Pascual Amorós, JJ.; Blas, E.; Cervera, C. (2010). Diet digestibility in growing rabbits: effect of origin and oxidation level of dietary fat and vitamin e supplementation. World Rabbit Science. 18(2). https://doi.org/10.4995/wrs.2010.18.0818