World Rabbit Science - Vol. 09 (2)-2001
URI permanente para esta colecciónhttps://riunet.upv.es/handle/10251/9974
Tabla de contenidos
- EFFECT OF BREED AND SEX ON RABBIT CARCASS YIELD AND MEAT QUALITY
- TECHNICAL NOTE : ATTEMPTS TO HARMONIZE CHEMICAL ANALYSES OF FEEDS AND FAECES,FOR RABBIT FEED EVALUATION
- DOE AND KIT PERFORMANCE IN A SMALL RABBIT POPULATION FROM SUBTROPICAL TRINIDAD
- PERFORMANCES DES ELEVAGES CUNICOLES MODERNES EN TUNISIE
- VARIANCE COMPONENTS AND RESPONSE TO SELECTION FOR REPRODUCTIVE, LITTER AND GROWTH TRAITS THROUGH A MULTI-PURPOSE INDEX
- NOTE: RELATIONSHIP BETWEEN SCROTAL TEMPERATURE AND SPERM MORTA LITY OF THE NEW ZEALAND WHITE RABBIT
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Publicación NOTE: RELATIONSHIP BETWEEN SCROTAL TEMPERATURE AND SPERM MORTA LITY OF THE NEW ZEALAND WHITE RABBIT(World Rabbit Science. ICTA. UPV, 2001) KASA, I.W:; THWAITES, C.J.[EN] Eight mature New Zealand White bucks (3049 ± 247g líve weight) were randomly allocated to one of 4 groups in descending order of the density of their semen. Rabbits were raised at 20ºC except during a single short period of 8 hours when they were introduced in a climatic chamber (CC) regulated at 20ºC (control], 32ºC, 32ºC + infrared heating at 1,9MJ/m2/h or 34ºC (groups 1 to 4). Semen quality was evaluated before treatment and then once a week during 8 consecutive weeks. During the stay in the CC, scrotal temperature increased rapidly within the first hour. Average scrotal temperature increased (P < 0.05) with each shortterm environmental temperature increase : 34.1 º - 36.5º - 37.0º and 37.9ºC for groups 1 to 4 respectively. The maximum level of dead sperm was recorded at the first week after hotroom exposure in each of the 3 experimental groups. Between temperatures, the highest level of mortality (16.3%) was recorded in the 34ºC group, followed by 32ºC + i.r. and 32ºC (11.3 and 7.8%). lt was only 1 % in the control group. A total of 3 weeks after treatment was required for the incidence of sperm mortality to return to normal. As a whole, it can be concluded that the exposure of bucks to short-term high ambient temperature is followed by a significan! degree of seminal degeneration.Publicación VARIANCE COMPONENTS AND RESPONSE TO SELECTION FOR REPRODUCTIVE, LITTER AND GROWTH TRAITS THROUGH A MULTI-PURPOSE INDEX(World Rabbit Science. ICTA. UPV, 2001) Moura, A.S.A.M.T; Costa, A.R.C.; Polastre, R.; Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasil; Fundação de Amparo à Pesquisa do Estado de São Paulo; Fundação para o Desenvolvimento da UNESP, Brasil[EN] Variance components and genetic trends were estimated for number of services/parturition (NS), parturition interval (PI), number born alive (NB), number weaned/litter born (NW), litter weaning weight (LW), 30-d individual weaning (WW) and 70-d (W70) weights and a multipltHrait selection index (MI) in rabbits from a closed population in Botucatu, Southeast Brazil. Phenotypic values for two litter (NW and LWW), and two individual performance (WW and W70) traits were included in the index. Individual selection according to the multiple-trait index was practised for a 2.6-yr period (January 1992 through July 1994). PerfQrrnance records collected for five years (July 1989 through July 1994) on 2,162 parturitions, 2,122 litters, and 10,440 individuals were included in the analyses. The general model used to estimate variance components and breeding values included the random effects of animal, maternal genetic, and permanent dam effects (for reproductive and litter traits) or common litter effects (for individual weight traits), and fixed effects of parity, parturition date, sex (for individual weight traits) and covariates of the inbreeding coefficient of the dam (for reproductiva and litter traits) or of the rabbit and its dam (for individual weight traits). lnbreeding coefficients ranged from O to 0.36. For reproductive and litter traits, estimates of permanent dam effects ranged from 0.03 to 0.09 and estimates of direct heritability ranged from 0.02 to 0.05. The estimated genetic correlation between NS and PI was 0.73. For WW, W70, and MI, estimates of direct and maternal heritabilities and direct-maternal genetic correlation were 0.08, 0.08 and 0.28; 0.18, 0.05 and 0.76; and -0.35, 0.59 and -0.46, respectively. Estimated common litter effects for WW and W70 were 0.44 and 0.26, respectively. Estimates of direct genetic trends/yr for NS, PI, NB, NW and LW were -0.0037 ± 0.0003 services, -0.200 ± 0.030 d, 0.034 ± 0.010 young/litter, 0.039 ± 0.006 young/litter, and 35.2 ± 4.6 g, respectively. Estimates of direct and maternal genetic trends/yr were 6.74 ± 0.39 g and 1.58 ± 0.60 g for WW; 17.20 ± 1.22 g and 8.35 ± 0.71 g for W70; and 4.91 ± 0.65 and -2.34 ± 0.39 for MI. Individual weight traits showed meaningful genetic trends with multiple-trait selection, whereas reproductive and litter traits showed slight, but favourable genetic changes. lt seems possible to achieve slow, but simultaneous improvement of litter and growth traits with a multipletrait selection program in rabbits.Publicación PERFORMANCES DES ELEVAGES CUNICOLES MODERNES EN TUNISIE(World Rabbit Science. ICTA. UPV, 2001) BERGAOUI, R.; KRIAA, S.[EN] Modern rabbit production in Tunisia started in 1980's. The following article deals with technical and economical performances in rabbit sector studied through a survey including 62 production units of the Tunis and Bizerte areas. Data analysis shows that average number of rabbit does per rabbitry was 112. The numerical productivity was poor : 28.7 rabbits sold/mother-cage/year. This low productivity can be considered as a consequence of bad management decisions mainly in term of repnduction control, breeding animal renewal and general management of the rabbitry. Moreover, low performances can be attributed to poor training of technicians and to low quality of available animals, nutrition or housing conditions... These performances are lower than the profitability levels which was estimated at 36 rabbits/mother-cage/year. Furthermore, Tunisian is not known to be a major rabbit meat consumer, his annual consumption is poor : 350 g/person/year. To increase the productivity level of the sector it is necessary : 1 I to train technicians in order to improve this management performers, 2/ to educate consumer in order to be aware of this quality of the rabbit meat and 3/ to develop new strategy which takes account for local conditions.Publicación DOE AND KIT PERFORMANCE IN A SMALL RABBIT POPULATION FROM SUBTROPICAL TRINIDAD(World Rabbit Science. ICTA. UPV, 2001) RASTOGI, R.K.[EN] This paper summarizes performance data collected from 226 does producing 1017 litters during 1985-93. Local, high-grade New Zealand White rabbits were housed in wire cages and fed mainly broiler finisher pellets (18% CP) and grass, free choice. The average kit weights at 3, 4 (weaning) and 12 weeks were 224 g, 311 g and 1.61 kg, respectively. The averages for daily gain between 3-4 and 4-12 weeks were 12 and 23 g, respectively. On average, a total of 5.4 kits were born per litter , of which 5.2 were alive; 4.3 survived until weaning at 4 weeks and only 3.9 were alive at 12 weeks . The year of kindling accounted for significan! variability in all performance traits studied except in kit weight at 4 weeks and daily gain between 3-4 weeks. The season of birth effect was significan! for kit weight at 3 weeks only and kits born during March through May weighed the heaviest. The average values for perinatal, preweaning and postnatal mortality were 3.7, 17.3 and 9.3%, respectively. On average, 26.7% of the breeding does died due to natural or accidental death. 39.5% of the breeding does produced three litters or fess and were culled mainfy due to poor prolificacy and fertility. Only 12.5% of the does produced 1 O fitters or more. Fully, 49.7% of the breeding does were culled from the herd before reaching 18 months of age.Publicación TECHNICAL NOTE : ATTEMPTS TO HARMONIZE CHEMICAL ANALYSES OF FEEDS AND FAECES,FOR RABBIT FEED EVALUATION(World Rabbit Science. ICTA. UPV, 2001) E.G.R.A.N.[EN] The aim of this document is to describe harmonized procedures of sorne basic chemical analyses useful for rabbit compound feeds and faecesthat have been approved within !he six teams forming the EGRAN group. For each criterion (dry matter, ash, energy, nitrogen, fa!, fibre), we report a brief definition, its main interest, and sorne general references used in animal research (ISO or AOAC standards). We also report !he principie of the analytical determination, a brief description of the practica! procedures, sorne suggestions, !he among laboratory variability recently measured in a collaborative study on digestibility of feeds for growing rabbit, and the recommended leve! of tolerance.Publicación EFFECT OF BREED AND SEX ON RABBIT CARCASS YIELD AND MEAT QUALITY(World Rabbit Science. ICTA. UPV, 2001) Ortiz Hernández, J.A.; Rubio Lozano, M.S.[EN] The objective of this work was to det~rmine the differences on yield and quality of carcasses of different sex (male and female) and breed (New Zealand (NZ), Californian (CA), Chinchilla (CH) and Rex (RX)). Ten rabbits (balanced sexes) of each breed were used. Rabbits were grown under the same conditions, fed the same commercial diet and slaughtered when reached Mexican commercial weight (2.00 kg). Carcass yield, percentage of the main tissues, chemical composition of meat, shear force of cooked longissimus dorsi muscle and sensorial characteristics were evaluated. Main effects (breed and sex) and interactions were statistically analyzed. Breeds were similar on dressing percentages. However, meat from 1 JZ carcasses had the higher dripping losses (5.44%); NZ male had heavier skin compared to their female counterparts. Carcass composition was very similar among breeds. Mate had a higher percentage (P<0.05) of bone compared to female (17.69 and 16.18, respectively). CH female had higher inter-muscular fat than NZ female (3.99 % vs 2.08%). Meat composition was also very similar among breeds with the exception of dry matter percentage. CA females had more intra-muscular lipds than CA mate. Shear force was similar among breeds and sexes. No differences were found for aroma, flavor and general satisfaction. However, RX meat was the most tender (P<0.05) compared to !he CA mea! (5.38 and 4.85, respectively), when sensorily evaluated. In conclusion, regardless of the production purposes of the breed (meat or fur), carcass yield and mea! quality are very similar for rabbits slaughtered at 2.00 kg.