Genetic and non-genetic factors affecting reproductive performance in exotic rabbit breeds under Egyptian conditions

Transcription

1 Genetic and non-genetic factors affecting reproductive performance in exotic rabbit breeds under Egyptian conditions Farghaly H.M., El Darawany A.A. in Baselga M. (ed.), Marai I.F.M. (ed.). Rabbit production in hot climates Zaragoza : CIHEAM Cahiers Options Méditerranéennes; n pages Article available on line / Article disponible en ligne à l adresse : To cite this article / Pour citer cet article Farghaly H.M., El Darawany A.A. Genetic and non-genetic factors affecting reproductive performance in exotic rabbit breeds under Egyptian conditions. In : Baselga M. (ed.), Marai I.F.M. (ed.). Rabbit production in hot climates. Zaragoza : CIHEAM, p (Cahiers Options Méditerranéennes; n. 8)

2 Genetic and non-genetic factors affecting reproductive performance in exotic rabbit breeds under Egyptian conditions ANIMAL PRODUCTION DEPARTMENT, FACULTY AGRICULTURE, ZAGAZIG UNIVERSITY, ZAGAZIG, EGYPT - Data on parturitions from Bauscat (BAU), New Zealand White and Californian (CAL) purebred does were analysed. by fixed and mixed model procedures. The data came from tw groups ose imported from Hungary (473) and one locally-born in Egypt The work was carried out to investigate the effects of group, breed,seasonofbirthandparityonreproductiveperformance.. Reproductive performance of the imported does was better than that o the locally-born does. The breed had significantly higher (P<O.Ol) litter size at different periods..(birth, i days) and lower litter weight at birth than NZW and BAU breeds. Season of birth showed significant effects on preweaning litter size and litter weight. The regression coefficients of litter size at birth, and on both gestation period and litter weight at birth were highly significant and it was significant for litter weight birth and at on gestation period. Heritability litter size at different ages were moderate values. The genetic correlation among each of litter.-and litter weight at different ages were positive and high. The phenotypic correlations among all reproductive performance traits were highly positive. The observed trends of the LZ and LW showed the unfavorable climate conditions depressed performance the locally-born does and indicate that these seem to be undergoing the adaptive during the period the study. Improvement of (phenotypic) one of the characters means Improvemnt other characters at the same time. Key words: Comercial rabbits, exotic, non-genetic and heritability. Introduction OPOKU & LUKEFAHR. To In Egypt, in the early date, little information is the Government attempted to availableaboutthedegreeof increase meat production by sub- adaptability genetic and sidizing large scale, production properties- in commercial rabbit imported purebred commercial populations reared in tropical and rabbits. reproductive The subtropical environments. performance exotic breeds of (LUKEFAHR et al. To rabbits deteriorates (e.g. low establish an adequate strategy of fertility and depressed growth) selection methods under new when introduced into a new adverse adverse conditions, is environment (DAMODAR& necessary to evaluate the environmental and genetic factors related to litter performance in exotic breeds.

3 The objective of the present nearest gram. Traits analysed we investigationistostudythe litter size (LZ) and litter weig changes that occur due to (LW) at birth (LZB & LWB), 21 adaptation in imported and (LZ21 & LW21) and 30 (L230 & LW30) locally-born rabbits in litter days. performance. In addition, the effects of environmental factors Climatological data, from the such as parity and season, and San El-Hagar Farm, included genetic parameters for minimum and maximum air reproductive performance, were temperatures and relative also evaluated under Egyptian humidity (%) at and h conditions. inside the house for the year December, January and Materials and methods February were Winter months; March, April and May the Spring HERD MANAGEMENT months; June, July and August the This work was carried out at Summer months and September, the San El-Hagar Agricultural October and November the Autumn Company Farm, San El-Hagar area, months. Least squares means S.E. Sharkeya Province, Egypt, during a for seasons are shown in Table one-yearproductioncyclethat Thedifferencebetweenseasons started in January The data were highly significant. set included three commercial rabbit breeds Bauscat (BAU),.New MEASUREMENTS STATISTICAL AND Zealand White (NZW) and METHODS Californian (CAL). The does and bucks were housed separately in The records analysed used individual galvanized wire comprised 2466 complete normal batteries. Batteries for does were parturitions from 600 does sired provided with external nest boxes by bucks and recorded during for delivery and nursing young. the year The purebred Bucks were allocated to the does rabbits included in the present at random at each mating period study represented two stages of and inbreeding was minimized by acclimatization of rabbits under avoiding closely related matings to subtropical conditions. The 473 (full-sib, half-sib and parent- does imported directly Budapest, offspring matings). The buck/doe Hungary represented the first ratio was low and this stageandthe locally-born allowed all matings does represented the second stag contemporaneously. The animals During the first. months after were reared under similar import, there were no locally-bo environmental conditions. They rabbits in production, and after 6 were fed ad libitum on a months no further importation to commercial pelleted rabbit ration. place. The imported does were not The composition of that ration included was the statistical crude protein, 3% ether analysis during the first months extract, crude fibre, of importing (by confounding mineral mixture Ca, and betweenseasonatdeliveryof Na) and soluble impor.ted and locally-born does). carbohydrate. digestible The The sires used were similar for energy was kcal per kg bothimportedandlocally-born ration. Constant fresh water was does. provided automatic drinkers with nipples. Data were collected Themethod least-squares at birth (within h after means was carried out by using delivery), and days. The GeneralLinearModelfrom weaningagewas days.all program The data were weights were recorded to the statistically analysed according

4 to the following models: for litter size (LZ) mean; B.= effect due to iu breed, i= 1,..3 BAU, 2= NZW 3= - effect due to the ja group, ji-l and 2 (l= imported rabbits 2= locally-born rabbits); Pk= effect due to k u parity k=l,.. 27; effect due to the season at delivery, 1,..4 (l= Winter 2= Spring 3= Summer 4= Autumn); bl&b = thepartialregression coefhcients of Y- 'klm (dependent variable) on gestaaon period (xl) and litter weight at birth and eijklm= residual randõm effect. for litter weight (LW) pk/ sa/ bl and eijklm -. as dsfindd ln mo el and Z, = eyfect due to mm litter sue birth at m=l,..rlo. (h2), genetic (rg) and phenotypic (r ) correlations by paternal haff-sib were computed by using the formulas as described by HARVEY, Results Least squares means S and the analyses of variance of LZ and LW at different periods are presentedintables 2 and 3, respectively. imported. The does were significantly higher than locally-born does in the LZB, 21 and 30 days and LW at the same time. Season of birth significantly affected LZ and LW at In preliminary analyses, the birth, 21 and 30 days. The highest two-and three-way interactions of LZB during winter, but LZ at 2 were observed to be statistically Sr 30 and LWB, 21 & 30 days were nonsignificant, these highest during spring. interactions were not included in the final models. Parityofdoesignificantly (P<O.OOl) affected LZ and LW at Variance components were birth, 21 and days. The first estimated by reanalysis date by parity recorded the highest LZB. using the least-squares and significant There were no maximum likelihood computer differences between LZB in program (HARVEY, 1990 ). A mixed parities from second to fifth. model (Model type of HARVEY, Each of LZ at 21 and 30 days were 1990) including sire within breed increasedasparityincreased. and doe nested sire within breed LWB, and 30 days increased by as random effects, as well as, parity. fixed effects as defined in model 1 were adapted. The variance Thetwosetsofregression components { Sir9s ( 02s), does analyses for LZB, 21 and days wi hin sires (a d) and residual made with fixed effects (groups of (a 3 e)} were obtained by equating does, breed, season of delivery the mean squares forandom and parity). The regression effects to their expected values coefficients LZB, 21 and (HENDERSON, 1953). Heritability days on gestation period and LWB the The effect of breed was highly significant for LZB, 21 and 30 days and LW at the same time. The breed was significantly higher than NZW and BAU in LZ at different periods but it was significantly lower than NZW and in LW at the same periods. Differences between NZW and BAU were not significant in all traits studied.

5 were highly significant (Table 2). studied were noticed during spr The regression coefficients of LWB (except for LZB during winter). and 21 on gestation period were The difference in this characters significant and among different seasons may be respectively), but regression attributed temporal the to coefficients of LW at 30 days on variation in climatic conditions. gestation period not was The differences among seasons we significant. LZB significantly highly significant for affected LWB, and temperature and relative humidity days (Table 3 ). (Table The results agree with the findings reported by LUI The Heritability ( h2 ), genetic - al. (1980) and RAND1 (1982) for and phenotypic correlation (rg & LZ. r ) for and between preweanlng lytter traits at different ages Parity had a significant effect are given in Table 4. The h2 for on LZ and LW at the ages studie LZ and LW were moderate. but it showed no definite trend in among each of litter size The an 3 both of LZ and LW at the ages litter weight at different ages studied. These results agree with were positive and high. The r between LZ and LW at differen! periods were highly positive. the findins reported et al. (1959) and NIEDZWIADEK - al. (1983) reported that effect of parity on LZB did show any consistent trend. _. et the not The results show the effects of The highly significant group (imported and locally-born regression coefficient values of does), breed, season of delivery LZ at different periods on and parity reproductive on gestation length clarified the performance. association between small LZB and increased length of gestation, The imported does showed noted ADAM by (1972) and reproductive performance superior PARTRIDGE et (1981) were to the locally-born does, having a confirmed in present the higherlzandlwatdifferent experiment. The highly significan periods. These results indicating of regression coefficient values that the locally-.born does were of LW at different periods on LZB affected negatively. by Egyptian clarified thelwatdifferent conditions more than their dams. periods increased with the increase of LZB, 'these results A highvariabilityisalso agreedwiththosereportedby foundamongthegenetictypes ATTILA BALLAY et al. (1988). studied (CAL, BAU and NZW), supported statistical by The paternal half-sib h2 for significances in LZ.and LW at at different age suggests that different ages studied. Does CAL improvement could be realized by showed a LZ at different ages selection. Similar, results were superior thenzwandbau. reportedbypatras (1985) However, both types of does (NZW KHALIL & (1986). The low ""9 h and BAU) showed a LW at different of LW at different ages indicates ages studied than the CAL does, that the relative importance of noted by Mach (1986), TAG-EL-DIN & additive genetic factors is low ALI (1989) and OUDAH (1990). andmostimprovementofthese traits of imported herd could be Season delivery showed realized improvement by of highly significant effects environment and management of the on traits studied. litter after birth, because the The highest LZ and LW at the ages period from birth to weaning is

6 most sensitive to environment and rabbits under Egyptian the management change. The low or conditions. Journal Applied Rabbit moderate values in the present Research, study for preweaning litter weight traits noted by KHALIL & ATTILA BALLAY, A., SZOMBATH and AFIFI et al. SZABO,E.andFOUP,M. The rg between LZ and LW at the Relationshipsbetweenthemilk same ages were positive, with production and fertility of Angora small standard error. These does. In Proceedings of the 4th results indicate that doe World Rabbits Congress, Budapest, producing high levels of LZ tend Hungary, to give higher LW. High genetic correlation among L2 and LW DAMODAR, andjatkarv.d. indicate the synergistic control AdaptabilityofBroiler of the same additive gene and rabbits under subtropical environmental deviations, climates. Indian Journal Animal influence traits above. Therefore, Science, selection of LZ would also improve the LW. The highly positive r Harvey, W.R. Users between and LW at different guide for LSMLMW and MIXMDL. periods agreed closely with those Mimeo, Ohio State University, reported by KHALIL & Q. U.S.A.. and AFIFI et al. from NZW and CAL rabbits. KAWINSKA, NIEDZWIADEK, and TUCZYNSKA, J. The Conclusions maternal ability of New Zealand White does. Roczniki Zootechniki, In conclusion, the observed trends the LZ and LW showed the unfavorable climate conditions KHALIL,M.H.OWEN,J.B.and depressed performance the locally- AFIFI, E.A. A review born does and indicate that these phenotypic and genetic parameters seem to be undergoing the adaptive associated with meat production process during the period of the traits in rabbits. Animal Breeding study under Egyptian conditions. Abstracts, Moderateandlow indicated comparatively large influences of KHALIL,M.H..OWEN, J.B.and environmental.effectsonthese AFIFI, E.A. A genetic traits. The r between preweaning analysis of litter traits in litter trai& were moderately Bauscat and Giza White rabbits. positive. Improvement Animal Production, (phenotypic) these of one characters means improvement other LUI, J.F., GIANNONI, M.A.G. and characters at the same time. BANZATTO, D.A. Effect season on litter performance. References Revista da Sociedade Brasileira de zootecnia, ADAMS,C.E. InUFAW Handbook the Care on Management of Laboratory Animals. Edition. Publ. Churchill Livingstone, Edinburgh, AFIFI, E.A., YAMANI, K.A., MARAI, I.F.M. and EL-MAGHAWRY A.M. Environmental and genetic aspects of litter traits in New Zealand White and Californian LUKEFAHR, S.D., ATAKORA, J.K.A. and OPOKU, E.M. Heritability of 90-day body weight in domestic rabbits from tropical Ghana,WestAfrica.Journal.of Heredity, MACH, Genetic aspects of meat production in rabbits. Part Chovatel,

7 ~ NIEDZWIADEK, KAWINSKA, J. PATRAS, The use and PALIMAKA, G. An heritability coefficients in evaluation of reproductive ability improving the performance New Zealand White female rabbits. Chovatel in Czech, 24: rabbits and some possibilities using these data in selection. RocznikiNaukowe. Zootechniki, RANDI, E. Productivity traits in two rabbit breeds: New ZealandWhiteandCalifornian. OPOKU, and LUKEFAHR, Rivista Zootecnia di Rabbit production and Veterinaria, development in Ghana: the National STATISTICAL ANALYSIS Rabbit Project experience. Journal INSTITUTE INC. User s Applied Rabbit Research, Guide: Statistics, Version 6 Edition, Cary, NC. OUDAH, Studies on TAG-EL-DIN, 1.H and some rabbit breeds and their Some reproductive and meat crosses. M.Sci thesis, Faculty of yield traits in four rabbit bre Agriculture, Mansoura, University, under small scale system EWPt production. Journal Agriculture Science, Mansoura University, PARTRIDGE, G.G., and Egypt CORRIGALL, W. Reproductive performance purebred in and crossbred commercial rabbits. Animal Production 1. Least squares means r S.E. of air tenperature relative hunidity according different seasons. -._._ ~ I--_-_..-- i 1! i Air terperature ;I Relative hunidity i i ( C) (%l I j Seasons i i! l.....f ~~, rean ! 89.9 f63.4 i i i I 1 : Winter j a a 1, a t0.94a i I Spring b b I b I b 1 ; Swmer ~ ~ i ~ ~ i Autumn j 23.2~0.18d d i i I Minimwn I Maxim i 8 hour I 15 hour I I l i 1 l - Within classification, mean bearing different letters, differed slgnificantly at (P<O.OOl).

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