Effect of Different Seasons on the Performance of Grey Giant Rabbits under Sub-Temperate Himalayan Conditions

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1 812 Effet of Different Sesons on the Performne of Grey Gint Rits under Su-Temperte Himlyn Conditions R. S. Bhtt*, S. R. Shrm, Umesh Singh, Dvendr Kumr nd V. Bhsin North Temperte Regionl Sttion, Centrl Sheep nd Wool Reserh Institute Grs vi Bhuntr, Kullu (HP) , Indi ABSTRACT : An experiment ws onduted on 190 progeny (winter -74; summer -59; riny -57) of 12 Grey Gint rits (10 femle +2 mles), to ssess the effet of different sesons in yer, on their reprodutive, growth nd produtive performnes long with feed effiieny, under su-temperte Himlyn onditions. The dily meteorologil ttriutes reorded during winter (Otoer to Mrh), summer (April to June) nd riny (July to Septemer) sesons, nd nlysed were minimum nd mximum temperture, reltive humidity nd rinfll. Vrious iologil prmeters reorded were doe weights t mting nd kindling, litter size t irth, litter weight t irth, kit mortlity, litter size t wening, litter weight t wening, weekly ody weight up to 98 d nd wener mortlity. Individul weight gins, dressing perentges, met weights, liver weights, rw-pelt weights, proessed pelt weights nd proessed pelt res t slughter on d 84 nd 98, respetively were lso reorded. The feed nd fodder ompositions nd their nutritive vlues during different sesons were lso nlysed. Averge mient temperture during winter, summer nd riny sesons were 13.2±2.8, 22.4±3.7 nd 24.8±2.3 C, respetively. The verge reltive humidity nd totl rinfll for winter, summer nd riny sesons were 68.9±1.5% nd 48±26.6mm, 66.3±4.8% nd 125.6±56.8 mm, nd 77.3±1.3% nd 116.3±90.4 mm, respetively. The weight of doe t mting nd kindling, litter size t irth, litter weight t irth nd litter size t wening were omprtively higher wheres litter weight t wening ws signifintly (p<0.05) higher during winter s ompred to summer nd riny sesons. The kit mortlity ws signifintly (p<0.05) higher during winter while the wener mortlity ws signifintly (p<0.05) higher during riny seson. At 84 d, the live weight per doe, slughter weight, dressing perentge nd liver weight were signifintly (p<0.05) higher during winter thn summer nd riny. Similrly, the gin in weight nd met weight t 84 nd 98 d were signifintly (p<0.05) higher during winter. The weight of rw pelt nd proessed pelt were reorded signifintly (p<0.05) higher during winter while no differene in the re of proessed pelts during different sesons ould e oserved. No differene in the iologil performne ould e oserved etween sexes in ny of the sesons. Roughge nlysis reveled omprtively higher rude protein perent nd lower rude fire perent during summer nd riny sesons thn in winter. The roughge dry mtter intke ws omprtively higher during summer nd riny sesons vis--vis onstnt mount of onentrte supplied during ll the three sesons. The digestiilities of dry mtter ws signifintly (p<0.05) lower, wheres tht of rude fier, id detergent fire nd ellulose were negtive during winter. Interestingly, the feed:gin ws exeedingly well during winter thn in other sesons nd it is onluded tht it ws the est seson for prodution of rits under su-temperte Himlyn onditions. (Asin-Aust. J. Anim. Si Vol 15, No. 6 : ) Key Words : Crss Trits, Feed Effiieny, Growth, Rit, Reprodution, Sesons, Su-Temperte Climte INTRODUCTION In tropil ountries, the high temperture or het stress, hndips the suess of rit frming (Cerver et l., 1997), s it leds to signifint redution in the dily weight gin, dily feed intke nd feed effiieny (Chierito et l., 1993). Similrly, the milk yield of rit mximized t 15 C mient temperture ws redued y 7.7 g for eh 1 C rise in the temperture (Ppp nd Rfi, 1988). The negtive effet of hot limte on rit growth nd reprodution ould e very useful for evluting reeding onditions in reltion to het stress (Finzi et l., 1992). Aove C of mient temperture, rits deresed their feed onsumption nd required more digestile energy (Les, 1983). At 30 C, the verge feed * Corresponding Author: R. S. Bhtt. Tel: ; Fx: Reeived Septemer 28, 2001; Aepted Jnury 8, 2002 onsumption ws reported to e deresed y 30% nd ffeted growth s well (Mtheron nd Mrtil, 1981). The effet of experimentl hot environment onditions in rits hve een extensively disussed in the lst two dedes minly on growth performnes nd feed intke (Chierito et l., 1992). But, the informtion sed on experimentl onditions, whih re often quite different from eh other, provide inomplete piture (Chierito et l., 1992) nd n not e implemented universlly t lest under frmer s onditions in developing ountries. In Indi, the postntl growth of different rit reeds under semi-rid onditions reveled signifint etter growth performne of Septemer-Deemer orn young ones ompred to those orn in Jnury-April (Gupt et l., 1992). However, informtion on the effet of different sesons on the iologil performne of roiler rits under su- temperte Himlyn onditions, in Indi, re lking nd the present experiment ws, therefore, undertken using Grey Gint rits.

2 EFFECT OF SEASONS ON RABBIT PERFORMANCE 813 MATERIAL AND METHODS An experiment ws undertken with 190 progeny (winter -74; summer -59; riny -57) of 12 (Ten femles nd two mles) Grey Gint rits, to ssess the effet of three mjor sesons on their growth performne, prodution prmeters, reprodutive performne nd nutrient utiliztion. The prent dult nimls of similr ge were red t lest one during eh seson. Three mjor sesons tegorized t this ple were - winter (Otoer to Mrh), summer (April to June) nd riny (July to Septemer) nd the dily meteorologil dt (minimum nd mximum temperture ( C), rinfll (mm) nd reltive humidity (%) were reorded during the experimentl period. During eh seson, the experiment with the progeny ws ontinued for period of d (till slughter). The weight of femles t reeding nd kindling, litter size t irth (LSB), litter weight t irth (LWB), kit mortlity, litter size t wening (LSW), litter weight t wening (LWW), weekly ody weight from wening to slughter nd mortlity in weners were reorded. Neworn kits were milk fed twie dy during morning nd evening nd 15 d fter irth, they were offered mshed onentrte diet long with doe s milk. The onentrte diet ws omposed of mize-30%, ground nut expeller-20%, sunflower ke-5%, soyflkes-5%, whet rn-15%, rie rn-15%, fish mel-3.5%, molsses-5%, minerl mixture- 1% nd ommon slt-0.5%. Additionlly, the feed (100 kg) ws supplemented with 10 g of vitmin A-D 3, K nd E with selenium mixture; 5 g eh of lysine nd methionine; 50 g of mgnesium oxide nd 250 g of Di-lium phosphte. At 35 d of ge, ll kits were sexed, tgged nd wened. Eh wenling rit ws kept individully in ll wire msh ges of stndrd size inside the house hving sestos roof nd wll mde up of hiken wire msh, therey providing similr housing nd mngement onditions. Eh niml ws given onentrte in the form of pellet out 50 g d -1 hed -1, with stndrd soop in the morning nd ws supplied wter d liitum. Additionlly, they were given sesonl grsses, d liitum (Festu rundine, Lolium perene, Trifolium repens, Psplum spp., Puereri thunergin, Pnium spp. nd Setri spp.), in the wilted form or their hy during winter, in the fternoon. The experiment ws rried out for period of d nd weekly ody weight of individul niml(s) ws reorded. At 63 d of ge metoli tril, of 5 d durtion, ws onduted with 4 nimls from eh group, to mesure the digestiility of nutrients during eh seson. The totl intke of onentrte nd roughge during the metoli tril ws reorded. Fees voided nd urine exreted were olleted nd representtive smples were tken for proximte nlysis (AOAC, 1990) nd fier frtions (Goering nd Vn Soest, 1984). At 84 d of the ge, rits were rndomly divided into two sugroups during eh seson. One of the groups ws slughtered t the 84 d y stndrd method (Cheeke et l., 1982) following nek dislotion. While, the other group ws rered for two more weeks nd slughtered t 98 d. All the nimls were fsted for out 12 h efore slughter nd their weights were reorded just efore slughter to lulte the dressing perentge on the sis of the weight of the hot rss, liver nd kidneys; wheres lungs nd hert were disrded. During ll three sesons, slughter of nimls ws done y the sme person to void the vrition in met nd skin dt. Prmeters like weight gin t 84 nd 98 d, hot rss weight, liver weight nd fresh pelt weight were reorded. Immeditely fter slughter, the skins were seured on strether while wrm nd with flesh side out. The pelt(s) fter drying were sujeted to the slt-id proess (Cheeke et l., 1982) nd their weight (g) nd re (sq. m.) fter proessing were lso reorded. The dt generted were sujeted to sttistil nlysis using nlysis of vrine (ANOVA) (Snedeor nd Cohrn, 1967). RESULTS AND DISCUSSION Meteorologil ttriutes The month-wise verge minimum nd mximum temperture ( C), rinfll (mm) nd reltive humidity (%) during different sesons is given in figure 1. The verge monthly temperture (minimum to mximum) during winter, summer nd riny sesons for the period under experimenttion rnged from 1.7 to 29.1, 10.1 to 33.1 nd 17.8 to 30.7 C, respetively. Averge temperture during the winter, summer nd riny sesons were 13.2±2.8, 22.4±3.7 nd 24.8±2.3 C, respetively. The verge reltive humidity nd totl rinfll for winter, summer nd riny sesons were 68.9±1.5 perent nd 48±26.6 mm, 66.3±4.8 perent nd 125.6±56.8 mm, nd 77.3±1.3 perent nd 116.3±90.4 mm, respetively. The rinfll ws reorded more during the end of June (due to pre monsoon rins) whih inresed the verge rinfll during summer s ompred to riny sesons. The reltive humidity during winter nd summer sesons ws lmost equl nd ws within the eptle limits for the optimum prodution (Les et l., 1986; Sndford, 1986). While it ws inresed onsiderly during the riny seson long with rise in verge mient temperture (24.8 C) mking it n unomfortle period to the nimls. Moreover, the differene etween the verge minimum nd mximum temperture during riny sesons ws lso deresed s ompred to winter nd summer. The produtive performne reported to impir in some wy t 25 C nd even smll flutution etween mximum nd minimum tempertures distured the growth performne of rits

3 814 BHATT ET AL. Min. temp Temp Mx. temp Temp Rinfll Reltive humidity Humidity Temperture C Ot Nov De Jn Fe Mr Apr My Jun Jul Aug Sep Month Reltive humidity (%) or rinfll (mm) Figure 1. Meteorologil ttriutes during different sesons (Chierito et l., 1992). Chemil omposition of onentrte nd roughge The hemil omposition of the onentrte nd roughge(s) re presented in the tle 1. The onentrte (pellets) ontined 21.3% rude protein (CP) nd 9.4% rude fier (CF). The higher CP nd lower CF thn the reommended levels, dvoted in the onentrte were to ompenste for their respetive low nd high levels in the roughge(s) given. The hemil omposition of roughge(s) (tle 1) reveled lower CP nd higher CF in Tle 1. Chemil omposition of onentrte nd roughge(s) in different sesons Nutrients Roughge Conentrte Winter Summer Riny Dry mtter (DM) Crude protein (CP) Crude fier (CF) Ether extrt (EE) Nitrogen free extrt (NFE) Aid detergent fier (ADF) Aid detergent lignin (ADL) Cellulose (ADF-ADL) Totl sh winter seson s ompred to summer nd riny sesons. The differene ould e due to the stge of roughge offered in the prtiulr seson; s during winter, rits were fed hy while in other two sesons fed lush green grss. In ddition, the loss of tender portion of grsses during hy-mking ould lso e responsile for the higher CF fed during the winter. The omprtively less ether extrt (EE) in the roughge (hy) offered during winter (tle 1), ould e due to lower mount of pigments, preursors of vitmin A nd other extrtle mterils in the hy. The mount of ellulose in the roughge(s) during different sesons ws proportionl to their orresponding CF levels. The mturtion of forges leds to deresed CP, inresed CF nd deresed nutritive vlue due to lignifition of stems (Cheeke, 1987). All the nutrients (onentrte+roughge) were within the permissile limits (NRC, 1977). Biologil performne The weights of the doe t mting nd kindling were omprtively higher, though non-signifint, in winter (figure 2), s ompred to summer nd riny sesons. It ws interesting to note tht the ody weight of doe deresed with n inrese in the verge mient temperture from winter to riny seson inditing the effet of temperture on the ody weight of the nimls. Sine, the reltive humidity in riny seson ws lso higher long with higher verge environmentl temperture, the negtive effet on the ody weight ws more entuted in this seson. Though, the reltive humidity of out 75% inside the niml house t temperture of out 10 to 13 C

4 EFFECT OF SEASONS ON RABBIT PERFORMANCE 815 Doe weight t mting (kg) Doe weight t kindling (kg) Litter size t irth Litter size t wening Litter weight t irth (kg) Litter weight t wening (kg) 84d live weight / doe (kg) Kit mortlity (%) 0 Wener mortlity (%) (n=59) 1.8 (n=57) (n=64) (n=59) Winter Summer Riny (n=56) (n=74) Figure 2. Biologil performne of rits during different sesons onsidered idel for rits; flutution in the temperture y more thn 5 C thn outside ould ffet the performne (Sndford, 1986). In this experiment, there ws no vrition in the inside nd outside temperture of the niml house owing to its onstrution, the inrese in temperture from winter (13.2 C) to riny seson (24.8 C) hs negtive effet on the ody weight of the doe t mting. Mertens nd De Groote (1990) lso reported low ody weight of doe t high mient temperture thn norml mient temperture though the differenes were non-signifint. The derese in ody weight due to the het stress hs een knowledged limiting ftor in tropil ountries (Finzi et l., 1992). The LSB ws lrgest (7.4±0.5 per doe) in winter followed y summer (5.9±0.6 per doe) nd riny seson (5.7±0.5 per doe); ut were non-signifint from eh other (figure 2). However, the LSB deresed grdully with inrese in verge mient tempertures from winter to riny seson. The non-signifint effet of seson of kindling on the LSB, similr to our oservtion, hd een reported (Ayyt et l., 1995). The LWB ws highest during winter ompred to riny followed y summer sesons (figure 2), though non-signifint from eh other, inditing no effet of the seson on the LWB, whih orroorted with erlier findings (Ayyt et l., 1995). A kit mortlity of 13.5% ws reorded during winter (figure 2) nd ws signifintly more (p<0.05) thn other two sesons inditing the negtive effet of winter on the survivility of kits. All deths of kit reorded during winter were due to strvtion, pneumoni nd overfeeding. It ws oserved tht during winter kits orn were reltively wek due to higher LSB nd needed extr re from hilling nd on ount of feeding; in ddition to mothering ility (Bhsin nd Singh, 1995). Similr signifint effet of old sesons on the pre wening mortlity hd een doumented (Ferrz et l., 1991). The LSW hd similr pttern to LSB during different sesons nd ws influened onsiderly y kit mortlity during winter (figure 2). The LWW ws signifintly (p<0.05) more during winter nd summer thn riny seson (figure 2). Individully, the 35 d weights (wening weight) during ll three sesons were differing signifintly (p<0.05) from eh other (figure 3). These findings reveled the signifint influene of different sesons on the growth of young ones from their irth to wening (35 d); s their LWB were non- signifint from eh other. The wener mortlity (etween 35 d-84 d) ws signifintly (p<0.05) more in riny seson (10.5%) s ompred to winter nd summer (figure 2). The erliest deth during winter nd summer ws reorded fter 70th d, while during riny seson deths ourred etween 35th nd 49th d of ge. All the deth(s) during winter, summer nd riny sesons were due to enteritis, pneumoni nd enteritis, respetively. The signifint deth of weners during riny seson ws possily due to environmentl stress nd signifintly low ody weight of young ones fter wening. Other importnt ftors, like lrge litter size, insuffiient milk prodution (Vlderm Dedez nd Vrel-Alverez, 1975; Torres et l., 1986; Viente nd Gri-Ximenez, 1992), ffeting post wening survivl nd growing pity were not signifint,

5 816 Body weight (g) 2,200 2,100 2,000 1,900 1,800 1,700 1,600 1,500 1,400 1,300 1,200 1,100 1, BHATT ET AL. Winter Summer Riny Age (d) Figure 3. Overll growth performne of rits during different sesons (Men±S.E.). The letters t the tops of the spots indite sttistil signifine; mens with different letters re signifintly different (p<0.05). during riny seson, in this experiment. The nlysis of weekly ody weights of weners (figure 3) indited signifintly (p<0.05) higher ody weight(s) during winter seson s ompred to other two sesons nd orroorted with findings of Remois et l., (1996). Between group omprison exhiited tht the ody weights t 35, 42, 49, 56, 63, 70 nd 77 d in weners, during ll three sesons, were signifintly (p<0.05) different from eh other with lowest weights reorded during riny seson. From 84 to 98 d, the ody weights in winter seson were signifintly (p<0.05) more s ompred to other two sesons while no signifint differene etween the ody weight of nimls during summer nd riny sesons ould e oserved for this period. The poor growth during riny seson up to 77 d ws possily due to dverse environmentl intertions, s the LWB, geneti mke up nd mngement ws similr. Animls orn in the riny seson performed omprtively etter fter 77 d of their ge due to fll in the verge mient temperture with the onset of winter. Sex-wise nlysis for growth reveled non-signifint differenes for weight gin from 35 to 98 d, during eh seson (figure 4). Comprison of ody weights mong femles (progenies) for different sesons reveled signifint (p<0.05) differene up to 70 d, with lowest weight reorded in the riny seson. From 70 to 98 d, the ody weights for femles were signifintly (p<0.05) higher in winter s ompred to other two sesons. The ody weights in mles during different sesons were similr to femle from 35 to 70 d, while signifintly (p<0.05) more in winter fter 70 d. Redued growth in ged rits t temperture over 25 C (Withorff et l., 1988) due to impired ody het dissiption through skin (Hrkness, 1988) ould e one of the resons for low growth during riny seson in this experiment. An effet of the month of irth on post wening gin of rits hd een ttriuted to the nutritionl nd limti onditions (Afifi, 1971) other thn the reed, yer nd prity (Mnitt nd Lukefhr, 1990). The overll gin in weight nd met weight t 84 nd 98 d were signifintly (p<0.05) more in winter s ompred to other two sesons (figure 5). In sex-wise nlysis, differenes were non-signifint etween femle nd mle during different sesons for these prmeters (figure 6). Sex-wise, femles nd mles hd signifint (p<0.05) gin in weight nd met weights t 84 nd 98 d during winter thn summer followed y riny seson. The dressing perentges were signifintly (p<0.05) different, t 84 d, during three sesons with highest in winter nd lowest in riny sesons (figure 5). While t 98 d the highest (p<0.05) dressing perentge ws reorded during summer nd lowest during riny seson. Sex-wise, t 84 d, the dressing perentges of mle nd femles were not differing signifintly from eh other (figure 6). Individully, for femles nd mles, the dressing perentges were signifintly (p<0.05) higher in winter thn summer followed y riny sesons (figure 6), due to their respetive slughter weights, s diret proportion existed etween slughter weights nd dressing perentges (Kulkrni et l., 1995). Liver weights, t 84 d, were signifintly (p<0.05) more during winter nd summer thn riny seson, wheres, t 98 d, the liver weight ws signifintly (p<0.05) more in winter thn summer nd riny sesons (figure 5). Liver

6 EFFECT OF SEASONS ON RABBIT PERFORMANCE 817 Winter - Femle Winter - Mle Summer - Femle Summer - Mle Riny - Femle Riny - Mle Body weight (g) Age (d) Figure 4. Sex-wise growth performne of rits during different sesons (Men±S.E.). The letters t the tops of the spots indite sttistil signifine; mens with different letters re signifintly different (p<0.05). weights were diretly proportionl to their respetive met weights t 84 d, ut no suh trend existed for liver weights t 98 d slughter. Sex-wise, the liver weight t 84 d ws signifintly (p<0.05) more in femle thn mle during winter (figure 6). The lowest liver weights were reorded in the femle nd mle during riny seson. On the other hnd, t 98 d there ws no differene in the liver weights of oth the sexes during ny of the seson. The pelt weights immeditely fter slughter (rw), t 84 nd 98 d, during winter, were highest nd signifint (p<0.05) thn summer nd riny sesons (figure 5). Sexwise, rw pelts weighed signifintly (p<0.05) more in mles nd femles during winter thn summer followed y riny seson (figure 6). Diret dependene of the pelt size on the ody weight of rit (Tylor nd Johnston, 1984) nd lower skin weights in het stressed rits s ompred to those kept in thermoneutrl zone (Chierito et l., 1996); eluidte the higher nd lower pelt weights, during different sesons, in the present experiment. The overll nd sex-wise nlysis of proessed pelt weights (figures 5 nd 6) followed trend similr to weights of rw pelts during different sesons. However, t 98 d slughter, the proessed pelt weight in riny seson ws omprtively etter thn summer possily due to the onset of winter when the nimls orn in riny seson rehed the slughter ge. It ws noted tht during proessing of pelt, out 64-69% of their rw weight ws lost during ll three sesons inditing tht suutneous tissues nd fsi did not ontriute muh to the inresed or deresed (rw or proessed) weights of the pelt. An importnt ftor-pelt re, whih otherwise ould hve influened the pelt weights, ws nonsignifint during different sesons in this experiment, therey, onfirming tht the vrition in pelt weights were due to the skin thikness. Nutritive index Plne of nutrition (tle 2) indited lowest nd highest dry mtter intke (DMI) during winter nd riny sesons, respetively. The inresed DMI nd roughge intke during summer nd riny sesons were due to the etter pltility of roughges owing to their suulent nture; s pltility delined with mturity of grsses (Churh, 1986). The higher protein nd lower fier ontents of roughge during summer nd riny seson were inditors of etter roughge qulity. The dily weight gin ws highest nd signifint (p<0.05) during winter months followed y summer nd riny sesons. The feed:gin ws est during winter thn summer nd riny sesons, inditing the suitility of winter seson for rit prodution. In spite of omprtively less dily dry mtter intke nd poor qulity of roughge (hy), the etter growth performne during winter ould e ttriuted totlly to fvorle environment, less disese stress nd etter feed: gin (p<0.05). On the other hnd, the etter qulity of roughges supplied during summer nd riny sesons ould hve ompensted for the het stress. The need of high energy density in growing rits during high temperture needed to llevite the therml stress (Cerver et l., 1997). The effet of sesons on the post wening weight gin nd performne, similr to our findings, hve een ttriuted to

7 818 Weight gin t 84 d (g) Weight gin t 98 d (g) Met weight t 84 d (g) Met weight t 98 d (g) Dressing % t 84 d Dressing % t 98 d Liver weight t 84 d (g) Liver weight t 98 d (g) Rw pelt weight t 84 d (g) BHATT ET AL. (n=31) (n=30) (n=32) (n=28) (n=31) (n=30) (n=32) (n=28) (n=31) (n=30) (n=31) (n=30) (n=32) (n=28) (n=63) (n=58) (n=50) (n=32) (n=28) Winter Summer Riny Rw pelt weight t 98 d (g) (n=32) (n=28) Proessed pelt weight 84 d (g) Proessed pelt weight 98 d (g) Proessed pelt re t 84 d (sq.m.) Proessed pelt re t 98 d (sq.m.) (n=31) (n=30) (n=32) (n=28) (n=31) (n=30) (n=32) (n=28) Figure 5. Prodution performne of rits during different sesons. Different supersripts for prtiulr prmeter indites sttistil signifine; mens with different supersripts re signifintly different (p<0.05). the hnges in nutritionl nd limti onditions (Afifi nd Emr, 1990). Digestiilities of nutrients (tle 2) reveled signifintly (p<0.05) lower digestiility of dry mtter (DM) during winter s ompred to summer nd riny sesons. The digestiilities of rude fier (CF), id detergent fier (ADF) nd ellulose were negtive during winter nd ould e due to mtured grsses (hy) fed to the rits. Digestiilities of rude protein (CP), ether-extrt (EE) nd nitrogen free extrt (NFE), during different sesons, were non-signifint from eh other. It is not unusul to hve negtive digestiility of fier in rits (Singh et l., 1988) nd ould e relted to proportiontely higher CF nd low CP in the roughge (Snhez et l., 1985). Grsses fed during summer nd riny sesons were either premture or prtilly mture nd therefore, hd etter digestiilities of CF, ADF nd ellulose. An inresed fiers, deresed proteins, digestiility nd nutritive vlue (Cheeke, 1987) nd deresed pltility (Churh, 1986) of forges, on mturtion, due to lignifition of stem ould possily explin the findings in this experiment. Overll, digestiilities of different nutrients did not orrelte well with the growth performne nd to the feed: gin during different sesons. Though, the nutritive vlue of feeding regime ws etter during summer nd riny sesons thn winter, the feed:gin ws superior during winter possily due to less therml stress. A higher het stress during riny seson, not only used signifint (p<0.05) mortlity ut lso outweighed the effet of etter nutrition on growth performne s well. CONCLUSIONS From this experiment, it ws onluded tht different sesons under su temperte Himlyn onditions did not hve ny signifint effets on doe weight t mting nd kindling, litter size t irth, litter weight t irth, litter size t wening nd proessed pelt res. The litter weight t wening, growth performne from wening to dy of slughter, kit nd wener mortlity, met weight, dressing perentge, liver weight, nd rw nd proessed pelt weights were influened signifintly y different sesons. In ddition, the superior feed : gin during winter proved to e etter seson for roiler rit prodution under onventionl mngement onditions.

8 EFFECT OF SEASONS ON RABBIT PERFORMANCE 819 Weight gin t 84 d (g) Weight gin t 98 d (g) Met weight t 84 d (g) Met weight t 98 d (g) Dressing % t 84 d (n=13) (n=13) (n=12) (n=7) (n=30) (n=33) (n=29) (n=29) (n=18) (n=32) (n=12) (n=7) Dressing % 98 d Liver weight 84 d (g) Liver weight 98 d (g) Rw pelt weight 84 d (g) Rw pelt weight 98 d (g) (n=12) (n=7) (n=13) (n=12) (n=7) (n=13) (n=12) (n=7) Winter - Femle Winter - Mle Summer - Femle Summer - Mle Riny - Femle Riny - Mle Proessed pelt weight 84 d (g) (n=13) Proessed pelt weight 98 d (g) Proessed pelt re 84 d (sq.m.) (n=12) (n=7) (n=13) Proessed pelt re 98 d (sq.m.) (n=12) (n=7) Figure 6. Sex-wise prodution performne of rits during different sesons. Different supersripts for prtiulr prmeter indites sttistil signifine; mens with different supersripts re signifintly different (p<0.05). Tle 2. Plne of nutrition, digestiility oeffiients of nutrients nd nutritive vlue of feeding regime in Grey Gint rits during different sesons Prmeters Winter Summer Riny Plne of nutrition (g d -1 hed -1 ) Conentrte intke (Dry mtter) Roughge intke (Dry mtter) Totl dry mtter intke Dily weight gin (g)-35 to 84 d 25.3± ± ±0.4 Feed:Gin (Pooled) Digestiility oeffiients (%) Dry mtter (DM) 36.5± ± ±3.9 Crude protein (CP) 62.9± ± ±3 Crude fier (CF) -10.9± ± ±5.6 Ether extrt (EE) 40.8± ± ±10.7 Nitrogen free extrt (NFE) 48.2±7 63.1± ±1.6 Aid detergent fier (ADF) -4.9± ± ±2.2 Cellulose (ADF-ADL) -16.8± ± ±0.1 Nutritive vlue of feeding regime (%) Digestile rude protein (DCP) Totl digestile nutrients (TDN) Figures ering different supersript in row signifintly (p<0.05) differ from eh other. REFERENCES Afifi, E. A A study of some eonomil nd produtive hrters in some strins of rits nd their rosses. PhD thesis. Fulty of Agriulture, Ain-Shms Univ., Egypt. Afifi, E. A. nd M. E. Emr Breed group nd environmentl ftors influening post wening dily gin in weight of pure-red nd ross red rits. J. Appl. Rit Res. 13: AOAC Offiil Methods of Anlysis (15 th Ed.) Assoition of Offiil Anlytil Chemists. Wshington. DC. Ayyt, M. S., I. F. M. Mri nd A. GH. El- Syid Geneti

9 820 BHATT ET AL. nd non-geneti ftors ffeting milk prodution nd pre wening litter trits of New Zelnd does under Egyptin onditions. World Rit Siene, 3: Bhsin, V. nd D. Singh Pre-wening mortlity in rits. Int. J. Anim. Si. 10: Cerver, C., E. Bls nd J. Fernndez-Crmon Growth of rits under different environmentl temperture using high ft diets. World Rit Siene, 5: Cheeke, P. R Rit feeding nd nutrition. Hrtourt Bre Jovnovih, Pulishers Ademi Press, In. Cheeke, P. R., N. M. Ptton nd G. S. Templeton Rit Prodution. The Interstte Printers nd Pulishers In. Dnville Illinois. Chierito, G. M., L. Biloni nd C. Rizzi The effet of environmentl temperture on the performne of growing rits. J. Appl. Rit Res. 15: Chierito, G. M., C. Rizzi nd V. Rostellto Effet of genotype nd environmentl temperture on the performne of the young met rits. World Rit siene, 1: Chierito, G. M., C. Rizzi nd V. Rostellto Effet of genotype nd environmentl onditions on the produtive nd slughtering performne of growing met rits. 6 th World Rit Congress, Toulouse, III: Churh, D. C Livestok feeds nd feeding. (2 nd Ed.). Prentie-Hll, Englewood Cliffs, New Jersey, USA, Ferrz, J. B. S., R. K. Johnson nd J. P. Eler Breed nd environmentl effets on reprodutive trits of Clifornin nd New Zelnd White rits. J. Appl. Rit Res. 14: Finzi, A., S. Nyvold nd M. El. Agroudi Evlution of het stress in rits under field onditions. J. Appl. Rit Res. 15: Finzi, A., S. Nyvold nd M. El. Agroudi Effiieny of three different housing systems in reduing het stress in rits. J. Appl. Rit Res. 15: Goering, H. K. nd P. J. Vn Soest Forge Fire Anlysis. Agriulturl Hndook No. 379, ARS, USDA, Wshington, DC. Gupt, S. C., N. Gupt, Riyzudin nd G. Singh Growth performne of met rits in semi rid tropil onditions in Indi. J. Appl. Rit Res. 15: Hrkness, J. E Rit ehviour s relted to environmentl stress. J. Appl. Rit Res. 11: Kulkrni, V. V., K. Gupt, R. Bhtt nd N. K. Mnuj Growth, rss trits nd met omposition of roiler rits. Indin J. Anim. Si. 65: Les, F Smll sle rit rering in developing ountries. World Rev. 46: Les, F., P. Coudert, R. Rouvier nd H. C. Rohmeu de The Rit Husndry, helth nd prodution. F.A.O. of the United Ntions, Vi delle Terme di Crll Rome Itly. Mertens, L. nd G. De Groote Comprison of feed intke nd milk yield of does under norml nd high mient temperture. J. Appl. Rit Res. 13:3-4. MNitt, J. I. nd S. D. Lukefhr Effet of reed, prity, dy of lttion nd numer of kits on milk prodution of rits. J. Anim. Si. 68: Mtheron, G. nd J. P. Mrtil Growth nd feed onsumption of rit does from wening to 4 months of ge in different mient temperture nd humidities. Zootehniques et Physiologiques. E.N.S.A. Rennes. NRC Nutrient Requirement of Rits. (2 nd Ed.). Ntionl Ad. Si. Wshington, DC. Ppp, Z. nd P. Rfi Impt of het stress on pregnnt rits nd on the development nd viility of their fetuses. 4 th World Rit Congress, Budpest, Remois, G., P. Lfrgue-Huret, A. Bourdillon nd H. Rouillere Effet of wening weight on growth performne of rits. 6 th World Rit Congress, Toulouse, Snhez, W. K., P. R. Cheeke nd N. M. Ptton Effet of dietry rude protein level on the reprodutive performne nd growth performne of New Zelnd White rits. J. Anim. Si. 60: Sndford, J. C The Domesti Rits. (4 th Ed.). Willim Collins Sons nd Co. Ltd. 8, Grfton street, London. Singh, B., H. P. S. Mkkr nd L. Krishn Utiliztion y growing rits of low rude protein diet with or without ure nd groundnut ke supplementtion. J. Appl. Rit Res. 9: Snedeor, G. W nd W. G. Cohrn Sttistil Methods. (6 th Ed.). Oxford nd IBH Pulishing Co. Clutt. Tylor, T. W. nd N. P. Johnston The effet of feed restrition on pelt size nd degree of prime in rex rits. J. Appl. Rit Res.7: Torres, C., M. Pl nd I. Gri Reltion de ls predids de gzpos deunte el engorde, XI Symposium de uniultur, Tere. Vlderm de Dez, G. nd H. Vrel-Alverez Geneti study on the improvement of some produtive hrters in rits. Agro Cieni, 21: Viente, J. S. nd F. Gri-Ximenez Growth limittions of sukling rits. Proposl of method to evlute the numeril performne of rit does until wening. J. Appl. Rit Res. 15: Withorff, E. K., C. E. Heird, J. M. Rkes nd Z. B. Johnson Growth nd reprodution of nutrient restrited rits in het stressed environment. J. Appl. Rit Res. 11:87-92.

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