Comparison of conventional and organic management conditions on growth performance, carcass characteristics and haematological parameters in Karacabey Merino and Kivircik breeds

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Growth performance, carcass characteristics, post-slaughtering and haematological parameters of Kivircik and Karacabey Merino male lambs in conventional and organic management systems were compared. The animals which were weaned at 7 weeks of age
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  ORIGINAL RESEARCH Comparison of conventional and organic managementconditions on growth performance, carcass characteristicsand haematological parameters in Karacabey Merinoand Kivircik breeds Deniz Soysal  &  Recep Cibik   &  Cenk Aydin  &  İ brahim Ak  Accepted: 1 December 2010 /Published online: 15 December 2010 # Springer Science+Business Media B.V. 2010 Abstract  Growth performance, carcass characteristics, post-slaughtering and haematological parameters of Kivircik and Karacabey Merino male lambs in conventionaland organic management systems were compared. Theanimals which were weaned at 7 weeks of age were dividedinto Kivircik conventional, Kivircik organic (KO), Karaca- bey Merino conventional and Karacabey Merino organic(MO) groups containing 12 lambs each. Fattening wasended when lambs attained 35 kg of live weight. The timeto attain the determined fattening weight was significantlydifferent among the groups, and Merino lambs havinghigher live weight gain were earlier than Kivircik lambs(  p <0.05). Overall conventional (CG) and organic grouplambs were also compared. Live weight gain, intra-abdominal fat amount, external fat thickness and visceralorgan weight were significantly higher in CG lambs (  p <0.05). Higher haematocrit and erythrocyte counts wereobtained with the CG group (  p <0.05), whilst triglyceride,total plasma cholesterol and lipoprotein (HDL, LDL,VLDL) levels between groups were not significant.Pneumonia was the unique infection, with an incidence of 50% (six lambs) and 16.6% (two lambs) for MO and KOanimals, respectively. The mortality rate was 16.6% (twolambs) for MO group, whilst no mortality was recorded for KO group animals. The present study has shown that although Karacabey merino lambs had higher growth performance compared to Kivircik lambs, organicallyfattened lambs in whole exhibited inferior growth perfor-mance. Lower infection and mortality observed withKivircik lambs suggested that they could be more resistant to infections and outdoor environmental conditions. Keywords  Organic lambing.Ecological rearing.Performance.Carcass.Haematology Introduction In organic agricultural systems, the main purpose is to produce higher quality food from healthy animals. In thissystem, animals should have access to outside areas and fedthrough grazing on pasture, and housing conditions shouldallow them to perform their natural behaviour. The use of man-made fertilisers, growth regulators, pesticides, medi-cines and feed additives is avoided in this system.Objectives of organic agriculture which are described inthe basic standards formulated by the International Feder-ation of Organic Agriculture Movements (IFOAM) arefocused on the preservation of biodiversity, provision of freedom and access to natural behaviour, and closed andsustainable nutrient cycles (Hermansen 2003). D. SoysalMarmara Animal Husbandry Research Institute,Band ı rma, TurkeyR. Cibik Department of Food Hygiene and Technology,Faculty of Veterinary Medicine, University of Uludag,Bursa 16059, TurkeyC. Aydin ( * )Department of Physiology, Faculty of Veterinary Medicine,University of Uludag,Bursa 16059, Turkeye-mail:  İ . Ak Department of Zootechnics, Faculty of Agriculture,University of Uludag,Bursa 16059, TurkeyTrop Anim Health Prod (2011) 43:817  –  823DOI 10.1007/s11250-010-9768-y  Data related to the statistics of organic production of livestockintheEuropeanUnionareincompleteornotupdatedregularly. In 1998, the percentage of organic sheep and goatswas estimated to represent nearly 0.4% of the total herds(Benoit et al. 2009). Organic sheep production is the highest in Austria compared to most other European countries andreaches 30% (von Borella and Sørensen 2004). Althoughoutdoor grazing on pasture is the main sheep productionsystem employed in Turkey, the number of certified organicsheep production is estimated to be lower than 1% (Soysal2006). However, agroecological rearing systems are gainingimportance and becoming more common.Despite the production costs being generally higher inorganic than conventional production systems, public aware-ness is growing and increasing numbers of consumers have been choosing organic foods that were accepted as a source of higher quality, healthier and better taste. Grass feeding canhave influence on the formation of lamb flavour in the meat (Fisher et al. 2000). Higher eating quality in terms of  juiciness, flavour and overall liking was obtained withorganic lamb than conventional lamb. Juiciness is attribut-able to the intramuscular fat content and pH of organic meat,whilst flavour is attributable to the higher level of linolenicacid (18:3) and total  n − 3 polyunsaturated fatty acids inorganic meats (Wood et al. 2004).Animal performance and meat quality may be influenced by different factors including breed, rearing systems, age,environment and post-slaughtering factors such as rate of rigor mortis and method of hanging (Troy 1995; Napolitanoet al. 2002; Mushi et al. 2009; Miranda-de la Lama et al. 2009; Hagos and Melaku 2009). The number of literature comparing conventional and organic livestock is growing;nevertheless, there have been relatively few studies inves-tigating the growth performance, carcass characteristic and blood parameters of sheep (Nurnberg et al. 2006;Matanovi ć  et al. 2007; Angood et al. 2008; Fisher et al. 2000). The present study was undertaken to compareconventionally and organically produced KaracabeyMerino and Kivircik lambs in terms of fattening perfor-mance, post-slaughtering and carcass characteristics, andhaematological parameters. The results obtained shouldcontribute to better understanding the effect of organic lamb production compared with conventional production. Materials and methods Animals and management conditionsThe experiment was performed in the Marmara AnimalHusbandry Research Institute. A total of 48 male lambs (24Kivircik and 24 Merino genotypes) were used as test material, and each genotype was divided into conventional(CG) and organic groups (OG) each composed of 12 lambs.The lambs received mother  ’ s milk during the first 30 day of age and mother  ’ s milk plus initial feeding (organic feeds for organic groups) until the end of the weaning period, whichwas ended at 7 weeks of age. At that stage, special attentionhas been paid to select the lambs having closer live weight in each group. CG lambs were reared separately in proper sized paddocks, whilst OG lambs were reared separately in paddocks at nighttime and grazed on the pasture in daytime.The size of paddocks and grassland for OG animals were inaccordance with the requirements described by IFOAM(Hermansen 2003). CG animals were fed ad libitumcommercial feed and dried common vetch (approx. 100 g per lamb), whilst OG animals received ad libitum organicconcentrate feed that was prepared in the research instituteaccording to the regulation of the Turkish Ministry of Agriculture on organic feeds (Anonymous 2002). Thisanimal group either grazed on pasture or fed directly grassobtained from the pasture. Feed components and chemicalcomposition of feeds used in the experiments for CG andOG animals are given in Table 1. For preventive purposes,the animals were vaccinated against ectima 3 weeks beforethe fattening as well as enterotoxemia and pseudotubercu-losis 3 weeks after the fattening. Any applications madeover the experiments were against internal and external parasites.Post-slaughter measuringBody weight gain and feed conversion ratio were recorded biweekly. Fattening was ended when the live body weight of lambs reached 35 kg. Six animals from each group wereslaughtered and dressed. Digestive tract and visceral organswere removed as described by Colomer-Rocher et al. (1987).The carcasses were left at 4°C for 24 h. Cold carcass weight,weight of digestive tract with content, weight of visceralorgans (liver, heart, lungs, spleen, kidneys), abdominal fat,external fat thickness (cm) and musculus longissimus dorsi(MLD) area (cm 2 ) were recorded.Chemical analysisPrior to analysis, feed grains and grass were ground in alaboratory grinder. Dry material content of feed and meat samples were determined according to AOAC (1990) bykeeping at 105°C for 3 h, whilst for total ash determination,the samples were burned at 580°C for 4 h. Total nitrogenand fat were determined as described by AOAC (1990).Haematological parametersAt the end of the fattening period, blood samples weretaken from five animals in each group and centrifuged. 818 Trop Anim Health Prod (2011) 43:817  –  823  Plasma cholesterol, triglyceride and lipoproteins (LDL,HDL, VLDL) were determined by an Abbott Aeroset System (Abbott Laboratories, Diagnostic Division, IL,USA). For haematocrit analysis, the blood samples werecentrifuged in heparinized capillary tubes for 5 min at 13,000×  g   (Nuve Laboratory Equipment, Ankara, Turkey)and analysed by a reader (International Equipment Co., Needham, MA, USA). Haemoglobin concentration wasmeasured spectrophotometrically. Erythrocyte and leuko-cyte numbers were determined using a haemocytometer Thoma chamber (W. Schreck, Jena, Germany). The level of reduced GSH in erythrocytes was determined by themethod of Beutler (1971).Statistical analysisStatistical analysis was performed using MINITAB andJUMP software (Minitab Inc. 1996; JMP. 5.0 2002). Data were subjected to an analysis of variance to determine theeffect of genotype and rearing system on growth rate, post-slaughtering and meat characteristics and haematological parameters. Comparisons among means were examined bythe least significance difference test. Results Live body weight gain of Kivircik and Merino lambs rearedin conventional and organic systems are presented in Fig. 1.Live weight of lambs at the beginning of the fattening was between 13.8 and 16.3 kg. The time required to reach thedetermined 35-kg live body weight varied among thegroups and changed from 70 to 126 days. KaracabeyMerino lambs had faster growing rate and shorter fattening period compared to Kivircik lambs. Similarly, growing ratein each genotype was significantly lower in OG lambscompared to the CG ones (  p <0.01), and in almost 1 month,growth retardation was recorded for OG lambs. Fattening Conventional feeding group Organic feeding groupFeed components Percentage Feed components PercentageMaize 43.15 Barley 78.00Wheat bran 25.80 Sun flower meal (protein 34%) 20.00Soybean meal (protein 44%) 6.00 Feed grade limestone 1.40Sun flower meal (protein 34%) 17.89 Salt 0.50Molasses 3.50 Premix 0.10Feed grade limestone 2.56Salt 1.00Premix 0.10Total 100 100Chemical compositionDry matter 87.45 88.95Organic matter 79.91 85.71Crude ash 7.54 4.51Crude protein 15.62 15.68Crude fat 3.78 1.60Crude cellulose 8.50 8.88 Nitrogen free extract 53.51 58.05Metabolic energy (kcal/kg) 2,466 2,514 Table 1  Feed components andtheir chemical compositionsused in conventional andorganic groups 101520253035400 14 28 42 56 70 84 98 112 126 Days    B  o   d  y  w  e   i  g   h   t   (   k  g   ) Fig. 1  Body weight gain of Merino Conventional (  square ), MerinoOrganic ( open circle ), Kivircik Conventional ( closed circle ) andKivircik Organic ( triangle ) lambs over the fattening periodTrop Anim Health Prod (2011) 43:817  –  823 819   period was 70 and 98 days for Karacabey Merinoconventional (MC) and Karacabey Merino organic (MO)respectively, whilst it was 98 and 126 days for Kivircik conventional (KC) and Kivircik organic (KO) lambs,respectively. Daily live weight gain was higher in CGlambs (  p <0.05), and the values obtained during fatteningwere 228±15.8 g for KC, 253±26.8 g for MC, 174±5.4 gfor KO and 177±18.1 g for MO lambs. The highest lifeweight gain was obtained with MC lambs between 57 and70 days of fattening with a calculated value of 343±14.3 g.Calculated feed conversion ratios were 4.879, 4.024, 4.659and 4,117 for KC, MC, KO and MO lambs, respectively.Six lambs from each group reaching about 35-kg live body weight were slaughtered and visceral organs, diges-tive tract and abdominal fat were removed before weighting(Table 2). Dressing percentage, calculated as the ratio of carcass weight to live weight, was almost 10% greater inCG lambs. Likewise, weight of visceral organs, intra-abdominal fat amount and external fat thickness weresignificantly higher in CG animals (  p <0.05). Interestingly,the digestive tract with content was heavier in OG animals.MLD area was also larger in CG lambs (  p <0.05), whilst itsextent was greater for MC breeds.Data related to the chemical characteristics of meat samples taken from MLD and legs are shown in Table 3.Dry matter and protein content of meat taken from CGlambs was significantly higher compared to OG lambs (  p <0.05). Fat content in meat samples were not different in OGand CG lambs; however, KO lambs had higher fat than KClambs whilst MO had lower than MC (  p <0.05).Analysis of haematological parameters revealed that haematocrit level and erythrocyte counts were higher inCG lambs (Table 4). However, although cholesterol,triglyceride and lipoproteins (HDL, LDL, VLDL) levelswere numerically higher in Merino lambs compared to theKivircik ones, there was no statistical importance betweenthe groups. Similarly, relatively higher levels were recordedfor CG animals, but there was also no statistical impor-tance. Cholesterol, triglyceride, VLDL and LDL levelswere 20.4%, 17.5%, 18.9% and 33.3% higher, respectively,in CG lambs compared to those of OG lambs. Furthermore,HDL level, known as good cholesterol, was 17.3% higher in OG lambs.During the rearing process, the diagnosed pneumoniawas the unique infection, with an incidence of 50% (sixlambs) and 16.6% (two lambs) occurring in MO and KOanimals, respectively. Whilst the mortality rate recorded as16.6% (two lambs) for the MO group, any lambs dead inthe KO group suggests that they could be more prone toenvironmental conditions. Discussion In the present study, faster body weight gain was obtainedwith Karacabey Merino lambs, indicating that growth rateswere affected by the genotype. Contradictory resultshave been published on different sheep genotypes. Macit et al. (2002) compared the daily weight gain of Awasi,Morkaraman and Tushin lambs and reported that Morkaraman lambs excelled Awasi and Tushin lambs. Incontrast, the study performed by Santos-Silva et al. (2002)on the Merino Blanca and crossbred Ile de France x MerinoBlanco revealed no significant difference between thegenotypes independently of the feeding system. Organicallyreared lambs exhibited important growth retardation com- Table 2  Effects of conventional and organic management systems and genotype × management interaction on post-slaughtering parametersMeasured traits Interaction of genotype and management Management  a  Kivircik Conventional( n =6)Kivircik Organic( n =6)MerinoConventional( n =6)Merino Organic( n =6)Conventional Group( n =12)Organic Group( n =12)Live weight 36.2±1.1 35.7±1.1 37.1±0.1 35.0±1.4 36.7±0.7 35.3±0.8Carcass weight (kg) 18.0±0.6 16.4±0.5 18.7±0.5 16.0±0.7 18.4±0.4a 16.1±0.4bDressing percentage 49.7±0.6 45.9±0.5 50.5±0.6 45.8±0.5 50.1±0.4a 45.8±0.4bWeight of digestive truck with content 6.6±0.2 8.7±0.33 7.0±0.2 8.4±0.4 6.8±0.1 8.6±0.3Weight of visceral organs(liver, heart, lungs, spleen,kidneys)1.75±0.03 1.66±0.04 2.01±0.04 1.74±0.05 1.88±0.03a 1.68±0.04bIntra-abdominal fat 0.7±0.06 0.5±0.05 0.4±0.02 0.2±0.02 0.5±0.04a 0.3±0.03bExternal fat thickness (cm) 0.5±0.05 0.4±0.02 0.6±0.04 0.2±0.06 0.5±0.04a 0.3±0.04bMLD area (cm 2 ) 14.6±0.7 12.4±0.4 18.8±1.4 14.3±0.6 16.7±1a 13.3±0.4b a  Values in the same row with different letters are significantly different (  p <0.05) 820 Trop Anim Health Prod (2011) 43:817  –  823   pared to conventional ones. This result is consistent withthe finding of Nurnberg et al. (2006) reporting better growth rates for finishing lambs under conventional feedingconditions. Lower daily weight gain and prolonged fatten-ing periods observed for organically reared lambs could belinked to unlimited dry matter intake, as outlined by Prioloet al. (2002), and the daily physical activities that animalshave exerted. Higher parasitic infestation in organic animalswould also be another reason for this retardation. Datarelated to the parasitic infestation of the present researchwere published elsewhere and indicated relatively higher helminths and ectoparasites in OG lambs (Girisgin et al.2009).Dressing percentage is one factor affecting the value of the quality of a slaughter animal. Although the lambs wereslaughtered at the same live weight, the dressing percentageof organically reared lambs was lower mainly because of their relatively heavier digestive track. This result is inaccordance with the findings of Bailey (1989) whospecified that cattle having high roughage diet, such ashay, silage or pasture, have lower dressing percentage thancattle on a high proportion grain diet. Another possibleexplanation of the higher dressing percentage could be thesignificantly higher intra-abdominal and external fat amount and higher visceral organ weights measured for CG lambs (Rodríguez et al. 2008).Pasture composition and organic rearing would have aninfluence on the fatty acid composition and meat quality(Dierking et al. 2010). Better carcass classification andhigher fatness score were reported for lambs from certifiedorganic herds (Hansson et al. 2000). Better eating qualityand juiciness would be attributed to the higher intramuscu-lar fat content of organic meats. Nevertheless, Nurnberg et al. (2006) reported no advantage of organic farming for thefat composition and the meat quality. In our study, we couldnot find a correlation between organic and conventional Table 3  Effects of conventional and organic management systems and genotype × management interaction on meat characteristicsMeat analysis Interaction of genotype and management  a  Management   b Kivircik Conventional( n =6)Kivircik Organic( n =6)Merino Conventional( n =6)Merino Organic( n =6)Conventional Group( n =12)Organic Group( n =12)Dry matter (%) 27.4±0.1a 26.9±0.1b 27.0 26.9±0.1 27.2±0.1a 26.9±0.1bTotal ash (%) 1.29a 1.31b 1.32 1.26 1.31 1.29Protein (%) 22.3±0.3 21.6±0.3 22.3±0.3 21.4±0.2 22.3±0.2a 21.5±0.2bFat (%) 2.3±0.1a 2.8±0.1b 2.7±0.3c 2.1±0.1d 2.5±0.1 2.5±0.1 a  Values in the same row with different letters are significantly different (  p <0.05)  b Values in the same row with different letters are significantly different (  p <0.05) Table 4  Effects of conventional and organic management systems and genotype × management interaction on haematological parametersParameters Interaction of genotype × management  a  Management   b Kivircik Conventional( n =6)Kivircik Organic( n =6)MerinoConventional( n =6)MerinoOrganic( n =6)ConventionalGroup( n =12)OrganicGroup( n =12)Hematocrit (%) 37.1±0.5a 33.9±1.3b 35.4±1.4 32.6±0.7 36.3±0.7a 33.2±0.7bHaemoglobin (g/dL) 14.9±0.3 14.2±0.5 14.8±0.6 13.8±0.5 14.8±0.3 14.0±0.3Leukocyte (×10 3 /mm 3 ) 7.7±0.5 8.9±0.8 7.3±0.8 8.0±0.7 7.5±0.5 8.3±0.5Erythrocyte (×10 6 /mm3) 15.544±0.6 14.043 ±0.1 14.756±0.8 12.933±0.8 15.173±0.4a 13.455±0.7bGlutathione (g/dL) 36.0±5.0 36.3±7.7 68.0±9.8 85.9±4.2 52.0±6.6 61.1±7.3Triglyceride (mg/dL) 20.3±2.3 16.8±1.6 23.8±2.4 20.8±2.8 22.1±1.7 18.8±1.6Cholesterol (mg/dL) 53.2±4.5 45.2±3.5 56.5±16.0 45.8±1.7 54.8±7.9 45.5±1.9HDL (mg/dL) 28.0±1.6 22.8±1.7 24.8±4.56 22.2±1.0 26.4±2.4 22.5±1.0LDL (mg/dL) 23.5±1.0 19.3±1.9 28.5±10.8 19.7±1.1 26.0±5.2 19.5±1.0VLDL (mg/dL) 4.27±0.4 3.5±0.2 4.7±0.6 4.0±0.6 4.4±0.3 3.7±0.3 a  Values in the same row with different letters are significantly different (  p <0.05)  b Values in the same row with different letters are significantly different (  p\ <0.05) Trop Anim Health Prod (2011) 43:817  –  823 821
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