İstabul Üiv. Vet. Fak. Derg. J. Fac. Vet. Med. Istabul Uiv. 39 (1), 55-62, 2013 39 (1), 55-62, 2013 Araştırma Makalesi Research Article Factors Affectig Milk Yield Estimated with Differet Methods i Brow Swiss Cattle Fige ÇAKILLI 1, Kozet AVANUS 1 *, Halil GÜNEŞ 1 1 Istabul Uiversity Veteriary Faculty, Departmet of Aimal Breedig ad Husbadry, 34320 Avcilar, Istabul, Turkey *Correspodig Author: Kozet AVANUS İstabul Üiversitesi Veterier Fakültesi, Zooteki Aabilim Dalı, 34320 Avcılar, İstabul, Türkiye e-mail: avaus@istabul.edu.tr Geliş Tarihi / Received: 16.11.2011 ABSTRACT The aim of this study was to determie the effects of some evirometal factors o milk yield levels that were estimated with differet methods i Brow Swiss cattle raised i Altıova Farm. Study was carried out uder similar feedig ad maagemet program. The effects of lactatio tur, year ad seaso were aalysed i terms of measurable evirometal factors. The data was statistically aalyzed by meas of the least-square method for the determiatio of the effects of evirometal factors ad by cotrast-test (GLM procedure). Lactatio milk yield (6294.7 kg, 6320.8 kg, 6313.9 kg) ad 305 day milk yield (5927.1 kg, 6016.2 kg ad 6047.5 kg) were estimated by Dutch (Hollad), Swedish ad Trapez methods i Brow Swiss cattle. The effects of lactatio tur, year ad seaso o lactatio milk yield ad 305 day milk yield were foud as statistically sigificat (P<0.001). Key Words: Brow Swiss, milk yield, evirometal factors ÖZET ESMER SIĞIRLARIN FARKLI METOTLARA GÖRE TAHMİN EDİLEN SÜT VERİMLERİ ÜZERİNE BAZI FAKTÖRLERİN ETKİLERİ Bu çalışma, Altıova Tarım İşletmesi de yetiştirile Esmer sığırları farklı metodlar ile belirlee süt verimlerie ait düzeyler ve bular üzerideki bazı çevre faktörlerii etkilerii belirlemesi amacıyla yapılmıştır. Araştırmadaki hayvalara ortak bir bakım ve besleme programı uygulamıştır. Çalışmada etkisi ölçülebilir çevre faktörleri olarak laktasyo sırası, yıl ve mevsimi etkileri üzeride durulmuştur. Verileri istatistik aalizleride, çevresel faktörleri etki paylarıı belirlemeside miimum kareler metodu ve buları karşılaştırılmasıda cotrast-testi, GLM prosedürü kullaılarak yapılmıştır. Çalışmadaki Esmer sığırları Hollada (Dutch), İsveç ve Trapez metodlarıa göre laktasyo süt verimi 6294,7 kg, 6320,8 kg ve 6313,9 kg, 305 gülük süt verimleri ise 5927,1 kg, 6016,2 kg ve 6047,5 kg belirlemiştir. Süt verimleride laktasyo sırası, yıl ve mevsim faktörlerii öemli olduğu bulumuştur (P<0,001). Aahtar Kelimeler: İsviçre Esmeri, süt verimi, çevre faktörleri This study was summarized from the first author s PhD thesis.
56 Fige Çakıllı, Kozet Avaus, Halil Güeş Itroductio Milk yield ca be icreased with optimizig the evirometal coditios ad improvig the geetic structure of the aimals. This ca be maaged by applyig a accurate selectio program to the aimals that are obtaied with ibreedig of highly productive import aimals or crossbreedig them with the ative breeds. Determiatio both of idividual milk yield value of the aimals ad effects of measurable evirometal factors o this value are depeded o choosig a accurate ad systematic selectio method for improvig milk yield characteristics i cattle breedig. Lactatio milk yield is determied i periodically exercisig milk yield cotrols by differet methods. Whe cotrol itervals are ot equal Dutch (Hollad) method, sice its practical, is the most preferred oe amog these methods. The mea milk cotrol value is cosidered to be maitaied durig lactatio i the Dutch method. I the Swedish method which is accepted as more sesitive, milk yield cotrol day is cosidered to be i the middle of cotrol period ad milk yield i cotrol day is accepted as average daily milk yield of aimals i this period. Accordig to Trapez method, milk yield i both betwee calvig first cotrol date ad betwee last cotrol dryig date were accepted as stayed the same as i daily milk yield i both first cotrol ad last cotrol respectively. The average milk yield of two cosecutive cotrol days also accepted as daily milk yield durig the period of these cotrol dates. Thus lactatio milk yield is estimated by addig the milk yields i the begiig ad last period ad radom periods of lactatio (Everett ad Carter, 1968; Göül, 1971; Göül et al., 1986; Gravert, 1987; Güeş, 1996; Johasso, 1961). Yield characters are determied by geetic structure ad evirometal factors durig the productio period which cosists of measurable affects such as age, year ad seaso ad omeasurable affects such as climate, illess, ad grazig. High productio level ca be obtaied by improvig both geetic structure ad evirometal coditios. Accurate stud selectio is possible with determiatio of effect of measurable evirometal factors o productio yields ad usig these i stadardizatio of a idividual. The aim of this study was estimatig both lactatio milk yield ad 305 days milk yield by Dutch, Swedish ad Trapez methods ad evaluatig some evirometal factors that effect o these characters i Brow Swiss cattle raised i Altıova Farm. Materials ad Methods This study was carried out with the data obtaied from Brow Swiss cattle i Altıova Farm that is located i Koya Kadıhaı ad related to Geeral Directorate of Agricultural Eterprises. Yield values betwee 1991 ad 1997 of Brow Swiss cattle i the eterprise were used. Idividual care ad feedig programme was applied to the aimals i Altıova Farm. Aimals were milked twice a day. Milk yield o the 15 th day of each moth was take ito cosideratio for performig milk yield cotrols. Computer based cotrollig ad feedig system that was itroduced i 1990-1991 to the farm, determied the stadard feedig ratio of cocetrate feed ad grass hay for aimal survival rate. Furthermore, additioal cocetrate feed was give accordig to computer based program depedig o the milk yield value of the aimals. The equatios below were used to calculate milk yield accordig to Dutch (M H ), Swedish (MS) ad Trapez (MT) methods (Göül, 1971; Göül et al., 1986; Güeş, 1996):
Factors Affectig Milk Yield Estimated with Differet Methods i Brow Swiss Cattle 57 M M H T ki i L a M S a ki ( A1 D) k1 i 2 i k k' ( A D) k ( A' A) ( S A ) k 1 1 i 2 I which M: lactatio milk yield, L: lactatio duratio, D: calvig date, S: dryig date, : is umber of milk yield cotrol, a: cotrol period, A ad A : cosecutive milk cotrol dates, k ad k : milk yield i cosecutive cotrols. Lactatios which lasted less tha 305 days were take directly without usig ay correctios for calculatig milk yield of 305 days. For loger lactatio periods correctio factors were ot use, they were calculated with the cotrols up to 305 days. Icomplete lactatio milk yields ad parameters of lactatio periods less tha 270 days were ot evaluated. Lactatio tur, year ad seaso effects were poited out i this study. The equatio below was used for statistics aalyzes about yield characteristics of Brow Swiss i this study: Y ijkl = µ + L i + S j + M k + e ijkl I which: Y ijkl : Yield value of the examied trait, μ: Expected mea, L i : Effect of the lactatio tur (i= 1-8), S j : Effect of the year (j= 1991-1997), M k : Effect of the seaso (k= Witer, sprig, summer ad autum), e ijkl : Radom error. Sice there were o daily milk yield values, real milk yield could ot bee detected. I the study, lactatio milk yield is ot give because there are ot the values of daily milk yield. Therefore istead of determiig the closest predictio method to reality, the differeces betwee mea values of commo groups ad subgroups of three differet models were compared. I order, to fid the effect ratios of the factors showig classified variatio ad the ratios of evirometal factors i geeral variatio were estimated by least square method ad sigificace cotrol amog meas of effect proportios (Searle, 1971) was determied by cotrast-test. The data were aalysed with the geeral liear models (GLM) procedure (Goodight ad Harvey, 1978; Searle et al,. 1980). Results Statistical cotrols of overall ad corrected meas of lactatio ad 305 days milk yield estimated by Dutch, Swedish ad Trapezoid methods i Brow Swiss cattle raised i Altiova Farm ad differeces amog subgroups that were created accordig to lactatio tur, lactatig started years ad seasos ad effectiveess of these factors ad determiatio degrees were give i Tables 1 ad 2. Expected meas of lactatio milk yield were foud 6294.7 kg, 6320.8 kg ad 6313.9 kg accordig to Dutch, Swedish ad Trapez methods. Lactatio milk yield determiatio degrees of factors, whose effects were examied, were calculated as 19.1%, 18.8% ad 18.9% respectively. Geeral effect of the factors whose effects were examied o lactatio milk yield, lactatio order ad the effects of lactatio year ad seaso were foud sigificatly importat at P<0.001 level for each three methods. The differeces amog corrected mea values, which were obtaied by gatherig ito groups of lactatio milk yield predictio methods accordig to lactatio tur, lactatio
58 Fige Çakıllı, Kozet Avaus, Halil Güeş year ad lactatio seaso, were foud statistically sigificat (P<0.05). I compariso of Dutch, Swedish or Trapez methods either expected mea, or mea values of subgroups, were foud statistically differet. Accordig to Dutch, Swedish ad Trapez methods expected meas of 305 days milk yield, were foud 5972.1 kg, 6016.2 kg ad 6047.5 kg respectively. Accordig to predictio methods 305 days milk yield effectiveess of examied factors were estimated as 24.7%, 24.5% ad 24.4% respectively. As i lactatio milk yield, idepedet ad geeral ifluece of lactatio tur, year ad seaso factors o 305 days milk yield was also foud statistically sigificat i P<0.001 level. The lowest ad the highest predictio values i subgroups of both lactatio milk yield ad 305 days milk yield were also foud i the same subgroups of predictio methods. Table 1. Tablo 1. Geeral ad corrected meas of lactatio milk yield (kg) by Dutch (Hollad), Swedish ad Trapez methods, effect proportios of the observed factors, compariso amog the groups, sigificace level (F values) ad determiig degree (R²) of Brow Swiss cattle. İsviçre Esmer sığırlarda Hollada, İsveç ve Trapez metotlarıa göre geel ve düzeltilmiş laktasyo süt verim ortalamaları (kg), gözlee faktörleri etki düzeyi, gruplar arası karşılaştırmalar, öem düzeyi (F değeri) ve belirleme derecesi (R²). Factors Dutch (Hollad) Swede Trapez Overall meas 1316 6219.6±46.18 A 6249.1±46.34 A 6242.0±46.32 A Expected meas 1316 6294.7±41.78 A 6320.8±42.01 A 6313.9±41.97 A All factors - F value (R²) 19.20*** (0.191) 18.79*** (0.188) 18.91*** (0.189) Lactatio tur - F value (R²) 13.14*** (0.057) 12.98*** (0.057) 13.05*** (0.057) 1 439-687.47 c -680.02 c -684.20 c 2 325-0.53 b 4.28 b -1.33 b 3 223 208.02 ab 213.58 ab 210.23 ab 4 130 362.51 a 380.28 a 375.74 a 5 83 265.72 ab 250.61 ab 261.35 ab 6 57 0.44 ab 35.92 ab 13.80 ab 7 30 48.13 ab 25.79 ab 37.53 ab 8 29-196.82 abc -230.44 bc -213.12 abc Year - F value (R²) 26.87*** (0.100) 25.91*** (0.097) 26.32*** (0.099) 1991 157-1242.91 e -1231.56 e -1239.36 e 1992 156-194.41 d -201.59 d -194.16 d 1993 178 87.76 cd 96.15 cd 91.63 cd 1994 183 203.64 bc 214.10 bc 215.70 bc 1995 236 463.12 ab 408.29 ab 435.12 ab 1996 244 574.71 a 586.30 a 579.46 a 1997 162 108.09 cd 128.31 bc 111.61 cd Seaso - F value (R²) 11.09*** (0.021) 11.20*** (0.021) 10.94*** (0.020) Witer 315 338.29 a 331.95 a 328.85 a Sprig 442 27.88 b 35.35 b 45.45 b Summer 337-349.48 c -360.96 c -353.48 c Autum 222-16.69 b -6.34 b -20.82 b a, b, c, d, e : Differeces betwee sub-groups with differet superscripts are statistically sigificat (P<0.05). A : The differeces betwee overall meas are ot sigificat (P>0.05). ***: P<0.001.
Factors Affectig Milk Yield Estimated with Differet Methods i Brow Swiss Cattle 59 Table 2. Tablo 2. Geeral ad corrected meas of 305 days milk yield (kg) by Dutch (Hollad), Swede ad Trapezoid methods, effect proportios of the observed factors, compariso amog the groups, sigificace level (F values) ad determiig degree (R²) of Brow Swiss cattle. İsviçre Esmer sığırlarda Hollada, İsveç ve Trapez metotlarıa göre geel ve düzeltilmiş 305 gülük süt verimi ortalamaları (kg), gözlee faktörleri etki düzeyi, gruplar arası karşılaştırmalar, öem düzeyi (F değeri) ve belirleme derecesi (R²). Factors Dutch (Hollad) Swede Trapezoid Overall meas 1316 5844.8±38.55 B 5923.7±39.31 AB 5953.3±39.88 A Expected meas 1316 5927.1±33.67 B 6016.2±34.35 AB 6047.5±34.88 A All factors - F value (R²) 26.56*** (0.247) 26.41*** (0.245) 26.22*** (0.244) Lactatio tur - F value (R²) 21.77*** (0.088) 22.26*** (0.090) 21.74*** (0.088) 1 439-712.39 d -741.26 d -746.88 d 2 325-33.27 b -34.15 b -38.11 b 3 223 214.65 ac 216.73 ac 212.00 ac 4 130 363.82 a 360.42 a 368.68 a 5 83 336.94 a 338.23 a 327.79 a 6 57 38.71 ab 70.04 ab 44.74 ab 7 30 21.71 ab -0.63 ab 32.45 ab 8 29-230.17 bc -209.38 bc -200.68 bc Year - F value (R²) 33.95*** (0.118) 32.65*** (0.113) 32.95*** (0.115) 1991 157-1084.95 d -1089.96 d -1116.61 d 1992 156-199.86 c -203.39 c -198.49 c 1993 178 45.30 bc 33.39 bc 43.57 bc 1994 183 166.50 b 153.01 b 172.41 b 1995 236 470.12 a 423.65 a 451.12 a 1996 244 541.54 a 568.00 a 562.16 a 1997 162 61.35 bc 115.30 bc 85.84 b Seaso - F value (R²) 11.81*** (0.020) 12.35*** (0.022) 12.49*** (0.021) Witer 315 275.39 a 281.97 a 288.62 a Sprig 442 60.42 b 64.08 b 65.90 b Summer 337-286.42 c -304.07 c -309.65 c Autum 222-49.39 b -41.98 b -44.87 b a, b, c, d, e : Differeces betwee sub-groups with differet superscripts are statistically sigificat (P<0.05). A, B : The differeces betwee overall meas are sigificat (P<0.05). ***: P<0.001. Discussio Lactatio milk yields that predicted by Dutch, Swedish ad Trapez methods were foud close to each other, differeces were determied as o-sigificat. After the ispectio of overall values, observed maximum differece amog the methods was 29.5 kg. Accordigly oe of these three methods ca be used for predictio of lactatio milk yield. Predicted 305 days milk yield were also foud close to each other. However the differece betwee Dutch ad Trapez methods were foud sigificatly importat at the level of P<0.05. Coicidece or milk yield divergeces i before ad after 305 days cotrols could be the reasos of the importace of eve a few differeces. These foudigs resemble the coclusios of Muda et al. (2006) i which accordig to cotrols performed i 21-56 days itervals, differeces betwee Dutch ad Swedish methods were reported as o-sigificat. Compariso of observed milk yields ad predicted milk yields were performed by
60 Fige Çakıllı, Kozet Avaus, Halil Güeş Muda et al. (2006), however oly predicted milk yields were compared i this study. Fidigs of this study were also similar with a study of by Kaya et al. (2002). It based o the compariso of differet milk yield cotrol applicatios ad estimatio methods i Holstei, Simmetal ad Brow Swiss cattle ad reported that differeces amog 305 days milk yield determied by Dutch ad Trapez methods were foud sigificat. I the preset study, the differeces betwee predictio methods i milk yield were ot sigificat. I cotrast to the curret study Orma ad Ertuğrul (1999) reported sigificat differeces amog Wood, Schaeffer ad Glasbey predictio methods i Holstei. Sarget et al. (1968) reported that Trapez method was more advatageous comparig to the Swedish method, however both methods were equally trustable. Göül (1971) compared two results with similar accuracy by Swedish ad Dutch methods ad cocluded similar results. Lactatio tur, as a importat factor i milk yield, was icreased i followig lactatios. Most Youg cattle i first calvig ad some i advaced years ot produce as much milk as mature oes could. It is expected that the begiig age of lactatio ad lactatio tur is importat for milk yield. Lactatio tur effects milk yield of lactatio ad 305 days that were evaluated separately by Dutch, Swedish ad Trapez methods, were foud sigificat at the P<0.001 level. A icrease was observed i the 4 th lactatio tur ad o-sigificat decreases were observed betwee followig lactatios util the 8 th lactatio tur. These fidigs were similar with the results of some other studies (Dağ et al., 2003; Fuerst ad Sölker, 1994; Koçak ad Ekiz, 2006; Özbeyaz ad Küçük, 1999; Tilki et al., 2005) ad similar with the fidigs of a study examiig the fertility ad milk yield of Brow Swiss cattle raised i Altıova Farm performed by İci et al. (2006). Milk yield will improve i followig years by keepig the high yielded aimals i herd, usig potetially high yielded bulls i isemiatio, icreasig the lactatio umber ad applyig a adequate maagemet program. Year was the most importat determiatio factor i this study (P<0.001). The highest icrease i milk yield was observed i the years betwee 1991 ad 1992 by modificatios i care ad feedig. Although health, care ad maagemet were optimized, aimals could ot reach the desirable yield values. Sice aimals were fed i herd, feedig them accordig to their idividual requiremets would help to icreases milk yield (Alpa, 1964). Sice computer based idividually feedig programme was started to be applied milk yield was icreased i the modificatio period. The results of this study show that year factor effect o milk yield i Brow Swiss cattle was sigificat as i the other similar studies (ASR, 2006; BSA, 2007; İci et al., 2006; SBZV, 2007). Although cattle were kept uder the same care ad feedig coditios the whole year, it was observed with all predictio methods that seaso effected o milk yield sigificatly at the P<0.001 level. Milk yield of the oes whose lactatio started i summer was determied sigificatly lower tha the others (P<0.05). The highest milk yield was foud i the oes whose lactatio started i witer. Accordigly it ca be cocluded that aimals are affected from high temperature durig summer more tha other seasos. Coclusio Although the differeces amog the overall lactatio milk yield ad subgroups for both lactatio ad 305 days milk yield were ot sigificat, the oly sigificat differeces was foud amog overall meas of 305 days milk yield with Dutch, Swedish ad Trapez methods. Milk yield icreased up to 5 th lactatio tha decreased greatly. It was observed that milk yield icreases till the 5 th lactatio but later it decreases. Therefore
Factors Affectig Milk Yield Estimated with Differet Methods i Brow Swiss Cattle 61 milk yield of the herd ca be icreased by cullig cattle after their 5 th or 6 th lactatio tur ad keepig the persistecy of lactatio period that milk yield riches at the highest level. As a coclusio it was determied that lactatio tur, year ad seaso effects that are observed as a evirometal factors, caused importat variatios o yield characteristics. Especially the effect of year factor o yields was determied as positive i followig years. Applyig care ad feedig program, selectio ad electio actively also cause to improve yield ad these differeces reflected as a importat effect of year factor. REFERENCES Alpa, O., 1964. Karacabey Harasıda yetiştirile Holştay ve İsviçre Esmer sığırlarıı bede ölçüleri, süt, süt yağı, büyüme ve döl verimleri üzeride karşılaştırmalı bir araştırma. Akara Üiversitesi Veterier Fakültesi Yayı No: 156, Akara. ASR (Arbeitsgemeischaft Süddeutscher Riderzuchtverbäde e.v.), 2006. Jahresbericht. Zahle, Date, Fakte/Besamug, Milchleistugsprüfug. http://asrrid.de/media_pdf/asr-jahresbericht%202006/ 18.pdf (Accessed: 13.04.2007). BSA (Brow Swiss Associatio), 2005. USA Aual Report. Brow Swiss Productio Averages. http://www.browswissusa.com/a_rpt.asp (Accessed: 26.04.2007). Dağ, B., Keski, İ., Zülkadir, U., Boztepe, S., 2003. Çumra Ziraat Meslek Lisesi de (Koya) yetiştirile Esmer iekleri süt verim özellikleri ve bu özelliklere ait tekrarlama dereceleri. Selçuk Üiviversitesi Ziraat Fakültesi Dergisi 17 (31), 13-17. Everett, R.W., Carter, H.W., 1968. Accuracy of test iterval method of calculatig Dairy Herd Improvemet Associatio records. Joural of Dairy Sciece 51, 1936-1941. Fuerst, C., Sölker, J., 1994. Additive ad oadditive geetic variaces for milk yield, fertility, ad lifetime performace traits of dairy cattle. Joural of Dairy Sciece 77 (4), 1114-1125. Goodight, J.H., Harvey, W.R., 1978. Least-squares meas i the fixed effects geeral liear model. SAS Tech. Report (R-103), SAS Istitute Icorporatio, Cary, NC. Göül, T., Kaya, A., Tömek, Ö., 1986. Süt Sığırcılığıda Verim Deetimi (İlkeler, Yötemler ve Uygulama). Ege Zooteki Dereği Yayı No: 2, Bilgeha Basımevi, İzmir. Göül, T., 1971. Sığırlarda Değişik Süt Verim Kotrol ve Hesaplama Metodları Üzeride Araştırmalar. Ege Üiversitesi Ziraat Fakültesi Yayı No: 177, Ege Üiversitesi Matbaası, İzmir. Gravert, H.O., 1987. Breedig of dairy cattle. I: Gravert H.O. (Ed) Dairy Cattle Productio World Aimal Sciece. Elsevier Sciece, Amsterdam. Güeş, H., 1996. Kumkale Tarım İşletmesi de 10 yıllık Siyah-Alaca sığır yetiştiriciliği üzeride araştırmalar. II. Süt verim özellikleri. İstabul Üiversitesi Veterier Fakültesi Dergisi 22 (2), 225-240. İci, S., Kaygısız, A., Efe, E.F., Baş, S., 2006. Altıova Tarım İşletmeside yetiştirile Esmer sığırları süt ve döl verim özellikleri. Akara Üiversitesi Ziraat Fakültesi Tarım Bilimleri Dergisi 12 (3), 1-9. Johasso, I., 1961. Geetic Aspects of Dairy Cattle Breedig. Uiversity Illiois Press, Urbaa. Kaya, A., Uzmay, C., Akbaş, Y., Kaya, İ., Tümer, S., 2002. Süt sığırlarıda farklı süt verim deetim uygulamaları ve hesaplama yötemleri üzerie araştırmalar. Turkish Joural of Veteriary ad Aimal Sciece 26, 193-199. Koçak, Ö., Ekiz, B., 2006. Etasif koşullarda yetiştirile Siyah-Alaca sığırları süt verimii ve laktasyo eğrisii etkileye faktörler üzeride araştırmalar. İstabul Üiversitesi Veterier Fakültesi Dergisi 32 (2), 61-69. Muda, D., Yertürk, M., Avcı, M., Karabulut, O., Bozkaya, F., 2006. Siyah Alaca ieklerde laktasyo verimii hesaplamasıda kullaıla farklı yötemler ve kotrol periyotlarıı karşılaştırılması. Fırat Üiversitesi Sağlık Bilimleri Dergisi 20 (3), 173-177. Orma, M.N., Ertuğrul, O., 1999. Holştay iekleri süt verimleride üç farklı laktasyo modelii icelemesi. Turkish Joural of Veteriary ad Aimal Sciece 23, 605-614. Özbeyaz, C., Küçük, M., 1999. Malya Tarım İşletmesi Esmer ırkı iekleride süt verim özellikleri. Lalaha Hayvacılık Araştırma Estitüsü Dergisi 39 (2), 7-16. Sarget, F.D., Lytto, V.H., Wall, O.G.Jr., 1968. Test iterval method of calculatig Dairy Herd Improvemet Associatio records. Joural of Dairy Sciece 51, 170-179.
62 Fige Çakıllı, Kozet Avaus, Halil Güeş SBZV (SchweizerischerBrauviehzuchtverbad), 2007. Leistugsprüfuge HerdebuchStatistikeMilchleistugsprüfuge. http://homepage. brauvieh.ch/idex.html?page_id=94&l=1 (Accessed: 13.04.2007). Searle, S.R., Speed, F.M., Millike, G.A., 1980. Populatios margial meas i the liear model: A alterative to least squares meas. The America Statisticia 34, 216-221. Searle, S.R., 1971. Liear Models. Wiley & Sos, New York. Tilki, M., İal, Ş., Çolak, M., Garip, M., 2005. Relatioships betwee milk yield ad udder measuremets i Brow Swiss cows. Turkish Joural of Veteriary ad Aimal Sciece 29, 75-81.