EVALUATION OF FACTORS AFFECTING SOMATIC CELL COUNT IN MILK 1

24 th Int. Symp. Animl Siene Dys, Ptuj, Sloveni, Sept. 21 st 23 rd, 2016. COBISS: 1.08 Agris tegory ode: L01 EVALUATION OF FACTORS AFFECTING SOMATIC CELL COUNT IN MILK 1 POSTER SESSION Dmjn FLERE 2, Mj PREVOLNIK POVŠE 3, Dejn ŠKORJANC 4, Mrjn JANŽEKOVIČ 5, Jnez JERETINA 6 Evlution of ftors ffeting somti ell ount in milk ABSTRACT Somti ell ount (SCC) is n importnt inditor of helth sttus of mmmry glnd, whih ffets lso tehnologil qulity of milk. The im of the present work ws to nlyse ftors influening SCC (reed, prity, lving seson nd yer, herd nd ow produtivity). The nlysis omprised AT4 milk reording dt for the 5-yers period for Sloveni (n 3.2 106 reordings). A suset of 10 % rndomly seleted herds (n 220,000 reordings) ws used for evlution of importnt ftors. Aording to our results, ow produtivity, prity nd reed re the most influentil ftors ffeting SCC. Higher milk yield (per dy or per stndrd lttion) is relted to lower SCC. Among reeds, the highest SCC ws oserved for Holstein reed, followed y Brown nd Simmentl reed nd Simmentl rossreeds (Simmentl milk reeds). Signifint inrese in SCC ws reorded with prity. Other studied ftors showed smller or negligile effet on SCC. Key words: milk, somti ells, mstitis, influening ftors 1 INTRODUCTION The eonomis of milk proessing in diries lrgely depends on the qulity of produed milk with somti ells eing the key prmeter of its tehnologil qulity, i.e. milk proessing qulity (Ruegg nd Pntoj, 2013). Lower somti ell ount (SCC) is relted to the inresed yield in the prodution of milk produts, extended stility of milk nd milk produts nd fvourle ontent/rtio of nutrients in these produts. Besides the omposition (the ontent of protein, ft, ltose, lium, phosphorus, et.), tehnologil qulity of rw milk in lrge prt lso depends on the helth nd hygiene in milk prodution hin. An inrese in SCC in milk is onsequene of immune response to inflmmtory proesses in the mmmry glnd. Somti ells onsist minly of leukoytes (> 95 %, the rest re ded epithelil ells). SCC is thus n inditor of the udder helth sttus nd signifies the prevlene of linil nd sulinil mstitis in diry herds (Smith, 1996; Dohoo nd Leslie 1991), whih, together with other ftors, uses lso drop of ow milk prodution pity (Brno et l., 2006). Due to reent lowering of milk purhse pries, Slovenin frmers re inresingly seeking for new solutions to lower the osts of milk prodution. One of the possiilities is the improvement of udder helth sttus, whih would ontriute to higher quntity nd etter qulity of produed milk s well s to the improved niml welfre. In Sloveni, overll monitoring of SCC egn in 2007 within regulr milk reording (Jeretin et l., 2007). Breeders n ess the SCC informtion (nd mny other useful reeding informtion) through the we por- 1 This rtile is prt of Mster thesis entitled Monitoring of ondition nd progrm of mesures for the derese of inidene of mstitis in Slovenin diry herds, issued y Dmjn Flere, supervisor Assist. Prof. Mj Prevolnik Povše, Ph.D. nd o-supervisor Jnez Jeretin, M.S. 2 Letuš 83, 3327 Šmrtno o Pki, Sloveni, e-mil: dmjnflere@gmil.om 3 University of Mrior, Fulty of Agriulture nd Life Sienes, Pivol 10, 2311 Hoče, Sloveni, e-mil: mj.prevolnik@um.si 4 Sme ddress s 3, e-mil: dejn.skorjn@um.si 5 Sme ddress s 3, e-mil: mrjn.jnzekovi@um.si 6 Agriulturl Institute of Sloveni, Hquetov uli 17, 1000 Ljuljn, Sloveni, e-mil: jnez.jeretin@kis.si 148 At rgiulture Sloveni, Supplement 5, 148 153, Ljuljn 2016

EVALUATION OF FACTORS AFFECTING SOMATIC CELL COUNT IN MILK tl Cttle of the Centrl dtse (CPZ Govedo t Agriulturl Institute of Sloveni); they re lso informed vi printed reports (Verič et l., 2006), SMS messges nd different edutionl tivities. However, reeders insuffiiently use these soures of informtion to improve their reeding work (Unuk et l., 2010). They usully underestimte the losses (redued milk prodution) due to udder disorders nd do not reognize the SCC redution s neessry mesure to inrese the effiieny of milk prodution. The progress in improving the udder helth sttus in ttle is thus slower s desired (Prprotnik, 2013). Another reson is proly insuffiient oopertion of reeders, veterinrins, diries nd other professionl servies. The experienes of mny EU nd worldwide ountries (for review see Flere, 2016) show onsiderle derese of inidene of sulinil mstitis due implementtion of preventive progrms to redue SCC (mstitis ontrol progrms) together with onstnt temwork of ll tors from the milk prodution re. Among the most reognised progrms is the progrm for qulity ssurne in diry ttle reeds (Cullor et l., 1994), whih sets out the rules for implementing the progrm on frms with the proposls of reserhers nd experts (NMC, 2013). It ws se for mny other mstitis ontrol progrms. Sine the eginning of monitoring SCC (in 2007), the improvement of the stte (i.e. derese of SCC) in Sloveni is estimted to out 4 % (CPZ Govedo, unpulished dt), whih is elow the desired level. Respeting urrent sitution, it would e highly ppreile to prepre nd implement mstitis ontrol progrm for Sloveni. However, to onstrut effiient prtil guidelines, it is importnt to nlyse urrent sitution. For this reson, it ws the im of the present work, to study the prolem of SCC in Sloveni with speil emphsis on ftors ffeting it. 2 MATERIAL AND METHODS The nlysis omprised the dt for the period of 5 yers (2010 to 2014) from the ttle dtse CPZ Govedo. Dt originted from regulr AT4 method of milk performne testing (test-dy every 4 weeks lterntively morning/evening) in ll ows in the herd nd omprised the dt on milk yield nd omposition. In the first step, ll ville dt for the seleted period were tken for Slovenin popultion of Holstein (SH), Brown (SB) nd Simmentl (SS) reed nd Simmentl rossreeds (SSX), i.e. rossings of SS with milk reeds suh s Red Holstein nd Montelird. After the removl of out 5 % of reords (e.g. missing or invlid SCC dt, AT reording performed from 1 st to 4 th dy fter lving) the resulted dtset omprised 3,208,309 milk reordings of 142,503 ows rered on 5,716 herds in ll regions of Sloveni. Some si sttistis were lulted to eluidte reent sitution in Sloveni. In the next step, the suset representing 10 % of rndomly seleted herds from the previous smple set ws reted. Some dditionl onditions were set: i) milk reordings in stndrd lttion only, ii) numer of dily reordings per lttion per ow 6 nd iii) numer of ows per herd 3. The otined suset omprised 221,387 milk reordings, 24,234 lttions, 1,359 herds nd 22,338 ows of SH (n = 9,955), SB (n = 2,889) nd SS (n = 6,398) nd SSX (n = 3,096). It ws used to ssess the effet of reed, prity, lving seson nd yer, herd prodution (s n inditor of frm mngement) nd milk yield (s n inditor of ow produtivity) on: i) SCC on SCC mesured t the reordings (6 12 reords per lttion), ii) verge vlue for SCC for the reordings within first 100 dys in milk (one reord per lttion). For the purpose of sttistil nlyses, logrithmi trnsformtion of SCC dt ws pplied to reh norml distriution of this vrile. Dt tretment ws rried out in SAS 9.2 using MIXED proedure with reed, prity, seson nd yer of lving in the model s fixed effets. Herd prodution nd milk yield were dded in the model s ovriles nd the effets of herd nd ull s rndom effets. y ijkl = μ + B i + P j + S k + Y l + β 1 (HP) + β 2 (MY) + e ijkl, where: μ verge, B i effet of reed (i = 1 4; 1-SB, 2-SS, 3-SH, 4-SSX rossing), P j effet of prity (j = 1 5; 1-1 st, 2-2 nd, 3-3 rd, 4-4 th, 5-5 th or ltter), S k effet of lving seson (k = 1 4; 1-spring, 2-summer, 3-utumn, 4-winter), Y l effet of lving yer (l = 1 5; 1-2010, 2-2011, 3-2012, 4-2013, 5-2014), β 1, β regression oeffiients, 2 HP herd prodution verge, MY milk yield (dily yield for SCC on, stndrd lttion yield for ), error. e ijk In se of sttistilly signifint effets, the differenes mong tretments were tested using Tukey test. At griulture Sloveni, Supplement 5 2016 149

D. FLERE et l. % reordings 35 28 21 14 7 0 26,5 19,1 19,3 15,3 19,8 <50 50-100 100-200 200-400 >400 SCC ( 1000) N = 3,208,309 Men SCC = 364,000 SCC somti ell ount, N numer of milk reordings Figure 1: Distriution of milk reordings ording to SCC lsses SCC ( 1000) 550 500 450 400 350 300 250 0 50 100 150 200 250 300 SCC somti ell ount Dys in milk Figure 2: SCC ording to dys in milk for the period of stndrd lttion 3 RESULTS AND DISCUSSION Aording to the literture, the defult limit etween helthy nd potentilly inflmed mmmry glnd is set t 200,000 somti ells per millilitre (ml) of milk, lthough only vlues etween 50,000 nd 100,000 highly relily denote helthy udder (Brkem et l. 1999). An- other importnt threshold relted to SCC is eptility of milk for the proessing in diries, whih vries onsiderly mong ountries (Hillerton nd Berry, 2004). In the EU, this vlue is set to 400,000 somti ells per ml of milk (the EU milk qulity stndrd; Counil Diretive, 1992); however, it refers to three-monthly geometri verge of ulk smples of ows in the herd. Current sitution in Sloveni (Fig. 1) shows tht the limit of 200,000 somti ells per ml of milk is exeeded in one third of reordings. Moreover, in lmost 20 % of reordings SCC is even over 400,000 per ml of milk. Overll, the verge SCC for the whole lttion mounts to out 360,000, ut it vries lot during lttion (Fig. 2, presenttion for stndrd lttion period). Very high SCC vlues oserved soon fter lving drop fst in few dys nd reh minimum in the seond month of lttion. After tht, SCC ontinuously rises until the end of lttion. The min im of the present study ws to evlute the effet of different ftors on SCC on (SCC mesured t reording) nd (verge SCC vlue for ll reordings within first 100 dys of lttion). Averge SCC 100 ws of our interest s the first 100 dys in milk represent ritil lttion stge; this is period with the lowest level of SCC (Fig. 2) nd the pek of lttion urve (highest milk prodution). Thus, inresed SCC in the first 100 dys of lttion hs the gretest influene on lttion milk prodution. Anlysis of vrine for SCC on showed sttistilly signifint effet of reed, prity, lving seson, yer of lving nd dily milk yield, while herd prodution verge hd no effet (Tle 1). Bsed on F-vlue, the effet of dily milk yield is evidently higher s ompred to other ftors. Estimted regression oeffiient () for Tle 1: Anlysis of vrine for SCCon nd verge SCC100 Effet SCC on DF SS MS F-vlue p-vlue DF SS MS F-vlue p-vlue Breed 3 10,249 3,416 179 < 0.0001 3 72.3 24.1 15.6 < 0.0001 Prity 4 28,929 7,232 2,672 < 0.0001 4 1039 259.8 167.8 < 0.00001 Seson of lving 3 187 62 46 < 0.0001 3 54.7 18.2 11.8 < 0.0001 Yer of lving 4 220 55 8.3 < 0.0001 4 6.58 1.64 1.06 0.3736 Herd prodution 1 51 51 0.10 0.7459 1 0.00 0.00 0.00 0.9548 Milk yield * 1 18,751 18,751 12,362 < 0.0001 1 724 724 468 < 0.0001 SCC somti ell ount, SCCon SCC mesured t milk reording, verge SCC100 verge SCC for ll reordings within first 100 dys of lttion, DF degrees of freedom, SS sum of squres, MS men sum of squres (=SS/DF) * dily vlue in se of SCCon nd stndrd lttion vlue in se of verge SCC100 150 At griulture Sloveni, Supplement 5 2016

EVALUATION OF FACTORS AFFECTING SOMATIC CELL COUNT IN MILK d 5 4.58 8 4 4.73 4.50 5.11 2 SB SS SH SSX SB SS SH SSX Breed Breed e d 1 6 8 0 0 1 2 3 4 5 e d 5.13 4.98 4.78 4.54 8 1 2 3 4 5 Prity Prity 1 4.79 4.74 2 4.75 2 8 4.73 spring summer utumn winter spring summer utumn winter Clving seson Clving seson P = 0.5808 4.79 1 2 1 4.72 vergescc 100 4.73 4.76 4.75 4.76 4.71 2010 2011 2012 2013 2014 2010 2011 2012 2013 2014 Yer of lving Yer of lving SCC somti ell ount, SCC on SCC mesured t milk reording, verge SCC for ll reordings within first 100 dys in milk, SH Holstein, SB Brown, SS Simmentl, SSX rossreeds of SS nd milk reeds. Figure 3: Effet of reed, prity, lving seson nd yer on SCCon nd verge SCC100 At griulture Sloveni, Supplement 5 2016 151

D. FLERE et l. dily milk yield ws 0.049 (dt not shown). In respet of relevne, the effet of milk yield is followed y the effet of prity, reed, lving seson nd yer. Similr results in nlysis of vrine were found for. The effet of milk yield (in stndrd lttion) ws pprently higher s ompred to other studied ftors. Estimted regression oeffiient () for stndrd lttion milk yield ws 0.00016 (dt not shown). Regrding the relevne, the effet of stndrd lttion milk yield is followed y the effet of prity, reed nd lving seson (no signifint effet of lving yer). Differenes in SCC on nd mong tretments re presented on Figure 3. Overll, it lower vlues ould e oserved for s this prmeter refers to the period of first 100 dys in milk, while prmeter SCC on oved the period of stndrd lttion. Among reeds, the gretest differene in SCC on nd ws oserved etween SH nd SS reed, whih is in ordne with findings of Zvdilov et l. (2011), where higher SCC ws oserved in Holstein s ompred to Simmentl reed in the first third of lttion. SB reed nd SSX rossreeds hd intermedite position, in se of they were even not signifintly different. In SSX, the SCC ws very similr ompred to pure SS reed. This proves tht rossreeding with milk reeds did not ffet onsiderle the udder helth. With prity, SCC on nd verge SCC 100 notiely inresed from the first to the fifth nd lter lttions with ll studied lttions differing signifintly (the gretest differene etween 1 st nd 2 nd lttion). This ould e the onsequene of nimls history, i.e. illnesses in previous lttions nd higher sensiility of udder in ltter lttions, whih is refleted in more intensive retion of moilising somti ells from surrounding tissue nd higher suseptiility of older ows for inflmmtions used y pthogen gents. Constnt inrese in SCC with prity is in greement with results of Brkem et l. (1999). The effets of lving seson nd yer were lso signifint; however, the differenes mong tretments were less pronouned s for reeds nd prities. SCC on nd rehed the lowest vlue in se of lving in utumn. The likely resons re moderte tempertures nd onstnt feeding during this seson. In ontrst, hot wether in summer nd poorly ventilted stles with high reltive humidity ould ontriute to the rise in mstitis ourrene. Regrding the yer of lving, we n see signifintly lower SCC on for the lst studied yer (2014) nd no differenes mong yers for. No speil progress in lowering SCC over time ws reported for Sloveni lso y Jeretin nd Bnik (2010). Negtive orreltion etween SCC nd milk yield (dily or stndrd lttion) denotes tht only helthy udder is expeted to hve the potentil for high prodution. It is lso relted to frm mngement s lned nutrition nd fvourle environmentl onditions ontriute to etter helth sttus nd higher milk prodution. 4 CONCLUSIONS Cow produtivity (milk yield), prity nd reed re the most influentil ftors ffeting SCC. Lower milk yield (per dy or per stndrd lttion) is relted with higher SCC. Among reeds, the highest SCC ws oserved for SH, followed y SB, SS reeds nd SSX rossreeds. Crossreeding of SS with milk reeds did not ffet onsiderle the SCC in milk. Distintive inrese in SCC ws reorded with prity (from 1 st to 5 th nd ltter). Other studied ftors (herd produtivity, yer nd seson of lving) showed smller or negligile effet on SCC. In one third of milk reordings, the SCC exeeds the limit (200,000 somti ells per ml) denoting helthy udder. To our opinion, suh sitution is mtter of onern nd deserves more ttention. It would e neessry to estlish oopertion of reeders, experts nd diry industry with the purpose to prepre nd implement mstitis ontrol progrm in Slovenin diry herds. 5 REFERENCES Brno, D. M., M, Y., Sntos, M.V. (2006). Influene of rw milk qulity on fluid milk shelf life. Journl of Diry Siene, 89, 15 19. Brkem, H. W., Deluyker, H. A., Shukken, Y. H., Lm, T. (1999). Qurter-milk somti ell ount t lving nd t the first six milkings fter lving. Preventive Veterinry Mediine, 38, 1 9. Counil Diretive 92/46/EEC of 16 June 1992 lying down the helth rules for the prodution nd pling on the mrket of rw milk, het-treted milk nd milk-sed produts. Cullor, J. S., Eenennm, A., vn Grdner, I., Perni, L., Dellinger, J., Smith, W. L., Thompson, T., Pyne, M. A., Jensen, L., Guterok, W. M. (1994). Performne of vrious tests used to sreen ntiioti residues in milk smples from individul nimls. Journl of AOAC Interntionl, 77, 862 870. Dohoo, I. R., Leslie, K. E. (1991). Evlution of hnges in somti ell ounts s inditors of new intrmmmry infetions. Preventive Veterinry Mediine, 10, 225 238. Flere, D. (2016). Spremljnje stnj in predlog ukrepov z zmnjšnje pogostosti mstitisov pri molznih v slovenskih čredh. Mgistrsko delo, Univerz v Mrioru, Fkultet z kmetijstvo in iosistemske vede: 55 p. Hillerton, J. E., Berry, E. A. (2004). Qulity of the milk supply: Europen regultions versus prtie. Proeedings 43 rd NMC Annul Meeting, 207 214. Jeretin, J., Bnik, D. (2010). Rezultti nlize ginj števil 152 At griulture Sloveni, Supplement 5 2016

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