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YE 8“ ll l l 3 O ICH lllll l a 5 3 6‘7/ 9/3 l ill l. 3 lflljljllllll l ”M" ’ \‘lll 6 3 82 "ll This is to certify that the thesis entitled EFFECT OF KNOWLEDGE OF DUE DATE 0N SUBSEQUENT LACTATION YIELD [A FUNCTION OF TYPE OF MATING: AI 0R NON-AI], AND ECONOMIC COMPARISONS OF VARIOUS RATIOS OF AI TO NON—AI MATINGS WITHIN HERD presented by Brian Wayne Troyer has been accepted towards fulfillment of the requirements for M.Sc. dPg?Pin Animal Science MAW Major professor Date M 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES rotum on or before dds duo. DATE DUE DATE DUE DATE DUE Mm w; 2 5 ms MAR 10'1997 W..— $ MAY 1 5 2002 H I vi. = l_———l :2 “7» fiT—r—l—T MSU Is An Affirmative Action/Equal Opportunity Inditution mormmormmmwmmmmm [Amwormormnm Alain-AI], AND mommapvamwsamosop nmmmmmm By Brianwaymmer A.THESIS Sunnitted to Michigan State University in partial fulfillment of the requirements for the degree of IMBSTERLOF'SCIENCE Department of Animal Science 1990 9055498 m mormmwmmwmmmwm [A mwormor'm: AIORNON—AI], AND mommarmasmosor' AI'IOW-AIWWI’IIENIERD By Brian Wayne Troyer DEAlactatimreccrdsfranloznidiigandairyhewsusingboth artificial insenination (AI) and natural service or non-AI ratings wereanalyzedtcdetemjneeffectcflomledyecfbreedingdatem length of dry period and productim in subsequent lactatim. Days dry mteraged7daysmrefcrrm-Almatedcavst1nnAInatedccws. Withinherddaysdrystarflarddeviatias fcrAImatedccwswereabcut 10days lessthanncn-AImatedccws. Amodelpredictingsubseqent 305 day milk indicated differences between AI and non-AI mated cows approached significance mly for second and later lactation cows in one of the 3 feeding schemes. Profitability of various ratios of AI sires to non-AI natings were examined by sinulaticn of 100 cow herd. Estimated breeding valuedcllarsardarpenseswerecmparedovermyearsfcrll ratios ofAItcncn—AI sires. Armlizedrelativenetherdincanedecreased substantially as proportion of AI sires used decreased. Iwmldlflcetcthanknr.‘meodoreA. Ferris forgivingmethe qapcrttmitytopmanadvanceddegreeinanappliedtcpicindairy Wardfcrhisamnagaart, mtandfriendship thmngtnrttheprccess. Iwculdalsclflcetothankmncnintmmneadcwandor. SherriuB.Nottfcrtheirsuppcrtaniencwraganentinservingmmy guidancecaonittee. Aspecialmtecfpraiseandthankstomyfieavenlyr‘atherwhc givesneanhgtcmylifearflwittmtwtmmcfthiswmldhave bempcssible. Iwmldliketcaclmowledgewiththankstheassistarneofferedby Cirdfoaffintypingthemnlscriptandmasteringmrdprccasscrs. Aspecialtharflcstcmyfamilyardfrienh fortheirprayersand encwragarmt, especiallytomyparents,l?alp1ardEsther‘Ircyer, for giving 113 the initial qporttmity to purse a college education. Iweatraraidmsdebtofgratiufletcmywife, Teresa, fcrher love, wpportardernouraganentfcrtheduratimcfthispmwss. Herpatiernearfiurflerstarflixy, especially sincethebirthcurscn, Nicholas, has beenmost appreciated. iii MEOFCIIH‘ENI'S MaterialsandnethodsIBIl Materialsardllethodsfl......... ...... .....47 ResaltsandDiscussicnI......... ........... 53 Damgram1cscfccwsandhercb...............53 WOOOOOOOOOCI.0.0.0.000... 70 PredictingBOS-mymilkproductim ..... 71 Predictmgmysnry94 W O O O O O O O O O O O O I O C O O O O O O O O O 102 Slmary - Predicting BOB-Day Production and days dry 104 iv . . M ResiJlts and 013G188]!!! II .................... 106 Stmry-Rscmnafiatia‘sw ...... ...11‘7 W119 1.1. 1.2. 1.3. 1.4. 2.1. 3.1. 3.2. 3.3. 4.1. 4.2. 4.3. LIST'OF”TAEIES Costscfamaturelargebreeddairybull ........ Reamfcrmingartificialinsanimtim. . . . . . . Meansardstarflarddeviatimcfdaysdrybylactatim Saxrcescfgaleticprcgress. . . ........... VariablesusedfranflIIAdatafile. . . . . . . . . . . Herddlaracteristicsheldccnstant. . ..... . . . . Herddlaracteristicsvaried. . . ........... Frequency of observatims, perca'ltage within observation, and sinple population means for all cows, AI/NAI ard parity subclasses for 305-day mature equivalent milk (um, 305-day milk (305M), Cow Index milk (CIM) , sire Predicted Difference milk (SPIN) , calf sire PredictedDifferencemilk (CSPD‘I) arddaysdry . . MeancfherdaveragesforBOS-daymmilkaml) arddays dryfcrallccws,anisub—herdaveragesfcrAInatedard mmw m. C O O O O O I O O O O O O O O O O O O O umber cbservaticms and pcpulatim mean values for 305-day mature equivalent milk (MEN) , 305-day milk (303!) , sire Predicted Difference milk (SPIN) and days dry within AI/NAI by parity subclasses ......... vi Page 9 13 24 27 36 49 49 50 55 58 4.4. 4.5. 4.6. 4.7. 4.8. 4.9. 4.10. 4.11. 4.12. 4.13. 4.14. 4.15. 4.16 Wafccws, abolassmearsarflstandarddeviatimof abolassneamfcr 305-chynatureeq11valentmilk (HEM), Cowhide-(milk (GEM), sire Predicted Differencemilk (SPIN), and calf sire Mediated Differunemilk ((31114) forallccwswithinAIpercentageclass. . . . . . . . . Mcfcows, arbclusmeamandstardarddeviatimcf abolassmeansfor 305-daynau1re ecpivalentmilk (HEM), GJerriexmilk (CJN), sire Predicted Differencemilk (SPIN), calf sire Predicted Differencemilk (CSPIM), and daysdryfcharitylardPeritwaithinherdAI perca'ltageclass(AIPC)................. mysdrymininnherdaverage,mmdnnherdaverage,ard manscf withinherdstardarddeviaticn daysdryfcr herdswithineadlAIperceritageclassWHH. Mmbercfccwsardarbclasspercentageoftctalwithin daysdryclass(wC);ardsinpleneanardstandard deviatim of calf sire predicted difference milk (Gm!) wiminuxforallparitytwcccws. . . . . . . . Mcfcwswithinherdfeedingsdlane, parityand AI:NAI subclasses ard sinple subclass neans for 305-day nature equivalent milk (MEN), 305-day milk (3054) , sire Predicted Difference milk (SHE), and days dry ...... Variable list for regressim mdels using 305-day milk a W W18 0 O O O O O O O O O O O O O O O O O Sumary of regressim mdels predicting 305-day milk pmechntim...” .............. Summary of results of predicting BOS-day milk; models [20:P1, 20:P2, 21:P1and21:P2] . . . . . . . . . . . . . Psarsm correlation coefficia'tts, level of significance, ardnmercfobservatiars forallccws ......... Pearsm ccrrelatim coefficients, level of significance, arrlnmbercfobservations fcrAImatedcows ....... Pearsm ccrrelatim coefficients, level of significance, ardnmbercfobservatims fcrNAImatedccws . . . . . . thanvaluesfcrage, sirePDi,cnlfsirePD4,daysopen anddaysdryforall,AImatedandNAInatedccws. . . . vii Page 60 61 65 66 67 69 72 73 77 87 89 90 91 4.17. 4.18. 5.1. 5.2. P393 Variable list for regressim mdels usirg days dry as depafient variable .................... 94 amrycfnndelspredictirgdayschy.......... 96 ArmlizedrelativenetincanepercowbyAImAIusage ratio, startingsire merit, herdsizeandservicesper cmchti ArnnlizedrelativenetincmeperherdbyAImAIusage ratio, starting sire merit, herd size, and services per mm. C O O O O O O O O O O O O O O O O O O O O O O 108 SumrycfspreadsheetmdelresultsimlMingnetAI Irm,netNm-AIIncane,NetHerdIncmeard ArmlizedmlativeNetImmeperherdandperccw. . . 119 viii The practice of artificial insaninatim (AI) in dairy cattle has beenavailabletccarmercialdairyprcducerssincethelate 1930's. AlargebcdycfresearchhassthItobeaprcfitablepractice, carparedtcnon-AI (NAI)(VanVleckardHerdersm, 1961; McDaniel and Kirg,l974; Hillersetal.,1982),whid1 involvesuseof natural irseminatimbyaherdbull. However,theuseofAIwithinthe naticnaldairyherdappearstobemly75%mcowsard55%mheifers (IberiandErvm, 1985; Schenerhcrn, 1986). Seykcraetal. (1980), rqacrtedthatmilkpredlntimmsmtdifferaltbetveenherdsusirg fran80-99%AIatflherdsusim100%AI. OnereasmgivenfcrthelackcfAIusagebymnydairy producers,isthatawellnmAIprcgmtakestccnuchtime. 'Ihis ismttypicellyacashexpalsetcpmdmers,butisatineexpense inthedaytcdaymnrfirgcftheirdairycperatim. 'menejcritychAIuseisinherdswhereacatbinaticncfAIand NAIisbeingused. 'memainreasmfcrtheNAIsirebeingusedisin siulatianvherepccrreprcductiveperfcrmameocwrsarflthemnis brurghtinfcr'bleanppurpcses". IfthisNAImatingissuccessful tlmthecowremainsintheherdinsteadcfbeingallledfcr reproductivefailure. 'missavingsinccwsmlstcffsettheccstcf mintainirgtheNAIsirearriqeneticlossesduetchisuse. 'Iheccst cfthesecnllsisthedifferenceinvaluebetweensalvagevaluecf themllcowandfairnerketvalueofarmlacarentanimlplusthe valuecfacalf. Aqrestimtoasktlmis,"ncesnm-A1usage became profitable at sane percentage?" 'nleoverallgoalcfthissudymstodetermimifthereisan ecumicbamefitorccsttcdairyprcrhcerswhcusesanelevelcf NAI. 'mefirstpcrtimcfthissmdywasanattarpttcdetermimif therewasamasurableecamiclosstcdairyprcducersvmenbreeding datesarfitherefcreduedatesweremtlomnduetcusecfm matirgs. 'Ihegcalwasthentcusethisasirprtinthesecord portimcfthesmdy,asimlatimmdel. 'mepurposecfthe sinllatim was to evaluate gametic and econanic differences in selectimsdaesarfldetermimifarrlvtmaprcdmercafldjtstify thecostcfmintainingaNAIsiremthefarmmtvmatpointand urderulatcmstraintsdcestherrn-Albreedingpmgrambecme profitable). Anassmptimismadethatdairyfarmerscanbettermanageccws atcalvingiftheycanacarratelypredictcalvingorchedates. This requiresthattheylombreedingdates,midlreqairesacwrate recordscf all matings, AIcrnatural service (rm-AI) alike. In herdswherenaunalservicesiresarernlsedwithagrcupofopen ccwscrheifers, itisdiffiwlttclombreedingdates. ‘Ihismay resultinmlreccrdedbreedingsmidlleadtcinprecisecrurflmcwn projectedcalvingcrduedates. Pcorpredictimcfduedatesresult indryperiodsthataretocshcrtcrtcclalg,andmisrenaganentof the feeding program during late lactation and prior to calving. Pctartiallythen,asidebenefittcusingAIsiresisthelomledge 3 of service dates which allowproducers to accurately project calving dates. Atmopartsttnywascaflrcted. 'mespecificobjectivescfthe firstpcrtimcfthisstulywere: 1) tcdetemineifmethcdcrtype ofmatirg (i.e., AIcr'NAI) influences length ofdrypericd, 2) to measuretheeffectcftypecfnatirgmprcdurtimintbefcllwing lactatim, 3) toevaluatetheeffect cftypeof mtirgmsubsequent lactatim predictim within various pr'eparttm-pcstparmm forage feeding some. ‘Ibespecificdajectives cfthesecmdpcrtimcfthissudywere to determine the effects of the following (:1 relative present value ardarnlalizedrelativenetincmewithinadairyherd: 1) theratic cfAItcNAIsiresused; 2) level of initial siremeritinPredicted Difference Dollars (PBS) for AI sires; 3) herd size; and 4) services per canepticn for AI sires. LWW HistoryOfArtificialInsanination Artificial hearinatim (AI)wasrepcrtedlyinuseintheU.S. at theexperim'rtalandfieldtrialstagesinl906.Itbeczneafcrmal artity in 1938 with the formticn the first AI cooperative in Na: Jersey (Spedrt, 1988). 'mefirstbreedirgcccperativeinuidligan wasfcrmedasnidliganAninelBreedersOoqaerativeInc.mJu1y27, 1944. Intheearlyyearsof AI, frun1938tol948, factorsother thangeneticinprovanentwerearfiaasized. 'meprinerygcalwastc prove that cows cadld be bred using artificial insaninatim(fiaed1t, 1988). AtthispcintthequalityofAIsiresbeimnedeavailabletc dairynenwerenctnuchbetterthanthcseusedinnaturalservice (rm-AIcrNAI)breedingprcgrans. Asareallt,theAIsiredccws weremtbetterthantheNAIsiredccwsmealardHadden, 1959). Hatmetal. (1958) studied intra-herd differencesinGecrgia. Altlnlgh AI sired Holsteins produced slightly higher fat percentage milkthanMIsiredrblsteiJB,theauthcrsfamdmomersignificant differunesbetwemtheodogmlps. WaddellanndGilliard (1959) reportedthedifferencesbetweenAIardNAIccwstobegeaterin higherproducirgherdsthaninlowerproducingherds. AIsired cattle were slightly, but not significantly, superior in production tcNAIsiredherdmates. 'nleyalsofarrdgreaterdifferencaswithin 5 HolsteinsthanGuemseysarfiJerseys. Hilleretal.(1964)grcuped Wbyperwltageofuusewitlfinherd. ‘Iheyfomdthatherds usinglOO%AI,SO%crmreAI,andlessthan50%AIhadslightly greaterprodlctimlevelsformilkthanherdsthatusedmAI. m,thesedifferernesweremtsignificant. Itshculdbenoted thatthiswasacmparisaacfherdaverages,midlincludes differencesinmnaganart,andaremtadirectcmparsimbemeenAI siredccwsardNAIsiredccwswithinherrh. PartoftheproblemwiththeqnlitycfAIsiresmsthe inacarracyofflaeAIsireprocfsvmidlweredstairedinmlycneherd (natural proofs). Inthelate40’saniearly50’sproga1ytestingcf mybfllswasintroducedasaneansofidentifyingsuperiorsires forAI(Specht,1988). Progalytestinguseddauglrterrecordsfrana nmbercf differentherdsinordertcrankAI sires. Specht (1988) callsthisonecfthemilestcnesinAI. Intheearly 50’s, electrmic data processingwas alsobeing introduced, which allowed for faster and more efficiart processing of thelargeammtscfdatarequiredtogenerateacalratesire evaluaticre. Fran 1935 to 1962 the daughter-dam cmparismwas used in sire evaluation. [hugtrter—herdmte carpariscns, first published in1962,wereaicptedinanattarpttcrawveerwiramentalbiasfrm thesiresmmarydletcherds,years,ardseasa1s. 'Iheseccmparisons helpedtcircreasetheacmracyofsireevaluaticns. ReseardlerebegantcmtetheresultantimreaseinAIcverNAI. VanVleck and Hendersm (1961) looked at New York DEA production records forthepericd 1950—1959. 'Ihey fourriAI siredccws significantly arpericr in milk and fat production in all years with 6 thisdifferanebein;significantinallyearsexcept1952ardl953 formilkard1953fcr'fat.'melarwgestdifferuicemscbservedin 1959withAIsiredcwsprodJcirg357.4lb1-oremilkardl7.621b mfatthanNAIsiredcows. 'l'trkeretal. (1960) fomdAIsired cowsprodicedJSJlbmrefatand3661bmremilkthanNAIsired cows. Corleyetal. (1963)hadsimilar resultsinaWisccrsinstudy whereAIsiredccwswereslpericrtoNAIsiredherctnatesby Wynlboffataru2701bcfmilk.'meyalscreported significant AI/NAI by herd interactim indicating these differences variedfrmherdtcherd. metal.(1965)canlctedasufly inGeorgialoddngatlenagaraitvariables. 'lheaveragepercerrt ofcowssiredbyAIvasasignificantvariable. Foreachninnease inAIsiredcowstheremsa7.51bimreaseinfatccrrectedmilk (Fonperlactatim. InflaelateéO'sarrlearlym'sadditionaldaarqsweremdein thegenetic evaluatim procedures. Cow index, Predicted Difference Milk(m4),andrqaeatabilitieswereaddedastcclsgeneticistsard dairymencouldusetoevaluateardselectsiresfcrbreedirgprcgrans Spedrt(1988). ‘nledevelqmaltcffllelbdifiedOartarporary OmparisaaCKB)in1974establishedafixedga1eticbasebasedm prodntimrecords collected frun 1960-74(Sped1t, 1988). 'misbase frunwhidltccmpareallsiresstabalizedsiremvaluesfrm sumrytcsurmry. 'missystancmparedcartarpcrarieswithin herds,ttnscmparingfirstparityanimlstoctherfirstparity animlswithinherdandccnparingsecmdardgreaterparityanimals with their cmtarporaries while adjusting corrtarpcrary herdnetes for geneticlevel. 7 nietcadvancesinga'eticevaluatia's,idartifyirgsupericru siresbecamemreacmrate,resultinginincmdifferalces mumm. udmnielammngumnfamdthatinthe registeredcnttlepqulatim,AIsiredccwshadhighermilkandfat yieldsinalmstallbreed-age-yearsubclasses. 'lheyfcurdsimilar, but less significant, differences ingrade cows (KinganndDaniel, 1974). 'meyalsomtedthattheinpactcfAIwasbeing uriereotimtedasmanyNAImllsweresiredbyhighPDAIsires. m,mvasbenefitimfrunthegairsnadebyfl. Sexielbach (1978) rQortedWisconsin differences cfAIoverNAIsiredcowswere 1108 lb of 305-day nature eqrivalart (ME) milk and 43 lb of fat in 1974,12001bofmilkard551boffatin1975,61111921130me andszlbof fatin1976. Powelletal. (1980) inasmdyinvolving 330,923 first lactatim Holstein recorcb, indicated that AI sires medarceededNAIsiresusedbysulbmlardlSlbcfPDFat (pus). Hillersetal. (1982) inastate chashirgtmstxdyshcwed thatAIsiredccwsweresupericrtoNAIsiredccwsby4991bcfmilk perlactation. Mstrfliesweredmeloddrgatherdaveragesandpercmtagesof AIwithinherd. Seykcraetal.(l980)cafluctedasurveystudy involviry 17,773 cowscnl47NorthCarolina farms whichwere classifiedbypercmtagecfAIusewithinherd. Productionpercow averaged10561bmilk(+or-460)noreforherdsusingatleastsoit AIcaQaredtcher'dsusing75’tcrlessAI. Keown(1988),inastudy imolvingniremidvesternstates,reportedthatherdsusirgloo%AI hadherdaveragesfcrmilkssllbhigherthanherdsmirgmlya muralservicedairyhllltobreedtheircows. Whencamaringherds 8 minglOmAIwiththoseusingacmbinatimofAIandm, the differs-losinherdaverageformilkwassmlbperyear. 'Ihese stuiiesevaluatedacrossherddifferences, notwithinherd differences. 'merefore,breadirgprogramismstedwithingeneral Wlevelofherds. 'lheeffectofbreedingprogrammnmtbe squaratedfranmnagarartlevel. mm 'Iheecornnicgainasscciatedwiththeincreasedmilkproduction dletcAIhasbeensuriiedbyseveralwcrkerswickirsalarfl Mel, 1969: mtt and Pearem, 1978; P011811 et al., 1980; Jdmton, 1978). Dickinscnarflucmniel (1969) reported increased incane-cver-feed-costswithAIsiredcattle. EverettandPearscn (1978)statedthattheeca'micbenefitscfAIareslwincaningbut producerscculdobtainlOOlbmcremilkperccwperyearusingAI sirescmparedtcNAIsires. Melletal. (1980) reportedthatAI siredcavsproduced$45noreingrossilwareperlactatimthanNAI siredccws. Inacmparism study, Jdmstm (1978) calwlatedcostsof using AIardcostscfneintainirganamr-alservicesiremthefarm. Usinga budget analysis amrcadl (Table 1.1), he calculated an annual costof usinganNAIsire of $459.96 (includes salvagevalue of ball). 'metctalcashexperflitureperyearwas $941.96 (variable ccsts+fixedcosts+laborcost)mid1waseq1altc$17.13perccw. Jdmstmdetermiredthatfcr$17perccw,dairynencc\nduseAIsires with 70% crhigher repeatability, P074 of at least 1000 milk and 15 fat,ardakrmntypeevalmtion. Dairyproducerewithabreed averagelerdof40ccwsand15mlacanentscwldaffcrdtcspend 9 WELL Costsofamurrelargabreeddairymll 2:519; will 0.. muselargebreeddairyhlll,replacedevery2toz.5years. ValueofbreedingllOccwspluslSheiferper-year @$8.50/animlbred. $467.50 Iessdeathlossfcrmll€2%cfvalue($750)........ 15,90 Netneoeipts $48200 W Feed Requirements for Cow: (a) corn eqziv. No. 2 sh (2130 lb) 38 bu e$2.30 perbu . . . 87.40 Soybeanneal-44% C.P. 200 lb @$10.00percwt . . . . . . 20.00 01:21. (um-18%?) 24 lb e$14.00perowt . . . . . . 3.36 Tracemineralsalt 241b6$5.30percwt 1.27 VitaminPremix 121b@$.50perlb 6.00 Forage (5.60th.E.) 5.1tonD.M. @$50.00pertm . 255.99 373.03 mm Bediirg 1.5ton@$30.00perton ........... . . 45.00 Veterinarianardfledicine . . . ............... 15.00 supplies ..... .. 8.00 'Ibtallivestcckcosts.................68.00 Intereste9%x1/Zstmoffeedandlivestockccst ..... 12,79 m1 varm1e m. 0 O O O O O O O O O O O O O O O O 0 460.73 mm anreciaticn, interest, insurance, taxesandrepairson minim-$1,979.00 (navccst) (b)x12%. . . . . . . . . 237.48 Depreciation, interest,insurancearrlrepairsmeq2ipnent $50.00(navccst)x18.5%................ 9.25 Interest,insuranceandtaxescnaverageinvestnmtincw— Cost $950, Salvage Value $720 (2400 lb 2: $.30). ($750+$720)/2x10% 73.50 Depreciatimmbull—(s7SOccstmiruss720 Salvage Valuex30% 9.00 Total fixed cost. . . ............... . . . 329.23 Netreceipts......... .............. .482.00 Issstctalvariablecosts... ............ 460.73 Retmnsabovevariableccsts ............. . 21.27 Iesstotalfixedcosts.......... ...... ...329.23 Rehmstclabcrandnanagarent ............. -307.96 Iaborcost:381nlrs@$4.00perhmr............. 152.09 Returnstomanagenent. ..... ...... ..—459.96 a) A forage ration of 2/3 hay (13% GP) and 1/3 corn silage (8% CP) isused. Includesa25%allcwance forwasteandstoragelosscf forageand5%wastemotherfeeds. Dailyintakecf 1%cfbcdy wt. (24 lb) for 11.2). p115 6.5 lb of 12% grain mix is used. b) 3111ng cost: R.D. Appleton University of Minnesota Dairy W Amlysis: Dairy Up Date #20: Table 15a: assumes 12% inflatimirmeasearflthatalZ'le’ bullpenisecpalthespace for3ccws. Milldngemiprentismtircltfled. Source: Jdmson, 1978. 10 $950peryeartobreedtheherdandhavethepctentialtogain$90 permimlingeneticinprovamrtfcrmflkyieldintheresultant W. GeneticlevelcfAISiresUsed Ibseardlershavereportedthatnoregeneticgaincculdbemadeif dairyfarmerslsingAIsiresselectedhigherPDsires (VanVleckand W, 1961; Dickirsa‘l 8rd ”11181, 1969: Everett, 1985). The madmamlalgeneticgaininanAIpqnlaticncfatleastlomoo ccwsisestimtedtcbeatleast2%cfmeanyield (Spectrtand msilliard, 1960). VanVleck and Hendemsm (1961) noted that genetic merithadinprovedbyabart.5%peryearfrun1953t01959. Powell etal.(1977)reportedanamualgeneticgaininmilkcflessthan .5%frm1960t01975. Ieeetal. (1985) reportedamlalgenetic progresscflllllbcfmilkperyearintheregisteredms. Holstein pqmlatimwhid1islessthanl%cfneanyield. 'nms,producerewere achieving less than 50% of possible genetic gain (Everett, 1985). MrettaMPearsm(1978) stated thatAIisonly superior if gochIsir'esarebeingused. Ferrisetal. (1980)cmcludedthat dumingfranNAItcAImdairyheiferswouldbeprofitableprovided thePstalueoftheAIsireissufficientlyhigh. Bertrardetal. (1985) indicated thatusinghighmdsires generated 12.5%moremilk arfl15.5%mreprofitperlactatimthandau;hterscfaveragem4 sires(averagesirerinthisstuiywas+cr-99lbfrmzero m1till977arrithentheaveragecfactiveAIsiresmsused). VanVleckandI-lendersm (1961) suggestedthatan increaserate of gareticprcgresscmldbenadeinmilkprcductimifselectim 11 criteriaputnoreeufilasismmilk. 'Iheyrepcrtedthatmreprogress wasmdeinfatpromctimthaninmilkprcducticnandniller (1977) suggested that the failure to intensively use bulls cf arpericr gameticneritfcrmflkwasthemajcrreasmfcrtheslowprogress. Puselletal. (1980) stated that PD’s for sires ofgradeccwswere highrthanPD’scfregisteredccws,thusiniicatingregistered breedersweresacrifichgproductimincrdertoselectmother traits. msseletal. (1986), reportingcngenetic trends, notedthat frun1960tol971,AIsiresinprcvedatagreaterratethanNAI sires. Frunl971tol978,NAIsiresinprcvedfasterthanAIsires hltatalcwerlevel. NAIsires-hadmrecppcrttmitytcdcsc becausetheywer'emlallysiredbyAIsiresofhighgaleticnerit. IevelscfArtificalIrsaninaticnUsage Spectrt (1988) inhisreviar ofthehistcrycf Artificial Ireanimtim(AI)saidthatmmajcrdevelqnentinnodern agrioll‘mre,withtheexceptimofhybridccm,hasbeenacceptedcr advarnedmrerepidlyarfihascontribrtedmretcchirynen'swelfare flmtheusecfAI. W,Almsandismtwittnltits detractors. W (1970) indicated thatdairymenwhcreliedcnthe saleofbreedirgstcckasapcrtimcftheirincaneregardedAIina differerrtlightthanthcsevmcscldmlymilk. AIhadinasense becaneacarpetitcrwiththaninthegeneticsmarket. 'merearestillasubstantialnmbercfdairyherdsmtusingAI today, altlnlghveryfavherdsareexclusivelynon-AI. Levelsan magevaryfrunregimtcregimwithintheUfi. (Crosser, 1977; 12 Powell etal., 1980;8ey1metal., 1980;91anks et al., 1983: Iosh ardErvm,1985;Sd1ernerhornetal.,1986;Kewn,l988). mffirgta'i (1973) reportedthatin197l, 48.6% cfthedairyccws intheU.S.werebeingbredAI,withMidxiganrepcrting48.9%bred AI. Using 1.75 millim first lactatimreccrdsPcwelletal. (1980) shfliedtrenisfrule73-78.‘Breyfanrifl1at78%cfthecowswere siredbyAIthls,withHidliganrqzor-ting69%. ANatimal AssociatimofAnimlBreedersMAB) shfly,&mebylnshaniErven (1985), famd that 38% cfdairymenintheU.s.bredallcowswithin theirherdAI,with12%breedingallcowsNAI,ard50%usirr;a cmbinatim of the two. 'Ihey also W that, natia'ially, 76.5% of theocwswerebredAIandSRcf-theheifersmrebredAI. 'Ihefour midwestern states of Michigan, Indiana, Chic arfi Illinois reported AI usagecf74.7%fcrcowsand56%fcrheifers. Itwasnotedthatas herdsizeircreasedtheperoentageofheifersbredAIdecreased. Sdlermerhcrnetal. (1986) foundthat70%cfthecowsinthe NortheasternU.S.werebredAI. However,50%oftheherdsuseda caminatimofNAIarriAI,withthispracticebeingmorecammin largeherdsthaninanallherds. Keown(l988),inauidwesternu.s. sufly,repcrtedthatAIwasthemlybreedingprcgramonSé%ofthe dairyfarms. 'Iwenty-twopercentusedacmbinatimcfAIandNAI, 12%usedAIcmlymthemilengcowsandlo%usedmAI. Mostcfthe NAIbreedirqprogr-ansinvolvedadairymll. Crosser (1977) found that (1110 farmersbred55t065% of their cowsAIandthatmincreaseinAIusagewasevidentwithinthe previous five years. A North Carolina surly (Seykcra et al., 1980) stated 78.5% of all cows and 25.5% of all heifers beirg bred AI with 13 49%ofthefansusirg100%AImthemilkingcows. Shanksetal. (1983) reportedthat96%ofdairyfarmsinanIllinoisstLdyusedAI atsanelevelwithintheirherds. lbasms FcrUsirg Artifical Insaninaticn maker (1970), inasmdyresearchingattiunestcwardsAIamlg Midligandairymen, mtedthatthenostinpcrtantreasmgiven for usirgAIwasthevalue farmersplacedontheavailabilitycfhigher glality sires (Table 1.2). 'IABIE 1.2. Reasais for using artificial irsaninaticn m ~ W availability of higher quality sires 50% don’t want to use bull 34% easier to keep breeding records 9% more ecumical 5% because neighbors use it 2% Source: Kicker, 1970. IcshandErven (1985) rarflreddairynen's reascrs for usingAI as: 1)useavarietycfbulls;2)AIsiredcowsarebettermilk promcerez3)AIsiredccwshavehighervalue:4)AIsiredcowshave highervalmfcrbreedimpxrpcsemarfifidiseasecmtrol. Board's mirymn(1985)repcrtedmtheviewsofagroupofselecteddairyuen camaingtlnmecfAImheifers. 'nlereascnsfcrusingAIover NAIweretc: 1)obtainthebestgeneti + 911m [2*le Yijm30+Si+H(i)j + Fk+Cl + (SC)11 + ”10‘1ij + 91:11:11.. [391] Yum-1.1+ Si+H(1)j 4’ Pk... C1 + (SC)11 + blmijnm) + bzwijm) + eijm [3:92] Yijm'u+Si+H(i)j + Fk+C1+ (SC)il + H‘Mjm’ + bamijklm) + eijklm Wm] Yijkm- u + Si + Ha” + Fk+ C1 + ($011 + blmijklm) + bzmijklm) + b3(xijklm) + eijklm [4:P2] Yijmsa u + Si + Hm)- + Fk+ c1 + (sqn + blu‘ijklm) + bzmijklm) + b3(xijmm) + b4(Dijk1m) + eijklm [5:P2] Yijklm‘ u + Si + H(1)j+ Fk+ (:1 + ($011 + bflAijmm) + bzwijklm) + b3(xijk1m) + b4<°1jk1m> + b5(zijklm) + eijklm [6:le 4O Yijm 3 u 4' Si + H(1)j + FR 4' C1 + (SC)11 + b1(Aijk1m) + bzmijklm) + bilwijklm) + 913m [7‘le Yijklm = u + Si 4' H(i)j 4* FR 4‘ C1 + b1(Aijk1m) + b3(xijk1m) + eijklm [8=P1] Yijklm " ‘1 + Si + 11(1):) + Fk + Cl + bla‘ijklm) + bzwijklm) + h3(xijm) + eijklm [3‘le Yijklm = u + Si + H(i)j + F}: + c1 + blmijklm) + bzmijklm) + b3(xijldm) + bilwijklm) + eijklm [9‘le Yijkl -—- u + 31 + Hm]. + PR + b1(Aijkl) + bzmijkl) + b3(xijk1) + b4(Dijkl) + b5(zijk1) + eijkl [10:P2] eijkl [ll3P13AI] 13308313) + eijkl [llzPZzAI] 41 b3(xijk1) + b4wijkl) + b5(zijk1) + eijkl [12:P2:AI] Yijkl = u + $1 4’ 11(1):) 4’ Fk + b1(Aijk1) + b3(xijkl) + eijkl [13:P1:AI] Yijkl = u + $1 + H(i)j + Fk + b1(Aijkl) + b2(Nijk1) + b3(xijk1) + eijkl [13 :P2:AI] b3(xijk1) + b4(Dijk1) + b5(zijkl) + eijkl [14:P2:AI] where: Yijklm = lactation yield in 305-day milk 11 = mean of observatims Si=thefixedeffectoftheith feedirgmnaganart sdiane (i =- 1,2,3,4) Hun =therardaneffectofthejthherdrestedwithinthe ith feeding managanent sdieme (j = 1,2,3...102) Fk-thefixedeffectofthekthnurthoffreshening (k=meun) C1=thefimedeffectofthelthtypeofservicesire (AI/NAI) (1 - 1,2) (86):“I =theinteractimof feedingmanaganentsdmeardtype of service sire. 42 b1==slope oftheregressim onanijklm, whereAijklm istheageatcalvingofthemthanimal b2 = slope of the regressim of Y mNijklm, whereNijklm isthesquaredageatcalvingofthemtharfimal b3=slcpeoftheregressimonmXijk1m, wherexijklm isthePredictedDifferenoemilkoftbesireofthe mthanimal b4 = slope of the regressim of Y on Dijklm, where Dijklm isthelengthofthedrypetiodindaysofthemth animal b5 == slme of the regression of Y on Zijklm, where Zijklm isthesquaredlagthofthedryperiodindaysofthe mthanimal eijklm = mnbservable randan residual error peculiar to any one observation of Yijklm e~N(O,IOZ) ijm = u + H3' + ‘3: + C:1 + blmijklm) + b3(xjklm) + ejm [15:p1] ij=u+nj+Fk+c1+b1(Ajk1m) +b2mjm) + b3(xjklm) + ejklm [15sz ijlm=u+Hj+Fk+C1+b1(Ajk1m) +b2(Njk1m) + b3(xjk1m) + b4(Djk1m) + ejkm [16:P2] ij=u+ Hj + Fk+b1(Ajnm) + b2(Njk1m) + b4(Djk_1m) + ejm [17:p2] where: HD' = the randon effect of the jth herd (j = 1,2,3...102) 43 Yijkln' u + 81 4’ 11(1):, + Fk+ C1 + (SC)11 + blmijklm) + bzmijklm) + b3(xijk1m) + b4(°(1)1jk1m) + eijklm [18:P2] Yijm=u+si+fi(i)j + Fk+C1+ (SC)11 + blu‘ijklm) + bzmijklm) + b3(xijklm) + b4(D(1)ijk1m) + b6mijk1n) + eijklm [19‘le where: b4 - slope of the regressim of Y on D(l)ijk1m, where D(l)ijklm isthelengthofthedryperiodindaysnestedwithin thelthtypeofservicesireofthemthanimal b6 8 sque of the regreesim of Y cm Wijklm, where Wijklm isthenmberofdayscpeninthepreviwslactatim ofthemthaniml Yijklm g u + 91 + H(i)j + Pk + C1 + b1(Aijk1m) + bzmijm) + eijm [20:p1] & [20:sz Yijklm = u 4' Q1 + H(i)j 4' Pk + C1 + (m)il + b1(Aijk1m) + b2(Nijklm) + eijklm [21:P1] 8 [21:P2] where: Qi=thefixedeffectoftheithAIpercentageclass (i - 0,1,20009) therardaneffectofthejthherdmstedwithintheith AI percentage class (j = 1,2,3...102), (i = 0,1,2...9) Qc(fl)-theinteractimofAIpercentageclassandtypeof servicesire “(in = 44 Models predicting Days Dry: an'“+3j+ck+°jk1 [mm] Yijn = u + (21 + Hmj + ck + eijkl [11am] Yijkl = u 4» Qt + Ha” 4» CR + «chk + eijkl [Irma] Yum = u + 91 + Hmj + ck + F1 + (9‘3ch + eijklm [mus] Yijkhn = u + Qi + H(i)j + Ck + F1 + (m)ik + b1(Aijk1m) + bzmijklm) + eijklm (“M51 Yijklm = u + 91 + 3(1):) + Ck + F1 + (OCH): + blmijklm) + bzmijklm) + b3(xijklm) + eijklm [[13:61 Yijm = u + Qi + H(i)j + Ck + F1 '4' b1(Aijk1m) + bzmijklm) + b3(x(k)ijk1m) + eijklm [MW] Yijm = u + Qi + H(i)j + Ck '4' F1 4' b1(Aijk1m) + bzmijklm) + b3(x(k)ijklm) + b4mijk1m) + eijklm [mY:8] where: ijl a days dry prior to lactatim of record u =- means of observatims Hj = the rarflan effect of the jth herd (j = 1,2,3...102) 45 Cksthefixedeffectofthekthtypeofservicesire (AI/NM) (k = 1.2) Qi=thefixedoftheithAIpercentageclass (i=o,1,2...9) H(i)j=ttxerarflaneffectoftliejtlat1erdr\estedwithin the ith AI percentage class (j - 1,2,3...102) QC(1k)=theinteractimofAIperca1tageclassandtype ofservicesire bl-sslcpeoftheregressimonmAijklm,whereAijklm istheageatcnlvirgofthemthaniml b2 a slcpe of the regressicn of Y m Nijklm, where Nijklm isthesqiaredageatcalvingofthemthaniml b3-slcpeoftheregressimonmxijklm, wherexijklmis the Predicted Difference milk of the sire of the mth animal (It: a slcpe of the regressim of Y m X(k)ijklm, where X(k)ijk1m is the Predicted Difference milk of the sire nestedwithinkthtypeof servicesireofthemthanimal. b4 = slcpe of the regression of Y on Wijklm, where Wijklm isthemndaerofdaysopenintheprevicm lactatim of themth animal eijm=ncnobservableranianresimalerrorpemliartoany me observatim of Yijklm e~N(O,Io?—) . Lbdels (Jet:P1)werermmparitya1ecowsand (xx:PZ) mdelswere nmmparitytdocows. Modelsllml, 11:P2, andlz:PZwererunmAI cowsmlywhilenodelslmpl, 13:P2and14:P2werenmmNAIcows mly. Generallinearllodels (GIN) wasusedbecauseitallcwedfor mltiple testing of differences between subclass means. Sequential sunsofsqzares ('IypeISS), andmeansquarewereccnprtedforthe nodal. Error, FValue, significame prcbability (PR> F), R-sane, Coefficientofvariatimardrootneansaneerrorwerealsocmprted 46 forthemdels. marsofthedmmdartvariablemrealsocalailated. 'IypeISSardpartialslmeofsanes('IypeIIISS)werecaprtedfor eachvariablealcngwiththeFvalueanim>EAnadditia1altestof thehypotheseswasdcnewiththeFvalueardPR>Fbeingcmprted usingGlElEasthehypottmis (numerator) effectandHEmXSOIEME) as the error (derminator) effect. This was dare to adjust for variation inthedependentvariablethatmduetotheeffectofherdnested within sauna. A solutim to norml eqnticms (paraneter estimates) wascmprtedforeadrparameterinthemdel.$tmdentstvaluefor testingthemllhypothesisthattheparaneterisequaltozerowas mlwlatedalcngwiththem>Fofgettingalargervalueoftifthe paraneteristrulyeqnltozero.Averysmallvalueforthis probability leads to the occlusion that the independent variable cartrihxtessignificantlytothemdel.lhestamlarderrerofthe estimteofthetruevalueoftheparameterwasalsocmulted. Ieastsanedmeansaaflweregeneratedbecausetheyallcwfor theomparisonofmbalanoeddatainabalarnedmnnerbetween subclass means. Probability values for the hypothesis Ho:rsq(i)=1mm were calculated. LWSANDW II anmics ofvaricus levels ofAIusagewithin herd. mm Research has strum the baefits of artificial insemination (AI) in dairy cattle. Mel and King (1974), Sendelbach (1978), Powell (1980), Seykora, et al. (1980), and Killers (1982) reported that milk prochctimpercowhasincreaseddietotheuseofAI. Dickinsonet al. (1969), Everett and Pearscn (1978), and Powell et al. (1980) statedthatmisimzreaseinpmductimhadresultedinanirmease innetincaletothosedairymenvmouseAI,catparedtodairyuenwho usenatmral servicesires (NAI). However, alargenndaerofdairymen courthuetomenahmalserviceshemusuallyinthereleofa cleanup bull (Seykora et al., 1980; Schemerhorn, 1986). They feel thiswillincreasenetimaneby: 1) decreasingthemmberofm aflledchetorepredtlctivefailurearri2)helpingtodatainagreater er efficiency by reducing services per conception, days open, arricalvin; interval. Seykora etal. (1980) reportedthat herdsmin; 100%AIhadlcwer reproductive efficiencythanherds using natural service sires for 1%t020% oftheirmatings. 'Ihecbjectivesofthissbidymretodeterminetheeffectsofthe following on relative present value and anmalized incane within a dairyherd: 1) theratioofAItoNAIsiresused; 2) level of initial sire merit in Predicted Difference Dollars (ms) for AI sires; 3) herd size; ard 4) services per caneption for AI sires. 47 48 Usirgacalputersinllatim static mdel,varicus levels ofAI usagewithinasimlatedherdwerecmpared. 'Iheherdwasassmnedto beclosed,meanin;noanimlswerebwghtorsoldforbreedingstock ardanimlslefttheherdthrughcnllingordeath. Survivalrates were.8, .6, .75, .4,ard.33franlst, erl, 3rd, 4th,anilater lactatiasasfrmastudyminguidiiganmirynerdlnprwanmt records frale'IB to 1979 (Ferrisetal., 1980). Nimperwltof fennleswereeliminatedfrtmtheherdthmlghclllimmneritwith ranianlossesnaldngupthedifferernetoeqialthemrvivalrates. Herddxaracteristicsaresxmrarizedin‘l‘ablesllardBJ. Imune the purpose of this sinulaticn was to evaluate genetic differencesinselecticnsdlemesfrunanewmicperspective. 'Ihus dollarremrnsduetogeneticinprcvalerrtwasthebasisfor ccnparisaw. ImmewasneasuredasEstilnatedBreedingValueDollars (EBV$)whidlisqualtotxotimOowIndexDollars (C15). EBV$ imanewasregressedtoactualincaneforageofcalvingbythe reciprocal of usmuam Erpivalent factors (Norman et al., 1974), reduced 30% foradded feed ardhealthcost (milliard, 1978) and disoountedoverlOyears. Geneticgairscmvertedtoirmtewere cmpanfledforeadlgeneratim. mpenses AIsireexpenseswerecalmlated. 'Iheyincludedthecostof semen, labor, ani facilities. A determination was made that mialdairyfarmerswmldmtlikelypaycversmpermitof m,ttmsthosesirescostirgmrethan$40permitweremt 49 MB 3.1. Herd Characteristics held eastant. Slunasaeristie Cow calving rate Calf sex ratio Calf survival rate Heifer survival rate Heifers freshening per year per 100 cows Average lactatiens per animal Beginning Oow Irriex Dollars for herd Standard deviaticn Cow Index Dollars for herd Initial sire merit for natural service sires in Predicted Difference Dollars Arnlal increase in sire merit in Predicted Difference Dollars Addedfeedeostsperadditimal $1000fmilkproduced Discount rate Planning horizon (years) 70% 50:50 85% 83% 35 -$23 55 $12 $30 10% 10 new 3.2. Herd Characteristics varied. szrursrerietig Ratio of AI to NAI sires Initial sire merit in Predicted Differa‘uce Dollars for AI sires (S) Herd size (cows) Services per eaceptim for AI sires (Isles 100:0..9o:1o..o:1oo 170,155,138,128 50, 100, 200 1.7, 2.2 midered. Prieepermitofsanenwasdeteminedbyaveraging pricesforsanenofrminirgsireswithineadlinitalsirenerit category. Prices were $21, $19, $16, and $15 for merit groups PD$ 170, 83$ 155, PD$ 138, and PBS 128, respectively (Board’s mirynen, 1986). Iaborcostwasestinatedtobe$5perinsaninatimand breeding facility cost was set at $100 per year. Natiral servicesireamlaleupenseswerebasedmworkdaaeby Natia‘lal Association of Animal Breeders (1985) (Table 3.3). Feed 5‘? 'IABLEBJ. Estimtedamlalmllcanyingeost. m m Feed $ 450 Iabor 300 Bedding 92 Veterinary 25 Facility maintenance and chpreciatien 350 net value $ 140 -140 Interest :Facility (15% m investmart) 525 :mn 29 mm. eosr $ 1692a a-mistotalisdmbledinherdusingZSires. Worksheetsource:NAAB(1985) costsassmnethebullismahighqualitydietofhay,grain,ani proteinmppleuent. Iaborimludesdaorecostsoffeedirgand cleanirgbullfacilityarribreedingcostsofmvirgcavtobull,or vice versa, for insaninaticn. Facility mintenance and depreciatim was calculated at 10% annally m the initial $3,500 capital investnentofasecuredpen. Netvalueofthebullistheeostof plrdlasemimsthesalvagevalueaftereneyear. Ammalinterest costsmthefacilityarflbillwerecalallated at 15%. Net 1mm Value 'Ihe analysis required the followirg calculations. PresentvalueimaneforAIsiredcows intheherd: 2 [(EBV3-FH$) X Nll/(l + (1)?) [1] i=1 IreeentvalueofirnmeofNAIsiredcowsinherd: n j£1[(EBV$-FH$) X Nzl/(l + (3):] [2] 51 where: i-ithyearofamlysis. n-nmberofyearsinanalysis, N-runberofcowsfor: NI-nnmerofeowsintheherdresultingfrmAImatings, Nz-nmberofcowsintheherdresultingfrmNAImatings, (Note: Nlanszwilltetalthesameforeadisimlatim within variousherdsizes e.g. 50, 100, 200). EBV$=neanofEstimatedBreedirgValueindollarsforthegrulpof ewe,whid1wasadjwtedfrunMatureEq4ivalenttoacual preductim forage. Dollar valueswerebasedm$12.20/1001b ofmilkand$.174milkfat differential, His-addedfeedandhealtheostsassociatedwithincreasedmilk predictim. '1hiswas$3.66/1001bofmilkor30% ofgress milkvalue (Imilliard, 1978). 'Ihenetafteraddedfeedand healtheostis$.085/1b of milk, and dadiscamtrateordesiredrateofremrnmimes‘tnent. ‘menetpmrtvalueineanefortheAIportimardNAIportien oftheherdweresmmedanithammltipliedbyananmalizatien factortodeterminetheamualizedincanestreamevertheperiodof thearalysis. IIhisvalueisreferredtoasAnmlalizedRelativeNet mama). Fumvariableswerecmparedusilqtheabcvenethod. ‘mesewere: 1) 10 ratios ofAItoNAImatings withintheherd: 100:0, 90:10, 80:20...., 0:100: 2) four levels of initial sire merit in Predicted Difference Dollars forAI sires: 170, 155, 138, andlzaaooordingto Jamary, 1986 (EDA Sire Sunmary average of 95th, 90th, 80th, and 70th 52 percentile ranking, respectively (Board’s Dairyman, 1986): 3) three herdsizes: 50, 100, arri200milkingcnw33and4)m1evelsof services per emoeptim for AI sires: 1.7 ard 2.2 services. Cmparisasweredaaetodeteminerelativedifferenoesinnet herd inocm with each possible embinatim of the four variables, resultirg in 240 soluticms. LWANDDISCIBSIQII Effectoftypeofmtimmdaysdrymflmilkprodntimin Wlactatim. 4.1 WGOFGIBANDHHUB 'meinitialdataseteontainedlz,657eowrecordsin104herds. Anedit ofreoordswithnoservieesire identificatim forthelast ealvingr'ednedthenmberofusablereoorrbtoms. Further elitingranovedreoordswithparity-agediscrqaanciesardherds luvilgfavusablereoorrh.‘n1efinaldataseteartained5469reoords frmloz herds. umberof cheervatimsandpopulatienmears (means for allcows in the data set) for 305-day naulre eqlivalent milk (MEN), 305-day acmalmilk (305M), days dry, waIndexMilk (cm), sire Predicted Differenoemilk (SPIN), ard calf sire (service sire forpregnancy which initiated lactaticn record) PDmilk (CSPDJ) for all cows are listedin'l‘able 4.1. Pepulatimmears foralleowsinthedatasetwere18,869 1b. HEM, 16,977 lb 3094, -121 CD4, 181 SPIN, 730 GP!!! ard 61 days dry ('I‘able4.1). 'Iheneanvaluefor mishigherthanthenidiigan [IIIA average (17,969 1b.), however, 3094 is slightly lower than the Michigan um (17,263 1b., 1111A, 1986). WWI-MAW Meanardstandarddeviatias (SD) ofherdaveragesforMEMand daysdrywerecalculated. 'meneanofherdaveragesform proactimwas 18,731 lb. withameanherdSDof 2272. 'Ihemeanherd averagefordaysdrywas60withaSDofherdaveragesof10.1 (Table 4.2). 53 54 ME 4.1. Frequency of observations, percentage within observation, and sinple population means for all cows, AI/NAI and parity subclasses for 305-day mature eqrivalerrt milk (NEH) , 305-day milk (30514), Cow Index milk (CD4), sire Predicted Difference milk (SPIN), calf sire Predicted Difference milk (CSPDI) and days dry. ME)! 3054 CD! SH)! (31414 MS M AIL CUB mu“ 5469 5469 3745 3597 3067 3752 MEN‘S 18869 16977 '121 181 730 61 AI Cbservaticns 3556 3556 2595 2494 3007 2846 E MEANS 19199 17534 '115 188 748 60 NAI weervatiens 1913 1913 1150 1103 60 906 m 18255 15942 '135 165 '194 66 Parity 1 W111“ 1677 1677 1217 1176 633 HEADS 18746 15123 '39 295 810 parity 2 W111“ 3792 3792 2528 2421 2434 3752 11mm 18923 17797 -161 125 709 61 55 WELL manofherdaveragesfor305-dayMEmilk(m4) arridays dryforalleows,andsub—herdaveragesforAImatedardNAImated cows. HEM Days dry man S11El Mean SDa Herd Avg Herd Avg All cows 18731 2272 60 10.1 AI rated cows 18805 2327 59 9.7 NAI mated cows 18623 2541 65 16.4 a-Standarddeviatienofmeanofherdaverages. mormmsmrmn 'Ihetypeofservieesireforeaeheowwasdeterminedtobeeither AIorm. 'mepurposeofthisclassificatienwastonaaalrewithin herddiffereneesbetweeneowsnatedAIszAI. 'Ihusbdosubclass poleatiaiswerecreated,meofAInatedeowsardcneofNAImated cows. IDHJIA‘I'ICNAVERACISKRCIWB 'menmberofebservatia'sstm35560r65%oftotalcowswere bredbyartificial inseminatim (AI) (Table 4.1). ‘Ihesebred ’raturally (NAI) totaled 19130r35%. 'Iheseresultsaresimilarto Crosser (1977) butslightly lessthanIoshandErven (1985). Iosh ardErvenreported74.7%ofthecowsbeingbredAIinfcurmidwnst states. Howevertheresultsinthepresentstudyarelikely differa'rtduetotheexclusimofherdsusinglomuardlmm. humerofreoordscmtaininginfornatimregardirgneritard daysdryislistedin'rable 4.1. Siremerit informatienwas availableen70%ofAImatedard58%ofNAInatedeowswhile(SPD4 wasavailiablem85%ofAIservicesireand3%ofNAIserviee 56 sires. 'mislackofinfornatimislikely, inpart,duetothelm numerofmhlllsttatreeeiveapreductimpreof. Subclassmeans Subclassnaans(a1tpqmlatimnearsofallcowsinasubclass acreesherds)ardSDofsubclassnaanswerecalallatedwithinAIand NAIamclasses. InemperirgAIandNAImmeasuresofmilk prechctim,meritanddaysdry,twogaweralteniencieswerenoted. anistratAIissuperiertoNAIarritheotheristlatthevariatien withintheNAIsubclassisgreatertlaninAIalbclass. Table4.1 annarizesaveragemilk,neritarridaysdryforallcowswithin AI/NAIsubclasses. AIbredeowsweresuperiortoNAIby9441bof MEN,15921bof30514,201bCD4,23SPD4arri9421bCSPD4. NAImated eowsaveraged6mredaysdrytlanAInatedcows(66vs60). albclassherdaverages Aalb-herdaverageofMENpreductimforbothAIarriNAInated eowswascalallatedfereachherd. 'IhuseachherdhadanAIherd average,NAIherdaverageard"allcows"herdaverage. miswasdene todaservegressdiffereneesbetweenAIaniNAInatedeowswittfin herdarrltolodcatdifferenoesinvariatimbetweenAIardNAImated cows within each herd. This calculation avoids differences between AInatedandNAImatedcowsduetomaragenantdifferemesbetween herds. MeanherdaveragedaysdryforAInatedcowswas59cmparedto 57 65 forMInatedeowswithSDofleanherdaverageof9.7ard16.4 respectively (Table 4.2). 'mis suggests difficulty indetermining wimtodryoffNAInatedeows. PARITY weervatims 'Ihenmberofdaervatiaswithintheparitywbclassesislisted within Table 4.1. 'Ihedatasetincllried 1677 (31%) first parity (p1) eowsand3792 (69%) seoordandgreeter parity (p2) cows. 'Ihisis similartoMidliganDairyHerdInprovelant(u-£I)averages(u-£LA, 1986). Table4.1sl'msthennflaerofparityrecordsthatocntained informtimforCflESPlMardCSPlN. Parityaaereoordshadmre merit intonation than P2 records except for (SPIN. Thirty-eight pereaItofPlrecordseartainedCSPlninfemtimemparedtoa%for P2anilals. mislavvalueforPlislikelyduetoahigher percaltageofPlnatirgsbeirgNAIanithelownmberofNAIrecords eartainirgminfornatim. Stbclassmeans Subclassneansforprechctimdataweresimilartotlatreported byuidiiganum (Ferris, 1986). MeanMEMforPlcowswaslfllb lessthan forP2 (18,746 lb. vs 18,923 lb.). Parityeneeows should tavebetterpedigreesgivingflmanadxantage,tndever, P2eowsmay havebeaieulledmoreheavily. 'meZ6741badvantagetoPZcowsin305-daymilkis, inpart expecteddletothemamrityofthemanimals. 58 abclassmearsforOowIIflexmilkwas-39forP1cows,empared to-161 forP2eows(Table 5.1). 'Ihisdifferenoe of 1221bisless t1anadiffereneeof16llbreportedinwrra1tnid1iganIHIAdata (IIIIANavsletter, 1989). SirePn4washigherforP1tl'anP2(295vs 125). 'misdifferenceof1701bislees tlancurrentuidiiganfliIA data, with a difference of 260 1b for SP!!! (1141A Newsletter, 1989) . TYPE OE'HDTINGIBY HABIT! Cbeervatims (hservatiens within type of rating (AI/NAI) by parity subclasses arelistedin'Iable 4.3. Ahigherpereentageofheiferswerebred NAIthanPZeovs (59vs24). Differencesaresimilartothese reported by Seykora et al. (1980) and Leah and Erven (1985). 'IAEIE 4.3. umber of observation and population mean values for 305-day nature emivalent milk (MEN) , 305-day milk (30514) , sire Predicted Difference milk (SP!!!) and days dry within AI/NAI by parity smaclasees. Hams parity AI/NAI N 1:3 33’ um 305M spm rays AI DRY P1 685 19 41 19191 15450 361 p2 2871 81 76 19201 18031 139 60 mm. 3556 m D1 992 48 59 18438 14897 237 P2 921 52 24 18057 17068 70 66 TUEEI. 1913 a-PereentageofPlandPZeowswithinAIorNAIalbclass. b-PercentageofAIaniNAInatedeowswithinparitysubclass, e.g. 41%ofP1cowswerebredAIwmile59%ofP1eowswerebredm. 59 AfflitiaaleamarismofparitymbclasseswithinAI/NAI classificatimirdicatedthatanofAInatirgswerefoercowsand 19%werefch1while52%ofNAInatingswarefer-P2cowsand48% werePz. Subclassmeans albclasqumlatimaveragesforproductimardmeritvaluesin 'I'able4.3shch1andP2cowsintheAIcJassprediced753ard1144 115mm, respectively, thantheirNAIcounter-parts. Heritvalues forSPnlwerehigherforPlinbothAIarriNAIclassesardhigherfor AIinparityclasses. Becausethesevaluesareasub—pqnlatimnaan(allAIandNAI natedcowsacreesherds) smeafthesedifferermsarelikelydueto differa'cesinherdnaragau'ttlevel. Withinherdcolpariscrswere da'aardarediscussedlater. nmmass 'IhepereaatageofcowsbredtoAIsireswithineadlherdwas calculated. Based on this calculatim, theherdswere thenplaced intocneoftenAIpercentageclasses (AIPC). Herdsusingdifferent levels of AI likely receive differalt levels of nanagalart. 'Ihe prinarypurpoeeinaralyzirgAIPCwastodetemineifanydiffererces inprcchctim,rerit,anidaysdryadstedbetweenherdsusing varyinglevelsofAI. ‘miswasdaiebycmparirgthemeancfherd averageswithineachAIPc. 60 Observations 'menrdaerofcowsardherdsineadiherdAIPCislistedinTable 4.4. ‘niealallestclasswasAIPC1,having aetardcf73cowsand the largest was.AIPC38'with.19 herds and 1138 cows. Table 4.5 Shows theenunber'of P1 and.P2 cows‘within.eachMAIPcigrouping. .AIPC!8 had the most observations in the P1 and P2 sdbclasses. WELL Wefcows,subclassmearsaarristandarddeviatim ofalbclassuaarsafor305—daymauneeq11valartmilka4fl4),0w Irfiexmilk (CD4), sirePredictedDifferencemilk (SPIN), andcalf sirePredictedDifferencemilk (CSPDI) forallcowswithinAI percentage class. 1014 (ED! SPDM CSPDM .AIPCNHERDS COWSIHEHN SD> COWSIMEAN SDI COWSIMEAN SD COWSIMEAN'SD 159 16076 3167 83 ~177 341 75 54 510 7 86 410 0 5 1 1 73 17973 2924 42 -305 370 39 -48 460 10 687 485 2 5 205 17692 3627 64 -109 426 108 252 482 43 877 588 3 6 324 18151 4531 114 -195 450 121 100 597 75 726 631 4 9 536 17948 3441 288 -133 410 245 161 654 197 737 685 5 12 602 18091 3349 368 -248 451 306 -1 702 310 666 546 6 13 872 19068 3877 620 -134 423 592 155 587 473 779 603 7 23 963 19250 3870 689 -98 423 696 212 580 595 844 621 8 19 1138 19646 3794 981 -97 452 898 210 633 864 650 623 9 9 597 19738 3407 496 -44 445 534 268 573 493 719 528 All Cows 121 437 3597 181 610 3067 730 606 *6 a: 5469 18869 3807 3745 a-Meansarristaniarddeviatimoftheneansareforallcovsacross tardswithineachAIpercentageclass. 'menmberofcbservatiorsform, CD4, SPIN, CSPu4 anddays drywithinead1AIPCgru1pislistedin‘I‘able4.4 (allcows) and 'I‘able4.5 (P1andP2eows). NoPlanimalshadCSPEMvaluesinAIPC's Oardl. ‘mislcwlevelispartiallyexplainedbytlagreater percentagecfheifersinthesegrwpsbeirgbredNAI. 61 M45. Wefms,abclasneetsaafistafiarddeviatia1aof abolasmsfcr305-dwnahneeg11valatmilk0fi4),€twmmflk (CIM), sireRedictedDifferanemilk(SH14), calfsirePredicted Diffe:erremilk(CSHM),arddaysdryfim'Ierity1adParity2wififinterd AIpamtapclms (AIPC). parity 1 (2114 SH)! (SH)! momma: so mm 8308” mammal WQNIO‘UHFUDNHO Q 1.5888 3228 22 17371 2491 57 183% 4011 86 1.8470 4440 193 17691 3701 1.99 179% 3235 291 1.9065 3785 282 1.9663 3657 336 1.9331 4371 149 1.9273 3154 38 -80351 13-1983% 14 25467 26-139315 1.1.9 q42400 151-179461 212-100428 212 4378 307 34409 125 45383 All 1677 18746 3875 1217 -39 414 29 12 32 25 103 119 26 226 286 1.39 1.1.76 305529 0 183681 0 342511 5665420 174546 8647275 202621 865978 124715 63735623 193628 86927645 340529121792547 414573 229847721 36150111373238 295592 633810625 Parity 2 CIR sax (SEN um AIECCDGW 83mm 93018 mmmsmsomsmsa @QQO‘U‘IOUNHO 97 16197 31.38 51 18233 3078 148 17456 3453 238 1.8036 4567 343 18092 3m 403 1.8181 3404 581 19069 3926 681 19079 3945 8% 1.9778 351.8 448 1%92 3476 45 '258 31.3 29 -353 353 50 -147 41.1 88 -211 484 169 -198 406 217 -295 438 4% -152 421 477 -140 435 6'74 -1.57 458 371 -73 461 46-104433 786410 27-151277 10687485 76 79 142 187 387 470 612 395 A11 37921892337762528-1614432421 214468 389056® 76614 677366Q 1316781897407m -81684 247648525 135564 387746589 151595 474857639 1.1.5638 635579568 236594 380715534 976232 516126 1467554 2336236 3435823 3985826 5736224 6706222 7965926 4456222 125611243470959937526127 a-Maasadstaflardfiviatimoffienearsareferallmsmrerds withinachAIperealtapclas. 62 'Iheseebservatia'swmldindicatettatprcdnersaredoinga betterjcbofnanagirgthebreedirgandcalvirgrecordsmtheir oldercowstlanthoseofheifers. Itmyalsobeanindicative meaameoftheinportameprcdnersplaeemrecordinginfonatimm heifers. Subclassmeans ‘I‘able4.4stmnarizessubclassmeansandSDofmbclassnearsfor MEI4withinAIPC.'IhemeanlevelofME14in:reasedasAIRd1arged franOto9. ‘merewasaslightdrminmfrmAIR3toAIR4 withanimeaseatAIRS. 'IherangeofMEMvaluesforallcows acrcsstheAIRclasseswas16,076 lb. forAIROtol9,738 lb. for AIPC9,adifferenoeof36621b. 'IheSDefthesubclassmeansfor MEMforthelOclassesdidmtarpeartovaryinanycorsistent merrier (Table 4.4) witharangecf 2924to4531. InnastAIRgrcups,P2cowswerehigherinME24thanheifers (Table4.5). WentheSDofthesubclassneanfchEMwashigher for heifers, irriicating a greater ammt of variability in this class. . 'Ihisgreatervariatimislikelyduetolessalllinginthepl pqnlatimccnparedton. AgreaterpercentagecfPZcowsare miled, cmparedtoPl, resultinginatrurratim ofthepopulaticn mthelcwendwhichcatmeslessvariatim. ‘IhePlpopulaticnhas lessstrirgartalllirgreqdralentsduetoacmmupractieemmany dairyfarrsefgivirgheifersa"seoorddance"ardpostponingthe mllirgdecisimmrtilthesecondlactatim. ‘Iheresultisamre cmplete popllaticn resulting in increased variation. 63 mtrerdsferPlarriPZwaresimilartothosefor"allcows". WflmAIPCOtOAIPC9wBre33851b.aIfl36951b.forPlardPZ respectively. WenvaluesweremorevariableacrcssAIRinPl. Subclassmeanm'sforallcowstreriedmasAIRincreased (Table 4.4) rargingfrun-305 (AIR 0)to-44 (AIR 9). Stardard deviatimofsmclassmeancm'sdidnotappeartovary significantly. MeansmrsforallcowstmdedtoircreaseasAIR imreasedwitharangeof—48(AIR1)to268(AIPC9). CSPIH’swere similaracrcssall classes ranging fran650 (AIR 8) to 877 (AIR 2) withanextrenely low value (86) inAIR 0. Itslmldbenotedthatthelownmbersofebservatimsinsane cftheAIPCsubclasses(mC$Pu4recortbinAIR's0anil) creates unreliablecomarisasofmeamardsnincsm‘lvalues. HeritdifferermsbetwemPlandPZacressAIRwereebserved. CoerriexMilk,SPu4ardCSPD4valueswerehigherforP1cowstlanP2 cowsinmostAIRsubclasses (Table4.5). 'Iheeaaoepticmswerein AIPC’SZ, 3,4ard7whereP2CSH14valueswerehigherthanP1 values. 'mesePlvaluescalldbeiracwrateduetothelcw perca'ltageofPlreoordseontainingCSPminfornatim. 'Ihelcw mmberofPldaservaticrscouldalsobetheresultofalargemmber oprrcvmsireswothAIardNADbeingusedmheifers. SubclassmeanardSDofalbclassmeandaysdrydidmtamearto varyacressAIR,exeeptforAIR2(Table4.5).'1hemeanwa561days drywitharangeof58to75andtheSDofmeandaysdrywas27with arangeof22t054. AveragesforherdswithinAIR Aherdaveragedaysdrywascmprtedfereachirdividualherd. Anaverageofthese"individ.alherd"averageswascalcllatedwithin eadrAIRsubclasstothain(AIPC) subclassmearsofherdaverages. 'nmeweremlallatedtodeterminegrcssdifferernesbemeenthe differartAIRgrchs. lbansofherdaveragedaysdrywithinAIPC (Table4.6) showedno najcrtradacressAIRclasses,withahighof71.2ardalcwof 56. Heansofsub—tardaveragesofdaysdryforNAImatedcows, exhibited nnre variation arrl slightly greater days dry when cmpared toAImtedews. Sub-herdaveragesforNAInatedcowshadgreater extrenesbe‘bdeenthehighardlcwherdaveragedaysdrymaximmard nininunvalues)withinAIPCttandidAImatedcows. Withinherdvariatim 'mestandarddeviatimofmeandaysdryforNAImatedcowsarriAI matedcowswithineadiherdwascalculated. 'Ihiswasthenaveraged for herds within each AIR to look at differerms in variability betweaicowsmatedAIardmwithinthesamelevelofAIusage. Table4.7showstlatthemeanofsub—herdSD’sfordaysdryis greaterforNAInatedcows. AverageSchrNAItrendsdomwardas AIPCdlargesfnnOto9arritheSDofNAIandAItenitobeclcser togetherasAIPCmovescloserto9. 'Ihiswculdindicateless variatimindaysdryinthehigherAIpercentageherdswhichmayin ulrniniicateahigl'ierlevelofmanagatantreslltinginbetter caltrolofdaysdry. 65 Wilt. mysdryminimmherdaverage,maxinmherdaverage, and meanherdaveragewithinAIpercentageclasses. AIpercartageclm 0 1 2 3 4 5 6 7 8 9 All Nunberofherds ALL 5 1 5 6 9 12 13 23 19 9 102 AI 2 1 5 6 9 12 13 23 19 9 99a NAI 5 1 5 6 8 12 10 18 14 3 82a mysm! Meanofherdaveraga AIL 61.6 58 71.2 61.5 58.4 55.9 58.7 64.1 56.4 62 60 AI 62 62 60.4 60.2 55 55.5 57.7 63.4 56.1 62 59 m 61 60 75.2 62.3 64.5 57.8 63.3 68.2 61.9 86 65 Maximherdaverage ALL 66 58 88 79 69 73 80 98 78 77 98 AI 63 62 74 73 65 72 83 94 76 77 94 NAI 68 60 98 84 78 80 89 109 89 137 137 Minimum herd average ALL 54 58 58 49 46 35 40 50 44 43 35 AI 61 62 47 49 46 26 32 53 43 43 26 NAI 54 60 49 48 43 40 33 48 39 59 33 a- 'notalnmberofherdsintheAIandNAIalbclassesislessthan totalnmberofherdscverallduetoelimiratimofsane subclassesbecauseoflcwnmbersofAIorNAIebservaticnsin saleherds. 66 met Pharaofwithinherdstardarddeviatimdaysdryforherds withineadiAIpercartageclass. AIpercaxtageclass 0 1 2 3 4 5 6 7 8 9 ALL AIL HERB 5 1 5 6 9 12 13 23 19 9 102 AW 30.1 25.7 41.4 28.4 21.1 19.3 20.5 19.2 19.7 21.1 23 AI m 2 1 5 6 9 12 13 23 19 9 99 AW 19.5 23 18.4 24.2 15.8 17.7 18.1 18.6 19.8 19.7 19 NAI m 5 1 5 6 8 12 10 17 14 3 81 AW 29.2 27 46 30.3 26.6 20.9 25.1 18.5 17.1 27.7 24 DAYSIRYCIASS mysdryclassesallmweredebeminedbydividinginiividual cow'sdaysdrybylo. Daysdryreoordsgreaterthan90weregmlped inaneclass(wC9). Chservatia's Table4.8showsthebrealdownofewswithindaysdryclasses (we) acressallherds. daservatiasrangedfranalwefZlcows (5%) ian0(1to9daysdry)toahighof1038cows(27%) forcows drybemeenSOt059days (11305). 'miswCSvalueissimilarto HidiiganUIIAvalueswith25%ofthecowsreportedinasimilardays dry category (1111A, 1988) . Subclasmeans Subclassneanscmprtedacressherdsformcmble4.8)were higherinlaverflJCclasseswithhighestbeingIOOOatwco. This valueismostlikelyhighduetoatallnmbersofcbsewatiensinthe 67 names. Wofeowsardsubclasspercentageoftotalwithin daysdryclass (000); amsinpleneanardstardarddeviatimofcalf sirepredicteddifferenoemilk(6m4) withinmeorallparitytwo cows. Days can we Dry N a: Mean SD 0 (0—9) 21 0.5 1000 685 1 (10—19) 49 1.3 665 541 2 (20-29) 123 3.3 770 654 3 (30—39) 289 7.7 721 645 4 (40-49) 664 17.7 732 589 5 (50-59) 1038 27.7 743 550 6 (60-69) 703 18.7 699 658 7 (70-79) 282 7.5 653 576 8 (80-89) 175 4.7 629 570 9 (90+) 408 10.9 633 576 uncalbclass. MeanCBPu40f732and743asebservedian4and we 5 respectivly are similar to mean (SPIN value of 748 for all AI bredcowsindataset(Tab1e4.1). ‘Ihemeanvaluesterrledtodecline aswcincreasedwithalcwof633atmc9. 'Ihisnayirdicatettat increaseddryperiodlergthistheresultofanextendedbreeding pericdardmstlikelythemeofalcwerPDAIhlllormprcvenm bull. SCENE Feedirgnanaganent"sdlane"wasdesignedinanattaipttomeasure theeffect ofachangeindietary forage at parturition while considering kmwledge ofdnedate. Herdswereplacedintofcur classesdesignedtoccnpareeffectsmcowsttathadadietdangeat partm'itimtocowsthatdidnot. Feedingsdiemelca'rtainedherds inwmidlcowsandheiferswerefedthesameforagepreardpostparttm dtn'irgboththeamr(JmIetoA1gust)ardwinter(SeptatbertoMay) 68 seasm. SdaneZemtainedherdsinwdridicowsardheiferswerefed thesamefcrageatpreandpostparhndn'ingthesmuermtdifferent forageatpreparhnversuspostparuminwinter. Schane3contained lardsinwhidicowsarriheiferswerefeddifferartforagesat meromversuspostparumdurirgtheamnerardthesameforagesat preandpostperummringthewinter. Sehene4cmtainedherdsin midlcowsardheiferswerefeddifferaxtfcragesatpreversus aaservatims 'mennmerofewsardherdsinead)feeding8d1aneislistedin Table4.9. Sdienelhadtlalargestmnberofcowswithsnofthe total. Sdme4had30%ard$dame3rad18%ofthetotal. Schenez had1%ofthetotalandwaselimiratedfranaralysisbecauseit curtainedmlymeherd. albclassmeans SdaeneBcowsramtedthehiglnstinlbomewith19,019 (Table 4.9).Sd1eme1eowsproducedslightlymre3oa4tlan8d‘1ene3 (17,062 vs17,054). Sdlene4ranked1astinbothcategories. These differenesdonotarpeartobesignificantwhidlwmldsuygesttlat sawdidmthavemmpactmaverageprcductimlevel. SireneritwasthehighestindeenechparedtoSdianeLIays drywasalsohighestinSdiemeL mismayalggestthatSdIaneB herdsusedbettersires,preamablyAI,arrihadgreatermandlcnger dryperiodswmileherdsusirgpoorersires,presmablymreNAI,had lowermandshorterdrypericds. 69 M843. Wofmewififintmdfeadhgsdm,parityafi mmmmmmfcwmmm milkom, 305-daymilk(30&t), simkadichadmflferanemflkfimn, addaysdzy. wmm mam bf m N N mm. (1143 single mars“ cm; 14:14 305 5334 [ms my sons 1 m P1 531 190m 15236 201 m P2 460 18096 17094 57 60 AI P1 317 19283 15508 356 AI P2 1468 19169 18048 80 58 AIL 54 2776 51 18972 17062 138 59 some 2 NAI P1 3 m1 P2 5 AI P1 0 AI P2 34 AIL 1 42 1 sum 3 ~ m1 P1 145 18234 14892 338 1011 P2 194 18377 17331 68 73 AI P1 174 19808 15940 425 AI P2 479 19231 18000 239 62 ALL 19 992 18 19019 17054 265 66 some 4 1m P1 313 17577 14320 253 mu P2 262 17754 16813 97 70 AI P1 194 18489 14915 320 AI P2 890 19196 17991 184 60 AIL 30 1659 30 18580 16752 205 62 Sdmlirnhflshenbinmidmmsammtfiersmfedue- Wmmmmmfiemm (whom) adwirterm (Sephalbertomy). admzfinlmmmmidumamdmmfiedfie- Mmmpostparumdmflemmarflhztdifferat mmmmmmmm. mmz'lhis lardvmdrqpedfxmchtaamlysisheaseitmttemlytmdin finfeaiirgsdme. Sdm3irn1uishenbinmid1mardheiferswemfeddiffermt WWWmmfinmaflfiem Sdare4fin11fleslmchinvifid1mardhejfersmfeddiffaat a-Wmfwaflmmm. 7O SGMBYPARITYBYAI/NAI Cbservaticns Table 4.9 liststherurberof obeezvaticms for 16 Sdme-AI/NAI-Parity stmclasses which were used to analyze the data. '111elargestgnmpoa1tained14680owsanitheanallest3m. SdnneZomtainedaflylherdwithucowsardwaselimjnatedfran analysis leaving the anallest subclass with 145 cows. Procmotim,mritarddaysdryva1ueswithinthesubclasses (Table 4.9) mamas simflartothosemportedearlier withAI beingwperiortoNAIinMEMarflBOSMwitlfinparity. Paritytwooows weresuperiortoPlinmilkproductimarfiPlsuperiortoninSPm. W mta analysis to this point reflects single averages depicting thepoleatim anddifferanes betweenhertb inthispopulation. MeandifferermsintteAIPC, 113C, anisduneszmclassaare manfledwimlzerdmnaganattlevelaswellaspotential differamsinfimdeffectsauIasage, seasonandqeneticlevel of iniividuals. Therefore, it is appropriate to dowithinherd analysis using regressim mdels. Wthesevaluesdohelp profileherds using different levels of AI and usirg different feeding practices. 4.2mcrmG305-mmxmw W0! Regressimmdelsmrmwimaselectedgramcffimd classificatim factors and covariates (Table 4.10). Dependent variablesmedfcrttneecwariatemdelswereBOS—daymflkaosu) andpreviousdaysdry. Wmiablesusedasfbaedfactcrs invariwsmdelsmefeedimsdme,herd,m1thcffrestming (seasm),typecfmting (AI/NAI),AIpercentageclass forherd (AIPC), interactimbebdeentypeofmtjngardfeedirgsd‘m,“ utter-actimbetwemAIPCarfltypecfmtim. Age,agesquared, sire PredictedDiffexernemilk(SPu0,daysdryarddaysdzysquaredwere imltfledinvarimsmdelsascovariats. PREDICI'DG BOS-DKY MIIK DEE Aqeinmflmatcalvirqwasimludedinallmdelsasa covariate. 'Ihe linear effect of age was significant in explaining variatim in all P]. mils except “8 20:P1 am 21:P1 (Tables 4.11 and 4.12). Parameter estimates (PE) for all models except 11:P1:AI mintteraryeof87tcl40withstardarderrcrs (SE) ranging fran 27 to 35.1. Model 11:P1:AI, midI included mly AI mated cows, had a PE of 169 arr! SE of 61 (Table 4.11). lbs difference in results when cmsidering AI hated cows separately (Model 11:P1:AI) nay Stagest that heifers mated AI were more sensitive to age at calving effect in relatimtcprcdnctimcritnayaggestthat, inthisdata set, the effect of type of mating (AI/MAI) is confamded with age for P1 cows. 71 72 Variable lista for regressim models using 305-day milk pt'cmctim. TAKE 4.10. .8 .8 .8 .8 8 888 88 8 8 8888 8888 8888888888888 88 8888888 88 88 8888888 88 88 uuuuuuuuuuau and mauuuu 2 2222 222 22 22 222222222 288 2m a :3 8,2, g 2, 33:38, a8832.328$232,328,383: mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm 8888888888888888888888888888888 888888888888888888888 888888 bmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm nnmmmmuummnmmmmnnunnummmnmmmmnn atcalvingsaned,ai=typecf schene,mth=mrthcf freshening, age- nating (AI/MI), sch*ai an interaction of feedjngmanagement schene 898 , spanssirePredictedDifferencemilk, dry8 =daysdrysquared,dc=dayscpen,aipc-AI 1‘25“? age at calving am 31:? percentageclass,andai*aipc=interactimcftypeofmat1‘ngard AIpercentageclass. anitype f b-P1-=Modelscontainirgmlyparitya1ecows. days dry, c-P2=mdelscontainirgmlycowswithtwccrmreparities. d-AII-McdelscontainjmmlyAInatedcows. f-mysdrycovariateismstedwithintypecfnatim. e-mauodelscartahfimmlyNAImtedcows. a-sch-feedirg 73 MB 4.11. Sunnary of regressim mdels predicting 305-day milk production. 1:2112 1:11213 2:P112 2:P213 3:P112 3:8213 4:P112 :2 0.328 0.33 0.329 0.33 0.329 0.33 0.369 :N- 1674 3753 1674 3753 1674 3753 1175 EERNMETER.ESTIMRTE (unbiased) AGE 93» 107”: 89** 107“ 87** 107** 140“ AGE? -- -0.65** -- -O.65** —- -O.65** -- :mnuu -- -- -—- -—- -- -—- 1.12** 1116: -—- -—— -- -—- -- -- -- m2 —- -— —- -- -- —- -- IEEEHPSOUAREDHMEANS4 Feeding Scheme 1 148698‘ 17414a 14854a 17403a 14851a 17440a 15094a 3 152 184 15206a 18441a 15208 18469a 153158 4 14968a 17955a 14954a 17944a 14928a 17852a 14866a Month of calving 1 15285 18205 15275 18197 15266 18187 15027 2 15913 18260 15910 18250 15913 18235 15902 3 15454 18860 15446 18852 15453 18850 15752 4 15220 18082 15202 18071 15199 18059 15188 5 15113 17967 15100 17955 15099 17947 15238 6 14644 17679 14632 17668 14621 17665 15027 7 14780 17491 14766 17481 14759 17465 14875 8 14375 17252 14364 17240 14350 17228 14329 9 14158 17528 14147 17516 14135 17504 13734 10 14764 17765 14759 17755 14728 17753 15015 11 15159 17889 15154 17879 15144 17873 15319 12 15307 18296 15301 18285 15281 18273 15693 'Iype of mating NA: -—- -- 15067a 17905a 15049a 17881a 15206a AI -- -—- 14942a 17953 14943a 17959a 14977a Feeding Scheme * Type of mating 1 N21 -—- —- -— -- 14930a 17493a 15224a 1. AI -- -—- -- -- 14771a 17386a 149633 3 NA: -- -- -—- -- 15134a 18519a 15277a 3 AI -- -- —- -—- 15283a 18418a 15353a 4 NAI -- -—- -—- -- 15083a 17630a 15116a 4 AI -- -- -—- -- 14774a 18074a 14616a l-lbdel ircltdesherdmstedwithin feedingsdlane. Z-PlsbbdelimludesmlyParity1cows. 3 -P2=Model includes aflycowswichcrmoreparities. 4 - 18 means with different superscripts are significantly different (P<.05). (** P <.01) (* P <.05) (ns = not significant) TABLE 4.11 (cart’d.) 74 4:P213 5:le3 6:P213 7:P213 8:P112 8:P213 9:P213 g 0.325 0.328 0.328 0.334 0.368 0.325 0.327 n- 2396 2378 2378 3713 1175 2396 2378 mm mm (unbiased) AGE 122M 120M 120M 104M 141M 122M 119" A882 -0.72** -0.7** -0.7** -O.63** —- -0.72** -0.7** SP1)! 0.81”! O.8** 0.8** -— 1.12» 0.81“! 0.8"! on -- 3 . 66m 11.2ns 2 .9ns -- -— 3 .6118 m2 -—- -— -0.04ns —- -— -- -- 1m 50mm) MEANS“ Feeding Schene 1 17680“ 17683“ 17684“ 17475“ 15095“ 17622“ 17626“ 3 18663“ 18653“ 18650“ 18468“ 15344“ 18642“ 18648“ 4 17880“ 17905“ 17904“ 17883“ 14900“ 17979“ 17998“ with of calving 1 18343 18355 18345 18201 15050 18347 18363 2 18349 18367 18366 18271 15911 18364 18385 3 19078 19094 19087 18860 15775 19077 19094 4 18112 18094 18100 18023 15201 18127 18111 5 17926 17897 17889 18029 15247 17950 17916 6 17954 17987 17992 17696 15053 17955 17992 7 17733 17740 17739 17552 14883 17750 17756 8 17441 17487 17492 17266 14337 17462 17511 9 17614 17606 17608 17509 13757 17626 17619 10 17987 17987 17988 17737 15076 17978 17984 11 17935 17934 17936 17885 15342 17920 17925 12 18419 18417 18409 18274 15723 18426 18428 Type of mating NAI 18158“ 18144“ 18142“ 17900“ 15240“ 18183“ 18178“ AI 17990“ 18017“ 18017“ 17984“ 14986“ 17979“ 18003“ Feeding Scheme * Type of mating 1 NAI 17899“ 1788 17876“ 17534“ -- -- -— 1 AI 17462 17481“ 17492“ 17416“ -- -- -- 3 NAI 18808 18752“ 18751“ 18485“ -- -— -- 3 AI 18519 18554 18549“ 18450“ -- -— -- 4 NAI 17769“ 17795“ 17798“ 17680“ —- -— -- 4 AI 17991“ 18015“ 18010“ 18085“ -- -- -— l-Hcdel imluiestmdnestedwithin feedingschane. 2-P1=HodelincludescnlyParity1cows. 3 -P2=mde1 includes mlycowswithz crmoreparities. 4 - IS mans with different aperscripts are significantly different (P<.05) . (4* P <.01) (* P <.05) (m = not simifimrrt) 75 mm: 4.11. (cant'd.) 1 10:P23 11:1:A?5 11:2:A.35 12:2:A95 13:1:N'26 13:2:N36 14:2:N36 3 0.328 0.347 0.321 0.322 0.443 0.435 0.431 n- 2378 547 1925 1911 628 471 467 iENRNMETERiESTflHNrE (Unbiased) A88 119» 169» 121» 123» 137» 125» 116» m2 -0.7» -- -0.71» -0.7» — -0.76» -0.72* smn 0.8» 1.02» 0.81» 0.78» 1.14» 0.59* 0.69* am 12.213 -— --- 0.11113 —- -- 28* non!2 -0.04ns -—- -- 0.003ns -- -- -0.09ns IIIEHPSOUAREDHMEANS‘ Feeding Sd'nennne 17589“ 15567“ 17522“ 17516“ 15185“ 17816“ 17848“ 3 18599“ 15217“ 18302“ 18366“ 15283“ 18807“ 18806“ 4 17953“ 15982“ 18061“ 18102 14614“ 17698“ 17894“ m of calving 1 18324 15645 18216 18264 14813 18553 18568 2 18339 16370 18448 18512 15815 17674 17743 3 19051 16150 18775 18847 15702 19421 19459 4 18069 15550 17889 17867 15103 18327 18505 5 17858 15633 17984 18004 15367 17097 17188 6 17954 16031 17860 17928 14753 17834 17910 7 17714 15494 17620 17637 14735 18071 18188 8 17472 15362 17275 17351 13953 17727 17865 9 17579 13516 17249 17267 14607 18849 19000 10 17945 15332 18021 18026 14756 17139 17278 11 17890 15842 17750 17748 15428 18594 18586 12 18371 16137 18451 18486 15478 18000 17904 'Iype of matixg NAI -- -- -—- -—- -- -- -—- AI ..- —. —— —— —— .— .— Feeding Sdneme * ‘Iype of rating 1 NAI -- -- -- -- -- -- -- 1 .AI -- -- -- -- -- -— -- 3 NAI -- -- -—- -- -—— -- -— 3 AI -- -- -—— -—- —- -- -- 4 NAI -- -- -- -—- -- -- -— 4 AI -- -—- -- -- -- -—- -—- 1-Allmdels imltflesherdrmtedwimin feedingschane. 2-1-Modelincludescn1yParity1cmvs. 3-2-Mcde11mluiesgnlycowswith20rmorepar1ties. 4-18 means with different superscripts are siguificantly different cP<.05). S-A-Model inclnries cnlyAImatedcows. 6-N=Mode1 imludescnlyNAImatedcms. (** P <.01) (* P <. 05) (ns = not significant) 76 MB 4.11. (cmt'd.) 3m. 15:P12 15:P23 16:P23 17:P23 18:P213 19:P213 0.368 0.325 0.327 0.333 .328 .359 n- 1175 2396 2378 3713 2378 2376 P88AMEPER.ESTIM8$E (unbiased) A88 140** 122** 119** 105** 121** 110** AGEZ -- -0.72» -0.7» —0.64» -0.7» -0.66» spun 1.12» 0.81» 0.8» -— 1.76» 1.67» on -- -- 3.6113 2.8113 -— -- IIIaF’ --5 -—-» -- -- -—- -—- wanting) AI 1.63ns -8.14** NAI 7.7* -1.69ns ears OPEN' 11.44** LEAST SQUAREDHMEANS4 Feedirg Sdnane 1 -- -—- -- -- 17684“ 17569“ 3 -- -- -—- -- 18630“ 18572“ 4 -- -- -—- -- 17895“ 17873“ thnth cf calving 1 15016 18169 18184 18043 ——- —-— 2 15877 18186 18206 18119 -- -—- 3 15741 18898 18915 18693 -- -- 4 15167 17949 17932 17872 -- -- 5 15213 17762 17737 17876 -- -- 6 15019 17777 17813 17536 -- -- 7 14849 17571 17577 17398 -— -- 8 14303 17284 17332 17115 -—- -- 9 13723 17447 17441 17357 -- -- 10 15042 17800 17805 17573 -- -- 11 15308 17742 17746 17725 -- -- 12 15689 18248 18249 18120 —- -- ‘Iype cf nnathg NAI 15206“ 18004“ 17999“ -- 18119“ 17857“ .AI 14952“ 17801“ 17824“ -- 18018 18152“ Feeding scheme * Type of mating 1 NAI -- -— —— -- 17890“ 17563“ 1 .AI -- -- -- -- 17479“ 17576“ 3 NAI -—- -—- —- -- 187 18414 3 AI -- -—- -—- —- 18559“ 18731“ 4 NA: -—- -— -- -- 17769“ 17593 4 AI -- -- -- -—- 18018“ 18150“ 1 - Model includes herd nested within sd'nennne. 2-P1I-Hodelinc1uieemlyParity1cows. 3 -P2=Model ircludesmlycowswichrmreparities. 4 - 18 means with different superscripts are significantly different (P<.05). 5-Daysdrycovariatewasnestedwithintypecfnatirg. (** P <.01) (* P <.05) (rs - not significant) 77 MB 4.12. Sunmary of reanlts of predicting 305-day milk; mdels [20:P1, 20:P2, 21:P1 and 21:P2]. $1111. '20:P112 20:P213 21:P112 21:P213 0.329 0.330 0.333 0.331 Na 1674 3753 1674 3753 PARAMETER.ESTIM8IE (unbiased) AGE 3113 107» 61115 107» A082 1.04ns -0.65** 0.36ns -O.65** 55114 -- -- -—- -- LEASTMSQUAREDHHEANS4 ‘Iype of mating NAI 14721“ 17380“ 14769 17482“ .AI 14595“ 17428“ NUN‘EST 17416“ AI Percentage Class 0 12408 15081 NCN‘EST 14843 1 14065 17273 uuuansr 17193 2 15236 17043 16370 17153 3 14591 16924 14634 16972 4 13575 17267 14756 17314 5 14251 16966 14256 16917 6 15293 18571 15333 18510 7 15074 17726 15072 17848 8 16376 18847 16430 19030 9 15709 18343 15902 18710 1-Model imluieslnrdnmtedwithinupercentageclass. 2-P1-ModelinzludesmlyParity1cows. 3 -P2=Model includes cnlycowswith2 ornnoreparities. 4 - 18 means with different snperscripts are significantly different ’75 .05). (** P < .01) (* P < .05) (ns = not significant) 78 AswasnotedinSectile, agreaterpercentageofmcowsthaan cows, in this data set, were bred NAI. In models 20:P1 and 21:P1 (Table 4.12), which contained AI percentage class (AIPC) as an independent classification variable, age was not significant in explaining variaticn. Parameter estimates were 31 and 61 with large SE's of 344 and 344.8 respectively. Agewassignificantinexplainirgvariaticninall P2mcdels. Parameter estimates ranged frunn 104 to 125, with SE’s of 11.7 to 14.6 extent in NAI mdels (11:P1:NAI, 12:P1:NAI) where SE’s were 40.7 and 40.8 (Table 4.11) indicating a greater amount of variation. 'Iheeffectofageisenpected, asMr'eearchhasshomageat calving to signifiwntly influence 305-day milk prcductia'n (Hayley and I-Ieizer, 1952; 00:15:00.1: et al., 1974; Schneider et al., 1981; Dias and Allaire, 1982) . HEW AgeeqnaredmsincluiedasacovariateintnDMmdels (20:P1 and21:P1)mid1cantainedAIPCasanindepenflentvariable. As expectedfcr first lactation aninnals, itwasnotsignificantin explainingvariatimintheeetwomdels (Table 4.12). AgeeqnaredwasincludedinallPZmdelsasacos/ariate. Itwas sigiificanntinecplairfingvariatiminmmdelswith PE’s of -.64to -.76andSE's cf .08tc .28 (Table 4.11). 'Iheszodelresultsare consistent with Snithandlegates (1962) wtnreportedtneregressim cf305-daymilkyieldmagewasa1rvilinearin mdelscontaining secgdarfilater lactatim cows. Comocketal. (1974), also reported a curvilinear effect of age on 305 milk production from work 79 flutirdicatedanircreaseinlactatianpmmctiantoQGnanthscf ageandthenadecline. mums Wefcnlvirg(freshmnth)wasincludedinallmdelsasa classification factor. It was significant in explaining variation in allPlnnodels,withtheeaweptian of [l3:P1:NAI],amodelcontainirg unly NAI mated cows with 628 cbservatia‘ns (Table 4.11). There were significant differences between several fresh mnth abolass305MISnnneans.Arankingcfthese30841$meanvalues irfiicatedfreshmnthschebruary,m'dnandDecanberreanltedin thehighest30§4prcducticnn. Freshnunthwasalsosignifimntinexplainirgvariaticninall P2mdelse3cept[l3:P2:NAIarxi14:P2:NAI],boflncantainirgmlym mated cows and few weervatigs. Significant differences were cbserved,inallmdels,bemeenseveralfreshmanth305MISmeans. Cowshavirgafreshnnnthcfnecanber,Jaruary,Februaryardmrdn, casistentlyr‘anksdhjghestinwfliprcmgticn. misislikelydue to effects of weather on the cow in early lactation, especially how sheresponisinlgtsnmnermorntlsi.e.remgedarpetite,anda subsegaent reduced dry matter intake. Physiclcgically, cows handle thestresscfpeakmilkprcducticnbetterinthecoolerweathercf fall,winterandspringconparedtctheheatcfthesunmner. Sumner heat stress canpourds the pnysiolcgical stress of early lactation predaotianresnltirginloweraverageprcductianforcowscalvirgin thatperiod. 80 Tuckeretal. (1960) r'qnortedsimilarresultsinastnfly inflicatingthatccvscalvingfrmnecadnertcnaypmducedmrethan meaivingnmametnmnghm. ‘Iheseresultsarealso mistant wimnsmracm, chvelcpalbymnetal. (1974), midnarecunentlyusedtcadjustmnrecordsfcrmonthcf fresheningeffect. Similarresultsarerepor‘tedbySdnneideretal. (1981),“10fanithatfall,winterardsprirgcalvingcmvsprcduced mthancowscnlvinginnsnmer. HERD Herd was included as a fixed classification factor in all mdels. Analysis nust be done within herd to adjust for differenms inmanaganentandenvirelnentbetweenherds. Herdwasnestedwithinn feeding scheme in those models cantaining feeding schane (Table 4.11) and it was nested within AIPC in four models (20:P1, 20:P2, 21:P1 and 21:P2) cantaining AIPC as an independent classification variable (Table 4.12) . Herd, as expected, was significant in all models. Paranneterestimates, inthceemcdelsmnereherdwasnotnestedin either sdnenne or AIPC (15:P1, l5:P2, 16:P2, l7:P2), were biased and ranged frann -7023 to 7171. Parameterestinatesinmdelswithherdnestedwithinschenewere biased and ranged fun -7223 to 5266 for Sdnene 1, -3727 to 5540 for Schenne3, -5089t05834 forSchene4. E'stinetesinnodelswithherd nestedwithinAIPCwerebiasedandhadarangefrun3642 (AIPC 9) to 6326 (AIPC 7). 81 some Feedingsdnanewasingludedinseveralmdelsasaclassificaticn factor. Inmmls,fsaiirgsdmwasrbtsignificantin explainirgvariatimmrwerethereanysignificantdifferenoes bemeenn305418neans(Tables4.ll).Inranking309418neanvalnm forthethreefeedingsdnenes,ancbservedtreflwasthatednene3 (differentfcrageprevspoctparhminthesnnneranrisamefcragepre anipostpartnninthewinteficasistentlyhadthehighestvalues withtheenmeptiancfnmdel 11:P1:AI,whidnincluded cnlyAImated heifers. InP2mdels,sdnsnnnewasneversignificantinexplaining variatim. HencesideringISmeans,therewerenosignificant differencesinBOlemductianbetweenthethreefeedirgednenes.A rankingcfthe3sdnsmesshowededneneacorsistentlyrankedhignest in308418meanvalues (Table 4.11). Manltsofthissunyirdicatethatthereisnotasignificant differenoebetweenanyofthefeedingednanessuflied. I-lowever, it isnobedthatthisevaluatianwasnotcaductedunflercantrclled experimntalcaditims. InaccrntrclledsundydmebchhnscnaIdOtterby(1981),cows whohadanabrnptdnangefrunprepartnmdiet (allbaledhay)to postparumndietmilagebasedtotalmixedratim (1148)) differed slightlymtnotsignifimntlyfruncowswhcdnargedfranpreparum sflagebased'nlldiettcapostparunmsilagebased'deiet. The mlldifferencescbeervedweremlyfcrthefirstlSdayscf lactatiananithenthedifferenesdisappeared. 82 InrankingISmanBofthe3feedingsdnenes,thehignest produtianlevelsoconrredwhenprqartnncowsandheiferswere Wormadifferentforageprogranthanmifldngcowsdnrirg theamrmntl'swdnelnen. 'nnismaybeinflicativeofsane positive effects of cattle spending more time outside or suggest less thanqtinnnntritiandmingcmfinenent.ltmyalsosnggestthat smefansdoaleesthanadegnatejobofprcvidingqualityforegeto Woowsardheifersduringthefall,winterandspring. This cunldbeforavarietyofreasms,anelikelybeingpoorforage mlymanagennentwiththeresultbeinglessfeedbeirgfedto prepartunncowsanriheifersatcertaintimesoftheyear. Itmayalso innicatebetternanagementanfarnsvdnerecattlearefedavarietyof foragesthrugtnnttheyear. 'nniswmldbeconsistentwithWaheedet al. (1977), who morted that feeding a variety of forages (including pasture) during the stunner auntie had a significant positive inpact mproductim. However, Keenan (1988), r'qnortedthat differences, betweenfanns,inforagefeedjngpracticesdidnotcontribute significantly to productian differences between herds. mornm'm; (AI/MAI) 'nnetypeofservicesireforeadncowwasdeterminedtobeeither AIorNAIanriimludedinseveralmdelsasaclassificatian factor. 'Ihisfactorwasthemainvariableofinnterestinthisstudy. Type of mating was nnever significant in explaining variation and thereweremsignificantdifferencesbetweenAIandNAIsubclasses wl'nenccnparingBOmISmeans (Tables 4.11and4.12). Actual 305MIS 83 meandifferenoesrargedfrcn47inmde12:P2to2541nModel8:P1, withNAIvaluesbeinggreaterinmstmodels. Basedanthesecovariatennndelsitwmldappearthattypeof matingdoesnothaveasignificantaffectmwithinherdtiom prcdnctian. anevnealonessofthissuflymsthatthetunanbsetsmI/NADwere likely affected differently by sans of the covariate factors inclnfled,asobservedinregrmsianresultswhenAIandNAIdatasets wereanalyzedsqnarately. Covariates fordaysdryweredland28 forAIandNAIaflasets,respectively,innmodelle:P2:AIarri l4:P2:NAI (Table 4.11). Analternativemthcdvmldhavebeentc nestvariablestobemeasuredwithintypeofmating. Nestingwculd allowforthedifferencesbemeenAIandNAImtedcowstobe adjnnted. Anotherweaknessofthissbriywasthatitwasnotacantrolled shay. ItwaspmoposedthatNAInnatedcowsweretreateddifferently atcalvingthanAInnetedcowsbecauseoflackofduedate. 'Ihismay nnothaveocanred. Agrossanalysisofherdnenagenenteffectwas danetoassessthepotentialaffectmaherdbasis.1niividualcows myhavebeennenageddifferentlyhnttheaverageeffectwithinthese herfiwasnotdifferent. 'nnisstuiyalsoreliedmtheacanracyoftheproducersmenory (asamned to be 100% acanrate), for information regarding feeding sdnennes,whidnneynothavebeennthecase. 84 WWBEIWEENSGMANDTYPEOFW 'Bneinnteractionofsdneneardtypeofmatingwasimluiedin models 3:P1, 3:P2, 4:P1, 4:P2, 5:P2, 6:P2 arnd 7:P2. The interaction didnotcontrihntesignificantlytovariatianwithinanymandm mdels. (beervatianoffeedingsdmeandAI/Nuabclasswmmmeans indicatedmsignificantdifferencesbeuaeensubclassesinm mdels. ISnnneanvaluesfor3054rangedfrm14616(Sdnenne4,AI)in Model 4:P1to18807 (Schane 3, NAI) innodel 4:P2. Thegreatestls mandifferencesbetweentypeofnnatirgwithinfeedingsdneneocanred withinSdnenelinmdels4:P2,5:P2,6:P2,ardinSdnene4inbbdels 3:P1,3:P2,4:P1and7:P2 withdifferencesfrmaboutBOOtoSOO lbs.,saneofwhidnwereinfavorofAIardsaneinfavorofNAI rated cows (Table 4.11) . SPIN Sire Predicted Difference milk (span) was incluied, as a covariate, toaccountforgeneticmeritofthecow. SirePlM, inall P1 models, was found to significantly influence variation of 305M. lbdels 4:Pl, 8:Pl and 15:P1 had PE of 1.12 annd SE of .15. Models with AI mated cows mly (11:P1:AI) and NAI mated cows mly (13:P1:NAI) had slightly different PE values, PE of 1.02 and SE of .20 and PE of 1.14 with SE of .24, respectively. Sire m4 was signifiant in explaining variation in all P2 models withmof .80to .81andSEof .11. 'nneexceptiontothesePE valuesocanredinmdelscontainingAI orNAImatedcowsseparately. 85 AlmlshadPEofJBtoJandSEof.12whileNAImodelshadPE's of .59to .69andSE's of .27. 'nnePE'sforPZmdelsinthisstudydifferfranPwelletal. (1980) , who reported regression coefficients of lactatian yield an SPm, within herds, tobeaboutl.02. Iactatian yields inPowell et al. (l980)wereMEadjusted(for-ageandeeason) andinthecurnent surlyws-dayvaluesmnnedwithageandseasonascovariates, however,themvaluesareexpectedtobenear1assm4isalready adjustedforageandseasm. Inadditim,themdelinthisstudy cantainedothervariablesnotimlmedinworkbyknelletal. MYSERY mysdrywasinoludedasacovariatein7mdels(5:P2,6:P2, 7:P2, 9:P2, 12:P2:AI, l4:P2:NAI and 16:P2. It was significant in explainingvariatianingnemdel (14:P2:NAI),whidnca'ntainnedanly NAImatedcows. ‘nneparameterestimteinthismodelwaszawithan SEofl3.9. 'n'nisPEvalueinndicatesthat,inthisdataset,foreadn adiitianaldrydayacavreceived,her30§4pmductimvmldingrease by281b. Ttgseresultsarenotcmsistentwithnmketal. (1987)ndno caductsdastriywherepreviansdayscpen,previcusdaysdryand present days men were fit sinnltaneously in regression models to deteminetheireffectan305-dayHEfatcor-rectedmilk(l=u4) prodnctian. They found days dry to be significant on “yield. 'meyreportedthatcwsdrywdaysorlessproducedmarkedlylessin the following lactation and that cows dry amrcxinetely 60 days prodncedthemstmilkinthenextlactation. Dryperiodslcrger 86 than60daysweresannanhat,butnotseverely,detrinnentalto prcdnctign. Arelatia'ahipbetweenageanddaysdrywasobservedinthis shay. thysdrywassignificzntinmdelsmm, 9:P2andl4:P2:NAI, mntilageeqnaredwasadded. anitharrllegates (1962) attributeda nllmnntofvariatignindaysdrytoageandcoppodtetal. (1974) rwortedthatdaysdryincreasedwith age, inndependentof treatnent. one to noted differences in days dry regression coefficients behaeenAIandNAIsubsetsabdels 12:P2:AI, 14:P2:NAI),daysdrywas rnestedwithintypeof mating (AI/NAT) intworegressicnngdels (18:P2 anfil9zP2)toadjustdaysdryseparatelyforAIaniNAInetedcows. Ibsults ofmnhl 18:P2 indicated daysdrywas significant in explainingvariatianin305MforNAImatedcowsbutnotAIneted cows. Parameterestimateswere7.7forNAIanril.63forAIcows (Table 4.11). Inmode119:P2,withmaddedasacovariate,this situatian was reversed, with days dry being significant for AI mated cowshntrgtforNAImatedcows. Paraneterestinneteswere-l.69for Mani-8.14 fcrAI(Table4.11). Thissuggestsmanddaysdryare correlated. Table 4.13amrtsthis. MS 3!! m mysdr'ysgnaredwasaddedasacovariateinmdels6zP2, 12:P2:AI, 14:P2:NAI. It was not significant in explaining variation withparameterestimates rangingfrcm-.09to .03 andstandarderrors from .04 to .07. quock et al. (1974), reported a curvilinear effect for days dry. Funk et a1. (1987) reported a nan-linear (but 87 MB 4.13. marsan correlatign coefficients, level of significance, am nnnber of observatigns for all cows. AGE: lififi! SE!!! (EH31! DOPEN DER! AGE 1.00000a 0.97544 -0.25536 -0.02937 0.16049 0.18772 0.0000b 0.0001 0.0001 0.1497 0.0001 0.0001 3753c 3753 2396 2407 3725 3713 AGEZ 0.97544 1.00000 -0.24162 -0.02729 0.14291 0.15924 0.0001 0.0000 0.0001 0.1807 0.0001 0.0001 3753 3753 2396 2407 3725 3713 SH)! -0.25536 -0.24162 1.00000 0.07023 -0.04345 -0. 05423 0.0001 0.0001 0.0000 0.0045 0.0338 0.0082 2396 2396 2396 1634 2385 2378 (SH)! -0 . 02937 -0 . 02729 0 . 07023 1 . 00000 -0 . 13039 -0 . 05729 0.1497 0.1807 0.0045 0.0000 0.0001 0.0051 2407 2407 1634 2407 2394 2385 m 0.16049 0.14291 -0.04345 -0.13039 1.00000 0.37278 0.0001 0.0001 0.0338 0.0001 0.0000 0.0001 3725 3725 2385 2394 3725 3708 am 0 . 18772 0 . 15924 -0 . 05423 -0 . 05729 0 . 37278 1 . 00000 0.0001 0.0001 0.0082 0.0051 0.0001 0.0000 3713 3713 2378 2385 3708 3713 a - Psarsan correlation coefficient. b - level of significance (Probability > |R| under nno:Rm=0) . c - Nunber of Wigs. 88 mtcnvilinear) effect of daysdxymfatcorrectedmilk (F04) Man. 'nnecnveofFu‘ImdaysdryrcsetoapeakmtSS-éo daya)andbegantcdeclineinac.nvilinearfaahim. m, at mintelyssdaysdryunedeelineofflnecmbecameleessevere (almat flat) ardfl'nanvirmally levelbeya'dlBOdaysdry. MYSOPEN lbbettermnerstanitherelatia'ahipebetwaanvariablesbelieved tobeinfluencinganeamther,ardtlmsthemsults,correlaticns mmtodetemineflnerelatiashipofage,agesqnared,8m4, m,dnysdryanddaysqaen(m). 'nneeecorrelaticnswerernmm t1neantiredataset,andmsubsetscfAIardNAImatedccws agentely. Inallthreegxunps(all,AI,m1)positive correlations (.34) endstedbemeendayscpenarddaysdrycrables 4.13,4.14,4.15) suggestingthatanircreaseindaysqnmwillbefcllcwedbyalmger drypericd.'misiscansistentwithpreviamreeeardn(nmketal., 1987),ardwithmeansfmuneamtsmdy. MeanmfcrAImted ccwaisladerthanforNAImtedccws,108vs136,ardtheanbseq.nent meandaysdryfctrAIislcwerthanforNAI,60vs66(Table4.16). It should be noted that a significant negative correlation (-.13) adstedbetweenCBPDlardlDCI‘ableLlMamestingthatasm immased, genetic level of service sire declines. 'missuggests thatasmincmasee,theuseoflcwm1nlsiresincreases. metathesu'angrelatimshipbetweenmanddaysdry, adiitianalregmssianmdelsmrenminclnflingdayscpenasa cavariate. m 4.14. 89 Foam correlatim coefficients, level of signifimnoe, and amber of cheervatims for AI mated cows. AEEQ! 55!!! (run)! DOPEN' II!!! AGE 1.00000a 0.97321 -0.24828 -0.01345 0.0000b 0.0001 0.0001 0.5122 2837c 2837 1925 2376 0.97321 1.00000 -0.23331 -0.01124 0.0001 0.0000 0.0001 0.5840 2837 2837 1925 2376 -0.24828 -0.23331 1.00000 0.06232 0.0001 0.0001 0.0000 0.0124 1925 1925 1925 1610 -0.01345 -0.01124 0.06232 1.00000 0.5122 0.5840 0.0124 0.0000 2376 2376 1610 2376 0.14125 0.12244 -0.01351 -0.10507 0.0001 0.0001 0.5544 0.0001 2822 2822 1916 2363 0.18068 0.15268 -0.03267 -0.04187 0.0001 0.0001 0.1534 0.0422 2812 2812 1911 2354 0.14125 0.0001 2822 0.12244 0.0001 2822 -0.01351 0.5544 1916 -0.10507 0.0001 2363 1.00000 0.0000 2822 0.34769 0.0001 2809 0.18068 0.0001 2812 0.15268 0.0001 2812 -0.03267 0.1534 1911 -0.04187 0.0422 2354 0.34769 0.0001 2809 1.00000 0.0000 2812 a - Foam correlation coefficient. b - Level of significance (Probability > |R| under HO:R-D=O). c - Nunber of obeervatims. 90 1!!!Ei4.15. Pearson correlatim coefficients, level of significance, and amber of ohaervatiens for NAI mated cows. m 2632 $9114 (3904 00pm AGE 1.00000a 0.98123 -0.27859 -0.55063 0.18392 0.0000” 0.0001 0.0001 0.0013 0.0001 916° 916 471 31 903 2522 0.98123 1.00000 -0.26991 -0.56085 0.16863 0.0001 0.0000 0.0001 0.0010 0.0001 916 916 471 31 903 8m: -0.27859 -0.26991 1.00000 -0.03559 -0.09498 0.0001 0.0001 0.0000 0.8689 0.0398 471 471 471 24 469 (31411 -0.55063 -0.56085 -0.03559 1.00000 -0.33826 0.0013 0.0010 0.8689 0.0000 0.0627 31 31 24 31 31 m 0.18392 0.16863 -0.09498 —0.33826 1.00000 0.0001 0.0001 0.0398 0.0627 0.0000 903 903 469 31 903 um 0.19681 0.16640 -0.10040 -0.15663 0.38906 0.0001 0.0001 0.0301 0.4001 0.0001 901 901 467 31 899 EUR! 0.19681 0.0001 901 0.16640 0.0001 901 -0.10040 0.0301 467 -0.15663 0.4001 31 0.38906 0.0001 899 1.00000 0.0000 901 a - Pearson correlatim coefficient. b - level of significance (Probability > |R| under m:RI-D=O) . c - Nnmber of cheervations. 91 ME 4.16 neanvalues forage, sire Pm, calf sire PIN, days cpenarddaysdxyfcrall,AInnatedardNAImatedcows. ALL C116 VARIABLE N MEAN STD EV W W AGE 3753 56 . 58 19 . 20 33 196 m2 3753 3570 . 74 2762 . 24 1089 38416 SH)! 2396 127 . 26 608 . 82 -2022 1847 (SH)! 2407 710 . 47 599 . 39 -2190 2010 00m 3725 114 . 50 63 . 01 -68 434 an 3713 61 . 18 27 . 17 1 283 NAI 1mm cove VARIABIE N MEAN S‘ID EV MIND!!! W ME 916 58.26 20.27 33 156 M382 916 3804 . 53 2907 . 09 1089 24336 SH)! 471 71 . 79 607 . 67 -1906 1814 ($1414 31 -293 . 68 589 . 04 -1780 960 norm 903 136 . 13 - 75 . 52 -32 425 an 901 65 . 72 35 . 82 1 283 AI mm) (“B VARIABLE N MEAN S'ID [EV HINDI]! MAXDUM M38 2837 56 . 05 18 . 82 33 196 PGEZ 2837 3495. 26 2710. 05 1089 38416 SH)! 1925 140 . 83 608 . 49 -2022 1847 cspm 2376 723 . 57 588 . 42 -2190 2010 00m 2822 107 . 58 56 . 75 -68 434 am 2812 59 . 72 23 . 57 1 258 92 Ms open was significant in explainirq variation in 3094 (Model 19:?2) with H: of 11.44 (Table 4.11). '11an is censistent with Funk eta1.(1987)vtnoreportedthatpreviwsdayscpenwashighly significant to max productien in current lactation. AIPC A]: percentage class (AIPC) was used as a classification factor in four'nnndelsszl, 20:P2, 21:P1ard21:P2. AIpercentageclasswas nctsignificantinacoountirgforvariationwiflninanymdel. AIPC subclass 30514 18 mean differences were significant in several cases hxtthereweremobservabletrerb (Table 4.12). 3OSIISmanvallnsraIgedfm12,407inAIPCO(mde120:Pl)to 19,030 inAIPC 8 abdel 21:P2). These results are similar to raw nearnsfranAIPCgrunpsobservedinSectim4.1. InlcokirngatISmeanvaluesitwascbsewedthattcpmSM pucoductimwasinAIPC6thmngh9wiunAIPC8(80-89%Atusage) beingthehighest. misissimilartcSeykoraetal. (1980)who reportedthatherdsusing75%t099%AIhadgreatermilkprcduction thanthoseusinglessthanfiitu. 'Iheseresultsarelikely iniicativeoflevelofnnaregementpresentinlnrdsatthevariws AIPClevels. mm m AIPC AND SGIEME MinteractimofAIPCardfeedingschenewasincludedinnndels [21:P1 and 21:P2]. It was not significant in explaining variation or 30514 18 man differems (Table 4.12) . 93 W Insults of this stnrly would suggest difficulty in separating the canfanflingeffectscfage, dayscpen, daysdryanitypeofmatingon 3054. me to unnamed relatiaflnips between irrleperdent variables, lulticollinearity may exist. mlticollinearity is defined as the edstezceofaneormrenearetactlinearrelatimsamngthe column of the regressor matrix, i.e. a large, significant correlatianbemaenirdeperientvariables inthennodel. Ifsevere mlticollinearity exists, least Squares eetinnates of parameters are Imam to be highly erratic (Gill, 1981) . ale solutien to deal with nulticollinearity is to obtain adiitieal data. 'Ibobtainmreacan'ateneasurenentsmeffect of type of hating it would appear a controlled sandy with other factors behngegnlvmldbensoessary . 'nneecolmicsofthattypeofsuxdy mybeprdnibitiveduetothelargenmberofcattlemvaricus farms thatvmldhavetobeidentifiedarddnservedcveranextededperiod of time. Statistical nethods for handling nnlticollinearity include ridge regressien, atedmiquedevelcpedhyfioerlandxennardwhidmhasbeen snmntobemmst (theprobabilitiescf'rypelarnd'rypeIII errors are little affected by nnnoderate deparune fran normality) against mlticollinearity (Gill, 1981) . 4.3 REDICI'DGDKYS [RY mm Rawmeanvalues fordaysdry (Tables 4.6ard4.7) suggestedthere aredifferenoesbeuieenAIarflNAImatedcows. 'Ibacocmtforthe canfanfljngofvariableswithherdmnaganentlevel itwasnecossary tcdowithinherdaralysismhwgtegressimmdels. mgreesimmdelswithdaysdryasthedgeflentvariablewere analyzed. Indepedentvariables included herd, age, age sgnared, unthof freshening (season), sire Predicted Differencemilk (SPIN), herdAIpercentageclass (AIPC), typecfnnnating (AI:NAI) arndthe interactian ofAIPCandtypeof mating (Table 4.17). ME 4.17. Variable lista for regression nnodels using days dry as dqaedent variable. m VARIABLE LIST 118:1 herd ai 121:2 aipc herd ai [122:3 aipc herd ai aipc*ai mm aipc herd ai aipc*ai mth cans aipc herd ai aipc*ai mth age age2 mm aipc herd ai aipc*ai mth age age2 spdnn 1mm aipc herd ai mth age age2 spdnnc Inna aipc herd ai mth age age2 spdmc do a-AIPC=AIpercentageclass,AI=typecfma‘ (AI:NAI),mth= nanthcffreshening,ACE=ageatcalving, =ageat calving squared, SE)! = sire Predicted Difference milk, 00 = days open. b-HordisnestedwithinAIPCinallmdelsewepthu. c-Sirem4ccvariateisnestedwiu1intypeofneting. 94 95 am Agemsinclnfledasacovariateinmdelsm5ardmm. It mssignifiwntinecplainirqvariationinbothmdels. Parameter estimteswere.88and.9ardSE'swere.10arri.12 (Table 4.18). Otherauthotrshavermortedarelatiaahipbemeenagearrllength ofdryperiod.&nithandlegates(1962)reportedthatdaysdry 1mm sligntly with increasing age. Sd'naeffer andI-Ienderson (1972)notedthatoldercowshadla1gerd1yperiodsthanyamger cows. Comocketal. (1974) stated thatdaysdryincreasedwith age, at wart five days per lactatien. Dias arriAllaire (1982) resorted theeffectcfthelegthcfdryperiod,mproductim,tobegreater foryunyercowsthanolder cows. Wiltanetal. (1967) stated that legthofdryperiodhadagreaterinpactansecondlactation canparedwithlaterlactaticns. (bx-relation results fun this study indicate a positive relatiaflfipbeulee'nageamdaysdry(.187fcrallcows) (Table 4.13)\tnidniscensistertwiththeabovefiniirgs. Increasinglength ofdrypericdasageincreasesislflcelyduetoreproductive m1“, i.e. irnzeaseddayscpenresultinghncreasedcnlving intemlmidnleadstoincreaseddaysdry. WW Agesqnnredwasimlnnedasacovariateinmodelsmmand new. Itms significant in explaining variation inbothmodels and had PE's of -.004 (Table 4.18). 'nniswunld anggest that agehas a slightly curvilinear effect an the length of the dry period, i.e. as 96 TABLE 4.18. Sumary of models predicting days dry. $11.1. mm natal 1:21:31 1:12:41 1121:51 1:111:61 0.131 0.131 0.133 0.141 0.181 0.204 n- 3713 3713 3713 3713 3713 2378 mm W (Unbiased) m -- -— —- -— O.88** 0.9“ m2 —- -- -- -— -0.004** -0.004** sma -— -- —- —- -— -0.001ns SPD4(AI) ~— -- -— -— -- -- AI —— -——— -— nun—- ...— —- m -- -— -— -- -— -- ms 09m —— —— -— -—- -- —- 1m sum m2 ‘lype of mating m 65.33 65.1: 65.3: 65.5a 653 65.2; A1 58.7” 58.5 59. 59.9” 59.3” 57.4 AI Percentage Clws 0 -— 59 65 . 64 62 50 1 -- 59 61 62 60 65 2 —- 71 69 69 68 64 3 — 61 61 62 62 72 4 —- 60 60 61 60 64 5 -- 57 56 56 56 52 6 -- 61 62 62 61 6o 7 -- 66 65 65 65 63 8 -— 60 58 59 60 59 9 —- 65 67 68 68 65 Mmth of calving 1 -—- -— -— 64 63 63 2 — —- -— 67 67 66 3 -- -- -— 66 65 66 4 -- -- -- 60 60 57 5 -— -—- —- 64 63 64 6 — --— -- 62 62 60 7 -- -—- -— 60 60 59 8 -- —- -- 58 58 57 9 -— -- -- 59 59 58 10 —— -— -— 63 63 60 11 —- -—- -- 64 63 64 12 -— —- -- 65 63 62 1-lbdel imltriesherdnestedwithinAI PercentageClass. 2 - 18 means with different superscripts are significantly different (P<.05). 3 -SirePu4ccvariateisnestedwithintypeofmting. (** P < .01) (* P < .05) (rns = not significant) 97 MB 4.18. (cant’d.) film. 1122:713 1112:813 0.197 0.293 N= 2378 2376 PARAMETER ESTIMATES (Unbiased) Am 0.91** 0.7** 3132 -0.005** -0.004** 31414 -— -— spawn) —- -- AI -0.0003** -0.001** NAI -0.005ns -0.004ns ms 09m -— 0.142** LEAST sum m2 ‘Iype of natirr; NAI 57.3: 59.4a AI 64. 61a AIPercentageClass )DOQGMhUNt-‘O Kanth of calving “gammqmmeuuw 1-l4odel includesherdnestedwithinAIPercentageClass. 2 - 18 means with different superscripts are significantly different (p<.05) . 3 -SirePD4ccvariate isnestedwithintypecfmating. (** P < .01) (* P < .05) (ns = not significant) 98 acavgetsolderthedrypericdimreasesinlength, toapeak, and mmmmmy. 'lheremsapositiveconelatimbelxeenagesquaredarfldaysdry (.159 forallcows, .153 farAInnnatedcowsand .166 fcrNAImated cws)('rables 4.13, 4.14 ard4.15). This iscansistent with Schaeffer aminedersm (1972) andcxnnock (1974), asreportedabove. mm ltnth of calving was inclnfled as a classification factor in mdelsnu:4,mY:5,ande:6. Itmssignificanntinecplaining variatianindaysdryinallthreemodels. (beervaticn of days dry 18 means indicated sane significant differencesbeuveenvaricusfresh-mnthclm,hcueverm significanttrenchwereobserveda‘able 4.18). It shouldbennoted thatthegrcupscfcowshavingtheshortestdryperiodstededtobe ttnsecalvingdringtheamuermnttrsflhly,hyustard$entenber wereshortest). mismndagreewithSdnaeffer-arriI-lederson (1972),unorqnortedthatsnmnerscalvershadshorterdryperiods thanthosecnlvirginotherperiodscftheyear. aneexplanationmay bethatcowscalvingduringthesnmerlikelycalvedprevimslyin flnesnmranrienteredthebreedimpericdinthefall. 'nnusthey megosedtolusenvimmentalstressardbredbackmrereadily thancowscalvingatothertimes. 'nnisvmldresultinshorterm ardthenpossiblyshorterdryperiods. 99 Hardwas includedasaclassificntion factor, nestedwithinAIPC inallmdelseanntlluzl,whereAIRwasnctnested. Itwas signifimnt in explaining variatim in all models. Averages within AIPCgrcnparelistedinlable4.16arurangedfrm50(AIPco,Model IRRG) to 72 (AIPC 3, m1 Mz6). TYIEOFMATIM Type of mating was included as a classificatian factor in all models. It was significant in explaining variatien in all models, Winks. DifferenesbetweenAI/NAI subclasslSmeansfor days dry were significant. Average dry period length for AI mated cows msleesthanNAIwithvaluesr‘arrgirgfrunmAtoS9.9daysdryand NAIvaluesrangingfm65to65.4daysdryinuodeIsmY:1tomy:7 (Table4.18). 'nnesevalueswculdleflcredencetotheprenisethatcowsbredAl aremanagedmrecorrectly,i.e.aredriedcffatamorecorrecttime duetolmowledgeofbreedjngdate. 'nmsAImatedcowshaveamore desirable dry period length. An alternative explanation of differencesindaysdrymaybethatthemajcrityoftheNAIbred cattleinthesehercbwereproblenbreeders. Asaresult,thecows sustainedlangerdryperiodsduetcanextefledlengthofdayscpen andcalvinginterval. W,morevariaticnwasobservedindays dryforNAImatedcowscarparedtoAImatedcattle. 'miswculd indicate loos precisian in dry off dates. One might prqaose that this (inserved difference would irdicate a lack of knowledge canoerningprospectiveduedate. 'nmstheproducerwasdryingcows 100 offbasedanprcjectionsbyaveterinariancrhiscwnmethods, which were inaccurate in a umber of cases. SPIN Sire Predicted Differece milk (SPD4) was included as a covariate in ncdel new. It was rct significant in explaining variation. ‘Ihiswasasexpected. Althmghcorrelatienresults indicateda . significant relatiachip between sun and days dry (-.05 for all cows ani -.1 for NAI mted cows) (Table 4.13 arnd 4.15) the correlatiens were so mall they likely mrldn’t contribute significantly to variation in days dry. AI nnated cows (model Imus) had a coefficient of -.03 but it was not significant. Differeces in the regressian coefficients for SPD4 were ncted betweenAI arumumatadcntue, thereforeSPD4wasnestedwithin typeofmating inncdelisYfl andIRY:8. Inbcthnncdels, SPll4was significant inecplaihingvariationindaysdry forAImatedcowsbnnt rct NAI mated cows. Par-aneter estimtes for AI were -.0003 (IRY:7) and -.001 (Irma) (Table 4.18). AIPC AI percentage class (AIPC) was inclined as a classification factor in all nncdels (eweprt 1123!:1, [mm arnd IRY:8). It was not significant in explaining variatien. Differences between sane AIPC subclasseslSmeans fordaysdryweresignificant, howevertherewere no significant trends (Table 4.18). 18 mean values (in models Mzz thruxghmw) rangedfrannalcwofsz inAIPCStoahighof72 in AIPC3. ‘Ihiswculdiniicatethat, inthisstudy, AIPChadno significant effect an length of dry period. 101 memmmwm 'nneinteractianofAIPCandtypeofmtingwasirclnnedinncdels [32:3, mu, 1:82:5andmh6 (Table 4.17). ‘nneinteractianwasrct significant inetplainingvariatianinnncdelsm:3,uu:4andm¥:5 (Table 4.18). Itwassignificantinexplainingvariatiminmodel m:6,whidnhadSPu4adiedasacovariatealflnnghasstated previously, SPIN itself was nnot significant. (Table 4.18). It should alsobenotedthatSPD4wassignificmntwithintypeofmatirqin mdelsmYflandtmlw. VlnenccnparingAIPbetypeofmatingsubclasslSmearsfcrdays dry, significantdiffereceswereobservedwithinAIPC's 2, 3,4and 6inncdelisY:3,M:4arde:5.AIvaluesrangedfrun56to60 daysdryandNAIvaluesfr'an64t078daysdry. Significant differecesindaysdrylSmeansexisted betweenAIPC'sz,4and§ inmdelmm. AIvalueswee49,56arc48ccmparedtoNAIvalms of79, 72arri56forAIPC'82,4ami5rewective1y. ItdmldbenctedthatRZvalueswereqnitelwfor-these models, ranging frann .131 to .204. (Table 4.18) DKYSOPEN Otherwfiuersreportarelatiashipbetweenlbarddaysdryflhnk at. al., 1987). Becausecfthisandtheresults of correlatia'ns deteminedfranthecnrrentdataset,dayscpenwasaddedasa covariateinenedaysdrynncdel (mm). Inadiitien, SPEMwas nnestedwithintypecf matingtoadjust for differems inregression ofSPlHandaysdryforAIandNAImatedcows. 102 mm:8,mvassignificantinecplainimvariatimindaysdry withPch.142. 'nnerewasasignificarntircreaseinsztnendays mmadhdtothencdel,.293inlmt:8verans.197inlmt:7 (Table 4.18). 'lhisindicates thatdaysQenisinportarntto Wmmlm. Aftertheadiitianofdayscpen(m:8),typeofmatingwasrct significant, indicating that the significzrce attributed to it in previcusmdelscwldpartlybednetodifferecesindayscpen. Due tcthecorrelatienbeuneendayscpen,daysdry,ardtypecfmating, antanflimccansaniitbecmcsdiffimlttcncasuretheeffectcf typecfmatingmdaysdry. unencthodtoavcidconfcnurriingmayhave beentonestmwithintypecfmating. ‘nniswculdallcwforthe adjustnentofAIandNAIseparatelyanithereforencrecorrectlyas cmoeedtousingtheaveragecoefficientfortheum. scam Resultsofthissurlyirdicatethatherd,age,mnthcf mm), arr] days (pen significantly effect the length of the dry period. Resultsalsoirdicatesmisrelatedtodryperiodlengfln inAImatedcwsbutnctNAInatedccwsarrithatAIPcisrct significanttolegthofdryperiod. 'nneinpactcftypeofnating seastcbeinportanthltamearstobemaskedbytheeffectcfdays cpenwl'nendayscpenisirclnriedinthemodel. mgessimarccorrelatimreantsaggestmcavshavean advantagebefcrestartingthenextlactatianbecancecflcngerdays cpenanddaysdry. Becauseofcorrelaticnsbetweenthesevariables 103 ardtypecfmtirc, itmsnctpossiblewithmethodsused,to detenineifAImatedcowsanflthereforelacwledgeofduedateshave a significant effect an snmsegnent lactatien milk prodnctien. 4.4m-Predictirq305-myproductiananfllhysnry Resultscfthisstnflyiniicatethattypeofmatingdoesnot significantly affect 305-day milk productian in the subsecpent lactatien, altlnngh it appeared to be nearly significant at times. Inhignpreacingtcrds,vtnidnareassnmedtobewellmanaged,cows mtedNAIpr'cdcedegnallytottceemtedAI. mileinlcwer prodcirg,lesswellmnagedherdsbothmIancAImatedcows produced similarly, indicating similar magenent level and treatment. 'nnusitappearsAlaniNAInatedcowsaretreated similarlyinmostherds. NAImatedcowshadincreasedmarridaysdryandhadiJncreased variatimindaysdry. 'Ihisincreasedvariatianindaysdrysuggests agreaternmberofcowshavirqtoostcrtortoolorcchyperiodsdue tctheprcdncereithernctkncwingwhentcdrythecowcffwoo stcrt)crtheexteniedbreedingperiod,irdicatedbyertededdays open, leadirgtoa lenger lactatienani lengerdryperiod. 'nnerefore,itappearsthatmmtedcowsmayhaveabiastogreater productien due to lenger no and days dry. Because of significat correlatiens between these variables, it was not possible with mflcdsusedinthissundytodetermine,withcertainty,ifAImated cows and therefore knowledge of due dates have a significant effect ansubseqnentlactatianmilkproducticn. Iffnmnesudyisdoneenthistcpic,itwouldbeusefulto createasubsetcfrecordscategorizedbydayscpenanddaysdryasa nearstoelimiretethecorrelatianbefiveentlctvnvariablesardthe resultant canfcnnrling of results that occurs. 104 105 It slmldalscberctedthatwithanircreaseinmeandaysdry formmatedcowstherewmldbeaneqnectatienofsaneircreasein variatimdnetothisircreaseinthemean. Inadditian, ifNAIsiresaretcedtokeepselectedccwsinthe herd, itisncstlihelythesearehignerproducingcows. 'mismay prcdceskaiedresults. Itamearsflnatfeedingmnagennentsdnanesdidrcthavea significant effect an 305-day milk productian. 5. WANDDISCIBSICNII mimofvaricuslevelsofAIusagewithinherd 5.1mm msults for annualized relative nnet incane (ARNI) forthevarious levels of AI usage, beginning sire merit in Predicted Difference Dollars (PD$), herdsizeanricecqtion rateareshcwninTable 5.1 enapercowbasis, ancTableS.2enaperherdbasis. Detailed resultsarelistedinAppendixA. 'lheARlI, percow (Table 5.1), ranngedfranahighcf $65, ina 200c::nwherdusinng100%AIwithsiremeritofPD$170anndservices percaceptianrateofl.7toalcwcf-$81, inaSOcowherdusinng 100% NAI. Values ofARleerherd (Table 5.2), rangedfrannahigh of $12,964, inna200cowherdusing100%AIwithsiremeritcfPD$170 andservicespercacepticn rate of 1.7 toa low of -$12,868 ina 200 cowherdusinng 100%NAI. 5.2 IEVELOFAIIBAG'E 'IenratiosofAImAIusagewerecmparedwithinherd. 'Iheywere 100:0, 90:10, 80:20, 70:30, ..., 0:100. As the level of AI usage decreased, andthecorcnrrentlevelofNAIuseircreased, ARNIper cowandperherddeclined. 'BnerangeofARNIdifferecesbetween 100:0 and 0:100 for the simulated herd was $7,228 to $25,827 dqenriing en level of sire merit, herd size, and conception rate (Table 5.2). 1) IneadncftheherdmodelsthelargestdeclineinAmI ooanred when the ratio of AI:NAI usage dnanged frann 100:0 to 90:10. 'nnisdeclineinvaluerangedfrunn$24to$43 inARNIpercow (Table 106 IEDSIZB-EO Annulmapratio 0:10) 10:90 20:80 30:70 40:60 50:50 60:40 70:30 80:20 90:10 100:0 arm can ens/(need ~68 as 170 ~81 ~55 ~43 ~32 ~21 ~10 0 10 20 63 as 15 ~81 ~69 ~57 ~45 ~34 ~24 ~14 ~4 5 15 58 as 138 ~81 ~70 ~58 ~47 ~37 ~27 ~18 -8 1 10 52 as 128 ~81 ~71 ~59 ~49 ~39 ~29 ~20 ~12 ~3 6 48 swan-2.2 as 170 ~81 ~69 ~57 ~46 ~36 ~26 ~17 ~7 2 10 53 as 155 ~81 ~70 ~59 ~48 ~38 ~29 ~20 ~11 ~2 6 48 as 138 ~81 ~71 ~60 ~50 ~40 ~31 ~22 ~14 ~5 3 44 as 128 ~81 ~71 ~61 ~51 ~42 ~33 ~25 ~17 ~9 ~1 40 I-IDSIEflOO Annaltmfiratio 0:100 10:90 20:80 30:70 40:60 50:50 60:40 70:30 80:20 90:10 100:0 SHE m malt-1.7 H3 170 ~64 ~50 ~37 ~25 ~14 ~3 8 18 28 38 64 H3 155 ~64 ~51 ~39 ~27 ~16 ~6 4 14 23 32 59 H3 138 ~64 ~52 ~40 ~29 ~19 ~‘9 O 10 19 28 53 R3 128 ~64 ~53 ~41 ~31 ~21 ~12 ~3 6 15 24 49 sen/cum .2 HS 170 ~64 ~52 ~39 ~28 ~18 ~8 1 11 20 28 54 H3 155 ~64 ~52 ~41 ~30 ~20 ~11 ~2 7 16 24 49 H3 138 ~64 ~53 ~42 ~32 ~22 ~13 ~4 4 13 21 45 HS 128 ~64 ~54 ~43 ~33 ~24 ~15 ~7 1 9 17 41 IE!) m0 AI:NAI Imp ratio (2 hnlls*) 0:1(D 10:90 20:80 30:70 40:60 50:50 60:40 70:30 80:20 90:10 100:0 sue m SER/(Dhlfl H3 170 ~64 ~50 ~37 ~25 ~13 ~3 8 18 28 38 65 33 155 ~64 ~51 ~38 ~27 ~16 ~6 4 14 24 33 59 H3 138 ~64 ~52 ~40 ~29 ~18 -9 1 10 19 28 54 H3 128 ~64 ~52 ~41 ~30 ~20 ~11 ~2 7 16 24 49 mam-2.2 H3 170 ~64 ~51 ~39 ~28 ~17 ~8 2 11 20 29 54 33 155 ~64 ~52 ~40 ~30 ~20 ~10 ~1 8 16 25 50 H3 138 ~64 ~52 ~41 ~31 ~22 ~13 ~4 5 13 21 46 H3 128 ~64 ~53 ~42 ~33 ~23 ~15 ~6 2 10 17 42 *~2mlsiresnneiinfic200c7wlcrd. I!!!) m AI:NAI map ratio 0:100 10:90 20:80 30:70 40:60 50:50 60:40 70:30 80:20 90:10 100:0 SM (£13) ML? m 170 ~4062 ~3419 ~2755 ~2151 ~1586 ~1047 ~515 ~1 497 991 3166 155 ~4062 ~3462 ~2832 ~2256 ~l7l4 ~12$ ~703 ~2(B 262 728 2876 138 ~4063 ~3504 ~2906 ~2357 ~1838 ~1354 ~879 ~410 46 487 2610 128 ~4063 ~3536 ~2963 ~2436 ~1941 ~1473 ~1022 ~575 ~135 287 2389 sun/(meg 170 ~4062 ~3472 ~2860 ~23(B ~1795 ~13CB ~828 ~366 80 522 2646 155 ~4062 ~3509 ~2926 ~23% ~1902 ~1441 ~986 ~538 ~115 304 2406 1.38 ~4063 ~3544 ~2986 ~2476 ~1997 ~1552 ~1117 ~688 ~271 1.30 2213 128 ~4063 ~3573 ~3037 ~2547 ~2(B9 ~1659 ~1245 ~836 ~433 ~48 2017 I!!!) W100 ABM 1m ratio 0:1(X) 10:90 20:8) 30:70 40:60 50:50 60:40 70:30 80:20 90:10 103:0 81m (as) sun/cred m 170 ~6431 ~5047 ~3719 ~2511 ~1381 ~3(B 762 1790 2785 3774 6432 155 ~6432 ~5132 ~3872 ~2721 ~1635 ~619 387 1375 2317 3249 5853 1.38 ~6433 ~5217 ~4020 ~2922 ~1885 ~915 33 971 1885 2766 5319 128 ~6434 ~5279 ~4134 ~3079 ~2m9 ~1154 ~252 641 1522 2365 4877 sun/me 170 ~6431 ~5151 ~3927 ~2823 ~17% ~823 137 1.060 1.951 2836 5391 1.55 ~6432 ~5227 ~4060 ~3004 ~2013 ~1090 ~179 716 1563 2401 4911 138 ~6433 ~5296 ~4179 ~3161. ~2202 ~1312 ~443 415 1250 2051 4527 128 ~6434 ~5354 ~4283 ~3303 ~2387 ~1526 ~6% 120 927 1695 4134 PER) moo AI:NAI map ratio (2 hnlls*) 0:1.00 10:90 20:80 30:70 40:60 50:50 60:40 70:30 80:20 90:10 100:0 SIRE (as) Wlfl m 170 ~12863 ~9994 ~7338 ~4921 ~2661 ~5(5 1623 3679 5670 7647 12964 155 ~12865 ~10165 ~7644 ~5342 ~3171 ~1138 873 2851 4733 65% 118% 1.38 ~12867 ~10334 ~7941 ~5745 ~3670 ~1731 167 2042 3870 5631 10739 128 ~12868 ~10459 ~8168 ~6059 ~4079 ~2209 ~ 403 1383 3144 4830 9854 seven-2 .2 170 ~12863 ~10202 ~7754 ~5546 ~3495 ~1547 373 2220 4003 5772 lCBBZ 155 ~12865 ~10353 ~8021 ~5907 ~3925 ~2CBO ~258 1531 3225 4901 9922 138 ~12867 ~10492 ~8258 ~6221 ~43(5 ~2525 ~786 931 26(1) 42% 9153 128 ~12868 ~10607 ~8465 ~65(5 ~4674 ~2953 ~1296 341 1953 3491 8368 *-2mIsirmuaedinfineZOO_u-.o¢ nou_.-:cc< use once:— esox so: .oeouc_ _<.ccz so: .olcuc. _< «o: uc_e:.oc_ cuss-es socc- usoeeeeoeae ea >s-Insu .— u4u